Musculoskeletal Disorders in the Workplace Principles and Practice 2nd Edition - nordin

Chapter 3b ● Lower cervical spine 53 Table 3b.4 Averages and standard deviations of rotations, translations, and coordinates of center of rotation as measured by computer-assisted methods Parameter* C1-C2 C2-C3 C3-C4 C4-C5 C5-C6 C6-C7 Penning Dvorak RX (deg) 15.4 11.7 16.0 20.1 21.5 21.0 Male 6.1 3.1 2.5 2.8 3.9 4.0 Figure 3b.22 Determination of the center of rotation by graphic method RX (deg) (Penning, 1960) and by using computer-assisted methods on a normal Female 12.9 12.3 18.3 22.1 24.1 21.8 population. (From Dvorak J, Schneider E, Saldinger P, Rahn B: J Orthop AZ (mm) 3.4 3.0 4.7 3.9 4.0 3.5 Res 9:828-834, 1991.) –3.8 2.4 3.2 3.6 2.9 2.0 AY (mm) 1.6 0.9 1.0 1.2 1.1 0.9 6.2 1.8 2.3 2.9 3.2 3.1 BZ (mm) 2.3 0.8 1.0 0.7 0.8 0.8 –1.4 6.9 8.5 10.0 9.8 8.4 BY (mm) 1.4 1.7 1.8 1.9 1.9 1.9 8.1 3.0 3.6 4.2 4.3 3.9 CRZ (mm) 3.0 1.3 1.2 1.0 1.0 0.9 –4.1 4.0 4.3 6.0 6.4 6.4 CRY (mm) 4.2 3.5 2.7 2.2 1.8 2.5 30.0 9.4 9.7 10.4 12.9 17.2 5.6 4.8 3.4 2.8 2.5 2.1 *See Figure 3b.20 for definitions. Table 3b.3 Summary of flexion-extension movements of healthy adults in vivo and in vitro Flexion/Extension (Total) Dvorak (1988) Dvorak (1988) Penning (1978)20 (In Vivo/Passive) (In Vivo/Active) White and Panjabi (1978)31 (In Vivo/Active) C2-C3 10.0 12.0 8.0 12.0 C3-C4 15.0 17.0 13.0 18.0 C4-C5 19.0 21.0 12.0 20.0 C5-C6 20.0 23.0 17.0 20.0 C6-C7 19.0 21.0 16.0 15.0 C2 C4 C7 Left bending Neutral Right bending Figure 3b.23 Segmental arch of the top angle according to Lysell.9 Figure 3b.24 Coupled axial rotation during lateral bending of the The flatter the articular surfaces, the flatter the top angle of the motion head. (From White AA, Panjabi MM: Clinical biomechanics of the spine, segments and vice versa. ed 2. Philadelphia, 1990, JB Lippincott.)

54 Chapter 3b ● Biomechanics of the cervical and thoracic spine Table 3b.5a Values of main lateral bending Table 3b.5b Values of coupled axial rotation according to various authors according to various authors Main side Moroney White and Coupled axial Dvorak (1987)3 Penning White and bending (1988) Penning (1978)20 Panjabi rotation (in vivo/passive) (1978)20 Panjabi (one side) (in vitro FSU) (in vivo/active) (1978)31 (one side) (in vivo/ (1978)31 active) C2-C3 4.7 6.0 10.0 C3-C4 4.7 6.0 11.0 C2-C3 3.0 3.0 9.0 C4-C5 4.7 6.0 11.0 C3-C4 6.5 6.5 11.0 C5-C6 4.7 6.0 8.0 C4-C5 6.7 6.8 12.0 C6-C7 4.7 6.0 7.0 C5-C6 7.0 6.9 10.0 C6-C7 5.4 5.4 9.0 FSU, functional spinal unit. Lateral bending of the cervical spine is normally coupled 10. Lang J: Craniocervical region, osteology and articulations. Neuroorthopedics with axial rotation to the same side.15,31 This means that the 1:67-92, 1986. spinal processes are moving in a direction opposite the motion (Fig. 3b.24). This coupled motion is of clinical importance 11. Lang J: Klinische Anatomie der Halswirbelsäule. New York, 1991, Georg Thieme because palpation of the spinal processes can serve as an indirect Verlag. indicator of disturbed function in motion segments. The lateral bending of the cervical spine below the first cervical vertebra has 12. Lang J, Bartram CT: Ueber die Fila articularia der Radices ventrales et dorsales des been variously reported by different researchers. According to menschlichen Rückenmarkes. Gegenbaurs Morphol 128:417-462, 1982. Penning,20 the lateral bending is 35 degrees, whereas White and Panjabi31 reported between 4 and 10 degrees per motion segment. 13. Ludwig K: Üeber das Lig. alare dentis. Z Anat Entwickl Gesch 116:442, 1952. Axial rotation, as measured with functional computed tomogra- 14. Luschka H: Die Halbgelenke des menschlichen Körpers. Berlin, 1858, Reimers. phy, is between 3 and 7 degrees,2,22 but an in vitro study19 15. Lysell E: Motion in the cervical spine. An experimental study on autopsy specimens. showed a higher result, between 8 and 12 degrees. Tables 3b.5a and 3b.5b summarize the segmental motions for lateral bending Acta Orthop Scand Suppl 123:1-61, 1969. with coupled axial rotation according to various authors. 16. Mendel T, Wink CS, Zimny ML: Neural elements in human cervical intervertebral REFERENCES discs. Spine 17(2):132-135, 1992. 17. Oda T, Panjabi MM, Crisco JJ, Bueff HU, Grob D, Dvorak J: Role of tectorial membrane 1. Cave AJE: On the occipito-atlanto-axial articulations. J Anat (Lond) 68:416, 1934. 2. Dvorak J, Hayek J, Zehnder R: CT-functional diagnostics of the rotatory instability in the stability of the upper cervical spine. Clin Biomech 7(4):201-207, 1992. 18. Panjabi M, Dvorak J, Crisco JJ, Oda T, Wang P, Grob D: Effects of alar ligament of upper cervical spine. Part 2. An evaluation on healthy adults and patients with suspected instability. Spine 12:726-731, 1987. transection on upper cervical spine rotation. J Orthop Res 9:584-593, 1991. 3. Dvorak J, Panjabi MM: Functional anatomy of the alar ligaments. Spine 12:183-189, 19. Panjabi MM, Dvorak J, Duranceau J, Yamamoto I, Gerber M, Rauschning W, Beuff HU: 1987. 4. Dvorak J, Antinnes JA, Panjabi M, Loustalot D, Bonomo M: Age and gender-related Three-dimensional movements of the upper cervical spine. Spine 13(7):726-730, normal motion of the cervical spine. Spine 17(105):5393, 1992. 1988. 5. Dvorak J, Schneider E, Saldinger P, Rahn B: Biomechanics of the craniocervical region: 20. Penning L: Normal movement of the cervical spine. AJR Am J Roentgenol 130: the alar and transverse ligaments. J Orthop Res 6:452-461, 1988. 317-326, 1978. 6. Dvorak J, Froehlich D, Penning L, Baumgartner H, Panjabi MM: Functional radiographic 21. Penning L, Töndury G: Entstehung, Bau und Funktion der meniskoiden Strukturen in diagnosis of the cervical spine: flexion/extension. Spine 13(7):748-755, 1988. den Halswirbelgelenken. Z Orthop 98:1-14, 1964. 7. Dvorak J, Panjabi MM, Novotny JE, Antinnes JA: In vivo flexion/extension of the 22. Penning L, Wilmink JT: Rotation of the cervical spine: a CT study in normal subjects. normal cervical spine. J Orthop Res 9:828-834, 1991. Spine 12:732-738, 1987. 8. Ingelmark BE: Üeber den cranicervicalen Übergang beim Menschen. Acta Anat 23. Reich C, Dvorak J: The functional evaluation of craniocervical ligaments in sidebending (Basel) 6:1-48, 1947. using x-rays. Manual Med 2, 1986. 9. Knese KH: Kopfgelenk, Kopfhaltung und Kopfbewegung des Menschen. Z Anat 24. Saldinger PF: Histologische Untersuchung des kraniozervikalen Bandapparates im Entwickl 114:67-107, 1949. Hinblick auf Weichteilverletzungen der Halswirbelsöule. Diss. med., Bern, 1987 (Leitung J. Dvorak). 25. Saldinger PF, Dvorak J, Rahn BA, Perren SM: Histology of the alar and transverse ligaments. Spine 15:257-261, 1990. 26. Simmons E, Marzo J, Kallen F: Intradural connections between adjacent cervical spinal roots. Spine 12(10):964-968, 1987. 27. Stoff E: Zur Morphometrie des oberen Kopfgelenks. Verh Anat Gesch Jena 70:575, 1976. 28. Töndury G, Theiler K: Entwicklungsgeschichte und Fehlbildungen der Wirbelsäule, ed 1. Stuttgart, Germany, 1958, Hippokrates-Verlag. 29. Töndury G, Theiler K: Entwicklungsgeschichte und Fehlbildungen der Wirbelsäule, ed 2. Stuttgart, Germany, 1990, Hippokrates-Verlag. 30. Werne S: Studies in spontaneous atlas dislocation. Acta Orthop Scand Suppl 23:80, 1957. 31. White AA, Panjabi MM: The basic kinematics of the human spine. Spine 3:12-20, 1978. 32. Wyke B: Neurological mechanisms in the experience of pain. Acupunct Electrother Res 4:27-35, 1979.

3cC H A P T E R This is referred to as a disability evaluation or examination. A more comprehensive overview of a disability evaluation is Evaluation of the Neck described below.5 Ronald Moskovich and Anthony Petrizzo IMPAIRMENT EVALUATION Neck, or cervical spine, pain with concomitant disability is a An impairment evaluation is another type of assessment tool common presentation among injured workers. Neck pain, how- regarding injury in the workplace. The distinctive contribution ever, is less prevalent than low back pain as a cause of worker of an impairment evaluation is the measure of functional loss absenteeism and represents less than 2% of all workplace injuries. or derangement of any body part, organ, or organ system. The 1-year prevalence rate of non–work-related neck pain in most Another purpose of an impairment evaluation is to measure, industrialized countries is approximately 20%; the prevalence of define, and determine the status of the patient’s (claimant’s) neck pain during a 1-month period in the United Kingdom is general health at a particular point in time. Establishing impair- reported to be 14%.21 In a cohort of patients with neck pain, ment can be accomplished using different objective methods, almost half had persistent neck pain 1 year later.10 based on guidelines set by the American Medical Association.3 A diagnosis-related estimate is an impairment method based on Overall, back pain is commonly cited as the second leading eight diagnosis-related categories (i.e., muscle atrophy, guarding, cause of absenteeism in workers and the primary cause of asymmetric motion) for each of the three spinal regions. A second workers’ compensation claims. In the Saskatchewan working approach in the diagnosis-related estimate method is the diagno- age population, 10% experience severe neck pain, with up to sis of a fracture or dislocation of the spine that, after appropriate 5% having neck pain that severely affects their activities of daily tests and treatment has been rendered, requires no further ver- living.4 Most of these injuries are diagnosed as either a strain ification. Impairment can also be documented based on assess- or sprain. For these types of milder neck injuries, analogous to ment of the patient’s range of motion (ROM). This method is the lower spine, it is a challenge to determine the precise based on loss of active range of motion (AROM) in addition pathoanatomic diagnosis before the initiation of therapy. to an accompanying diagnosis and a spinal nerve deficit. The AROM approach is usually reserved for instances when a diagnosis- STANDARD EXAMINATION related estimate is not applicable.3 Interestingly, the ability to participate in work activity is not included in calculating impair- Evaluation of the cervical spine requires a history, using standard ment percentages. interviewing principles; a physical examination, focused on elimination of the pertinent negatives; and utilization of The impairment evaluation is performed after the patient is functional assessment scales to measure the impact of cervical determined to have achieved the highest possible level of recov- dysfunction on common daily activities. This crucial assessment ery but before they return to work-related activity. Any deviation of the history with specific questions is used to rule out or deter- from predetermined normal criteria or from the patient’s prior mine the need for an urgent workup, a static and/or dynamic health status is translated into an impairment rating. Impairment physical examination, laboratory studies, and further diagnostic can then be converted to impairment percentages, which reflect and prognostic evaluations. Although the approach to a patient the degree to which the impairment decreases the individual’s injured at work should not differ from that of a patient who ability to perform activities of daily living. The development of injured his or her neck during recreational activity, patients referred an impairment rating is based on clinical decision making, for work-related cervical spine injury have another aspect added whereas its purpose usually is to determine financial remuneration to their evaluation and assessment: critical return of the patient to the claimant by a third party.5 to pre- or near preinjury function to resume prior income-related activities as soon as possible. Table 3c.1 Goals of a disability examination5 DISABILITY EXAMINATION 1. Establish a diagnosis 2. Quantify impairment The critical distinction between a standard medical examina- 3. Determine if examinee is capable of performing specified tasks tion and a disability examination or impairment evaluation, 4. Determine if examinee can attend work lies not only in obtaining the information, but what to do once 5. Determine if examinee can work in the occupational environment pertinent information is obtained (Table 3c.1).5 For example, 6. Determine if worker poses a threat to others in the workplace once it is determined that a patient fell at work and is diag- 7. Make a recommendation regarding job modifications nosed and treated for the neck injury, the patient must be 8. Extrapolate into the future further evaluated for his or her ability to attend work and func- tion in the workplace, albeit with possible job modifications. a. Recommend treatment(s) b. Derive a time course c. Specify how treatment(s)/time will change points 1 through 7

56 Chapter 3c ● Evaluation of the neck EVIDENCE-BASED MEDICINE the patient’s own words. History of the present illness should include the location, duration, and concise description of symp- In recent years, there has been a shift by research and evaluative toms and the timing, setting, any aggravating or relieving factors, bodies to apply evidence-based medicine (EBM) techniques and associated manifestations and prior treatments, to include and outcomes as a foundation for clinical decision making.11 their effects. It is important to establish whether or not there is a The U.S. Agency for Health Care Policy and Research (AHCPR), relationship between the injury and symptoms and the patient’s which convenes expert multidisciplinary nonfederal panels to work activities and/or work setting. This part of the history may develop clinical practice guidelines for specific conditions and require close attention to draw subtle but meaningful informa- treatments, has similarly embraced the EBM perspective: tion from the patient, in part because their pain or discomfort Comprehensive evaluation of the results from randomized con- can make this information difficult to convey or because they trol studies is the best available scientific evidence on which to may not be aware of the relationship. From this type of detailed base clinical decision making. The working goal of the AHCPR’s dialogue with the patient, a statement of the probability that the musculoskeletal panel is to determine a model for the clinical injury is work-related is developed. utility of various diagnostic and therapeutic interventions for low back pain.5 The primary cause of many injuries can be obvious, whereas causes or etiologies of the injuries require deeper evaluation. This model for evaluating low back pain, although not inter- Patients commonly present with neck complaints after a vehicu- changeable for cervical issues, has sound principles that can be lar injury, a fall, or rough sport contact. Workers who perform effectively applied to treat cervical spine disorders. The AHCPR overhead activities or who carry loads that could strain the neck promotes a change in the former paradigm for treating acute muscles may also develop debilitating neck or arm pain. The low back pain, from focusing care exclusively on the pain itself symptoms of cervical disease can radiate cephalad to the skull to improving patients’ activity tolerance once all red flags for or caudal to the extremities, where repetitive light to moderate critical disorders have been eliminated.1 It is our suggestion that work activity may be poorly tolerated and reveal underlying the low back pain model, although not a blueprint for manage- existing pathologies. The presence of a radicular component to ment, can be applied to effectively treat cervical disorders as well. the patient’s pathology necessitates documentation of the nature The fact that this approach could be advantageous for both and sources of each of the symptoms. clinician and patient, at minimum, underscores the importance and necessity of excluding red flags through the history and The patient’s prior medical history and a review of systems physical examination. The fact that the patient would now be provide an account of his or her general state of health. A thorough more focused on movement behavior, and perhaps earlier than musculoskeletal history should be done to establish the presence with prior treatment paradigms, underscores an added relevance or absence of overall joint pain, stiffness, swelling, arthritis, gout, to work-related injury cases. and low back pain. All illnesses and surgeries should be recorded. A history of gastrointestinal diseases, specifically gastritis and An interest in consistent and well-substantiated assessment ulcerative disorders, should be taken, because patients with and treatment paradigms are not limited to clinical medicine set- cervical ailments may require treatment with nonsteroidal anti- tings. A landmark U.S. Supreme Court ruling, in 1993, amended inflammatory drugs. Specific hereditary predisposing conditions the Federal Rules of Evidence to require experts giving medical for inflammatory arthropathies, such as rheumatoid arthritis, depositions to have reliable data to substantiate their testimony.2 psoriatic arthritis, and ankylosis spondylitis, may be discovered Since that ruling, concepts supporting and policies enforcing in the review of family history. Details of tobacco smoking should EBM have expanded through input from epidemiology, outcomes also be incorporated into the history. Positive associations research, policy makers, and clinicians. To adopt an evidence- between current smoking and nonspecific back pain were found based approach for the care of patients with neck problems, it is in 18 of 26 studies in men and 18 of 20 studies in women.3 important that practicing clinicians understand the process Any history of accidents, at work or home, or occupational expo- of critically evaluating the accuracy of individual studies in the sures must be explored, because they can reveal risky habits or literature, know the natural history of cervical spine disorders, hazardous conditions. Relevant workers’ compensation issues and be able to use that knowledge and their clinical experience should begin to emerge through the history, but their presence as a check-and-balance to their practice decisions. or impact may continue to be revealed during care of the patient. HISTORY A comprehensive psychosocial history is a valuable but often Interview overlooked part of the evaluation. Nonphysical or psychosocial factors such as job or life satisfaction can affect disability status A description of the injury and of the precipitating events and treatment outcome. Key features of this review include provides indispensable information for the treating physician. the patient’s life-style, home situation, and vocational and recre- The inciting incident can be acute in onset or chronic with a ational activities. Notably, a history of mental illness, in particu- progressing debility. Documentation must include how and lar depression and anxiety, must be addressed. Patients may be when the precipitating event occurred as well as its duration. reticent to disclose such information, so its importance and practical function for treatment and recovery should be carefully The history should begin with the identification and essential and objectively expressed to the patient and, if necessary, sensi- demographics of the patient: age, sex, race, and occupation. tively probed. Finally, a list of the patient’s current medications, The chief complaint(s) should be recorded, at least initially, in including prescription, herbal, holistic, over-the-counter, and “borrowed” must be reviewed.

