Orthopaedic Knowledge Home Study by R. Alexander

Chapter 66 Pediatric Spinal Deformity Daniel J. Sucato, MD B. Stephens Richards III, MD Idiopathic Scoliosis vertebral angle difference (RVAD) as described by Metha. If the rib overlaps the vertebral body at the apex Idiopathic scoliosis is the most common type of scoliosis of the curve (phase 2 rib), the curve is likely to progress, and, as its name implies, there is no known definitive whereas a phase 1 rib pattern (no overlap of the rib) re- etiology for this condition. It is defined as a lateral cur- quires measurement of the RVAD to assess for curve vature of the spine with a Cobb angle of 10° or greater progression. A patient with a phase 1 rib and an RVAD and axial plane rotation. The sagittal plane usually dem- greater than 20° has a significant risk for curve progres- onstrates hypokyphosis in the thoracic spine, junctional sion. Careful observation is warranted in patients with kyphosis between two structural curves, and segmental these curves, and treatment with an orthotic device is in- hypolordosis of the lumbar spine when a structural dicated for those curves that have shown progression or curve is present. Classification of idiopathic scoliosis is are greater than 30°. For the young patient with a large usually defined according to the age of the patient at curve or those patients who do not tolerate an orthotic the time of curve development as follows: infantile device, a Risser cast is appropriate to “loosen up” the (from birth to age 3 years), juvenile (from age 3 years to spine and allow for improved wear of the orthotic de- 10 years), and adolescent (from age 10 years to 18 vice. years). The age classifications, although somewhat arbi- trary, allow the surgeon to characterize curves and assist Surgical treatment should be delayed as long as pos- in treatment algorithms from the outset. sible, primarily because of the concern with creating a small chest and its detrimental effect on pulmonary func- Infantile Idiopathic Scoliosis tion. Although there are no definitive indications for sur- gical treatment, progression despite orthotic treatment Infantile idiopathic scoliosis is uncommon, and its etiol- or curves greater than 50° are generally accepted indica- ogy is not determined. However, patients who present tions. A variety of surgical treatment strategies have with this presumed diagnosis require more careful eval- been described, with the most predictable outcome re- uation because an underlying cause is more often found sulting from an anterior and posterior fusion. Posterior with infantile idiopathic scoliosis than juvenile and ado- instrumentation is generally recommended, and it is pos- lescent scoliosis. A recent multicenter study demon- sible in even small patients because of the newer and strated that 21.7% of patients who presented with infan- smaller instrumentations that are currently available. A tile idiopathic scoliosis measuring greater than or equal 5-year follow-up study of 13 patients demonstrated that to 20° had neural axis abnormalities, and 80% of these convex epiphysiodesis combined with a Luque trolley re- patients required neurosurgical intervention. The au- sulted in overall good results, and instrumented growth thors of this study recommended that an MRI scan be was 32% of what was expected. Newer instrumentation obtained at the time of presentation for any patient with using dual posterior rods and connectors in the middle presumed infantile idiopathic scoliosis whose curve of the construct to allow intermittent lengthenings have measures 20° or greater. demonstrated favorable early results. This approach ap- pears to limit the typically high complication rate ob- Infantile idiopathic scoliosis is the least common served in the traditional growing rod scenario. Longer type of idiopathic scoliosis. It is more commonly seen in follow-up is required for these patients. males when compared with juvenile or adolescent idio- pathic scoliosis (1:1 male to female ratio), and left Juvenile Idiopathic Scoliosis curves are more often reported. Juvenile idiopathic scoliosis occurs in patients between Spontaneous correction of infantile idiopathic scolio- the ages of 3 to 10 years; approximately 15% of all pa- sis may occur, and can be predicted based on the posi- tion of the rib relative to the vertebra and the rib- American Academy of Orthopaedic Surgeons 775