Chapter 3c ● Physical examination 57 Table 3c.2 Red flags in cervical spine evaluation Tumor Osteomyelitis Spinal cord compression Trauma Age > 50 Intravenous drug abuse Bowel/bladder dysfunction Trauma in patient < 50 years Cancer history History of immunosuppression Gait dysfunction, balance problems Low velocity trauma in patient > 50 Unexplained weight loss History of fever, night sweats Fine motor dysfunction, clumsiness Corticosteroid use Nocturnal pain History of urinary tract infection Arm pain, weakness or skin infection Modified from Clinical Practice Guidelines, AHCPR. Red flags of the sagittal curves is a transition zone where alignment is neutral relative to the vertical sagittal axis of the body. The After inquiring about the presenting complaint, it is appropriate cervical spine is well balanced in the sagittal plane so that C1 to focus on “red flags,” the presence of which command urgent and C7 should be centered over the weight-bearing axis, and a evaluation. These red flags include a history of trauma, tumor, or plumb line should descend through T12 and continue caudally infection, among others. Patients should be questioned regard- through the anterior portion of S1. The cervical lordotic curve ing changes in any bowel and bladder habits, specifically an normally ranges from 25 to 50 degrees with an apex at C4 inability to fully empty the bladder, a feeling of fullness after (Fig. 3c.1). urinating, and any history of bladder or bowel incontinence. Again, these may be difficult questions for patients, and they Assessment of cervical ROM is important from a functional should understand that even quite minimal changes in these and diagnostic perspective. ROM should be assessed with an behaviors may be important to follow-up if they occur with any inclinometer and recorded during the examination. Inclinometers frequency or intermittency. Even though a neurologic examina- can be mechanical or electronic, and the use of even a simple tion will be done, it is important to question the patient about home-made device is preferable to a “guestimation.” An incli- noticing any loss of manual dexterity as well as the development nometer can easily be made by punching a small hole through of headaches. Patients should be specifically questioned regard- the center point of a protractor, passing a string through the hole ing recent fever, weight loss, night sweats, and nocturnal pain. and through a washer (to act as a weight), and tying the string in Table 3c.2 identifies some of the more common red flags. a loop. The loop of string indicates the degree of inclination on the protractor scale. A plastic scoliosis protractor can be used or PHYSICAL EXAMINATION a paper protractor downloaded from www.eece.ksu.edu/∼hkn/ files/protractor.pdf and pasted onto a card for use. Inspection C1, C2, and C7 are atypical vertebrae with respect to The physical examination typically begins with a general visual morphology and function, whereas C3 to C6 are commonly inspection of the patient’s health and conditioning. It is impor- described as typical cervical vertebrae. The atlantooccipital joint tant to inspect the skin for general and isolated color changes. acts as a pivot for the flexion/extension motion of the cranium, Warmth and redness are common physical findings with acute with 13 degrees average flexion/extension and 8 degrees lateral musculoskeletal strain. Posture is examined for asymmetry in bending, allowing only a few degrees axial rotation.6 The atlantoax- positions such as lateral bending or rotation and the presence of ial complex (C1-C2) has a total axial rotation of approximately abnormal sagittal and coronal curves. Ambulation should be 80-90 degrees, coupled with a flexion and extension of approxi- observed for an ataxic broad-based gait, commonly seen in mately 10 degrees and minor lateral bending. The prominent myelopathy, and any inability to heel-walk or toe-walk, seen with motion of the subaxial cervical spine is flexion/extension with motor weakness and ability to accomplish tandem gait (walk some segmental rotation, the latter being both facilitated and on a straight line), which may be compromised in myelopathy constrained by the alignment of the apophyseal joints and the or cerebellar disorders. presence of the uncinate processes. The C5-C6 interspace is gen- erally found to have the greatest range of flexion and extension Range of motion motion of the subaxial spine.6 A regional evaluation of the spine is part of the overall assessment. Subtle secondary motion, or coupled motion, of the cervical The spine has four normal sagittal curves. There is a fixed sacral spine occurs in response to the primary motion. The coupled kyphosis and a primary thoracic kyphosis that are apparent at pattern of the cervical spine occurs with motion in the axial, birth. Cervical lordosis develops when the infant can maintain an sagittal, or coronal plane, for example, the direction of axial upright head posture. The next curve, which typically develops rotation in the subaxial spine is such that the spinous processes once a child starts to walk, is the lumbar lordosis. Between each rotate into the convexity of the spine on side bending. AROM is performed by the patient at the instruction of the examiner and is one of the cornerstones in the determination of functional limits, assessment of improvement, and demon- stration of disability when evaluating permanent impairment.5 AROM is performed by the patient alone on instruction by

58 Chapter 3c ● Evaluation of the neck Figure 3c.1 Lateral radiographs of the cervical spine of various individuals of different ages. Clockwise from top left: A 16-year-old girl with normal cervical spine lordosis and normal disk space. A 46-year-old woman with mild loss of the normal cervical lordosis, noted in the mid-upper cervical spine. A 51-year-old woman with multilevel cervical spondylosis manifesting as narrowing of the intervertebral disk spaces at C4-C5 and C5-C6 with endplate changes and marginal osteophytes. A 73-year-old woman with advanced spondylosis and a frank reversal of the normal cervical lordosis as a result of marked multilevel diskogenic degenerative changes. the examiner. In passive range of motion (PROM), the patient is be able to bend the head to the right and left, as though attempt- assisted by the examiner to reach the maximum range. Often, ing to touch the ear to the shoulder but keep the shoulder from PROM allows for more ROM in all planes. In the absence of rising at the same time. This motion is also referred to as side or pain, PROM can be performed to the anatomic barrier, whereas lateral bending. Flexion/extension ROM is assessed by having AROM is typically hindered by a physiologic barrier created the patient flex or touch the chin to the chest and then extend or by extant pathology or patterns of disuse not related to the pre- bend the neck backward. Neck extension is generally restricted senting symptoms. ROM of the cervical spine is performed by and may be painful for patients with cervical stenosis or nerve having the patient rotate the head to the right and to the left. root compression, although the opposite may also occur. All End points of motion should be symmetric. The patient should these motions should be recorded in degrees using a goniometer

Chapter 3c ● Neurologic examination 59 or, preferably, an inclinometer. Spurling’s test (see below) may be administered at this time. Palpation While the patient is lying down, a thorough palpatory assess- Figure 3c.2 The cervical dermatomes are indicated. The C5 to T1 ment of muscle tension, tenderness, and tissue texture abnormal- dermatomes are expressed in the upper extremity and develop as the ities from spasm or contracture of the superficial anterior and embryonic limb bud does, extending from the trunk. posterior musculature must be performed. The examination of the neck with the patient seated and the examination of cranially upto provide sensation to the vertex of the scalp. the upper thoracic spine are often integrated. The sternocleido- The lesser occipital nerve of the cervical plexus (ventral ramus of mastoid muscle runs obliquely from the mastoid process of C2) supplies sensation to the skin of the scalp behind the ear as the skull to the lateral border of the sternal notch and may be well as the skin of the ear. Pathologic conditions affecting the C2 injured in sudden hyperextension injuries of the cervical spine. nerve result in occipital neuralgia. The dorsal ramus of C3 (third The trapezius muscle originates from the inion and the spinous occipital nerve) distributes cutaneous sensation to the upper processes from C1 (atlas) to T12 (last thoracic vertebra); it flares neck and scalp. The dorsal rami (sensory) of C4-C6 provide sen- out to insert on the clavicle, acromion, and spine of the scapula. sation to the posterior neck in a cephalad to caudal direction. Spasm in this muscle can best be palpated on the lateral aspect of the neck. The scalene muscles are palpable in the anterior The cutaneous nerves of the upper limb, on the other hand, paratracheal area. They originate on the transverse processes are derived from branches of the brachial plexus, and thus each of the cervical vertebrae and insert bilaterally on the first and one is comprised of more than one nerve root.24 The dermatomal second ribs. These muscles function to laterally flex the neck pattern in the extremities is patterned on orderly embryologic (side bend) and help the attached ribs elevate during forced limb development. Clinical differentiation between dermatomal inspiration. Within this region, three anatomic sites of neural sensory loss and a peripheral nerve deficit helps distinguish compression have been implicated in thoracic outlet syndrome: cervical radiculopathy from other neurologic problems. between the anterior and middle scalenes, between the clavicle and first ribs, and between the pectoralis minor and the upper The upper lateral cutaneous nerve of the arm is the termina- ribs. The levator scapula originates on the rib’s posterior tuber- tion of the lower branch of the axillary nerve. Its cutaneous cles and inserts on the upper medial border of the scapula. distribution is the lower half of the deltoid muscle and the long This muscle is tender to palpation when in spasm. Anomalous head of the triceps brachii. The sensory branches of the radial cervical ribs may be palpated and can be confirmed radiologi- nerve are the posterior cutaneous nerve of the arm that distrib- cally; they may be involved in thoracic outlet obstruction but utes to the middle third of the back of the arm, the posterior usually exist only as an anatomic anomaly. cutaneous nerve of the forearm, and the superficial branch of the radial. All the above arise from the posterior cord of the brachial The cervical spine has an abundant supply of superficial and plexus. The lateral cutaneous nerve of the forearm distributes into deep interconnected lymphatics to return the lymph to the the lower lateral and the anterior surface of the arm. This nerve vascular compartment in the thorax. Palpation of the cervical is the cutaneous branch of the musculocutaneous nerve which lymph nodes can elicit tenderness in adenopathy caused by tumor arises from the lateral cord of the brachial plexus. The medial cuta- or infection. neous nerve of the arm provides sensation to the posterior surface of the lower third of the arm, as low as the olecranon, NEUROLOGIC EXAMINATION and the medial cutaneous nerve of the forearm covers the ulnar aspect of the forearm down to the hand. These are sensory The neurologic examination provides both direct and indirect branches of the ulnar which arises off the medial cord of the brachial methods of determining damage to the spinal cord and nerves by plexus. The shoulder receives its cutaneous sensation proximally examination of their sensory, motor, and reflex distribution. The from the cervical plexus, specifically from the supraclavicular aim is to identify an anatomic level for possible neurologic deficit. nerves of C3 and C4. Sensory examination and dermatome testing Motor strength examination The sensory component for each spinal nerve originates in a The dorsal and ventral rootlets at each level unite to form a dermatome, a segmental portion of the skin. Each cutaneous mixed spinal nerve. The motor roots arise from the anterior horn innervation generally follows the distribution of the underlying muscle innervation (Fig. 3c.2). However, there are exceptions and variations to this generalization in the cervical spine. The suboccipital nerve (dorsal ramus of C1) exits the spine between the skull and C1 and has no cutaneous distribution. The dorsal branch of C2 is the greater occipital nerve, which distributes

60 Chapter 3c ● Evaluation of the neck C4 These demonstrate the overlapping character of upper limb innervation (Fig. 3c.4). Dorsal scapular n. C5 Reflex examination Suprascapular n. C6 Pathologic alterations in the basic stretch reflexes are important Lateral C7 findings in neurologic disease. Deep tendon reflexes are a mis- pectoral n. nomer, because they are actually muscle stretch reflexes initiated by excitation of the afferent muscle spindle fibers. These 1a afferent Musculo- Lateral Posterior C8 fibers synapse directly onto the proximal dendrites and soma of cutaneous n. the motor neurone, completeing the reflex arc, resulting in a T1 reflex muscle contraction. These monosynaptic reflexes are help- Axillary n. ful for localizing the level of pathology in the cervical spine or Medial T2 nerve root and for differentiating a lower motor neuron lesion Medial Long from an upper motor neuron lesion. Although some examiners grade the intensity of reflexes on a scale of 0 to 3, we believe Radial n. pectoral n. thoracic n. it is more realistic to grade them as absent or present, because there are variable individual reactions to reflex testing. Deep Median n. To subscapularis Medial cutaneous tendon reflexes can be influenced by age, metabolic factors, and Ulnar n. anxiety levels in the patient. Brisk, or hyperreflexic responses, teres major nerves to the arm however, may be abnormal findings on reflex testing. latissimus dorsi and forearm Typically, upper motor neuron lesions involve the spinal cord and cause hyperreflexia. Lower motor neuron lesions depress Figure 3c.3 Diagram of the brachial plexus. There is a complex reflexes. For example, the nerve of C5 mediates the biceps reflex interconnection of nerve tissue. Note the differentiation between the and that of C6 can be tested through the brachioradialis nerve roots, which arise segmentally, and the ultimate peripheral reflex and C7 through the triceps reflex (Table 3c.4 and Figs. 3c.5, nerves, which are usually an amalgam of two or more nerve roots. 3c.6, and 3c.7). cells and thus lie ventral to the sensory rootlets; they exit the Long-tract signs spinal cord through the foramen above the named cervical vertebrae and carry their fibers to the striated muscles. Because After injury to the corticospinal tract of the spinal cord, abnor- there are eight cervical nerves and seven cervical vertebrae, the mal reflexes, or long-tract signs, can be elicited that are not C8 nerve root exits below the C7 body. From C5 to T1, these typically found in normal individuals. These reflexes suggest nerves separate and recombine to form the brachial plexus where the presence of lesions proximal to the anterior horn cells and the fibers are reconfigured into trunks, divisions, and cords represent clinical signs of myelopathy. Below are select examples. before finally forming independent branches (Fig. 3c.3). The ● Clonus is elicited by the examiner rapidly dorsiflexing the resulting nerves are thus of mixed root origin and are named musculocutaneous, axillary, radial, median, and ulnar, innervating ankle and maintaining slight pressure while counting the pulsed muscles in the upper extremity. Evaluation of the efferent contractions on resistance. Greater than four beats of clonus nerves is achieved by testing the muscles they innervate. Motor is considered abnormal. strength is objectively evaluated using a six-point grading system ● Lhermitte’s sign (a.k.a. the barber’s chair phenomenon) is a (Table 3c.3). symptom of radiating shock-like sensation down the back with neck flexion. Testing begins with assessment of the patient’s breathing. The ● Babinski’s sign is an abnormal reflex elicited by stroking the phrenic nerve (C3-C5) is the motor nerve to the diaphragm, lateral border of the plantar surface of the foot with a blunted although it also contains many sensory and sympathetic fibers. pointy object, which elicits dorsiflexion of the great toe with If the patient is breathing adequately without the use of acces- fanning and dorsiflexion of the small toes (Fig. 3c.8). A nor- sory musculature, the diaphragm is functionally intact.19 mal response is plantar flexion of all toes. A positive Babinski sign indicates damage to the corticospinal tract or injury to The C5 nerve root innervates the deltoid muscle, and along the spinal cord. with C6 it also innervates the biceps muscle. The C6 nerve root ● Oppenheim’s sign is indicative of disease of the pyramidal also innervates the wrist extensors. The C7 motor distribution tract and is performed by sliding the pointed back of the reflex includes the triceps muscle, the wrist flexors, and finger extensors. hammer up the crest of the tibia. A positive test elicits a response similar to a positive Babinski sign; the great toe Table 3c.3 Evaluation of motor strength15 extends whereas the small toes flex and splay. ● Hoffman’s sign is a pathologic reflex elicited by flicking 5 - Normal and flexing the distal phalanx of the patient’s middle finger. 4 - Able to overcome moderate resistance (not symmetric to contralateral side) When the sign is present, there is prompt adduction of the 3 - Able to accomplish full range of motion against gravity thumb and flexion of the index finger on the ipsilateral side 2 - Able to accomplish full range of motion with gravity eliminated (Fig. 3c.9). 1 - Only trace muscle contraction 0 - Flaccid

Chapter 3c ● Neurologic examination 61 B AC DE FG Figure 3c.4 Testing a full array of individual muscles permits the examiner to form an accurate assessment of the affected nerve roots and to assess whether the injury is due to a specific peripheral nerve injury. Comprehensive examination is necessary because of the overlapping neural supply to individual muscles. A: infraspinatus (suprascapular nerve; C5, C6): external rotation of the upper arm at the shoulder. B: deltoid (axillary nerve; C5, C6): abduction of the upper arm. C: biceps brachii (musculocutaneous nerve; C5, C6) flexion of the supinated forearm. D: triceps (radial nerve; C6, C7, C8): extension of the forearm at the elbow. E: bracioradialis (radial nerve; C5, C6): flexion of the forearm at the elbow with the forearm in neutral rotation. F: extensor carpi ulnaris (posterior interosseous nerve; C7, C8): extension and abduction of the hand at the wrist. G: extensor digitorum (posterior interosseous nerve; C7, C8): extension of the fingers at the metacarpophalangeal joints.

62 Chapter 3c ● Evaluation of the neck HI JK LM Figure 3c.4 Cont’d H: Flexor carpi radialis (median nerve; C6, C7): flexion and abduction of the hand at the wrist. I: abductor pollicis brevis (median nerve; C8, T1) abduction of the thumb at right angles to the palm. J: flexor digitorum profundus I and II (anterior interosseous nerve; C7, C8): flexion of the distal phalanges of the index and middle fingers. K: third and fourth palmer interossei (ulnar nerve; C8, T1): finger adduction by the patient on the left as the examiner pulls a card. L: dorsal interosseous muscle (ulnar nerve; C8, T1): abduction of the fingers. M: abductor digiti minimi (ulnar nerve; C8, T1): abduction of the little finger. ● An inverted brachioradialis reflex is elicited by tapping the ● A scapulohumeral reflex is elicited by tapping the vertebral brachioradialis tendon and observing ipsilateral finger flexion. border of the scapula at the tip of the scapula spine or the base of the inferior angle. A normal response should be retraction ● In the finger escape sign, the patient is asked to hold his or her of the scapula by the rhomboid muscles (C4-C5). Absence of fingers in an extended and adducted position. If the two ulna- retraction is abnormal. most digits drift into abduction and flexion within 30-60 sec- onds, the patient is deemed to have a positive finger escape sign. ● A pectoralis reflex is an indication of hyperreflexia. The reflex is present when tapping the pectoralis tendon elicits flexion ● In a grip and release test, the patient should be able to rapidly of the elbow or dorsiflexion of the wrist (Fig. 3c.10). make and release a fist 20 times within 10 seconds.

Chapter 3c ● Neurologic examination 63 Table 3c.4 Muscle nerve root origins Upper extremities Root level tested Nerve foramen Pectoralis C5-T1 — Biceps C5-C6 C4-C6 Brachioradialis C5 C5-C6 Triceps C7 (C8) C6-C7 Figure 3c.6 The brachioradialis reflex is tested by a direct tap on the muscle tendon. Figure 3c.5 Biceps reflex: Support the forearm with the patient’s Figure 3c.7 The triceps reflex can be more easily elicited if the arm elbow at a right angle and apply light tension to the biceps tendon with is supported so that the forearm hangs freely or by supporting the arm your thumb, which should then be hit lightly with the reflex hammer. in the horizontal gravitational plane.

64 Chapter 3c ● Evaluation of the neck Specialized physical tests Figure 3c.8 A positive or extensor plantar response, also known as a The distraction test is an example of a provocative maneuver that Babinski sign. The sole is scratched from the lateral aspect of the heel can relieve symptoms of spondylosis or radiculopathy. While forward and then medially across the ball of the foot. the patient is sitting or lying down, the palm of the examiner’s dominant hand is placed under the base of the skull and the nondominant hand placed under the chin. The head is gently distracted, increasing the pressure to about 5-7 kg. A positive sign provides symptomatic relief of neck or arm pain. An axial compression test is a provocative maneuver intended to elicit the neck or arm pain a patient may be experiencing intermittently. This is performed by placing up to 5-7 kg of pressure on the top of the head, preferably while the patient is sitting. A positive response precipitates or increases the patient’s symptoms. A distraction test can be performed after this test to attempt to provide some relief. Spurling’s sign is a maneuver to provoke symptom radiation. The patient laterally flexes and extends the neck (rotating the head to the symptomatic side), after which the examiner applies axial compression to the spine. A positive result causes pain or tingling that starts on the ipsilateral side of the neck or shoulder and radiates distal to the elbow (Fig. 3c.11). Spurling’s test has been shown to have a sensitivity of 30% and a specificity of 93% when confirmed with electrodiagnostic studies.17 Pronator reflex (a.k.a., ulnar reflex) is produced by tapping the volar aspect of the distal radius, or alternatively the styloid process of the ulna, with the forearm in a neutral position and the elbow flexed. The normal response is forearm pronation and adduction of the hand. The pronator reflex represents a muscle stretch reflex of the pronator teres that would make it helpful in evaluating C6 and C7 root lesions.14 The Valsalva maneuver is a provocative test that exacerbates arm pain when a patient bears down or coughs. These symptoms result from the increase in intrathecal pressure. Figure 3c.9 Hoffman’s sign is positive or present if the act of flicking (flexing) the distal phalanx of the index or middle finger (black arrow) elicits a flexion of the thumb (white arrow) and/or other fingers.

Chapter 3c ● Evaluating the impact of neck pain 65 Figure 3c.10 Position of the examiner’s fingers over the pectoralis Figure 3c.11 Spurling’s test: Hold the patient’s neck in extension tendon to test for a pectoralis reflex. for a few moments. Typical symptoms of brachialgia may be elicited, and if not, the test can be augmented by adding a lateral tilt of the Tests for thoracic outlet syndrome include maneuvers that head toward the symptomatic side as shown above. These maneuvers are presumed to tighten the thoracic outlet, such as arm hyper- increase the degree of foraminal compression. abduction, the “elevated arm stress test,” or the Adson test, all of which may provoke the patient’s typical symptoms of pain EVALUATING THE IMPACT OF NECK PAIN and/or paresthesia or affect the radial pulse. The Adson test, also called Adson’s maneuver, is performed with the patient The standard history and physical examination provide objective in a sitting position. The patient’s hands rest on the thighs, findings that support subjective complaints to develop an the examiner palpates both radial pulses as the patient rapidly overall assessment of cervical spine disorders. This “standard” fills his or her lungs by deep inspiration, and, holding his or examination does not often assess the impact of the disability her breath, hyperextends the neck and turns the head toward on a patient’s life quality. Functional scales can be potentially the affected side. If the radial pulse on that side is decidedly or useful to measure the impact of disease on the performance of completely obliterated, the result is considered positive. In the common daily activities. Defining a standard evaluation for Allen test, which is sometimes also described in the literature as functional disability is difficult, because functional activity can the Adson test, the arm in which the patient is experiencing be influenced by many factors independent of symptoms and symptoms is raised and rotated while the head is turned away signs such as age, psychologic ability to cope with disease, and from the affected side. If the strength of the pulse is reduced in the demands of professional activity.8 Well-validated instruments either of these two tests, it indicates compression of the subcla- for evaluating neck dysfunction are widely available (Table 3c.5). vian artery. For individual patient follow-up evaluation, the Patient-Specific All the above are nonspecific tests. If they are positive, however, there may be an indication to perform further studies.

66 Chapter 3c ● Evaluation of the neck Table 3c.5 Standard instruments for evaluating SPECIAL TESTS neck dysfunction Imaging studies of the spine Medical Outcomes Study 36-Item Short Form Health Survey After the development of a working pathologic and anatomic Neck Disability Index18 diagnosis, appropriate imaging studies should be selected to demonstrate and confirm the diagnosis. Routine spinal imaging Copenhagen Neck Functional Disability Scale12 is not recommended during the first month of symptoms except in the presence of red flags. Northwick Park Neck Pain Questionnaire13 Radiographs Patient Specific Functional Scale22 Plain radiography is the most widely available modality for imaging Neck Pain and Disability Scale23 the cervical spine. The cervical (C) spine series consists of anteropos- terior and lateral views to visualize the entire cervical spine and an Functional Scale has high sensitivity to change and thus repre- open-mouth odontoid view to assess the odontoid and C1-C2 joint sents a good choice for clinical use.16 (Figs. 3c.12 and 3c.13). A swimmer’s view may be required to assess the cervicothoracic junction if the C7-T1 level is obscured by the The MOS 36-Item Short Form Health Survey (SF-36), patient’s shoulders on the lateral cervical radiograph. Lateral flexion developed for the Medical Outcomes Study, is an example of a and extension radiographs should also be obtained in patients traditional scale for functional assessment.20 This questionnaire with a history of trauma and patients with extensive degenerative has demonstrated an overall usefulness in the general reporting disease. These radiographic views permit assessment of cervical of musculoskeletal ailments; however, it does not report on alignment, degenerative changes, assessment of bony architecture specific neck pain or disability. The Neck Disability Index is a in the vertebral bodies, and gross evaluation of the soft tissues. 10-item questionnaire designed to assess pain-related limitations Oblique radiographs can be used to assess encroachment of the in activities of daily living. The test is scored as a percentage of neural foramina (Fig. 3c.14). Radiographs should be the first-line maximal pain and disability. The scale is categorized by activity; diagnostic modality for patients presenting with neck pain when however, some questions are not pertinent for all patients. The any of the following red flags are present: recent significant trauma Copenhagen Neck Functional Disability Scale is a 15-item ques- or recent mild trauma in patients over 50, prior cancer or recent tionnaire requiring yes, no, or occasional as responses. The infection, neck pain worse at night or worse with rest, and history Northwick Park Neck Pain Questionnaire has nine five-part ques- of intravenous drug abuse or corticosteroid use. tions requiring responses of 0-4. The Patient Specific Functional Scale is unique in that it requires the patient to generate a spe- Radiographs are the least sensitive of the imaging modalities cific list of problems emphasizing the limitations most affecting in predicting symptomatology once tumor, trauma, or infection the patient. The Neck Pain and Disability Scale is a unique is excluded. A cervical sprain or strain leave no direct radiographic 20-item questionnaire in which a visual analog scale is assigned to each discomfort. The 20 items measure intensity of pain and its interference with the vocational, recreational, social, and func- tional aspects of living and the impact of emotional factors. Figure 3c.12 Lateral and anteroposterior radiographs of the cervical spine of a 34-year-old patient who had a disk herniation at C6-C7 with a clinical radiculopathy. The plain lateral film shows narrowing of the C5-C6 disk space (arrow) with a bony bar between the two vertebrae. That was not appreciated on the MRI. Note also the loss of cervical lordosis. The C5-C6 uncovertebral joint is indicated by an arrow on the anteroposterior radiograph.

Chapter 3c ● Special tests 67 Figure 3c.13 Open mouth view: A frontal view of the atlantoaxial evidence, nor does a herniated disk. Although the presence (C1-C2) joint can be obtained radiographically with the patient’s mouth of degenerative disk disease can be visualized on radiographs, open as the teeth no longer obscure the direct view. In this example, it cannot predict symptoms or disability status.9 As much as both right and left C1-C2 facet joints are clearly seen, the dens is 25% of the population has radiographic degenerative changes clearly visualized equidistant from both facet joints, and a partial view by age 50, and 75% have degenerative changes by age 70.7 It is is even obtained of the occipitocervical articulations. the strength of this literature that persuades against the use of routine cervical spine radiographs alone to evaluate disability. Computed tomography Computed tomography (CT) is a noninvasive diagnostic modal- ity that provides excellent visualization of the cervical bony anatomy, helps evaluate osseous pathology, and assesses the integrity of the spinal canal. When CTs are supplemented with myelography, one can also evaluate soft tissue structure and impingement of nerve elements. That being said, studies directly comparing magnetic resonance imaging (MRI) and CT myelo- gram with respect to identifying pathology can yield conflicting results. However, general consensus points to the advantage of the CT myelogram in identifying osseous pathologies such as fractures, osteophytes, and bony foraminal encroachment. MRI studies better demonstrate soft tissue impingement, spinal cord edema, and myelomalacia. The ability of current multiplanar CTs has greatly enhanced the detail of the spine but also escalates the risk of false positivity. Scans can be reconstructed electronically in any desired plane to better visualize pathoanatomy (Fig. 3c.15). Figure 3c.14 Oblique cervical radiograph: The right-sided neural Figure 3c.15 Midsagittal reconstructions of the cervical spine of a foramina can be clearly visualized. The black arrow indicates the right 56-year-old man who has an os odontoideum. Note the very short dens C4-C5 intervertebral or neural foramen; the C5 nerve root traverses (odontoid process) that results in multiplanar atlantoaxial instability. the foramen. The small osteophytes arising from the right C3-C4 The anterior ring of C1 (arrow) is normally aligned in neutral; there is uncovertebral joint (joint of Luschka) are identified by the white arrow. posterior C1-C2 subluxation in the extended position and marked The mild foraminal stenosis can be appreciated when comparing the anterior C1-C2 subluxation in flexion. Note the marked anterior foraminal dimensions with the normal adjacent foramina. reposition of the C1 ring in flexion resulting in the posterior arch of C1 approaching the C2 body and causing severe spinal stenosis.

68 Chapter 3c ● Evaluation of the neck Three-dimensional multiplanar CTs are extremely useful to Figure 3c.16 Three-dimensional reconstruction of the cervical spine demonstrate the complex anatomy of fractures and spinal defor- of a child with a congenital hemivertebra (arrow). There is also a split mity, be it congenital or other (Fig. 3c.16). or butterfly vertebra at C5. Magnetic resonance imaging indicator of spinal cord or nerve root compression. Plain myelo- graphy is typically enhanced with the addition of a CT. Myelography MRI uses radiofrequency pulses within a strong magnetic field is a good test for patients in whom spinal root or cord compres- to produce an image without the use of ionizing radiation. sion is suspected and for patients who have received metallic MRI is a potentially useful modality for evaluating spinal cord pathology in the presence of brachialgia. MRI is also an excellent imaging modality to assess the soft tissues in the cervical spine and their contribution to compression of the nerves and spinal cord (Figs. 3c.17, 3c.18, and 3c.19). MRI provides excellent visualization of the spinal cord for masses or lesions and cysts as well as for the myelomalacia seen in chronic compression and edema seen in various acute pathologies. Spinal pathology, such as diskitis or local abscess, can be well identified with MRI. However, many of the abnormalities seen on MR images may be incidental, resulting in the potential for over-diagnosis. Nevertheless, in the presence of many of the red flags for pathol- ogy, MRI provides indispensable information that can rapidly help confirm or rule out serious clinical problems. Myelography Myelography uses nonionic contrast injected intradurally to indirectly visualize soft tissues in the canal. Filling defects are an AB Figure 3c.17 Cervical magnetic resonance imaging (MRI) of a 26-year-old woman who has a large C6-C7 disk herniation. (A) Sagittal MRI. (B) The axial image through the C6-C7 disk (D) shows the large herniation (H) and the compressed spinal cord (SC).

Chapter 3c ● Special tests 69 A B Figure 3c.18 Cervical magnetic resonance imaging (MRI) of a 34-year-old woman who had a left C7 radiculopathy. (A) Midsagittal and parasagittal MRIs show the apparently small disk herniation. (B) Axial MRI at C5-C6 demonstrates normal anatomy, whereas at C6-C7 there is a large disk herniation (white arrow) extending into the left neural foramen and compressing the C7 nerve root. Note the normally patent right-sided neural foramen. implants, which render an MRI ineffective. Myelographic studies injected into various body systems) to gauge the chronicity of a also permit acquisition of (dynamic) images of the spinal cord and bony lesion such as a fracture, neoplasm, or a focus of osteomyelitis nerves taken with the neck flexed, extended, laterally tilted, or and to monitor disorders affecting bones. Scintigraphy is a very rotated (Fig. 3c.20). Soft tissue or bony impingement on the neural sensitive imaging modality; however, it is not very specific. The elements may be demonstrated in positions other than neutral. bone scan detects the distribution of a radioactive agent injected Note that there are now MRI scanners that also permit a full range throughout the venous system. After injection, a scintillation of movement and the opportunity to obtain dynamic scans. camera detects the radioisotope’s distribution in the body, most importantly its concentration in the skeleton. Areas of increased Barium swallow metabolic activity are imaged as increased isotope uptake on a full body scan. Visualizing swallowed radiographic contrast fluoroscopically can demonstrate mechanical compression on the esophagus from Electrodiagnostic studies anterior osteophytes and differentiate dysphagia from other pathologies. Examination by electrodiagnostic methods is useful to docu- ment radiculopathy and to confirm nerve root impingement. Bone scans These studies additionally facilitate the diagnosis of peripheral A bone scan uses the technique of scintigraphy (diagnostic tech- nique of recording the distribution and uptake of radioisotopes

70 Chapter 3c ● Evaluation of the neck A B Figure 3c.19 Cervical magnetic resonance imaging (MRI) of a 51-year-old man who had cervical myelopathy. (A) The sagittal scans show multilevel spinal stenosis. T1- and T2-weighted scans are shown. (B) Axial scans through the disks show central spinal stenosis from C3-C4 to C6- C7 with spinal cord compression. entrapment syndromes and peripheral neuropathy. The tests partial denervation pattern that manifests as increased amplitude commonly include needle electromyography, nerve conduction and a longer duration of the motor unit potential. Fibrillations, studies, and somatosensory evoked potentials. or small-amplitude, single muscle fiber potentials, may also be present but are nonspecific and usually seen in the acute stage. Electromyography Insertional activity from movement of the electrode is normal in electromyographic studies, but if it persists after electrode Measuring the electrical activity of muscle fibers at rest and motion ceases, it is described as prolonged insertional activity when active provides diagnostic information on the degenerative and can be a sign of radiculopathy. When these tests are done or healthy status of muscles and their innervation and distin- within the first 2-3 weeks after injury, the results are falsely neg- guishes neurogenic from myopathic disorders. The electromyo- ative as it takes time to develop denervation. graphic evaluation in chronic cervical radiculopathy shows a

Chapter 3c ● Conclusion 71 AB Figure 3c.20 Cervical myelogram. (A) Lateral (left) and anteroposterior (right) views of the cervical spine of a 56-year-old man with neck and arm pain and early signs of cervical myelopathy. Compression of the thecal sac is well seen on the lateral view at the C4-C5 and C5-C6 levels when his neck is extended. The anterior-posterior view demonstrates a paucity of contrast at those levels and truncation of the exiting nerve roots. Normal nerve root filling is noted at C6-C7 and distal levels. (B) Postmyelogram axial computed tomography images clearly demonstrate bilateral foraminal stenosis at C4-C5, whereas at C6-C7 the nerve root sleeves can be seen to fill well with the contrast (arrow). Nerve conduction studies potentials are not specific in elucidating spinal root dysfunction but can be useful in determining spinal cord abnormality that Using nerve conduction studies to evaluate how well nerves affect cord pathways. transmit electrical signals provides an assessment of the overall condition of both individual nerves and whole nerve structures. Laboratory screening Measured electrical parameters are usually the signal amplitude and signal onset latency. These measured values are then com- Laboratory studies provide valuable clinical evidence for patients pared with established normal parameters to determine the site presenting with atypical neck complaints or those suspected of of a compression. Nerve conduction studies are useful to evalu- tumor or infection. A complete blood count with differential can ate acute and chronic peripheral entrapment neuropathies that help detect a response to infection, blood dyscrasias, and medica- mimic radiculopathy. Nerve conduction velocity and latency tion side effects. changes are not typically found in cervical radiculopathy unless there is extreme demyelinization of axons. The erythrocyte sedimentation rate and C-reactive protein are categorized as acute phase reactants commonly used in ortho- The F-wave response tests electrical conduction through pedics to detect evidence of an infection or a connective tissue motor roots (Table 3c.6). The F-wave is recorded after maximal disorder. Although both indices serve the same primary function, stimulation of a motor nerve. The amplitude, shape, and latency clinicians often use them simultaneously, because the C-reactive should change with each stimulation. Clinical parameters usually protein is quicker to respond to either improvement or wors- evaluated are response time, or latency. Because the F-wave is ening of a clinical course. A comprehensive metabolic panel, dependent on the integrity of the entire motor unit, it can assess including Ca+, phosphorus, uric acid, alkaline phosphatase, and proximal neuropathies. acid phosphatase, can help detect metabolic bone disease. Another parameter with which to document nerve abnormalities CONCLUSION is through the recording and measurement of sensory nerve action potentials. Abnormal sensory nerve action potentials are noted Evaluation of the cervical spine in workplace injuries requires a with damage to the nerve from the dorsal root ganglion while they multidimensional workup that facilitates, first, ruling out serious are normal in pure radiculopathy, as the presumed lesion is pathology before initiating therapy for the work-related injury proximal to the sensory ganglion. In patients with sensory deficit and, second, evaluation of the patient’s work setting relative to in the hands, recordings of sensory nerve action potentials make the patient’s recovery process for a rapid and safe return to work a differentiation between lesions of dorsal roots and peripheral activity. The trend in evaluating cervical spine injuries increas- nerves possible. ingly involves more emphasis on EBM to guide treatment. Using EBM as a guide facilitates a rapid evaluation with concise Somatosensory evoked potentials elimination of red flags for spinal pathology. Returning to work Somatosensory evoked potential recordings can be used to evaluate the integrity of the central nervous system and peripheral sensory neurons. Because most peripheral nerves in the upper extremity carry fibers from multiple roots, somatosensory evoked

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Am J Phys Med Rehabil 73:338-340, 1994. Extensor carpi radialis longus C5, C6 15. Medical Research Council: Aids to the examination of the peripheral nervous system. London, 1980, Her Majesty’s Stationary Office. Posterior interosseous nerve 16. Pietrobon R, Coeytaux RR, Carey TS, Richardson WJ, DeVellis RF: Standard scales for measurement of functional outcome for cervical pain or dysfunction: a systematic Supinator C6, C7 review. Spine 27:515-522, 2002. 17. Tong HC, Haig AJ, Yamakawa K: The Spurling test and cervical radiculopathy. Extensor carpi ulnaris C7, C8 Spine 27:156-159, 2002. 18. Vernon H, Mior S: The Neck Disability Index: a study of reliability and validity. Extensor digitorum C7, C8 J Manip Physiol Ther 14:409-415, 1991. 19. Wagner R, Jagoda A: Spinal cord syndromes. Emerg Med Clin North Am 15:699-711, Abductor pollicis longus C7, C8 1997. 20. Ware JE Jr, Sherbourne CD: The MOS 36-item short-form health survey (SF-36). I. Extensor pollicis longus C7, C8 Conceptual framework and item selection. Med Care 30:473-483, 1992. 21. Webb R, Brammah T, Lunt M, Urwin M, Allison T, Symmons D: Prevalence and Extensor pollicis brevis C7, C8 predictors of intense, chronic, and disabling neck and back pain in the UK general population. Spine 28:1195-1202, 2003. Extensor indicis C7, C8 22. Westaway MD, Stratford PW, Binkley JM: The patient-specific functional scale: validation of its use in persons with neck dysfunction. J Orthop Sports Phys Ther Median nerve 27:331-338, 1998. 23. Wheeler AH, Goolkasian P, Baird AC, Darden BV: Development of the Neck Pain Pronator teres C6, C7 and Disability Scale. Item analysis, face, and criterion-related validity. Spine 24:1290-1294, 1999. Flexor carpi radialis, C6, C7 24. Woodburne RT, et al: The Netter Collection of Medical Illustrations: Volume 8 Musculoskeletal System. New Jersey, 1997, Novartis Pharmaceutical Corporation. Flexor digitorum superficialis C7, C8, T1 Abductor pollicis brevis C8, T1 Flexor pollicis brevis C8, T1 Opponens pollicis C8, T1 Lumbricals I and II C8, T1 Anterior interosseous nerve Flexor digitorum profundus I and II C7, C8 Flexor pollicis longus C7, C8 Ulnar nerve Flexor carpi ulnaris C7, C8, T1 Flexor digitorum profundus III and IV C7, C8 Hypothenar muscles C8, T1 Adductor pollicis C8, T1 Flexor pollicis brevis C8, T1 Palmar interossei C8, T1 Dorsal interossei C8, T1 Lumbricals III and IV C8, T1 Abductor digiti minimi C8, T1 Adapted from Medical Research Council: Aids to the examination of the peripheral nervous system. London, 1980, Her Majesty’s Stationary Office.

CHAPTER 3d Table 3d.1 Causes of neck and neck-related pain syndromes Treatment Options for Disorders of the Localized neck disorders Cervical Spine Osteoarthritis (apophyseal joints, C1-C2-C3 levels most often) Rheumatoid arthritis (atlantoaxial) James N. DeBritz and Sam W. Wiesel Juvenile rheumatoid arthritis Sternocleidomastoid tendinitis As with any pathophysiologic condition, treatment of neck Acute posterior cervical strain pain depends on the proper diagnosis. Neck pain has multiple Pharyngeal infections etiologies (Table 3d.1) that may result from trauma as well as Cervical lymphadenitis from chronic atraumatic conditions. Understanding these etiolo- Osteomyelitis (staphylococcal, tuberculosis) gies requires detailed knowledge of both the anatomy of the Meningitis cervical spine and its relationship to neurovascular structures as Ankylosing spondylitis well as comprehension of the natural history of cervical spondy- Paget disease losis and myelopathy. Diagnosis of neck pain can be more easily Torticollis (congential, spasmodic, drug involved, hysterical) accomplished by dividing clinical complaints into several main Neoplasms (primary or metastatic) categories, including axial neck pain, neck pain with an asso- Occipital neuralgia (greater and lesser occipital nerves) ciated radiculopathy, and neck pain with signs and symptoms of Diffuse idiopathic skeletal hyperostosis myelopathy. Once the proper diagnosis is established, treatment Rheumatic fever (infrequently) can be directed in a focused and individualized manner. Gout (infrequently) Lesions producing neck and shoulder pain This chapter summarizes some of the most common cervical Postural disorders spine disorders to aid in their diagnosis. The reader is instructed Rheumatoid arthritis on how a pertinent history, directed physical examination, and Fibrositis syndromes diagnostic findings can be used to establish a diagnosis. Treatment Musculoligamentous injuries to the neck and shoulder options are discussed in detail, and finally a diagnostic and Osteoarthritis (apophyseal and Luschka) treatment algorithm is presented that integrates the information Cervical spondylosis into a usable format. Intervertebral osteoarthritis Thoracic outlet syndromes ANATOMY Nerve injuries (serratus anterior, C3-C4 nerve root, long thoracic nerve) Lesions producing predominantly shoulder pain A detailed understanding of the osseous and soft tissue structures Rotator cuff tears and tendinitis of the neck is a prerequisite to fully understand the pathophysi- Calcareous tendinitis ology of neck pain and cervical spine disease. Once a pathologic Subacromial bursitis process temporarily or permanently distorts the normal anatomy Bicipital tendinitis of the neck, a compensatory response may occur that often Adhesive capsulitis presents to the individual as pain. Reflex sympathetic dystrophy Frozen shoulder syndromes With the exception of C1, each cervical vertebra articulates Acromioclavicular secondary osteoarthritis with the adjacent vertebra through the facet, or zygapophyseal, Glenohumeral arthritis joints. These are gliding joints characterized by capsules and Septic arthritis synovial membranes in addition to ligamentous support. The Tumors of the shoulder facet joints are innervated by the dorsal ramus of the associated Lesions producing neck and head pain with radiation nerve roots. Axial neck pain can be produced by facet joint Cervical spondylosis injections in asymptomatic individuals, providing evidence that Rheumatoid arthritis it can originate from the facet joints themselves.2 This informa- Intervertebral disk protrusion tion can be used to direct treatment in certain cases, as discussed. Osteoarthritis (apophyseal and Luschka joints, intervertebral disk, The amphiarthrodial joints that join each vertebral body osteoarthritis) through intervertebral disks play an important role in the patho- Spinal cord tumors logic process of the spine as well. Although varying in size Cervical neurovascular syndromes depending on the level of the spinal column, all intervertebral Cervical rib disks are identical in their structural organization. The internal Scalene muscle portion of the disk is comprised of the nucleus pulposus that Hyperabduction syndrome is contained around its periphery by the annulus fibrosus. Rib-clavicle compression From Wiesel SW; Neck pain, ed 2. Charlottesville, VA, 1992, The Michie Company, pp. 60-61.