Pediatric Spinal Deformity Orthopaedic Knowledge Update 8 tients with idiopathic scoliosis have juvenile idiopathic present. The rate of progression in these curves is ap- scoliosis. Females are more commonly affected than proximately 1° per year. males, and this disparity increases with age. As with ado- lescent idiopathic scoliosis, right thoracic curves are Patients with adolescent idiopathic scoliosis should more common. have a complete and organized clinical evaluation to confirm the diagnosis, rule out neural axis abnormalities, The natural history of juvenile idiopathic scoliosis is and assist in determining treatment. A careful inspec- one of steady progression until age 10 years, when tion of the skin is necessary to rule out lesions such as curves generally progress fairly rapidly. Unlike infantile café-au-lait spots (neurofibromatosis) and cutaneous idiopathic scoliosis, 95% of all patients with juvenile id- manifestations of dysraphism. The extremities, especially iopathic scoliosis have progressive curves, whereas only the feet, should be inspected to ensure that no deformi- 5% resolve. The thoracic curves tend to progress more ties (cavovarus feet indicating neural axis abnormalities) commonly and require fusion more often. Curve pat- are present. Observation of gait (including heel and toe terns may change with extension of the primary curve walking) will allow the surgeon to obtain a general or a development of secondary structural curves. sense of the patient’s strength and coordination. The neurologic examination should include an assessment of As with those with infantile idiopathic scoliosis, pa- motor function in all muscle groups, a sensory examina- tients with juvenile idiopathic scoliosis should have MRI tion, and deep tendon reflexes. Abdominal reflexes that studies to evaluate the neural axis because of a 20% to are symmetric confirm a normal neural axis; when ab- 25% incidence of abnormalities. These abnormalities of- dominal reflexes are asymmetric, the surgeon should ob- ten require surgical treatment; therefore, it has been tain an MRI scan. Examination of the patient’s back in- recommended that MRI be done at the time of the ini- cludes an assessment of balance, trunk imbalance, waist tial evaluation. asymmetry, pelvic tilt, and limb-length discrepancy. Shoulder height differences are important, especially The nonsurgical treatment of juvenile idiopathic when deciding whether an upper thoracic curve requires scoliosis is similar to that for adolescent idiopathic scoli- fusion. The Adams forward bend test is performed to osis. Bracing is used to treat patients with curves that analyze axial plane deformity, which is an indication have progressed to 30° or for those with curves exceed- that the curve is structural. Asymmetric forward bend- ing 20° that have demonstrated 5° of progression. Surgi- ing of the patient or tenderness of the spine to palpation cal management is also similar to that for patients with may indicate a neural axis abnormality. adolescent idiopathic scoliosis, although the crankshaft phenomenon assumes greater importance in the skele- Initial radiographic examination should include PA tally immature patient. and lateral radiographs of the entire spine (lower cervi- cal spine down to the hips). The PA radiograph should Adolescent Idiopathic Scoliosis be used to evaluate the spine and determine the Cobb angle for all curves. Skeletal maturity should be assessed Adolescent idiopathic scoliosis is relatively common, using the Risser sign and the maturity of the triradiate with a reported incidence of 2% to 3% for curves be- cartilage (open or closed). The PA radiograph should al- tween 10° and 20°, and an incidence of 0.3% for curves ways be assessed to ensure that two pedicles are present greater than 30°. There is an equal incidence of smaller for each vertebra, no signs of congenital vertebra exist, curves among males and females, whereas the female to and that there is no evidence for other abnormalities male ratio of curves greater than 30° is 10:1. such as neurofibromatosis (penciling of the ribs, en- dosteal scalloping, or significantly wedged vertebra). An The natural history of adolescent idiopathic scoliosis assessment of spinal balance can be made by dropping a has been well studied, and it is generally accepted that C7 plumb line and comparing it with the center sacral curves progress in two scenarios: (1) continued spine vertical line. Structural characteristics of the proximal growth and (2) large curve magnitude despite the com- thoracic curve include T1 tilt, Cobb angle of greater pletion of spine growth. Continued spine growth is as- than 30°, Nash-Moe apical rotation of II or greater, and sessed using an array of both clinical and radiographic a transitional vertebra between the upper and middle parameters. Clinical parameters include female menar- thoracic curves of T6 or lower. Recently, the clavicle an- cheal status and height measurements performed at gle (the angle subtended by the intersection of a hori- each clinic visit to determine growth velocity. Peak zontal line and the line that is tangential to the highest growth velocity is approximately 10 cm per year and oc- points of each clavicle) has been shown to be the best curs just before the onset of menses in females. Radio- predictor of postoperative shoulder balance. The lateral graphic parameters that indicate skeletal immaturity in- radiograph can be used to assess sagittal balance, which clude an open triradiate cartilage, and a Risser grade 0 is variable, and to ensure that thoracic hypokyphosis is to 1. Following the completion of growth, curve progres- present. The rib heads of the thoracic curve should dem- sion is more likely for patients with thoracic curves ex- onstrate apical lordosis in patients with adolescent idio- ceeding 45° to 50° and thoracolumbar/lumbar curves ex- ceeding 40°, especially when coronal imbalance is 776 American Academy of Orthopaedic Surgeons