74 Chapter 3d ● Treatment options for disorders of the cervical spine Figure 3d.1 Cross-sectional view showing the cervical nerve root, dorsal and ventral primary rami, recurrent meningeal or sinuvertebral nerve, and sympathetic plexus. Note the proximity of the disc space, vertebral artery, and facet joints. (From Rao R: Instr Course Lect 84A(10):1872-1881, 2002.) Both the nucleus pulposus and the annulus fibrosus share a sim- Muscles in the neck are divided into anterior and posterior ilar composition and are comprised mainly of water, proteogly- groups. Anterior muscles are comprised mainly of the strap cans, and collagen. They differ, however, in their organization muscles and the sternocleidomastoid. The neck musculature and in the type of collagen present. Type II collagen is found in forms several distinct layers posteriorly. From dorsal to ventral the nucleus pulposus, and type I collagen is present in the annu- lus. The cervical intervertebral disks are wedge-shaped to accom- Figure 3d.2 Axial pain patterns provoked during discography at each modate the uncinate processes and the corresponding joints of cervical level. A: level between second and third cervical vertebrae; Luschka, a bony articulation between the vertebral bodies. B: level between third and fourth cervical vertebrae; C: level between fourth and fifth cervical vertebrae; D: level between fifth and sixth The blood supply and innervation of the intervertebral disks cervical vertebrae; and E: level between sixth and seventh cervical of the cervical spine have been well defined. Branches of the vetebrae. (From Rao R: Instr Course Lect 84A(10):1872-1881, 2002.) sympathetic plexus and the ventral nerve root form the sinuver- tebral nerve that innervates the intervertebral disk, supplying portions of the annulus, the posterior longitudinal ligament, the periosteum of the vertebral body and pedicle, and the adjacent epidural veins (Fig. 3d.1). In a review of clinical findings of cervical diskography, Grubb and Kelly5 showed a correlation between reliable patterns of pain and each cervical disk. These pain patterns and axial pain patterns produced by facet joint injections are summarized in Figures 3d.2 and 3d.3, respectively. In addition to the major articulations of the cervical spine and their innervations, the soft tissue structures of the cervical spine and the neck play an important role in neck pain. The vertebrae are bound together by many ligaments. The anterior longitudinal ligament and the weaker posterior longitudinal ligament bind the vertebral bodies along the anterior and poste- rior surfaces, respectively, and run from the skull to the sacrum. The segmental denticulate configuration and intricate associa- tion with the intervertebral disk is characteristic of the posterior longitudinal ligament, and a prolapsed nucleus pulposus is most likely to be permitted lateral to these expansions. The ligamentum flavum is a strong elastic ligament that connects the laminae of each of the vertebrae and runs from C2 to the lumbosacral interval. A continuation of the supraspinous ligament, the ligamen- tum nuchae, runs from C7 to the occiput and along with the interspinous and intertransverse ligaments serves to stabilize further the spinal column architecture.

Chapter 3d ● Acute herniated disk 75 will usually reveal only some local tenderness lateral to the bony spine. The loss of motion in individual patients is variable and tends to correspond directly with the intensity of the pain. True muscular spasm, defined as continuous muscular contrac- tion, is rare, except in severe cases of torticollis in which the head is tilted to one side. Because radiographic studies in neck strain are usually normal, plain films are generally not warranted on the first office visit. If the pain persists for more than 2 weeks, however, a radiograph should be obtained to rule out other more serious causes of neck pain such as instability or neoplasia. Treatment Figure 3d.3 Composite map of axial pain patterns produced by The prognosis for patients with cervical strain is excellent because injections into the facet joints at the second through seventh cervical the natural history of this disorder is complete resolution of all levels. (From Rao R: Instr Course Lect 84A(10):1872-1881, 2002.) symptoms over a period of several weeks. Therapy consists primarily of rest and immobilization, often with the use of a soft are the trapezius and levator scapulae, splenius and longissimus, cervical orthosis. Certain medical interventions such as antiin- semispinalis, and suboccipital muscles. These muscles assist in flammatory agents and/or muscle relaxants may aid in the acute scapular rotation (trapezius and levator scapulae) and rotation, phase of pain management, but they do not appear to alter the flexion, and extension of the neck. Strain of these muscles can natural course of the syndrome. also contribute to neck pain. Although no good randomized, prospective, clinical trials have studied their efficacy, trigger point injections do seem empirically to work well. The purpose of a trigger point injection is to decrease inflammation in a specific anatomic area, with apparently superior results the more localized the trigger point. These injections can be repeated at 1- to 3-week intervals. NECK SPRAIN ACUTE HERNIATED DISK The condition of nonradiating neck pain with a concomitant A herniated disk results when the nucleus pulposus protrudes loss of motion has been referred to incorrectly as neck sprain. through the fibers of the surrounding annulus fibrosus and Correctly termed cervical strain and one of the most common occurs around the fourth decade of life while the nucleus pulpo- neck disorders, this often occurs in the absence of a distinct sus remains gelatinous. Stookey15 and Rothman and Marvel13 traumatic episode. Most commonly, the pain is located in the described three types of soft disk herniations (Fig. 3d.4), with middle to lower part of the neck, and although the pain is not the posterolateral herniation being the most common due to the secondary to trauma, its onset can be acute. The pain associated anatomy of the posterior longitudinal ligament, as previously with cervical strain is often a dull ache that is exacerbated by mentioned. Herniations occurring posterolaterally produce movement. In addition, a component of referred pain may be predominantly motor signs and symptoms. As opposed to those involved. This is not, however, true radicular pain secondary to in the lumbar region, disk herniations occurring centrally may mechanical compression of a nerve root. The pain is referred cause myelopathy because of the presence of the cord in the generally to other mesenchymal structures derived from a cervical region. similar sclerotome during the process of embryogenesis. The most common referral patterns include the posterior of the The most common levels for herniation are at the C6-C7 shoulder, the occipital area, the scapular region, and the anterior and C5-C6 levels. Those at the C7-Tl and C3-C4 levels are chest wall, also known as cervical angina pectoris. The source of uncommon, and those at the C2-C3 level are extremely rare. the pain is most commonly believed to be the ligaments and Interestingly, not every disk herniation is symptomatic. The pres- musculature of the cervical spine.14 As previously illustrated, ence and severity of symptoms depend on the individual’s spinal however, both facet and disk disease can contribute to axial reserve capacity, the presence or absence of associated inflamma- neck pain and should be considered as a source of the inciting tion, the size of the herniated fragment, and the presence of con- complaint (Figs. 3d.2 and 3d.3). comitant disease processes such as uncovertebral joint osteophytes. Once the precise location, frequency, and quality of the pain In general, a herniated disk affects the nerve root of the have been determined, careful questioning should then address next lowest cervical level: A C3-C4 disk affects the C4 nerve the presence, if any, of subtle long-tract signs, including bowel root, a C4-C5 disk affects the C5 nerve root, and so on. The or bladder dysfunction and gait abnormalities, to avoid missing radicular symptoms then correspond to the involved nerve root. the diagnosis of myelopathy. Physical examination of the patient In addition, as previously stated, a herniated disk may cause some long-tract signs because of the presence of the spinal cord at the cervical level.

76 Chapter 3d ● Treatment options for disorders of the cervical spine Figure 3d.4 Types of soft disk herniations. (From Boden SD, et al: use to pain so severe as to preclude use. In addition, attacks of The aging spine: essentials of pathophysiology, diagnosis, and treatment. sharp pain may radiate into the hand and fingers with associated Philadelphia, 1991, WB Saunders.) paresthesias. Pain severe enough to awaken the patient at night is common. Most patients have symptoms consisting primarily of arm pain. Although it may begin in the neck region, the pain radiates The differential diagnosis of radicular pain must be considered. down into the shoulder, arm, forearm, or hand along a clearly Pathologies that range from tumors to nerve entrapment syn- defined dermatome. The onset of pain may be gradual, although dromes share the common trait of mechanically compressing acute tearing or snapping sensations may occur. The arm pain a nerve root and imitating radicular symptoms. Other neuro- may vary in intensity from a dull cramping pain in the arm with logic diseases can masquerade as a radicular process, however, and should also be contemplated. Classic differential diagnoses include a Pancoast tumor, which is an apical lung tumor often accompanied by Horner syndrome because of disruption of the sympathetic chain, and thoracic outlet syndrome, which can be diagnosed on physical examination. Physical examination may reveal some decreased motion of the neck that may be so severe as to manifest as frank torticollis. Any maneuver (such as the Valsalva maneuver) that stretches the involved nerve root may recreate the pain pattern. Spurling’s test, in which the neck is extended, may often make the pain worse by further narrowing the involved intravertebral foramina. Additionally, coughing, shoulder abduction, and axial compres- sion tests are often positive in patients with compression radicu- lopathy. The axial compression test is performed by pressing down on a patient’s head while he or she is either sitting or lying down. A positive finding consists of worsening or repro- duction of radicular symptoms. The shoulder abduction relief test is positive if radicular symptoms are decreased when a seated patient elevates one hand above the head with the elbow flexed and the shoulder abducted to 90 degrees. An axial manual trac- tion test is performed with the patient supine. A positive finding consists of a decrease or complete absence of radicular symptoms when 20 to 30 pounds of axial traction is applied. The finding of a neurologic deficit on physical examination greatly aids in the diagnosis, although in the setting of a chronic radiculopathy, the neurologic examination may be normal. Because subjective sensory changes are often difficult to inter- pret, the neurologic examination must show a diminution of reflexes, motor weakness, or atrophy to be significant. Henderson et al6 found a diminished deep tendon reflex in 71% and a demonstrable motor deficit in 65% of 846 patients with cervical radiculopathy. The specific motor and deep tendon reflex changes noted depend on the cervical nerve root that is compressed by the herniated disk. Because the C3 and C4 nerve roots do not have a uniquely testable reflex or motor innervation, involvement of these roots corresponds to sensory changes in their respective dermatomes. The remaining cervical nerve roots do exhibit testable motor and reflex changes in addition to sensory deficits in their corresponding dermatomes (Table 3d.2). The specific motor innervation of the individual nerve roots allows the examiner to pinpoint the level of disease with good accuracy. Because plain films are most often normal they are nondiag- nostic, leaving the clinician to rely on the history and physical examination to arrive at the diagnosis of an acute herniated cervical disk. Occasionally, disk space narrowing is seen at the involved interspace, or oblique films may show foraminal narrowing. Plain films are useful primarily for ruling out other causes of arm and neck pain, such as instability and neoplasia. Other diagnostic tests, such as electromyography (EMG) or myelography, are not useful as screening tests and should be

Chapter 3d ● Cervical degenerative disk disease 77 Table 3d.2 Neurology of the upper extremity steroids is not necessary but may prove useful in the more refrac- tory cases. In this case, a tapering dose schedule over a period of Disk Root Reflex Muscles Sensation 7 days can be used. C4-C5 C5 Biceps reflex Deltoid Lateral arm Injections of local anesthetic and steroid into the cervical C5-C6 C6 Biceps Axillary nerve epidural space may provide some pain relief. This again is based C6-C7 C7 Brachioradialis Wrist extension Lateral forearm on the premise that inflammation plays a significant role in the C7-T1 C8 reflex Biceps Musculocutaneous production of radicular symptoms. This procedure, however, T1-T2 T1 (biceps reflex) requires considerable experience and technical competence and Wrist flexors nerve carries with it a risk of complications. Some authors have had Triceps reflex Finger extensions Middle finger limited success with this procedure, but we do not routinely use Triceps cervical epidural steroids. Finger flexion Medial forearm Hand intrinsics Med. Ant. Brach. The prognosis for patients with an acute herniated cervical Cutaneous nerve disk is generally very good. If patients are compliant with the rest Hand intrinsics Medial arm and immobilization program as outlined, most are able to return Med. Brach. to work within a period of 1 month, at least under light duty Cutaneous nerve conditions. Indications for surgical intervention in the treatment of an acute herniated disk include persistent radicular pain unre- used more to confirm diagnoses based on a detailed history sponsive to at least 3 months of conservative therapy, progressive and physical examination. In addition, the routine use of com- neurologic deficit, static neurologic deficit in the presence puted tomography (CT) or magnetic resonance imaging (MRI) of radicular-type pain, and radiographic studies such as CT or is not warranted. These sensitive studies may reveal herniated MRI with a myelogram confirmatory of clinical signs and disks that are clinically insignificant: In a study of 63 asymp- symptoms (Fig. 3d.5). Diskectomy for pain relief has been shown tomatic individuals, 10% showed evidence of cervical disk to be greater than 90% effective when performed for the proper herniation on MRI.1 diagnosis. Treatment CERVICAL DEGENERATIVE DISK DISEASE The primary mode of treatment for an acute herniated disk is rest Cervical degenerative disk disease can produce cervical spondy- and immobilization. A cervical orthosis greatly improves the losis in isolation or in concert with a number of syndromes, chance that the patient will remain at rest. The collar must fit including myelopathy, radiculopathy, myeloradiculopathy, and properly and hold the head in a neutral to slightly flexed posi- associated visceral or vascular encroachment. Radiculopathy tion. If the neck is held in hyperextension, the patient often is secondary to spondylosis is not discussed separately because it uncomfortable and therefore noncompliant in its use. Once does not significantly differ from radiculopathy secondary to the acute pain starts to subside, the patient should be weaned acute herniated disk disease as previously described. slowly from the orthosis and should likewise increase activity gradually. If the patient complies with the rest and immobiliza- Spondylosis tion, the use of analgesics is often not necessary, although a brief course of analgesic medicine may occasionally be required in The human cervical spine has a high degree of mobility and flex- severe cases. Benzodiazepines and muscle relaxants can act as ibility. It has paid the price for this mobility with an almost central nervous system depressants but as such have a limited universal propensity for degenerative change. Cadaveric studies role in the treatment of acute herniated disk disease. have revealed that nearly everyone will demonstrate some degree of degenerative change in the cervical spine by age 55. Cervical Drug therapy does, however, have an important role in com- spondylosis is a term used to describe the chronic process of bination with rest and immobilization. Evidence now suggests degenerative changes that occur as part of natural aging. These that herniated disks are capable of eliciting an immune response include changes in the vertebral body, intervertebral disk, uncover- characterized by the secretion of cytokines such as interleukin-1, tebral joints of Luschka, zygapophyseal joints, ligamentum interleukin-6, nitric oxide, and prostaglandins, which have mul- flavum, dura, and soft tissues. tiple effects on tissues, including direct stimulation of nerve ending and sensitization of nociceptors.7 By inhibiting the pro- The primary cause of cervical spondylosis appears to be age- duction pathway of some of these mediators, antiinflammatory related changes that occur in the intervertebral disks, including medications such as nonsteroidals have a role to play in sympto- loss of annulus fibrosus elasticity, desiccation of the nucleus matic relief. Many such medications can have adverse gastroin- pulposus, and narrowing of the disk space with or without asso- testinal side effects but can generally be well tolerated for brief ciated disk rupture. Narrowing of the disk space creates excessive periods. The patient should be educated on these side effects, motion between vertebral segments, causing secondary changes however, and should be instructed to stop taking the medication such as osteophyte formation, facet joint and ligamentum immediately if side effects occur. Routine use of oral systemic flavum hypertrophy, inflammation of synovial joints, and pos- sibly microfractures. Ultimately, spinal canal and lateral recess stenosis may result. These changes are seen in varying degrees in patients with spondylosis and to a lesser extent in asymptomatic

78 Chapter 3d ● Treatment options for disorders of the cervical spine JS C5 AB Figure 3d.5 Magnetic resonance images of a 45-year-old man with unilateral C6 radiculopathy. (A) Midsagittal view showing more pathologic anatomy than a parasagittal view of the unaffected side (arrows). (B) Parasagittal view of the affected side showing hard disk pathology (arrow). (From Boden SD, Rothman RH, Wiesel SW, Laws ER, Boden SD: The aging spine: essentials of pathophysiology, diagnosis, and treatment. Philadelphia, 1991, WB Saunders.) elderly individuals and can produce a variety of clinical signs and against a background of chronic disease, rest and immobilization symptoms depending on the severity. However, not everyone are generally beneficial. Aspirin or other nonsteroidal antiinflam- has clinically symptomatic complaints. Friedenberg and Miller4 matory medications may be helpful also for an acute exacerba- showed a lack of correlation between symptoms and degenera- tion and may be needed on a chronic basis to abate symptoms. tive changes seen on plain radiographs of the cervical spine. As previously described, trigger point injections may be of These changes become clinically significant only when directly value also both diagnostically and therapeutically. A soft cervical related to symptoms. orthosis may assist in resting and immobilizing the cervical spine. Cervical isometric exercises and changes in the patient’s Historically, the typical patient with cervical spondylosis is daily activities such as work habits, sleeping positions, and auto- over 40 years of age and has a complaint of neck ache. Referred mobile driving may be useful adjuvant therapies in the treatment pain patterns discussed above include shoulder pain, suboccipital of these chronic patients. In this patient population, the use of referred pain, occipital headaches, intrascapular pain, anterior manipulative techniques and traction protocols should not be chest wall pain, or other nonspecific symptoms such as blurred performed. vision and tinnitus. Spondylosis with myelopathy Physical examination of a patient with cervical spondylosis often reveals little in the way of objective clinical findings. When the previously described degenerative changes of the Neurologic findings are generally normal in isolated spondylosis cervical spine become so severe as to impinge on the spinal cord, without radiculopathy or myelopathy. Some decrease in motion a pathologic process termed myelopathy is produced. Spinal cord of the cervical spine may be evident. Point palpation may reveal and nerve root compression produces myeloradiculopathy. Having some tenderness along the midline of the neck and in areas of been described already in detail in relation to acute herniated referred pain. disk disease, radiculopathy is not addressed here. Plain radiographs are obtained primarily to rule out more Those patients with developmental cervical stenosis are serious causes of neck pain. Plain films in the anteroposterior, more prone to the development of spondylitic myelopathy at a lateral, and oblique planes reveal varying degrees of change, younger age. Etiologic factors in the reduction of canal reserve vol- including disk space narrowing, osteophyte formation, foraminal ume include hypertrophy of the ligamentum flavum, facets, lamina, narrowing, facet degeneration, or instability patterns. Once again, and dura with redundant annulus fibrosus; foraminal osteophyte these changes do not directly correlate with the presence or compression of radicular vessels; vertebral osteophyte cord com- severity of clinical symptoms. pression; tethering of the cord by dentate ligaments; and ossifica- tion of the posterior longitudinal ligament or ligamentum flavum. Treatment The mainstay of therapy for patients with cervical spondylosis is conservatism. In the presence of acute exacerbation of symptoms

Chapter 3d ● Rheumatoid arthritis 79 A reduction in volume of the spinal canal can result in direct system syndrome with corticospinal tract involvement and canal compression and intrinsic or extrinsic ischemia. Edward weakness of both the upper and lower extremities. and LaRocca3 demonstrated that development of myelopathy with spondylosis is almost certain with canal diameters of less The differential diagnosis for patients with cervical spondylitic than 10 mm. Patients with canals 10-13 mm in diameter are myelopathy includes such disorders as multiple sclerosis, amy- at risk, and those with canals 13-17 mm are myelopathic otrophic lateral sclerosis, spinal cord tumors, syringomyelia, disk prone. Myelopathy rarely develops with canal diameters greater herniation, intracranial lesions, low-pressure hydrocephalus, and than 17 mm. subacute combined degeneration. Each of these should be ruled out with appropriate history, physical examination, and diagnostic In addition to these static considerations, dynamic changes studies. in the cervical spine may result in myelopathy. Penning and van der Zwaag described the pincer mechanism in 1966. In this Plain radiography in these patients generally demonstrates mechanism, the spinal cord becomes compressed between the typical degenerative findings, including spinal canal narrowing by anterosuperior margin of the lamina of the inferior vertebrae prominent posterior osteophytes, variable foraminal narrowing, and the posteroinferior osteophyte (i.e., hard disk disease) of the disk space narrowing, facet joint arthrosis, and instability. MRI superior level. Flexion of the spine causes stretching of the cord can demonstrate structural and parenchymal changes (Fig. 3d.6). over vertebral body osteophytes, with extension possibly result- The myelogram also is valuable in demonstrating the typical ing in retrolisthesis of one vertebral body on another or buckling washboard appearance (Fig. 3d.7) with multiple anterior and of the hypertrophied ligamentum flavum. All these dynamic posterior dye column defects. The posterior defects are produced changes can cause compression of the cord as it passes through by facet joint arthrosis and ligamentum flavum buckling. the cervical canal. Treatment Clinically, most patients are between 40 and 60 years of age when initially seen, with males affected more often. Myelopathy Studies looking at the natural history of cervical spondylitic develops in fewer than 5% of patients with cervical spondylosis. myelopathy are inconsistent and often difficult to compare Although a history of trauma may occasionally be given, the because of the lack of a universal classification system. Some onset is more often insidious. Acute myelopathy generally reflects common factors, however, can be identified. The age at onset a central soft disk herniation producing a high-grade block. The and duration of symptoms before the onset of treatment are natural history is one of deterioration initially, followed by a prognostic factors. Increased age at diagnosis and delay in treat- plateau in deficit lasting for several months. The exact clinical ment for longer than 1 year indicates a poor prognosis. Most picture is variable, with a patchy distribution of deficits. This patients in these series had periods without progression, or distribution depends on the number of levels involved and the plateau phases, interspersed with periods of rapid deterioration. severity of cord impingement at each level. Some patients had a steady progression of the disease with resultant severe disability. Conservative therapy rarely reverses Typically, patients have a gradual onset of numbness and the myelopathy, although in a patient who is a poor surgical paresthesias with associated weakness and clumsiness. Often, a candidate because of concomitant medical conditions, conserva- history of difficulty writing is elicited. Lower extremity symp- tive measures such as immobilization and rest with a cervical toms may precede those in the upper extremity and include gait orthosis are viable options. In general, however, management of disturbances, peculiar leg sensations, weakness, hyperreflexia, patients with myelopathy requires surgical decompression of the spasticity, and clonus. Upper extremity findings that may initially spinal canal and prevention of further spinal cord impingement be unilateral often progress bilaterality. These include hyper- and vascular compromise. Progression of the myelopathy after reflexia, a brisk Hoffmann sign, and muscle atrophy, particularly surgical decompression is uncommon. Both anterior and poste- of the hand intrinsics. Abnormalities in micturition are seen rior surgical procedures have been reported to lead to improve- in approximately one third of cases and connote a more severe ment in the myelopathy of patients with cervical spondylosis. cord impingement. Sensory changes are a less reliable sign of myelopathy. Spinothalamic tract signs may be seen with distur- RHEUMATOID ARTHRITIS bances in pain and temperature sensation in the upper extrem- ities, thorax, or lumbar region. These may be characterized by Approximately 2% to 3% of the general population is affected a stocking-glove distribution. Dorsal column function can be with rheumatoid arthritis. Of these, 86% show radiographic affected with resultant vibratory and proprioceptive disturbances. evidence of cervical spine disease, and 60% have clinical signs Impingement on the dorsal division of the nerve root may and symptoms of cervical spine involvement reflecting the ero- produce unusual dermatomal sensory changes. sive inflammatory changes characteristic of this systemic disease process. The clinical variable that is the most consistent indicator In the event of a severe myelopathy, one of several spinal of cervical spine involvement is the presence of hand deformities.11 cord syndromes may develop. These include (1) Brown-Sequard syndrome with ipsilateral motor dysfunction, contralateral pain, Involvement of the cervical spine consists of three distinct and temperature dysfunction one to two levels below the motor syndromes: atlantoaxial instability, basilar invagination, and involvement; (2) central cord syndrome with upper extremity subaxial instability. Although atlantoaxial instability is the most involvement greater than lower extremity involvement; (3) trans- common of these syndromes, Ranawat et al12 showed that they verse lesion syndrome, which occurs most commonly with tend to occur in combination. They found that 60% of patients involvement of the posterior columns, spinal thalamic tracts, and had atlantoaxial instability, 16% had basilar invagination, and corticospinal tracts; (4) brachialgia cord syndrome with upper 60% had subaxial instability. Risk factors for the development extremity radicular symptoms and long-tract signs; and (5) motor

80 Chapter 3d ● Treatment options for disorders of the cervical spine Figure 3d.6 (A) A sagittal 500-ms TR/17-ms TE image in a patient who sustained a cervical extension injury. Note the disruption of the anterior longitudinal ligament at multiple levels (solid white arrows) and the traumatic disk herniations (open arrows). Pinching occurs at the C5-C6 level (black arrows). (B) A parasagittal 500-ms TR/17-ms TE image shows anterior longitudinal ligamentous disruption (arrows) and prevertebral soft tissue swelling. (C) The midline sagittal 2000-ms TR/30-ms TE 7-mm image demonstrates ligamentous disruption (white arrows), prevertebral edema (e), and pinching at C5-C6 (black arrows). The canal compromise appears more serious on this 7-mm sagittal image, most likely because of a partial volume effect from the lamina laterally. (D) A 2000-ms TR/60-ms TE midline sagittal image shows similar findings, again with prevertebral edema (e), ligamentous disruption (white arrows), and some increase in signal intensity of the spinal cord at the site of compression (black arrows). (E and F) 2000-ms TR/90- and 120-ms TE images with similar findings, although the increased signal intensity within the spinal cord secondary to edema is more obvious on those more T2-weighted scans. The absence of any significant focal areas of decreased signal intensity indicates a relative absence of intramedullary hemorrhage (contusion) and a more favorable prognosis. Despite the initially severe neurologic deficit, this patient eventually recovered significant function. (From Modic MT, Masaryk TJ, Ross JS: Magnetic resonance imaging of the spine, ed 2. St. Louis, 1994, Mosby Year Book.)

Chapter 3d ● Rheumatoid arthritis 81 SM SM 3–89 3–4 C 12 mm SM 4–5 A D SM 3 4 5 6 B Figure 3d.7 (A) Lateral roentgenogram of a 43-year-old man with complaints of left shoulder pain, gait abnormality, and leg weakness. He had mild spondylotic changes and a congenitally narrow cervical canal (12 mm). (B) Lateral myelogram showing significant extradural defects at C3-C4, C4-C5, and C5-C6. (C) A computed tomography myelogram shows large uncovertebral spurs (arrows) plus soft disk material protruding at C3-C4. (D) Severe spinal cord flattening at C4-C5 from the disk and an osteophytic ridge. (From White AH, Schofferman JA: Spine care, vol. 2. St. Louis, 1995, Mosby Year Book.) of atlantoaxial instability include prolonged systemic steroid recumbency. Range of motion may be limited, and crepitation use, long disease duration, older age, and erosive peripheral joint or sensations of frank instability may be present, in which case involvement. Lhermitte’s sign may be elicited with motion. Neurologic changes can be variable and are often difficult to interpret in rheumatoid Patients with cervical spine involvement secondary to patients, who may have severe involvement of the upper and rheumatoid arthritis often have occipital neuralgia caused by lower extremities. Physical examination should be performed compression of the greater occipital branch of C2. This gives the very carefully to rule out upper motor neuron signs, such as typical complaint of headaches when upright that is relieved by

82 Chapter 3d ● Treatment options for disorders of the cervical spine hyperreflexia and spasticity, and the presence of abnormal Prognostically, these patients tend to do very well with con- reflexes, such as the Babinski and Hoffmann signs. Brainstem servative measures, and only a small percentage die of medullary involvement by compression of the invaginated dens and/or compression from significant atlantoaxial disease. Atlantoaxial associated pannus can result in symptoms of vertebrobasilar disease gradually worsens with time, with only 2% to 14% of insufficiency. Other nonspecific findings may include the onset patients exhibiting progressive neurologic symptoms. To sum- of bowel or bladder incontinence or retention, development of marize, surgical intervention should be considered in the pres- spasticity, and a change in ambulatory status. ence of (1) more than 3.5 mm of mobile subaxial subluxation on flexion-extension views, (2) atlantoaxial subluxation greater Evaluation of patients with any of these clinical symptoms than 8 mm in the presence of spinal cord compression on should first begin with plain radiographs of the cervical spine. flexion-extension radiographs, or (3) cranial settling indicative of Common findings include osteopenia, facet erosion, disk space basilar invagination in the presence of radiographic evidence narrowing, and subluxation of the lower cervical spine (step (MRI) of cord compression. Additionally, in the absence of ladder). Clinical management and operative indications can be these findings, the presence of a progressive neurologic deficit defined by five radiographic measurements: (1) the anterior is a strong indication for surgical intervention. atlantodens interval, (2) the posterior atlantodens interval, (3) the McGregor line, (4) the Ranawat measurement, and (5) the HYPEREXTENSION INJURIES (WHIPLASH) Redlund-Johnell measurement10 (Fig. 3d.8). Basilar invagination occurs with upward migration of the odontoid process into Most hyperextension injuries to the cervical spine result from the foramen magnum with resultant brainstem impingement. rear-end automobile accidents, which cause acceleration hyper- Radiographic evaluation includes a measurement of the distance extension injuries in the drivers of the struck cars. Falls and from the tip of the odontoid to beyond the MacGregor line. This sports injuries contribute to the remainder of the hyperextension is seen on the lateral view of the cervical spine and represents injuries. This injury has great economic considerations. The term a line drawn from the tip of the hard palate to the posterior whiplash injury was introduced by H. E. Crowe in 1928, and since base of the foramen magnum. Normally, the dens should not that time it has become a major source of litigation potential. protrude more than 4.5 mm above this line. Protrusion more than 8 mm in females or 9.7 mm in males may be an indication The pathophysiology behind a hyperextension injury involves for surgery. A CT may be helpful in determining radiographic the soft tissues of the neck region.9 Usually, the driver of the struck landmarks, which tend to become more diffuse in the rheuma- automobile is relaxed and unaware of the incipient collision. toid patient. Subaxial subluxations are also evaluated on dynamic When struck from behind, the automobile accelerates forward flexion-extension views of the spine. Significant subluxation acutely. If no headrest is present, the driver’s head is thrown back is defined as translation of one vertebral body on another of and the neck forced into hyperextension as the torso continues 3.5 mm or more or disk space angulation of 11 degrees or more. onward with the automobile. The sternocleidomastoid, scalenes, and longus coli muscles are extended beyond their elastic limit Treatment and are severely stretched or torn. Tears of the longus coli muscles may be associated with a concomitant tear of the sym- Most of these patients can be managed conservatively despite pathetic trunk and result in Homer syndrome. Further hyperex- the fact that cervical spine involvement may develop in a signif- tension may result in injury to the larynx or esophagus with icant number. The mainstay of nonoperative therapy is a hard subsequent hoarseness or difficulty in swallowing, respectively. cervical orthosis (Philadelphia collar), which produces sympto- Injury to the anterior longitudinal ligament may result in matic relief without actually affecting the atlantoaxial interval. hematoma formation with cervical radiculitis or injury to the Medical treatment of these patients plays a crucial role in intervertebral disk. Furthermore, when the head is thrown back- nonoperative management. Medications such as oral steroids, ward, the jaw generally lags behind, resulting in injury to methotrexate, leflunomide, and other disease-modifying the temporomandibular joint as the jaw falls open. When the antirheumatic drugs are administered under the supervision of a head recoils forward, the skull may strike the driver’s wheel or rheumatologist. windshield, resulting in a head injury. Figure 3d.8 (A) Measurement of anterior atlantodens interval and posterior atlantodens interval. (B) The Ranawat method for measurement of vertical setting. (C) The Redlund-Johnell method for measurement of vertical setting. (From Monsey RD: J Am Acad Orthop Surg 5:240-248, 1997.)

Chapter 3d ● Cervical spine treatment algorithm 83 Hyperextension injuries in elderly patients with preexisting development of a long-term psychoneurosis. Strict bed rest may cervical spondylosis may acutely compress the spinal cord as be necessary for 3 to 5 days if the symptoms are severe. Heat in the already limited spinal reserve volume is overcome. This cord the form of hot soaks or heating pads may be useful. Although compression can take the form of a frank paralysis or a central narcotics should be avoided, medical therapy in the form of non- cord syndrome. narcotic analgesics, nonsteroidal antiinflammatory medications, and muscle relaxants is helpful. Activity should be restricted Patients with a hyperextension injury are generally examined according to symptom severity. 12 to 24 hours after the initial traumatic event. It is at this point that the patient starts to feel stiffness in the neck and pain at the Characteristically, improvement should occur after 2 weeks base of the neck made worse by motion. The pain becomes of treatment as outlined earlier. If improvement does not occur, progressively worse, and eventually the slightest head or neck an additional 2 weeks of rest and immobilization should be movement elicits severe pain. The anterior cervical musculature prescribed with the addition of home cervical traction. Low- may be tender to palpation, and the patient may have hoarse- weight traction consisting of 7 to 10 pounds for 20 to 30 minutes ness, dysphagia, or pain with chewing or opening the mouth. per day generally gives symptomatic improvement. Persistence of Pain may radiate into both shoulders and arms and upward into symptoms past 4 weeks should alert the physician to search for the base of the skull. Other pain patterns may include the ante- another etiology. If headaches persist, a CT of the head should be rior of the chest, interscapular region, and vertex of the skull. obtained to rule out a closed-head injury. If arm or shoulder pain persists, CT of the spine and/or EMG should be performed. The potential for a closed-head injury even in the absence of visible head trauma should not escape the examiner. Concussion In general, symptoms should be resolving by 6 weeks, although can occur secondary to mechanical deformation during the complete resolution may take as long as 1 year.8 Persistence of acceleration-deceleration phase of the injury. This may result in symptoms beyond 6 weeks of severity equal in intensity to that headache, photophobia, mild transient confusion, fatigue, tinni- in the initial period may alert the physician to secondary gain tus, or transient concentration abnormalities. from pending litigation, and compensation neurosis should be suspected. Before assigning this diagnosis, the physician should Physical examination must be complete from head to toe so certainly rule out any significant pathology by a careful history, that other associated injuries are not overlooked. The potential physical examination, and appropriate diagnostic testing. The for a “chance fracture” of the lumbar spine exists if the patient physician should not, however, over-treat the patient and encour- was wearing a lap seatbelt. The head should be examined for any age a retreat into a life of incapacitating neck pain. evidence of a closed-head injury. A unilateral dilated pupil may suggest an injury to the sympathetic chain as it travels along the The point at which the patient is able to return to the work longus coli muscles with resultant Horner syndrome. It may also force depends on both the severity of the hyperextension injury indicate significant intracranial pathology in a patient with an and the type of work involved. Patients performing heavy man- altered level of consciousness. Temporomandibular joint tender- ual labor may require 3 to 4 weeks of treatment before returning ness should be assessed as well as suboccipital tenderness, which to work, whereas those in less demanding positions may be able may indicate that the head struck the top of the seat. to return after only 2 weeks. Limitations on the work performed should consist of no lifting of objects heavier than 50 pounds, A careful and thorough neurologic examination should be no bending, and no prolonged periods of stooping. These restric- performed. Again, particular attention should be paid to elderly tions should remain in effect for the first 3 weeks that the patient patients, who may have baseline spinal stenosis secondary to has returned to work. cervical spondylosis with resultant cord injury or central cord syndrome. If any objective neurologic deficit is identified, Depending on the severity of the injury, the prognosis is further diagnostic tests, including CT and/or MRI, are necessary. generally good for complete recovery. Occasionally, a 5% to 10% CT is better at providing bone detail, whereas MRI is better at disability rating is appropriate in an honest patient in whom demonstrating soft tissue disruption such as intervertebral disk symptoms persist during hard manual labor. protrusion. CERVICAL SPINE TREATMENT ALGORITHM In most cases of hyperextension injury, only soft tissue disruption occurs. Plain radiographs should be obtained, how- The goal for patients with neck pain is to obtain an accurate ever, to rule out unsuspected facet dislocations, facet fractures, diagnosis and administer the correct therapy at the appropriate odontoid fractures, or spinous process fractures. In most cases, time. The previously presented clinical entities have been organ- these films are normal or may show some straightening of the ized into a standardized approach,16 a graphic display of which cervical spine. As noted, other diagnostic studies such as a is presented in the form of an algorithm in Figure 3d.9. The algo- head CT should be obtained as the history and physical findings rithm aids in establishing the proper diagnosis and guides in dictate. the delivery of the proper treatment. A summary of treatments categorized by pathology is listed in Table 3d.3. Treatment The algorithm begins with evaluation of those patients seen Treatment involves primarily rest and immobilization. Rest for neck pain with or without associated arm pain. Patients consists of a soft cervical orthosis that assists in relieving muscle with a history of trauma and associated fractures and/or disloca- spasms and prevents quick movements of the head. Collar wear tions are excluded. The first task is a thorough medical history beyond 2 to 4 weeks should not be encouraged, because this and physical examination to rule out the presence of cervical may result in weakening of the neck musculature and, in turn, myelopathy, as discussed earlier.

84 Chapter 3d ● Treatment options for disorders of the cervical spine Figure 3d.9 Cervical spine algorithm. (From Wiesel SW, et al: Neck pain. Charlottesville, VA, 1988, The Michie Company.)