Orthopaedic Knowledge Update 8 Chapter 66 Pediatric Spinal Deformity pathic scoliosis, and its absence should warrant investi- fective in treating thoracolumbar/lumbar curves that gation of the neural axis with MRI. A recent study measure between 25° and 35°. demonstrated that 97% of patients with adolescent idio- pathic scoliosis and a normal MRI study had apical lor- Surgical Treatment dosis, whereas this sign was absent in 75% of patients with scoliosis and a syringomyelia. The presence of a Generally, the indications for surgical treatment of pa- spondylolysis and/or spondylolisthesis should always be tients with adolescent idiopathic scoliosis are thoracic evaluated at the lumbosacral junction and is present in curves greater than 45° in the skeletally immature pa- 1% to 2% of patients with adolescent idiopathic scolio- tient or greater than 50° in the skeletally mature pa- sis. Preoperative radiographic assessment should include tient. Because thoracolumbar/lumbar curves are more supine best-effort bend films to the right and left. likely to progress despite a smaller curve magnitude, surgical intervention is indicated for patients with MRI should not be used as a screening tool and is curves greater than 40° to 45°, especially when there is indicated when there is an atypical curve pattern, ab- significant rotation and/or translation. The first goal of sence of thoracic lordosis, atypical pain, neurologic ab- surgery is to prevent curve progression with spinal ar- normalities or foot deformities, or extremely rapid curve throdesis. The second goal of surgery is to safely im- progression. prove the three-dimensional deformity. Surgical plan- ning depends on the radiographic and clinical deformity The King-Moe classification has been traditionally present and the skeletal maturity of the patient. Fusion used for determining curve types in patients with ado- levels depend on the surgical approach used and a care- lescent idiopathic scoliosis. This is a five-part classifica- ful assessment of the radiographs and clinical deformity. tion that was developed to describe thoracic curve pat- The standard, more traditional posterior approach can terns to help guide the surgeon when implanting be used for all curve patterns, and it is best for double Harrington instrumentation. As with many orthopaedic or triple curves. The anterior approach is more com- classifications, it has fair interobserver and intraobserver monly used for thoracolumbar/lumbar curve patterns reliability. The newer classification system described by because removal of the disk assists in achieving im- Lenke and associates provides a more comprehensive provement in coronal plane deformity, and lumbar lor- evaluation of both the PA and lateral radiographs and dosis can be restored. The anterior approach can also be also uses best-effort supine bend films. The following used for thoracic curve patterns, especially when hy- three components are defined in this classification sys- pokyphosis is present. In this instance, correction is tem: curve types (1 through 6), lumbar modifiers (A, B, achieved with convex compression, which produces ky- or C), and thoracic kyphosis (negative, N = normal, or phosis. Use of anterior instrumentation requires close positive). Although more comprehensive, this classifica- attention to screw length and direction (in the vertebral tion system has 42 possible combinations and therefore body) because of the proximity of the aorta to the left introduces more complexity into the curve evaluations. side of the spine in patients with right thoracic scoliosis. When each of the three components were evaluated in- dividually, the reliability was similar to that of the King- For those undergoing posterior instrumentation and Moe classification. As with any classification system for fusion, an anterior diskectomy and fusion should also be adolescent idiopathic scoliosis, it should always be used performed in those who are skeletally immature (Risser in conjunction with a careful clinical evaluation of the grade 0 with open triradiate cartilage) and in those pa- patient. tients who have very large (> 80°) and stiff (< 50% flex- ibility index) curves. Nonsurgical treatment includes observation and management with an orthotic device. Observation is in- Advances in spinal instrumentation have improved dicated for any curve less than 45° in a skeletally mature the correction of scoliotic deformities. Studies have patient without significant clinical deformity. In the skel- demonstrated improvement and maintenance of defor- etally immature patient, observation of curves less than mity when pedicle screws are used in the thora- 25° is warranted. Bracing is used for the skeletally im- columbar/lumbar spine (Figure 1). The use of pedicle mature patient (Risser grades 0, 1, or 2) with a curve be- screws in the thoracic spine also improves curve correc- tween 30° and 45° or an initial curve between 20° and tion when compared with hooks, and initial reports 25° that