Chapter 3d ● Cervical spine treatment algorithm 85 Table 3d.3 Treatment options for cervical spine then divided into two groups depending on whether neck or arm pathology pain (brachialgia) is the predominant complaint. Neck sprain Spondylosis Hyperextension/ For those patients whose main complaint is neck pain and whiplash for whom conservative therapy for 6 weeks has failed, plain radi- Rest Rest ographs, including flexion-extension films, should be obtained. Soft orthosis Soft orthosis Rest Several of these patients will have evidence of instability, the cri- Activity modification Activity modification Soft orthosis teria for which include horizontal translation of one vertebra NSAIDs Isometric exercises Moist heat on another of 3.5 mm or an angular difference of 11 degrees Muscle relaxants NSAIDs Activity modification between adjacent vertebrae. Most of these patients do well with Trigger point injections Trigger point injections Physical therapy nonoperative management consisting of education and bracing, Acute herniated Spondylosis with NSAIDs but those who do not may require segmental spinal fusion. Rheumatoid arthritis disk myclopathy A second group of patients have changes characteristic of Rest Rest/immobilization Hard orthosis degenerative disease. Radiographic findings include osteophyte Soft orthosis (nonoperative candidate) Steroids/DMARDs formation, loss of intervertebral disk height, narrowing of the NSAIDs neural foramina, and zygapophyseal joint osteoarthritis. As pre- Oral steroids ↓ ↓ viously mentioned, degeneration of the cervical spine may be a Epidural injections Surgical decompression Surgical fusion normal part of the aging process. The difficulty arises in determin- ↓ ing which of the degenerative changes are clinically significant. Diskectomy The most significant change has been found to be narrowing of the intervertebral disk height, particularly at C5-C6 and C6-C7. DMARDS, disease modifying antirheumatic drugs, NSAIDs, nonsteroidal antiinflammatory Treatment of these patients consists primarily of antiinflamma- drugs. tory agents, support braces, and trigger point injections. During quiet periods, isometric exercises should be used. Reexamination If a myelopathic process is confirmed, surgical intervention is necessary to monitor for the development of myelopathic should be considered in a timely fashion. The best results are symptoms or signs. obtained with only one- to two-motor unit involvement and relatively short duration of symptoms. Further studies, including Most patients who have normal plain films receive a prelim- myelography or MRI, should be performed to define precisely inary diagnosis of neck strain. After failure to improve with the neural compression. Adequate surgical decompression should conservative therapy, these patients should have a thorough then be performed. medical evaluation and a bone scan to rule out infection, neo- plasia, or inflammatory arthritis as the etiology of the neck pain. If cervical myelopathy is ruled out, most patients should then If this workup proves negative, they should then undergo psy- be started on a course of conservative management. Regardless chosocial evaluation and receive treatment, if appropriate, for of the etiology of the neck pain, all patients are treated equally depression or substance dependence, both of which can frequently in this regard. Initially, this nonoperative management consists be found in patients with neck pain. If the psychosocial findings primarily of immobilization and drug therapy. A well-fitted soft prove normal, the patient is considered to have a diagnosis cervical collar should be worn for 24 hours per day to prevent of chronic neck pain. Treatment therefore consists of thorough awkward positioning and movements during sleep and while education and support, detoxification from narcotics, and insti- awake. In addition, antiinflammatory medications, analgesics, tution of an exercise program. Antidepressant agents may prove and muscle relaxants will improve patient comfort. to be useful, and frequent reevaluations are necessary to avoid overlooking any serious pathologic process. Most patients will symptomatically improve with this pro- tocol within approximately 10 days and should then start to be Other large groups of patients in this algorithm are those in weaned over the next 2 to 3 weeks. Additionally, their level of whom arm pain is the predominant symptom. The etiology of activity should be gradually increased, and they should start a this pain may be either direct pressure from a herniated disk or series of exercises aimed at strengthening the paravertebral mus- inflammation about a nerve on hypertrophic bone (hard disk culature. If the condition remains unimproved, patients should disease). Other causes of extrinsic compression of the vascular continue full-time collar wear and pharmacologic management. or nervous structures supplying the upper extremity, including pathologic processes of the chest and/or shoulder region, may If no significant improvement in symptoms is seen after 3 to imitate brachialgia also and must therefore be ruled out. A thor- 4 weeks, a trigger point injection at the point of maximum ten- ough history and physical examination, including an Adson derness should be considered. This is performed with a combi- test, shoulder examination, and Tinel’s test of the carpal, cubital, nation of 10 mg of corticosteroid and 3 to 5 ml of 1% lidocaine. and ulnar tunnels, should be performed, with additional appro- If this is likewise not successful at 4 to 5 weeks, a trial of home priate studies possible, based on the results. If an Adson test is cervical traction may be considered. positive, vascular studies and EMG should be performed to evaluate causes of thoracic outlet syndrome. Compression of For patients with neck pain, a total period of 6 weeks of the brachial plexus may occur secondary to vascular structures, conservative management should be pursued. Most patients cervical ribs, muscular or fibrous bands, or neoplastic processes. respond to this program and return within 2 months to their Additionally, an apical lung carcinoma can cause brachial plexus previous life-styles. If, on the other hand, the symptoms fail to compression with or without Horner syndrome from sympa- resolve within 6 weeks of conservative therapy, the patients are thetic chain involvement (Pancoast tumor).

86 Chapter 3d ● Treatment options for disorders of the cervical spine If plain films of the chest and shoulder are negative and fail REFERENCES to reveal a source of extrinsic compression, EMG studies should be performed. If these indicate peripheral nerve compression, 1. Boden SD, McCowin PR, Davis DO, Dina TS, Mark AS, Wiesel S: Abnormal magnetic- surgical decompression at the site should be performed. In the resonance scans of the cervical spine in asymptomatic subjects: a prospective presence of radicular symptoms, a myelogram or MRI should investigation. J Bone Joint Surg 72(8):1178-1184, 1990. be performed, and if the results are consistent with the neu- rologic deficit, history, and physical findings, surgical decom- 2. Dwyer A, Aprill C, Bogduk N: Cervical zygapophyseal joint pain patterns. I. A study in pression of the nerve root should be undertaken because normal volunteers. Spine 15:453-457, 1990. conservative treatment results in persistent symptoms. 3. Edward WC, LaRocca SH: The developmental segmental sagittal diameter in com- This algorithm is applicable to all patients with nonspecific bined cervical and lumbar spondylosis. Spine 10:43-49, 1985. neck or arm pain and provides a rational approach to the ther- apeutic and diagnostic sequence of events. The goal of this 4. Friedenberg ZB, Miller WT: Degenerative disc disease of the cervical spine. J Bone approach must always be to treat appropriately the etiology Joint Surg 45A:1171-1178, 1963. of the pain while avoiding unnecessary tests and therapeutic interventions and, most importantly, to minimize the chance of 5. Grubb SA, Kelly CK: Cervical discography: clinical implications of twelve years of overlooking other serious pathologic processes. experience. Spine 25:1382-1389, 2000. CONCLUSION 6. Henderson CM, Hennessy R, Shuey H: Posterolateral foraminotomy for an exclusive operative technique for cervical radiculopathy: a review of 846 consecutively oper- This chapter summarizes some of the major pathologic processes ated cases. J Neurosurg 13:504-512, 1983. that affect the cervical spine. A detailed description of the anatomy and of the pathophysiology is provided to aid in the 7. Kang JD, Stefanovic-Racic M, Mcintyre LA, Georgescu HI, Evans CH: Toward a biochemi- understanding of these clinical entities. In addition, the clinical cal understanding of human intervertebral disc degeneration and herniation: contri- workup of each disease process is discussed, covering the present- butions of nitric oxide, interleukins, prostaglandin E2 and matrix-metallo-proteinases. ing signs and symptoms, corresponding physical examination, Spine 22:1065-1073, 1997. and pertinent diagnostic studies. A special emphasis is placed on the treatment of cervical spine disease, which is individualized 8. McNab I: Acceleration injuries of the cervical spine. J Bone Joint Surg 46A:1797-1799, for each pathologic process. Finally, a treatment algorithm is 1964. presented that provides a coherent clinical decision-making process combined with a standardized approach to treatment of 9. McNab I: The whiplash syndrome. Orthop Clin North Am 2:289-403, 1971. cervical spine disease. 10. Monsey RD: Rheumatoid arthritis of the cervical spine. J Am Acad Orthop Surg 5:240-248, 1997. 11. Oda T, Fujiwara K, Yonenobu K, Azuma B, Ochi T: Natural course of cervical spine lesions in rheumatoid arthritis. Spine 20:1128-1135, 1995. 12. Ranawat CS, O’Leary P, Pellici P, Tsairis P, Marchisello P, Dorr L: Cervical spine fusion in rheumatoid arthritis. J Bone Joint Surg 61A:1003-1010, 1979. 13. Rothman RH, Marvel JP: The acute cervical disc. Clin Orthop 109:59-68, 1975. 14. Rothman RH, Marvel JP: The spine, ed 4. Philadelphia, 1999, WB Saunders. 15. Stookey B: Compression of spinal cord and nerve roots by herniation of nucleus pulposus in the cervical region. Arch Surg 40:417-432, 1940. 16. Wiesel S: Neck pain, ed 2. Charlottesville, VA, 1992, The Michie Company.

3eC H A P T E R postures and forces (Fig. 3e.3). These elements should be recorded along with their duration, frequency, and cause. For example, in Workplace Adaptation the claims processor job described in Table 3e.1, extreme reaches to the workers’ side are required 80 times per day to get unfini- Thomas J. Armstrong shed files and 80 times per day to put aside finished files. Workers must reach over the files and rotate their forearms to use The deviation of neck, shoulder, and elbow postures from neutral the keyboard 6 hours per shift. In the assembler job described in positions is associated with adverse health effects such as fatigue Table 3e.2, the workers must reach for parts beside and behind and chronic muscle, tendon, and nerve disorders. The effects of them 2400 times per 8-hour shift; they must elevate their elbow these disorders range from minor discomfort and degraded above shoulder height and rotate their forearm 14,400 times per performance to disability. Available data suggest that the time at shift, and so forth. onset of adverse effects decreases with increasing exertion dura- tion, frequency, and force. This does not mean, however, that The analysis should also include an inspection of infrequent some postures can or should be maintained indefinitely without or irregular elements. For example, in the claims processor job interruption. Also, it does not mean that brief exposures to extreme (Table 3e.1), 3 of 10 claims are set aside to await additional infor- postures are not desirable. mation that must be retrieved by telephone. In the assembler job (Table 3e.2), 1 of 12 screws is defective and requires additional The relationship between certain work activities and adverse movements and time to replace. By their very nature, it may be health effects is referred to as the “dose-response” relationship hard to identify irregular elements from existing job descriptions (see Chapter 1). The dose-response relationship provides insight or observations. Often they are identified via worker and super- into how work can be designed to minimize the risk of possible visor interviews. adverse health effects or to facilitate the return to work of persons in whom an adverse effect may have developed. Unfortunately, SPECIFICATION OF ADAPTATIONS sufficient data are not yet available to specify job designs that provide a specific level of risk. For example, it cannot be said The causes of the physical stressors should be apparent from the how many times a group of workers can exert a horizontal force work evaluation. The tabulation of stressors and their causes of 50 N to engage the bit of a powered screwdriver weighing 15 N illustrated in Tables 3e.1 and 3e.2 provide a systematic format at an elevation of 1.5 m before unacceptable health effects would for developing possible adaptations. This format also provides develop in a given fraction of them. It is extremely important insight into how the overall stressfulness of the job is affected by that the work equipment and procedures be evaluated at all stages the proposed control measures and how one adaptation may of design and implementation. affect other stressors. For example, in Table 3e.1 it can be seen that the claims processors are exposed to 2 hours of a stressful Workplace adaptation entails three basic steps14: shoulder-neck posture per day to hold the phone handset. It can 1. Evaluation of the proposed or existing job; also be seen that a headset or a bracket attached to the handset 2. Specification of adaptations; could reduce this exposure. Yet another adaptation might be 3. Evaluation of adaptations. passing uncompleted files to another worker who does all the phoning; however, this solution could result in increased key- It may be necessary to repeat one or more of these steps one board times and other undesirable effects. or more times to achieve a desired level of control. Reaching for documents is associated with cart location and EVALUATION design. It follows that locating the carts close to the workers’ side and modifying them with a fold-down side would reduce Evaluation entails documentation of the process, equipment, pro- reaching. Because these reaches occur an average of only once cedures, and environment and assessment of stressors, including every 3 minutes, it can be argued that this work element is by posture, force, duration, and frequency.1,7 The documentation is itself unlikely to produce adverse health effects; however, it can performed from available job descriptions, time studies, workplace also be argued that when combined with other factors, this inspections and measurements, equipment specifications, and reaching could result in an adverse effect or could aggravate an interviews with workers and supervisors. This information is then existing case. An analysis of the low cost associated with park- used to identify stressful postures and forces necessary to reach, ing the carts close to the workers versus the possible cost of hold, and use work objects and the duration and frequency of medical treatment and lost work for disabled workers would these exertions. Tables 3e.1 and 3e.2 and Figures 3e.1 and 3e.2 support locating carts close to the workers. Such an analysis illustrate evaluation summaries of two jobs: claims processor and would probably also support a modification of the cart with assembler. drop sides. An assessment of stressful postures and forces entails examining Workplace adaptations may involve modification of each step of the operation for extreme neck, shoulder, and elbow ● Work processes; ● Work standards; ● Design of methods; ● Workplace layout; ● Equipment; ● Training.

88 Chapter 3e ● Workplace adaptation Table 3e.1 Sample documentation and analysis of “claims processor” job for identifying and controlling shoulder and neck stressors TITLE WORKER Claims processor Skilled male and female keyboard operators STANDARD Fifth percentile female to 95th percentile male stature Complete 80 claims per day ERGONOMIC STRESSORS EQUIPMENT Stressor Computer, keyboard, 13-inch color monitor and claim processor software POSTURE Desk Reaching for unfinished files (80 times per shift) Staple remover Reaching over file on lap to use keyboard (6 hr/shift) Stapler Looking down at file (4 hr/shift) Telephone with handset Extending the neck to see monitor through bifocals (2 hr/shift) Adjustable-height chair Reaching to put aside finished files (80 times per shift) Carts for holding files Inward forearm rotation and wrist deviation to position hands over keyboard METHOD (6 hr/shift) 1. Get file from cart—place on lap in front of keyboard Holding phone between neck and shoulder (2 hr/shift) 2. Remove staples Proposed Adaptation 3. Sort documents Provide access for carts so that it can be positioned to minimize reaching 4. Perform keystrokes to open file Provide adjustable tray to hold file above keyboard 5. Perform keystrokes to update file Provide corrective lenses that do not require worker to extend neck 6. Call for information as necessary—3 calls per 10 claims Investigate variable geometry keyboard to reduce forearm rotation 7. Perform keystrokes to close file Provide headset for phone 8. Staple documents Investigate adjustable keyboard holder 9. Stamp and date file Investigate wrist rest 10. Place finished file in cart Provide adjustable monitor holder 11. Note: occasionally claims processor cannot finish file and will set it Stressor FORCE aside at the front of desk until someone calls back with necessary Lifting files weighing up to 50 N from cart to lap (80 times per shift) information MATERIALS and from lap to cart (80 times/shift) Files weighing 5-50 N Proposed Adaptation ENVIRONMENT Provide access for cart so that it can be positioned to minimize reaching Inside overhead fluorescent lights with diffusers Investigate drop side for cart Work processes refer to the technologies used for completing corner closest to them. A methods change may also require an the work objectives. In the claims processor example (Table 3e.1), equipment change and worker training. the technologies are keyboards and telephones. Alternative tech- nologies include scanners and electronic mail. In the assembler Workplace layout refers to the position of equipment and work example (Table 3e.2), the technologies include threaded fasteners; objects in the workplace. In the claims processor example, the alternative technologies include clips and adhesives. workplace layout includes the position in space of the carts with files, the keyboard, the monitor, the phone, and the active file Work standards refer to the quantity and quality of work pro- with respect to the worker. Adaptations include repositioning the duced in a given time. In the claims processor example, the stan- carts to reduce reaching, adding equipment to allow repositioning dard is 80 claims per 8-hour shift; in the assembler example, the of the keyboard, and supplying adjustable document and monitor standard is 2400 motor assemblies per 8-hour shift. The work holders. In the assembly example, adaptations include equipment standard is an important factor in how many times per day workers to reposition the parts bin and adjustment of the suspender so must assume a given posture or exert a given force. Reducing that the tool can be positioned to minimize reaching. work standards is generally considered an adaptation of last resort; however, it may be shown that the lost productivity is more than Anthropometric data may be used to estimate reach distances.3,11 offset by the reduced cost of medical treatment and lost work for Average link length proportions can be used with population stature a disabled worker. data to estimate vertical, horizontal, and lateral reach limits (Fig. 3e.4). Caution should be used in interpreting reach predic- Work methods refer to the procedures or sequence of move- tions based on link length data. A reach distance based on average ments used to perform the job. In the assembler example, the proportions and a given percentile stature may correspond to a method entails getting motors from a bin, placing them on the different percentile reach. Work locations should be made as line, and driving six screws. A methods change to reduce reaching adjustable as possible to accommodate individuals and should would be to unload one corner of the bin and then rotate it be tested with user trials.8,12,14 Reach data for U.S. civilian popu- 90 degrees so that the workers are always working from the lations are available from U.S. National Health surveys.13

Chapter 3e ● Evaluation of adaptations 89 Table 3e.2 Sample documentation and analysis of “assembler” job for identifying and controlling shoulder and neck stressors TITLE Reaching for parts located to side and behind worker (300 times/hr) Assembler Reaching for screwdriver located overhead (300 times/hr) STANDARD Driving 1800 screws/hr with pistol-shaped driver requires elevation of elbow Assemble 2400 motor assemblies per 8-hour shift EQUIPMENT and forearm rotation Assembly line (1 m above floor level) Reaching upstream and downstream to keep up with production line Power screwdriver suspended above line Rack and bin for holding parts (50% of time, but 90% of time when bad screws are encountered) METHOD Proposed Adaptation 1. Get motor assembly from bin (weight, 40 N) and position on Position trays close to worker and production line to minimize reaching Unload trays one corner at a time and then rotate tray 90 degrees to subassembly 2. Get handful of screws with one hand minimize reaching 3. Get screwdriver with other hand Adjust tool suspender to minimize tension and locate tool as close as possible 4. Position screw in screwdriver × 6 5. Drive screw (1 of 12 screws is defective and must be backed out to point of use Investigate use of in-line tool with articulating arm to control torque and replaced) Investigate indexing production line in which work object stops until released ENVIRONMENT Inside overhead fluorescent lights with diffusers by worker WORKER Position work object as close to edge of production line as possible to Males and females Fifth percentile female to 95th percentile male stature minimize reaching ERGONOMIC STRESSORS Investigate quality control program to avoid defective screws that take extra Stressor POSTURE motions to try and to reject Reaching for motor assemblies located to side and behind worker Stressor FORCE (300 times/hr) Lifting motor assemblies weighing 40 N from bin (300 times/hr) Pulling down power tool into work position (300 times/hr) Proposed Adaptation Investigate small hoist or air balancers to facilitate transferring motors to line (See above recommendations for tool suspender) Equipment refers to hardware such as tools to drive fasteners or ● Workers or work representatives; shape and smooth surfaces, containers, jigs, fixtures for holding ● Purchasing; parts, and seating to support the worker. A proposed adaptation ● Sales and technical representatives from suppliers; in the claims processor example includes modification of the cart; ● Catalogs, brochures, and technical specifications; adjustable holders for the keyboard, monitor, and files; and a ● Scientific papers, books, and magazines. headset for the phone. In the assembly example, equipment changes include an in-line screwdriver with articulating arm, an In general, the team approach is the most effective way to mobi- indexing assembly line, and a turntable for the parts bin. lize the resources necessary to develop and implement workplace adaptations. On occasion, however, the problems are conspicu- Training entails instructing workers on the hows and whys of ous and the solution is clear so organizing a special team is not arranging and performing their work. In the claims processor merited. example, it should be explained to the workers where they should position the carts and why this is necessary to prevent possible Development of adaptation is not an exact process. shoulder problems. Follow-up training and evaluations should Consequently, all adaptations should be evaluated to ascertain be performed to determine whether the workers understand and their effectiveness. follow the specified procedures. If procedures are not followed, further evaluations should be performed to determine why they EVALUATION OF ADAPTATIONS are not followed. Ideally, adaptations should be evaluated in terms of their effects The design of adaptations should draw on all available on upper limb disorders. Unfortunately, such evaluations are dif- resources. Available resources vary from one situation to another, ficult. Upper limb disorders develop over long periods of time. depending on the size and type of industry. Possible resources To determine the effect of a given adaptation on the occurrence include of disorders would require identification of a group of several ● Job designers, such as engineers, facilities people, and setup hundred workers, implementation of the adaptation in a random subset of these people, and some kind of comparison adaptation people; in the others.6 The population would then have to be tracked for ● Safety and health personnel, such as doctors, nurses, industrial hygienists, and safety personnel; ● Supervisors;

90 Chapter 3e ● Workplace adaptation AB f Figure 3e.1 (A) Illustration of a claims processor job. (B) Major e stresses include reaching for documents, holding the telephone, reaching for the keyboard, looking down at documents, and reaching a to get and put aside documents. (C) Possible claims processor job interventions include an adjustable document holder (a), adjustable d b monitor holder (b), adjustable keyboard holder (c), drop-side cart (d), headset for phone (e), and optically correct glasses (f). c C 1 or more years. Unfortunately, such studies are extremely difficult adaptations have already been implemented. In other cases it and expensive. It is difficult to find large groups in which adap- may be necessary to develop prototypes and conduct pilot testing tations can be randomly assigned. Work activities are generally on a small number of the proposed interventions. Worker feedback dictated by production schedules that may cause the work popu- can be obtained through interviews; however, care should be lation to shrink or swell. In addition, non–health-related factors taken to avoid leading questions.9 The questions should be struc- may cause a turnover in the work population. Although evalua- tured in such a way as to provide guidance on how to enhance tion of health patterns is an important means of identifying the adaptation. For example, one of the proposed adaptations workers and jobs that merit further evaluation and assessing an for the assembly job was the use of another tool and locating it overall program, in most cases it provides only limited feedback to minimize reaching. In this case, workers could be permitted to about specific adaptations. try several tools and then rank them in order of preference. They could also be asked to try the tools at several locations and rate Adaptations can be evaluated by using the same methods that them on a scale of 0 to 10 where 0 is “too low,” 5 is “just right,” were used for the initial job evaluations. This analysis should and 10 is “too high.”2,12 Even though these measures do not begin as the adaptations are developed on paper and continue ensure that future shoulder, neck, or elbow problems will not through the prototype, pilot testing, and implementation phases.8 develop, they do provide a basis for selecting a work configuration In some cases it may be possible to identify and evaluate other that minimizes stress on the worker. jobs at that work site or other work sites where the proposed

Chapter 3e ● Evaluation of adaptations 91 0\" 12\" 24\" 36\" Figure 3e.2 (A) Work station layout for an assembler. (B) Proposed interventions for the assembler example include using a narrower conveyor to reduce reaching over line “dead space,” using an indexing line so that the worker does not have to “chase” the assemblies, and using a smaller box of parts mounted on a turntable to reduce reaching to the side and behind the worker. Shoulder Elbow A 90˚ 60˚ 0\" 12\" 24\" 36\" Shoulder Elbow B 90˚ 60˚

92 Chapter 3e ● Workplace adaptation Neck deviation Neck flexion or extension Elevated elbow Reaching behind the back Extreme elbow flexion Outward forearm rotation Inward forearm rotation Figure 3e.3 Shoulder and neck stressors include extreme neck, shoulder, and elbow postures and force. (Modified from Armstrong TJ: Hand Clin 553-565, 1986.) Discomfort patterns can also be used to evaluate work designs SUMMARY before and after they are implemented.4,5,10 Workers are shown pictures of the body and asked to identify and rate areas of The available data are not yet sufficient to develop design speci- discomfort. Discomfort patterns provide information about many fications that can be used to achieve a given level of risk of neck, parts of the body, as well as those parts likely to be affected by the shoulder, and elbow disorders; however, the data do provide stress of concern and the proposed adaptation. Often, the variation insight into some of the things that can be done to reduce risk. from within and between workers is considerable, and rigorous Control of disorders entails three basic steps: (1) evaluation of statistical conclusions may not be possible. 0.186 0.146 Occasional Figure 3e.4 (A) Average link length proportions can be 0.129 0.108 reach used with population stature data to estimate vertical, horizontal, and lateral reach limits. (B) The outer arc represents maximum reach without bending. The inner arc represents maximum reach without bending and not flexing the shoulder more than 30 degrees to minimize loads on shoulder tissues. 1.000 Frequent reach 0.818 0.630 AB

Chapter 3e ● References 93 the job to determine the frequency, duration, and cause of 5. Harms-Ringdahl K: On assessment of shoulder exercise and load-elicited pain in the extreme reaches and forces; (2) specification of adaptations; and cervical spine. Biomechanical analysis of load-EMG-methodological studies of pain (3) evaluation of the adaptations. It may be necessary to repeat provoked by extreme position. Scand J Rehab Med Suppl 14:1-40, 1986. these steps before the desired level of control is achieved. Development of workplace adaptations should be integrated into 6. Hennekens CH, Buring JE, Mayrent SL, eds: Epidemiology in medicine. Boston, 1987, an ongoing program that includes health surveillance, job surveys, Little, Brown. evaluation of affected workers and jobs, medical management, training, and a team approach with participation from all levels 7. Keyserling WM, Armstrong TJ, Punnett L: Ergonomic job analysis: a structured approach of the organization. for identifying risk factors associated with overexertion injuries and disorders. Appl Occup Environ Hyg 6(5):353-363, 1991. REFERENCES 8. McClelland I: Product assessment and user trials. In JR Wilson, EN Corlett, eds: 1. Armstrong TJ: Ergonomics and cumulative trauma disorders. Hand Clin 2(3):553-565, Evaluation of human work: a practical ergonomics methodology. New York, 1990, 1986. Taylor & Francis, pp. 218-247. 2. Armstrong TJ, Punnett L, Ketner P: Subjective worker assessments of hand tools used 9. McCormick E: Job and task analysis. In G Salvendy, ed: Handbook of industrial in automobile assembly. Am Ind Hyg Assoc J 51(12):639-645, 1989. engineering. New York, 1982, John Wiley & Sons, pp. 2.4.1-2.4.21. 3. Armstrong TJ, et al: Repetitive trauma disorders: job evaluation and design. Hum 10. Saldana N, et al: A computerized method for assessment of musculoskeletal discomfort Factors 28(3):325-336, 1986. in the workforce: a tool for surveillance. Ergonomics 37(6):1097-1112, 1994. 4. Corlett EN, Bishop RP: The ergonomics of spot welders. Appl Ergonom Mar:23-31, 1978. 11. Ulin SS, Armstrong TJ, Radwin RG: Use of computer aided drafting for analysis and control of posture in manual work. Appl Ergonom 21(2):143-151, 1990. 12. Ulin SS, et al: Effect of tool shape and work location on perceived exertion for work on horizontal surfaces. Am Ind Hyg Assoc J 54(7):383-391, 1993. 13. U.S. Department of Health, Education and Welfare: Weight and height of adults 18-74 years of age: United States, 1971-1974. Vital Health Stat 11(211), Hyattsville, MD, 1979, National Center for Health Statistics. 14. Wilson JR: A framework and a context for ergonomics methodology. In JR Wilson, EN Corlett, eds: Evaluation of human work: a practical ergonomics methodology. London, 1990, Taylor & Francis, p. 6.

4C H A P T E R Lower Back

4aC H A P T E R include defining and quantifying the pain experience and con- trolling the effects of individual and cultural factors on pain per- Epidemiology: Incidence, ception and interpretation. Studies can be complicated also by Prevalence, and Risk uncertain reliability in a person’s recall of symptoms and by vari- Factors ations in how researchers define their presence.83 Michele Crites Battié, Tapio Videman, and Douglas Gross Back pain problems, moreover, are identified through numer- ous different reporting systems, primarily health surveys and The high prevalence and social and economic impact of low back symptom complaints noted in clinical or workplace settings. pain and related disability are well recognized. Low back pain is In North America, for example, in contrast to some other indus- one of four musculoskeletal conditions specifically targeted by trialized countries, pain in the workplace becomes known or regi- the Bone and Joint Decade (2000-2010) initiative endorsed by the stered through the filing of an incident report or workers’ World Health Organization.15,106 Related to the workplace, back compensation claim, and back pain is labeled a “back injury.” injury claims comprise the most expensive category of industrial Taylor91 described a complex chain of events that leads to the injuries40,65 and are one of the most common causes of disability production of industrial insurance and sickness data and makes in adults under 45 years of age.24,90 In response to this problem, it clear that the occurrence of back pain incidents registered in many workplace programs and medical services have been the industrial setting cannot be equated to the occurrence of designed to prevent back problems or to minimize their negative morbidity. Failure to distinguish between studies of different consequences. Limited progress has been made, however, in alle- back-related outcomes such as spine pathology, back symptom viating this common condition and its consequences. complaints, industrial injury claims, absenteeism, and long-term disability may lead to misleading generalizations and inaccurate When the underlying condition and risk factors for an ailment conclusions. are understood, prevention and treatment strategies can be ration- ally based and well directed. In such situations, interventions are Along with different low back pain problem case definitions likely to be successful. Unfortunately, medical science still lacks themselves are the influences and potential biases of the systems information sufficient to guide the prevention and treatment of through which they are registered. An example of the potentially common back pain. Epidemiologic studies have sought to gain large effect of health system differences has been provided by information that could be helpful in guiding these efforts. Cherkin et al,23 who compared rates of back surgery in 11 devel- oped countries and examined the association between these rates Epidemiology generally refers to the study of occurrence rates and the number of neurologic and orthopedic surgeons per capita. of diseases and especially factors associated with disease occur- They found that the rate of back surgery was at least 40% greater rence or nonoccurrence. A primary goal of such studies is to in the United States than in any of the other countries investigated obtain information about the disease cause. However, challenges and more than four to five times that of England and Scotland. of the most basic nature have hindered epidemiologic studies of They also found that the rate of back surgery was positively corre- back problems. lated with the number of surgeons per capita (Fig. 4a.1). CHALLENGES FACING EPIDEMIOLOGIC Assessment of occupational and other STUDIES OF BACK PAIN PROBLEMS relevant exposures Definition of the problem In addition to the challenges posed by definitions, influences, and biases involved in back pain are the methodologic chal- A central challenge of epidemiologic studies of back pain prob- lenges of measuring occupational and other relevant exposures. lems is that in the vast majority of cases the underlying pathology Occupational exposures that appear frequently on lists of sus- or condition is unknown.29,89 Current clinical examination meth- pected risk factors are vehicular vibration and physical loading ods rarely identify the underlying pathology of either acute or involving heavy lifting, bending, twisting, and sustained nonneu- recurrent back pain in the absence of major trauma. Despite this tral postures. Virtually all inhabitants of developed countries are reality, there is a tendency to approach back pain as though exposed to these factors during leisure time and work. Exposure it were a specific disease or injury state. Miettinen and Caro67 is therefore a matter of degree and requires reliable valid methods cautioned that epidemiologic studies based solely on a com- of measurement. Unfortunately, practical tools to identify plaint have limited value and that inferences to pathology can be and quantify the different exposures in epidemiologic studies of misleading. A complaint is a voluntary behavior and as such can be large populations are not fully developed. Further complicating influenced by a variety of factors other than physical pathology. measurement is that for many outcomes such as structural changes Further problems encountered in studying any type of pain of the spine, data are needed on lifetime loading rather than sim- ply on current conditions. Most studies have used the job title as an indicator of occu- pational loading. This simple method of estimating occupational exposure can be highly inaccurate. The activities and environ- ments of persons with similar job titles can vary substantially, and the loading profiles of workers who remain in one occupa- tion for many years can change greatly. Moreover, most persons

98 Chapter 4a ● Epidemiology: incidence, prevalence, and risk factors 1.2 Back surgery rate 1 United States (as compared to the United States) 0.8 Netherlands 0.6 0.4 Denmark 0.2 Finland 0 Ontario Norway 0 South Australia New Zealand Manitoba Sweden England Scotland 10 20 30 40 50 60 70 80 90 100 110 Number of orthopaedic surgeons and neurosurgeons (per million people) Figure 4a.1 Relationship between the relative supply of orthopedic surgeons and neurosurgeons in a country and the country’s back surgery rate. (From Cherkin DC, Deyo RA, Loeser JD, Bush T, Waddell G: Spine 19:1201-1206, 1994.) hold several different types of jobs during their working years, such as frequency, intensity, and duration, yet adaptation to and their current positions may poorly reflect the physical load- loading, which is an expected result of regular exercise, receives ing experienced over their working lives. It has also been shown little attention in studies of occupational loading. It is often that workers in sedentary jobs tend to engage in more physically stated that one reason for disability is that work demands exceed loading leisure-time activities than do workers with physically the capacity of the worker. The level of physical demands over heavy jobs, which can confound attempts to investigate the effects prior months, however, is a primary determinant of individual of occupational loading.50 Conceptually, studies designed with capacity, which should include an adaptation of strength to rou- the aim of understanding the effects of physical loading on back tine daily work demands, as is the case with exercise training. pain problems should be assessing total loading exposures both within and outside the work environment. Such studies are very Yet perhaps the greatest challenge in studies of the association seldom performed. between workplace exposures and back pain incidents and “injury” claims in the developed countries of the world is the Identifying factors associated with risk can give clues about injury model commonly used to explain the presence of back causation, but an understanding of the basis for associations is pain. Under the injury model, occupational physical loading required to formulate optimal prevention strategies. Leino58 exposures are believed to be primarily responsible for damage to showed that greater exercise activity was associated with fewer the back and related pain. This belief naturally leads to greater back symptom reports and back findings, for example, and attribution of symptoms to occupational exposures as workers Videman et al95 found that former elite athletes had significantly search for possible causes of their problem. Attributing back pain fewer back pain complaints than did nonathletes. If exercise has to work activities may be further enhanced within a workers’ a protective effect and decreases the risk of back symptoms or compensation system that offers clear benefits to causation lying spine pathology, then exercise participation could be expected to with work. These inherent problems to studying back pain report- help prevent back pain. Exercise is also a marker for other healthy ing in the workplace and its association with work activities life-style behaviors, as well as higher education, higher life satis- greatly complicate, and in some cases may invalidate, study find- faction, and lower occupational physical demands and psychoso- ings and their interpretation. cial problems,85 all of which can affect back pain reporting. Because physical loading from certain forms of exercise and sports can Causation versus exacerbation increase spine pathology, exercise itself may not be directly benefi- cial and may even have some harmful effects on the spine, so that Another unresolved issue is that of back pain causation versus the apparent benefits are produced instead by factors not associ- exacerbation. Certain occupational exposures, like heavy materi- ated with exercise. If this were the case and exercise were only a risk als handling in bent and twisted postures, awkward sustained indicator, exercise without other changes in life-style would be postures, or other forms of physical loading, play a role in the unlikely to decrease back troubles. Before interventions are conditions underlying back symptoms that is not well under- planned, it would be important to sort out whether exercise is a stood. Whether physical loading contributes to the pathology beneficial factor or only an indicator of “healthier” life conditions. underlying common back pain or simply exacerbates symptoms from an already present underlying condition is a matter of An odd paradox exists in perceptions of the effects of physical current controversy. loading at work and at leisure. Physical loading associated with work and with leisure or sport activity share many dimensions

Chapter 4a ● Incidence and prevalence 99 Some evidence suggests that routine physical loading expo- high estimates, whereas low back pain that is defined as pro- sures, such as seen in occupations with heavy physical demands, longed or disabling yield estimates toward the lower end of the may have a modest role in influencing underlying pathology and range. What is clear is that back pain problems are ubiquitous in a role in exacerbating such pathology. Videman et al99 controlled the general adult population. Work-related low back pain must be for spine pathology and found that a history of back symptoms viewed against this high baseline. Whether or not a back “injury” was correlated with physical loading. This finding supports the has occurred at the workplace, back pain among workers is com- belief that loading exacerbates symptoms from existing condi- mon, and many believe that their work is to blame. This is a tions. The same study found that annular tears were more com- natural and expected consequence of beliefs fostered by the monly found in subjects who engaged in occupations involving injury model that back pain problems are the result of structural heavy physical loading, which suggests that it can lead also to damage caused by physical demands. increased risk of some structural failures. The role of occupa- tional loading in degenerative changes and pathology, however, Further complicating the determination of occurrence rates is appears to be considerably less than previously thought. the recognition that back pain cannot be neatly categorized as acute or chronic. Instead, it is a fluctuating condition characterized INCIDENCE AND PREVALENCE by recurrences or exacerbations of varying severity and pain-free periods.103 In many cases an underlying condition appears to influ- As mentioned previously, there are no standard definitions for ence propensity for symptoms and occasional flare-ups loosely determining the presence or absence of back pain problems in related to a variety of individual and environmental factors. This the general population; instead, various definitions and methods recurrent variable nature of back pain within individuals com- for collecting such data are used. This leads to wide variations in monly leads to misclassification of the presence or absence of prevalence and incidence estimates. A systematic review of the contributing conditions and influences occurrence rates and scientific literature from 1966 to 1998 presenting data on the observed associations with suspected risk factors. prevalence of low back pain yielded point prevalence estimates from 12% to 33%, 1-year prevalence estimates from 22% to 65%, Also important to the incidence and prevalence of low back and lifetime prevalence estimates from 11% to 84%.102 Another pain reporting in the workplace are significant overall trends in review of the literature on low back pain prevalence estimated industrial injury reporting. The mix of industrial injury claims has the point prevalence specifically in North America at 5.6%, but changed dramatically over past decades, with increasing domi- similarly broad ranges were noted in prevalence estimates as in nance of back and other ill-defined musculoskeletal complaints the aforementioned review.63 over traumatic accident-induced injuries. Ostry78 clearly depicted this trend in a summary of short-term work loss claims from 1952 These wide ranges are influenced by many factors, not the to 1996 in British Columbia. He presented the relative number least of which is the definition of low back pain used in terms of of claims attributable to strains, which includes the categories pain severity, duration, and associated disability. Responses to of back strain, overexertion, and other strains and sprains, as such questions as “Have you ever had low back pain?” result in compared with claims for impact (falls, slips, blows from objects, and so forth) and other miscellaneous injuries (Fig. 4a.2). During the years studied, a dramatic decline occurred in the proportion 900 800 Impact Strain 700 Miscellaneous 600 500 400 300 200 100 0 1952 1954 1956 1958 1960 1962 1964 1966 1968 1970 1972 1974 1976 1978 1980 1982 1984 1986 1988 1990 1992 1994 1996 Figure 4a.2 Proportion of strains, impacts, and miscellaneous injuries of accepted short-term time loss claims per year in British Columbia, 1952-1996. (With permission of the Canadian Public Health Association. From Ostry A: Can J Public Health 91:36-40, 2000.)

100 Chapter 4a ● Epidemiology: incidence, prevalence, and risk factors of impact injuries from over 80% of all injury claims in the late claims and 33% of all costs.104 Medical costs were overshadowed 1960s to slightly over 30% in 1996. Conversely, claims for strains by indemnity costs that represented nearly 66% of total claims rose from approximately 10% of all injury claims to 50%. costs. These figures are similar to those from other studies reported from the United States at around the same time88 and somewhat Overall, in recent years occupational injury and illness rates in lower than figures from Australia from the early 1990s.77 North America have shown a downward trend. The U.S. Survey of Occupational Injuries and Illnesses, generated by employer RISK FACTOR ASSOCIATIONS workplace incident logs, revealed a decline in nonfatal injuries in private industry from a high of 9.2 cases per 100 full-time workers Structural pathology and tissue injury in 1978 and 1979 to a low of 6.6 cases per 100 full-time workers in 1997, the last year for which data were analyzed.30 Similar trends Back pain is commonly used as a synonym for spinal illness or, were observed in Ontario, Canada from 1993 to 1998, where a in the case of the workplace, spinal injury, although it is obvious 29% reduction in lost-time compensation claims was seen.72 The that they are not the same and that the causal factors for the reasons for the decline are unclear. It has been speculated that it underlying pathology and reporting of back pain can be different. could be due to more effective prevention or treatment programs Some pain could originate from a metabolic disturbance such as that influenced incidence or time loss, greater reluctance by muscle fatigue, which could be expected to recover fully without employees or employers to report incidents, or changes in criteria remaining identifiable pathology. Physical loading exceeding the for the diagnosing of some of these conditions by health care tolerance of a structure produces a structural pathology with pain. providers.12 The reduction may be due also to shifts in dominant This true injury and other factors, such as severe degeneration or industries and more generalized economic, social, cultural, or leg- infections, could lead to irreversible pathologic conditions, the islative trends that have affected injury reporting. Of the approx- symptoms of which could be triggered by routine or “physio- imately 5.7 million injuries reported in 1997, representing 93% of logic loading.” all injuries and illnesses documented in employer records, how- ever, the category of “strains, sprains, and tears” accounted for a This could be one explanation for the result that previous his- disproportionately large share of cases with days away from tory of back pain is one of the most consistent predictors of later work. Nearly half of these involved the back.30 back pain.13 Commonly used “disability” scores estimate avoid- ance of defined functions due to back pain (the modifying effect Looking specifically at low back pain claims and associated of reported physical loading on pain). The correlations of under- disability and costs in North America, a downward trend has lying illness with sickness absenteeism, permanent disability been noted since the late 1980s. Using a large sample of claims pension, and use of health care due to back pain, however, are from the privately insured U.S. workers’ compensation market, generally low. Hashemi et al44 examined length of disability for low back pain claims and associated costs during the period of 1988 to 1996. As Clinical relevance of spine pathology in previous studies,88 the distribution in terms of disability and costs was highly skewed. Depending on the year, 4.6-8.8% of Studies of factors associated with the pathology of spinal struc- claims with a disability duration lasting over 1 year accounted tures have received relatively little attention, although the disk for 78-90% of the total disability days and 65-85% of the claims has been commonly thought to be responsible for most back costs. Over the study period from 1988 to 1996, the mean length symptoms and has been a primary target for diagnostic and ther- of disability decreased by 61%, whereas the mean and median apeutic interventions related to spinal disorders. Knowledge of cost per claim decreased by 41% and 20% respectively, suggesting the macropathoanatomy and micropathoanatomy of the spine that the most influential changes occurred through a reduction is consequently limited with respect to painful conditions. in long-term disability claims. Concurrently, a 34% decrease in For example, we do not know the clinical value of osteophytes, the annual low back pain claim rate was reported in the United disk space narrowing, disk bulges, end-plate changes, interverte- States from Bureau of Labor and Statistics data between 1987 bral foramina and spinal canal anthropometry, or facet joint and 1995, although it was noted that the trend was not monoto- degeneration. In the past decade even our understanding of the nic. There was a sharper decrease in costs, one of 58%. Yet in clinical relevance of disk herniation and annular ruptures has 1995 the rate of low back claims in the United States was 1.8 per changed. 100 employees, still representing a major health problem in the workers’ compensation system.71 Some studies have shown an association between disk pathol- ogy and back pain reporting, but degenerative findings are also These changes in back incident and claims rates seem to be a common among asymptomatic subjects.14,16,99,105 Certain mecha- part of the larger trend for declines in all work-related injury and nisms have been suggested to explain associations between disk illness reporting. In Washington state, for example, there was a pathology and back pain. Full annular ruptures reaching inner- decrease of approximately 24% in the incidence rate of back vated disk structures could be associated with back pain through claims from 1989 to 1996 and a similar decrease of 27% in all several mechanisms. Annular tearing can lead to disk herniation claims during the same period.44 Although a significant variation with nerve compression, has been shown to produce pain by bio- exists among industry sectors, Yamamoto107 reported a trend for chemical effects, and is the pathology allowing nerve ingrowth a decline in the number of recognized occupational low back into the disk.5,33,34,76 Disk degeneration could make the disk pain cases in Japan as well. mechanically incompetent, allowing abnormal motion between neighboring disks and leading to pain in innervated structures in In a large study of over 730,000 claims initiated from 45 U.S. the functional unit.73 Several other structures in the spine, such states in 1989, available through a Liberty Mutual Insurance Company database, back-related claims constituted 16% of all