has demonstrated 5° of progression. Although demonstrate safe placement (Figure 2). However, ana- numerous braces are available today, the Boston and tomic studies demonstrate that it may be challenging to Charleston braces are most commonly used. The Boston place thoracic pedicle screws, especially on the concav- brace can be used to treat all curve patterns. Successful ity of the curve, because of the narrow width of the treatment depends on the amount of time the brace is pedicle and the proximity of the aorta laterally and spi- worn, as was reported in a recent study in which a com- nal cord medially. Improvement in lateral and posterior pliance monitor was incorporated into the brace. The translation of the thoracic spine may not be significantly Charleston (nighttime) brace has been shown to be ef- improved when compared with segmental hook and American Academy of Orthopaedic Surgeons 777

Pediatric Spinal Deformity Orthopaedic Knowledge Update 8 Figure 1 Preoperative AP (A) and lateral (B) and 3-year postoperative AP (C) and lateral (D) radiographs of a 14-year-old girl who underwent posterior spinal fusion and instrumentation with a combination of hooks, sublaminar wires, and pedicle screw fixation. Restoration of coronal and sagittal balance is seen in the postoperative radiographs, with excellent correction of the lumbar curve. Figure 2 Preoperative (A and B) and 2-year postoperative (C and D) radiographs of a 14-year-old boy after posterior spinal fusion and instrumentation using pedicle screw fixation alone. wire fixation; however, the improvement in the ability to rior thoracoscopic release/fusion performed with the pa- correct axial rotation may prove to be its greatest ad- tient in the prone position is very effective and better vantage. Confirmation of screw placement is more diffi- tolerated when compared with a thoracoscopic release cult in the thoracic spine because radiographic visualiza- with the patient in the lateral position. Thoracoscopic tion is obscured by the ribs and soft tissues. The results instrumentation for single thoracic curves achieves cor- of using electromyographic stimulation of screws to con- rection comparable to open anterior or posterior instru- firm intrapedicle placement is not as reliable as lumbar mentation (Figure 3). Although less scarring provides screw stimulation. excellent cosmetic improvement, the duration of thora- coscopic surgery continues to be significantly longer The thoracoscopic approach to perform an anterior when compared with more conventional approaches. release appears as effective as open thoracotomy and has minimized the incisions required for anterior access Despite recent advancements in spinal instrumenta- to the spine. A recent study demonstrated that an ante- tion and techniques, the ultimate goal of surgical treat- 778 American Academy of Orthopaedic Surgeons

Orthopaedic Knowledge Update 8 Chapter 66 Pediatric Spinal Deformity Figure 3 Preoperative (A and B) and 3-year postoperative (C and D) radiographs of a 14-year-old girl after a thoracoscopic anterior spinal fusion and instrumentation. ment is to achieve solid fusion while minimizing compli- consistent, and comparable in reliability and validity to cations. Autogenous iliac crest bone continues to be the the Medical Outcomes Study Short Form-36 Health Sur- gold standard to promote fusion in adolescent idiopathic vey Questionnaire (SF-36). The Scoliosis Research scoliosis. Neurologic monitoring using somatosensory- Society-22 Patient Outcome Instrument (SRS-22) is evoked potentials and/or motor-evoked potentials is now shorter and more focused on health issues related to the standard of care. A 50% decrease in amplitude and/ scoliosis than is the SF-36. Following surgical treatment or an increase in latency of 10% are generally considered for adolescent idiopathic scoliosis, outcomes using the thresholds for concern for neurologic injury when assess- SRS-22 have shown significant improvement from the ing patients using somatosensory-evoked potentials. Crit- preoperative status in the domains of pain, general self- ical threshold values for motor-evoked potentials are not image, function from back condition, and level of activ- as clear and are dependent on the mode of stimulation. ity. Improvement in coronal Cobb angle correction does The Stagnara wake-up test, which is used when neurolog- not correlate with improved SRS-22 scores. ic injury is suspected, is the gold standard for neurologic assessment. Acute complications from the surgical treat- One study reported that minimum 20-year follow-up ment of adolescent idiopathic scoliosis are relatively rare. for patients who had posterior surgery with Harrington However, the need for revision following a posterior spi- instrumentation for idiopathic scoliosis demonstrated nal fusion can be as high as 19%, with revision for late- similar back function when these patients were com- onset surgical pain from prominent hardware occurring pared with an age-matched control group from the gen- in 8% of patients. Delayed infections can occur up to 3 to eral population. Those who underwent