Chapter 4a ● Risk factor associations 101 as muscles and tendon insertions, are possible sources of back increased linearly from 0 to 72% between the ages of 39 and pain. The condition underlying most back pain remains 70 years.45 Although these findings relate to people and work unknown, however, and the structural changes mentioned are conditions around the turn of the century and the definition of currently of little clinical value. “spondylosis” is not clearly stated, the rapid linear increase is notable. In a review article, Miller et al68 reported a similar Hereditary influences on disk degeneration increase in grades II to III disk degeneration from 0% at age 20 to about 90% at age 70 years. The authors also concluded that There has been a dramatic paradigm shift over the past decade with radiographic data are corroborated by macroscopic findings. respect to determinants of disk degeneration and pathology. This shift is clearly depicted by the contrasting conclusions of two Frymoyer et al37 compared the radiographs of three groups of reviews on the topic of “degenerative disk disease” written a men between the ages of 18 and 55 years: men with no history decade apart. After an extensive review of the literature in 1992, of back pain, men with moderate back pain, and men with severe Frymoyer35 concluded, “Among the factors associated with its back pain. In these three groups the frequency of Schmorl’s nodes, occurrence are age, gender, occupation, cigarette smoking, and claw spurs, disk heights at the L3-L4 and LS-S1 levels, the disk exposure to vehicular vibration. The contribution of other factors vacuum sign, and transitional vertebrae were similar. The radi- such as height, weight, and genetics is less certain.” A decade later ographic findings that differed in the three groups were traction in 2002, Ala-Kokko1 concluded, “Even though several environ- spurs and/or disk space narrowing between L4 and L5, but these mental and constitutional risk factors have been implicated in this findings did not correlate with occupation, occupational lifting, disease, their effects are relatively minor, and recent family and or whole-body vibration. Specifically with respect to driving and twin studies have suggested that sciatica, disk herniation and disk associated whole-body vibration, findings have been somewhat degeneration may be explained to a large degree by genetic factors.” conflicting, but the current weight of evidence suggests no notable effect on disk degenerative findings. Arguably the most Traditionally, degeneration of the spine has been viewed as an well-controlled study to date on the subject did not find lumbar outcome of the accumulation of lifetime mechanical insults and disk degeneration or pathology to be associated with lifetime injuries imposed on normal aging changes. During the 1990s the driving.9 Riihimaki82 found that concrete reinforcement workers dominant effect of hereditary factors became clear, but the tradi- had a relative risk of 1.8 for disk “space narrowing as compared tional view still maintains wide support.1,35 The traditional view, with house painters and a relative risk of 1.6 for ‘spondylo- however, makes it difficult to explain the very high concordance phytes’.” They concluded that heavy physical work enhanced the in degenerative signs observed in lumbar spine magnetic reso- degenerative process in the lumbar spine. nance images in monozygotic twin pairs highly discordant for occupational exposures. In a study of determinants of disk An autopsy study of 86 subjects by Videman et al99 showed degeneration in 115 pairs of identical twins, occupational physi- that occupations that involved sitting, standing, and walking cal loading explained from 0 to 7% of the variance in disk degen- without heavy physical loading were associated with the eration in the lumbar spine and age (ranging from 35 to 70 years) least degeneration. Workers with heavy physical loading had below 10%, whereas the combined effect of genes and shared the highest incidence of annular ruptures, and sedentary environmental factors accounted for 30-60% of the total vari- work was associated with the highest degree of general disk ance in disk degeneration.11 The observed significant individual degeneration. differences at all ages in the degree of disk degeneration support a conclusion that there are crucial individual differences in pre- Studies using magnetic resonance imaging reported risks of disposition to this problem. Using a classic twin study, Sambrook 0.35 and 0.57 at the age of 20 years among asymptomatic and et al84 reported that heritability estimates explained 74% of the symptomatic subjects and 0.09 among asymptomatic subjects at variance of the “overall score of disk degeneration” of the lum- the age of 11 years.79,86 In addition, Boos et al17 demonstrated bar spine. The results from these twin studies suggest that heredity histologically verified annular tears in a group of subjects aged has a dominant role in disk degeneration compared with the 11-16 years and endplate cartilage pathology among 3 to 10 year importance of all commonly suspected adulthood exposures. The olds. The adjusted disk signal intensity reflecting the water con- role of genetics has been confirmed additionally in several studies tent of nucleus pulposus has been shown to change rapidly in identifying gene forms associated with disk degeneration.4,51-53,97 early years between the ages of 9 and 77 years.68,98 Obviously, It is likely that more genes associated with disk degeneration and degeneration begins before individuals are exposed to workplace symptoms will be found over the coming years, enhancing our factors. All adults have disk degeneration, and only the degree of chances to investigate so-called gene-environment interactions spine degeneration varies. That degenerative changes are present and leading to better understanding of the etiopathogenesis of already in childhood further underlines our limited understand- disk degeneration. ing of the etiology of spinal degeneration. Occupational and other influences on disk Many researchers have studied spine degeneration based on degeneration radiography, which provides good measures of disk space nar- rowing and annular insertions to vertebrae (osteophytes), Most epidemiologic studies in the area of common spinal disor- although its overall relevance for the intervertebral disk is not ders have been of back symptoms, and the literature related to clear. A study of more than 15,000 adults did not show that heavy the epidemiology of spine pathology is limited. In an excep- work was associated with spine degeneration in radiographs, tional study of musculoskeletal findings based on 1000 consecu- although men had more degenerative signs than women. tive autopsies, the occurrence rate of “spondylitis deformans” Lawrence56 reported that lumbar disk degeneration was most common in persons with physically heavy tasks compared with more sedentary workers, but only in men. Hult49 showed the

102 Chapter 4a ● Epidemiology: incidence, prevalence, and risk factors prevalence of disk degeneration to be nearly 100% by age 59 in with higher lifting strength requirements. They also found a workers with heavy physical work, and similar degenerative find- higher incidence of back pain reporting in persons who demon- ings were noted about 10 years later among those engaged in strated less strength on isometric strength testing than that light work. Interestingly, however, important differences between deemed necessary to meet job demands, as compared with those the groups with heavy and light physical work were observed at whose strength met or exceeded demands, although the associa- baseline, and firm conclusions about the relative role of occupa- tion was not statistically significant. Limitations of this study were tional physical loading on disk degeneration cannot be made. that only 25 low back incidents were reported and controls for Conflicting findings in the scientific literature and failure to iden- other factors influencing back pain reports were not undertaken. tify a dose-response relationship have not led to a convincing demonstration of the primacy of workplace factors in causing Cady et al19 later reported on physical fitness as an indicator anatomic abnormalities.10,96 of risk in 1652 firefighters over a 3-year period. Fitness was defined by a composite score based on aerobic capacity, strength, SUMMARY and flexibility measures. They found that firefighters with low “fitness” levels were about nine times more likely to report a back In principle, the determinants of all degenerative processes are injury than those in the “most fit” group. The few injuries similar. A function of individual constitutional factors, including reported among the highly fit were the most serious, however, in genetics, they are modified by behaviors and extrinsic exposures. terms of cost. Again, the effects of age, previous back pain, and As studies progress in the area of spinal degeneration and struc- other potentially confounding factors were not reported, making tural variation, genetic influences appear to play a dominant interpretation of the results difficult. role. Occupational exposures, representing different loading con- ditions, alone appear to have only modest affects on disk degen- Isokinetic lifting strength was investigated as a predictor of eration and pathology. Virtually all humans are exposed to the low back injury claims among nurses in a study by Mostardi types of physical activities that have been suspected of accelerat- et al,70 who concluded that lifting strength was a poor predictor ing lumbar degeneration during either work or leisure, with expo- of subsequent back symptoms and injury reports. Another prospec- sure being simply a matter of degree. Their influences vary due to tive study of back injury reports in nurses reported by Ready recovery times, adaptation level, and stage of degeneration, among et al81 reached similar conclusions about isometric lifting strength other factors. It is likely also that there are as yet unknown fac- and other general fitness parameters. The factors that discrimi- tors contributing to degeneration. In the end, both environmen- nated most between the nurses who did and did not report sub- tal and constitutional factors have some role in all degeneration, sequent back injuries were previous receipt of compensation, and only their relative magnitudes vary.21 smoking status, and poorer job satisfaction. Work-related back pain reporting In the Boeing study, a prospective cohort study of industrial back pain complaints in 3020 aircraft manufacturing workers, Industrial back “injury” incident reports and claims filing involve isometric lifting strength, maximal aerobic capacity, and lumbar specific definitions of back problems to be distinguished from range of motion were among the factors that were not associated structural pathology, symptom complaints solicited on surveys, with subsequent complaints. Other than having had current or or problems identified through health care visits. Most developed recent back problems at the onset of the study, the strongest pre- countries have systems for filing complaints of work-related injuries dictors of future back pain reports were negative perceptions of and illnesses with their own sets of rules, costs, and benefits. In dis- the workplace, including low job task enjoyment and social sup- cussing such systems in the United States, Hadler41 emphasized that port and emotional distress.13 The only factor from the baseline filing a complaint forces the person to conform to the workers’ physical examination that was strongly associated with future compensation paradigm. He stated, “By definition, work task reporting was back pain elicited on straight leg raise testing, description is causal. By inference, the illness is a manifestation which probably represents another aspect of recent or current back of major structural damage.” As we have discussed, both of these problems also known to influence future risk.7 Yet in multivariable assumptions are highly controversial. analysis, considering the numerous suspected risk factors under investigation, less than 10% of the variance in the reporting of We found 13 prospective longitudinal studies that investigated work-related back pain was explained. The study findings under- predictors of industrial back pain reports.13,19,22,31,38,46,48,55,69,70,81,83,93 line the multifaceted nature of back pain reporting in industry and Early studies focused largely on physical factors, whereas more the limited predictive ability of most suspected risk factors. recent research attempted to account for other factors influenc- ing back pain reports. A later extension of the Boeing study looked specifically at back incident reports that resulted in the formal filing of indus- Chaffin and Park22 performed some of the earliest prospective trial insurance claims. Lower job satisfaction and a poorer research in this area. In the early 1970s, they conducted a study of employee appraisal rating by the employee’s immediate supervi- back incident reports in 411 men and women who engaged in sor were associated with back injury claims. Given the findings manual lifting in their work at an electronics manufacturing com- of the earlier analysis of back incident reports, this result was not pany. The study focused on the effects of occupational lifting and surprising. A more notable finding of the later analysis was that mismatches between individual strength and job requirements. these psychosocial factors were similarly associated with They reported an association between low back pain and jobs non–back injury claims as well. It would appear that certain psy- chosocial factors may predispose to the filing of injury claims, but the study did not provide evidence of significant differences between those who filed back injury claims and those who filed other types of injury claims.9 Such findings caution against

Chapter 4a ● Summary 103 stereotyping persons who file back injury claims as being dis- of multiple prevention strategies stated, “The results concerning tinctly different from those filing other injury claims with respect prevention for subjects not seeking medical care are sobering. to “preinjury” psychosocial factors. As Leavitt57 stated, “The Only exercises provided sufficient evidence to conclude that unfortunate problem is that stereotypes have consequences. they are an effective preventive intervention.”60 Doubts raised by labels often shape evaluation and treatment of industrial workers in problematic ways, to the extent that their Subsequent disability integrity and status as patients is challenged.” Evidence suggests that back symptoms have always been present Since the Boeing study, researchers have continued to search to some degree among humans and likely always will be. for risk indicators and have expanded the investigation more Episodes of these symptoms are, however, typically manageable fully into multiple domains including the physical, social, and and relatively short-lived. A systematic review of the prognosis of psychologic. Numerous potential risk indicators, including expo- acute (<3 weeks) low back pain indicated that the prognosis of sure to repetitive trunk rotation, low supervisor support, and lack this condition is largely positive.80 Although back pain is a recur- of control over work duties, have been reported. Many of these ring phenomenon, most individuals recover from episodes indicators have been found through exploratory studies, how- quickly and experience little disability. The vast majority ever, and few results have been taken to the next crucial stage of (68-86%) of individuals off work due to back pain returns to confirmation or replication in a separate cohort. Exploratory work within 1 month, and further improvements are seen for up investigations have many inherent risks, including observing sta- to 3 months. In the small minority experiencing pain and dis- tistically significant associations by chance that do not actually ability for 3 consecutive months, however, little further improve- exist or are biologically implausible.2 More trust can be placed in ment in important clinical outcomes is seen. Although some findings that have been validated through confirmation studies. chronic back pain sufferers are able to cope with their pain and continue to work, a portion remains off work and experiences Although confirmation studies in this area of research are extended time loss.20 Within the workplace, it has been reported rare, six indicators have been reported in multiple studies to that approximately 10% of back injury claimants with extended increase the probability of future back pain reports: low job sat- work loss account for approximately 10% of back-related indus- isfaction,13,48,55,81,83 heavy physical work requirements,31,38,55,69 trial insurance costs.88 Long-term disability is therefore the out- low social support at work,13,93 previous low work performance come that poses the greatest threat to the individual and the ratings,13,55,93 smoking status,8,81,93 and previous history of low greatest cost to society. back problems.13,83,93 The magnitudes of each of these associa- tions have been relatively low, with odds or rate ratios typically Disability is typically represented in the work environment as ranging between 1.5 and 3.0 and accompanied by confidence absenteeism. An examination of factors associated with illness intervals approaching 1.0. It is clear also that individual worker absenteeism led Backenheimer6 to conclude that “absence strength levels do not predict future injury.7,69,70,81 Although the behavior is, in considerable measure, a cultural and social phe- above results have been substantiated in multiple investigations, nomenon.” He claimed also that “a biological frame of reference it is unknown whether the associations observed indicate causal is too narrow to explain the condition of being ill.” There is now relationships, especially regarding the psychosocial and physical a large body of evidence that these notions apply also to absen- indicators. Although theories abound for how both psychosocial teeism and disability from back problems. Great variability is and physical stressors could result in reports of back pain, it is observed in back pain disability and work loss durations among possible that indicators from within one domain influence indi- nations and disability systems that would not be expected if dis- cators within the other. It has been theorized that individuals ability were purely a biologic phenomenon.47,100 Long-term back with higher workloads may be more likely to have lower job satis- pain disability is a relatively new phenomenon in the history of faction.27 Alternatively, individuals under psychologic stress may Western civilization, and its dramatic growth since World War II be exposed to altered biomechanical forces through changes in suggests that factors other than physical pathology are influenc- posture or movement strategies.66 Further research is required to ing its development. This is not to say that many working people clarify the potential interactions arising between physical and do not genuinely experience back pain or that severe symptoms psychosocial indicators. One study in which interaction effects do not cause physical limitations of some duration. On the con- between predictor variables were studied found independent trary, numerous health surveys indicate that back symptoms are effects of both psychosocial and physical variables, possibly extremely common in both developed and Third World coun- indicative of unique effects for each.55 tries.3,75,101 What appears to have changed in many societies, how- ever, is the public perception of back pain as an “injury” or Although some work has been done to elucidate which medical problem and its effect on work life in terms of disability. factors are associated with industrial back pain reporting, the practical value of predictive models or preemployment screening One striking example of the tremendous growth in back pain for identifying specifically who will or will not experience or disability seen in many of the developed countries comes from report symptoms is questionable. The magnitude of associations the U.S. Social Security Disability Insurance System, where from for individual predictor variables and overall predictive accuracy 1957 to 1976 the incidence of disability awards increased by of created models has been relatively low, and practical difficul- approximately 270%, a rate 14 times that of the population ties arise when attempting to apply results from large samples growth (Fig. 4a.3).87 Similarly striking increases in the incidence to individual workers. Additionally, attempts at prevention of disability awards have occurred in Finland, Sweden, and based on knowledge of suspected risk factors such as workplace England.74 Although there is some evidence that the increasing ergonomic modification have been largely unsuccessful.26,64,94 In fact, authors of one systematic review evaluating the effectiveness

104 Chapter 4a ● Epidemiology: incidence, prevalence, and risk factors Figure 4a.3 Social Security Disability Insurance awards by diagnosis: percent increase from 1957 to 1976. (From Fordyce WE: Back pain, compensation, and public policy. In JC Rosen, LJ Solomon, eds: Prevention in health psychology. Hanover, NH, 1985, University Press of New England.) trends have leveled or reversed, disability associated with back level appeared to be greater on claim duration than on claim inci- pain remains widespread.71 dence. This suggests that a key issue for workers’ compensation systems to contend with may be determining an optimal wage Factors other than just the presence of back symptoms influ- replacement ratio. ence back symptom reporting and long-term disability. Multiple literature reviews have been published examining what factors are Inappropriate medical management has been implicated also related to prolonged disability or work loss.25,59,92 Consistently, a as a contributor to the growing disability problem. The rise in multifactorial model of disability incorporating factors from disability and increasing health care costs and utilization despite physical, social, psychologic, and occupational domains is advo- advances in medical technology led Frymoyer and Cats-Baril36 to cated. Of likely importance to the onset and persistence of dis- raise the question, “Have medical professionals of all types ability are cultural norms; socioeconomic conditions, including become part of the problem rather than part of the solution?” unemployment rates and opportunities for compensation; and Erroneous back pain beliefs of both health care professionals and physical and psychosocial work environments.25,54,59,101 Many the general public, including frequent suspicions of and investi- studies seeking to identify predictors of prolonged disability gations for major pathology and fear-avoidant beliefs in cases of have enrolled subjects already in subacute or chronic states, simple back pain, appear to influence back pain disability.61 In however, thus confounding results and reducing generalizability regards to the desynchrony between current evidence-based to more acute cases. The authors of a systematic review of acute treatment guidelines and popular opinions, Deyo28 stated, “The back pain prognosis reported identifying only one study of high new back pain guidelines represent such a substantial shift from the methodologic quality that included a clinically relevant predic- traditional approach that the public will need to be re-educated.” tor.80 Clearly, further research is needed to accurately identify Indeed, a recent public reeducation attempt through a social acute back pain patients at risk of developing chronic conditions. marketing campaign in Victoria, Australia, which portrayed the positive prognosis of back pain and conveyed the importance of Compensation availability appears to affect the length of dis- staying active, was effective in altering beliefs and reducing work- ability in the case of both surgical intervention32,43 and conserva- related disability.18 tive care.39,42 However, Leavitt57 noted that most studies citing an association between compensation and back pain reporting and CONCLUSION AND IMPLICATIONS disability failed to take into account the effects of physical demands of the job; these can affect the outcome and differ sig- Back pain continues to be a major burden for developed coun- nificantly between compensation and noncompensation groups. tries. Since the earlier version of this chapter was written for the He attempted to disentangle the effects of these factors and first edition of this book, further epidemiologic studies have found that work-related back symptom reports were associated been undertaken in an attempt to understand the prevalent and with more time loss than were non–work-related back symptoms, costly condition of low back pain. Because they substantially even after controlling for the degree of physical job demands. In alter the conceptualization of occupational back pain, several addition, a related literature synthesis by Loeser et al62 concluded discoveries are particularly noteworthy. that when all other factors are held constant, the existing economic studies imply a positive relationship between the level First, lumbar spine degeneration, long considered a conse- of wage replacement benefits and both the incidence and duration quence of the accumulation of mechanical insults and injuries, of workers’ compensation claims. The relative effect of benefit