surgery had a 4 years postoperatively and can present as a small drain- greater likelihood of having back pain (78% versus ing wound or fluctuance, accompanied by low-grade fe- 58%) and lumbar pain (65% versus 47%). In a 50-year vers and a mildly elevated erythrocyte sedimentation follow-up study of untreated patients compared with a rate. Treatment consists of removal of the instrumenta- matched control group, the authors reported a greater tion and primary closure, followed by oral administration incidence of shortness of breath (22% versus 15%), of antibiotics. Intraoperative cultures usually grow Sta- which was associated with a Cobb angle of greater than phylococcus epidermidis or Propionibacterium acnes, an 80°. Despite a greater likelihood of chronic back pain organism that requires culture incubation up to 2 weeks. (61% versus 35%), patients with scoliosis were produc- tive and functioning at a high level. Scoliosis Research Society-22 Patient Outcome Congenital Spinal Deformities Instrument Congenital vertebral abnormalities lead to a variety of spinal deformities, including scoliosis, kyphosis, or a This health-related quality-of-life patient questionnaire combination of the two. Its cause remains unknown. Ge- was developed to correlate patients’ perceptions and netic abnormalities or any other traumatic or teratologic satisfaction with their scoliotic deformities. Studies have type of maternal insults during pregnancy are rarely Ki- shown this instrument to be simple to use, internally American Academy of Orthopaedic Surgeons 779

Pediatric Spinal Deformity Orthopaedic Knowledge Update 8 dentified in patients with congenital vertebral abnor- company unilateral segmentation defects on the concav- malities. Recently, congenital scoliosis has been docu- ity of the curve may adversely affect thoracic growth, re- mented in two monozygotic twins, a finding that sulting in severe limitations in pulmonary function and contradicts most of the findings in the congenital defor- growth. This rare condition is known as thoracic insuffi- mity literature. A potential increase in exposure to ciency syndrome, which is defined as the inability of the chemical fumes and carbon monoxide in mothers of thorax to support normal respiration or lung growth. children with congenital spine deformities has also been Left untreated, progressive deterioration occurs and can reported. result in death at an early age. Methods to expand the thoracic cage are being investigated, with the goals be- Spinal dysraphism, which includes numerous abnor- ing to provide an acute increase in the thoracic volume malities such as diastematomyelia, syringomyelia, diplo- with stabilization of any flail chest wall defects and to myelia, Arnold-Chiari malformations, intraspinal tumors, maintain these improvements as the patient grows. and tethering of the spinal cord, is consistently found in 30% to 40% of patients with congenital spinal deformi- In patients with severe congenital scoliosis, plain ra- ties. MRI, which best identifies these dysraphic abnor- diographs may not provide sufficient information re- malities, has been recently recommended for all patients garding vertebral abnormalities. Should surgical inter- with congenital spinal deformity as part of the initial vention be necessary, a CT scan with reformatted three- evaluation, even in the absence of clinical findings. The dimensional reconstruction provides excellent detail for mere presence of a potentially tethering intraspinal le- the understanding of the deformity. These reconstruc- sion may be sufficient reason for prophylactic surgical tions are extremely valuable in the preoperative plan- treatment to address the lesion before the development ning for severe deformities. MRI of the spine also must of any neural dysfunction. This approach, in the absence be done for all patients with congenital scoliosis who of neurologic findings, remains controversial. are undergoing surgical intervention to assess intracanal abnormalities (30% to 40% prevalence). Currently, re- Congenital Scoliosis formatted images from MRI can provide a clear picture of the canal contents despite the severe three- The variety of vertebral anomalies found in congenital dimensional deformity associated with some congenital scoliosis makes its natural history uncertain. The two ba- scoliosis patients. sic types, defects of vertebral formation and defects of vertebral segmentation, may occur separately or in com- Although bracing has no beneficial effect on congen- bination. In 80% of patients with congenital scoliosis, ital curves, it may help to control long flexible compen- the anomalies can be classified into one of the two satory curves below the congenital component. The pri- types. mary goal of surgical intervention is to stop further progression. Partial correction that can be obtained Defects of vertebral formation may be partial or safely is an added benefit. Even if the curves are rela- complete. True hemivertebrae result from the complete tively small (< 40°), once curve progression has been failure of formation on one side and cause the forma- confirmed, surgical intervention should be undertaken. tion of laterally based wedges consisting of half the ver- Surgery should be performed prior to the development tebral body, a single pedicle, and hemilamina. When of notable deformity, a concept different from that in id- present in the thoracic spine, hemivertebrae are usually iopathic scoliosis. Various surgical approaches are used accompanied by extra ribs. When located at the lum- depending on patient maturity, deformity location, and bosacral junction, a significant obliquity between the type of deformity. These approaches include anterior spine and pelvis can result and is usually accompanied and posterior convex hemiepiphysiodesis, anterior and above by a long compensatory scoliosis. This lumbosac- posterior spinal fusion, posterior fusion with or without ral deformity is best treated surgically (usually with instrumentation, hemivertebra excision, and spine os- hemivertebrectomy) at an early age before the compen- teotomies. Expansion thoracoplasty, a new approach to satory curve becomes fixed. surgery for congenital scoliosis, is indicated for very young patients who either have or will potentially have Defects of segmentation result in an osseous bridge thoracic insufficiency syndrome. It consists of lengthen- between two or more vertebrae, either unilaterally or ing the concave hemithorax with rib distraction by involving the entire segment. The combination of unilat- means of a prosthetic rib distractor (Figure 4). This re- eral failure of segmentation and contralateral hemiver- sults in increased growth of both the concave and con- tebra carries the worst prognosis in congenital scoliosis vex sides of the curve, thus allowing additional volume because it produces the most severe and rapidly pro- for growth of the underlying lungs. This technique, cur- gressive deformity. Curves of this kind located in the rently undergoing clinical trials, appears very promising. thoracolumbar spine can be expected to exceed 50° by the age of 2 years. Without treatment, patients with tho- In patients with severe congenital spinal deformities, racolumbar, midthoracic, or lumbar curves experience slow gradual correction has recently been reported to severe deformity at an early age. Rib fusions that ac- be successful in some individuals using preoperative 780 American Academy of Orthopaedic Surgeons

Orthopaedic Knowledge Update 8 Chapter 66 Pediatric Spinal Deformity Figure 4 A, Radiograph of a 4-month-old girl with congenital scoliosis, fused ribs, and a unilateral unsegmented bar. B, Radiograph of the same patient at age 11 years. After several expansion thoracoplasty procedures, the patient’s hemithorax is increased in size beyond that expected with no intervention. halo traction for 6 to 12 weeks. If this method is used, the two. In contrast to congenital scoliosis, failure of seg- very close monitoring for any neurologic change (numb- mentation in congenital kyphosis is less common and ness, tingling, and weakness) is essential. When partial produces much less deformity than failure of formation. correction is obtained or a plateau has been reached, In type 1 kyphosis, there is a partial (or complete) defi- the spine is stabilized by instrumentation and fusion. ciency of the vertebral body, but the posterior elements remain present. With growth, a relentless progression in Few patients with congenital scoliosis secondary to a the kyphosis occurs, leading to anterior impingement on hemivertebra need to have the hemivertebra excised. the spinal cord. When this type of deformity is diag- The main indication for hemivertebra excision is a fixed nosed, plans for surgical intervention should begin im- decompensation in a patient in whom adequate align- mediately because of the risk of neurologic deficits. ment cannot be achieved through other procedures (usually involving a hemivertebra of the fourth or fifth In type 2 kyphosis, the anterior portion of two or lumbar level). Although a combined anterior and poste- more adjacent vertebral bodies are fused, which leads to rior resection has been the standard procedure for a deformity that is less progressive, produces less defor- hemivertebra excision, several recent studies report suc- mity, and has a much lower risk of paraplegia than that cess with excision through a posterior approach only, seen in patients with type 1 kyphosis. with correction maintained using transpedicular instru- mentation. When imaging congenital kyphosis, MRI will pro- vide the clearest picture of the spinal cord and, in very Congenital Kyphosis young patients, the clearest picture of the vertebral bod- ies. Cord compression may be evident on MRI before Congenital kyphosis represents an abrupt posterior an- any clinical neurologic deficits. Three-dimensional imag- gulation of the spine resulting from a localized congeni- ing of the spine using CT scan reconstructions is useful tal malformation of one or more vertebrae. This defor- for the evaluation of the vertebral anomalies, especially mity is caused either by defects of formation (type 1), in the older child. Both tests should be obtained before defects of segmentation (type 2), or a combination of any surgical intervention. American Academy of Orthopaedic Surgeons 781

Pediatric Spinal Deformity Orthopaedic Knowledge Update 8 Because nonsurgical treatment has no beneficial ef- Patients usually present with pain localized to the fect on congenital kyphosis, the use of an orthotic de- low back that is usually aggravated by extension activi- vice is inappropriate. In patients with type 1 kyphosis, ties and relieved by rest. Radiation of the pain into the surgical intervention should be considered, even in the buttocks or posterior thighs is uncommon and a neuro- infant, with the primary goal being prevention of future logic deficit is rare. Unless the slippage is high grade, the paraplegia. If the deformity is recognized in patients back alignment appears normal and no localized tender- younger than age 3 to 5 years and before the kyphosis ness is present. Hamstring tightness may be present and exceeds 50°, simple posterior fusion without instrumen- can lead to a shortened stride length. In patients with a tation may be considered. A hyperextension cast is used high-grade slip, the buttocks may appear flattened, a postoperatively for 4 to 6 months followed by a thora- step-off may be palpable between the area of the unaf- columbosacral orthosis for another 6 months. This ap- fected lumbar spine and loose posterior elements, the proach may allow for some growth anteriorly in the ab- torso may appear short, and an olisthetic scoliosis may normal region of the spine, which, over time, may result be present. L5 or S1 nerve root compression symptoms in progressive improvement in the localized kyphosis. are rare. Alternatively, in patients with kyphosis that exceeds 50°, an anterior release with strut graft must accompany the Spondylolisthesis is always evident on an upright lat- posterior fusion. In the older child or the adult, com- eral radiograph of the lumbosacral junction, but spondy- bined anterior and posterior arthrodesis is mandatory. lolysis may be difficult to visualize. If suspicion of spondylolysis is high, oblique lumbar radiographs Rotatory Dislocation should demonstrate sclerosis, elongation, or a distinct defect in the pars interarticularis. If these radiographs Segmental spinal dysgenesis, congenital dislocation of are not conclusive, single photon emission CT may dem- the spine, and congenital vertebral displacement of the onstrate increased uptake in patients with recent spine are conditions that create the most severe local- spondylolysis or prefractured stressed regions, but may ized kyphosis of the spine and lead to a neurologic defi- be normal in patients with established spondylolysis. CT cit in 50% to 60% of patients. These conditions can be will definitively demonstrate the occult fracture that difficult to differentiate from one another. The deformi- may not be evident on oblique radiographs. MRI is not ties include severe kyphosis; anterior, posterior, or lat- needed for diagnosis. eral subluxation of the spine; and scoliosis in association with a severely stenotic spinal canal. The treatment re- The two most common types of spondylolysis seen quires combined anterior and posterior spinal fusion be- in children are isthmic and dysplastic spondylolysis. Isth- cause posterior fusion alone is insufficient to achieve mic spondylolysis is more common and represents a fa- solid arthrodesis in patients with these types of congeni- tigue fracture of the pars interarticularis. The dysplastic tal instabilities. Exploration and augmentation of the type occurs only at L5-S1 and results from congenital posterior fusion mass should be considered because of a dysplasia of the L5-S1 facet joints. Patients with this high occurrence of pseudarthrosis. No sudden correction type of spondylolysis have an elongated pars interarticu- should be attempted in older patients with severe angu- laris and are more prone to developing neurologic lar kyphosis and progressive neurologic deficit. Function symptoms and deformity during growth. must be favored over cosmetic appearance. Neurosurgi- cal decompression should be used only for patients with Traditionally, radiographic sagittal descriptions of a proven recent and progressive neurologic deficit. spondylolisthesis have involved the Meyerding classifi- cation (grades I through IV) and the slip angle. The Spondylolysis and Spondylolisthesis Meyerding classification measures the forward transla- tion of L5 on the sacrum. The slip angle measures the Spondylolysis is a defect of one or both of the pars in- sagittal rotation of L5 on the sacrum and reflects the lo- terarticularis in the posterior element of a lower lumbar calized kyphosis at this junction, increasing in higher- vertebra. Although it generally results from repetitive grade deformities (Meyerding grade IV or spondy- stress to the pars interarticularis, it can occur abruptly. loptosis). Pelvic incidence, a newer radiographic Seen in 4% to 6% of the general population, spondylo- measurement that assesses the sacral anatomy and its lysis has a predilection in those whose activities involve relationship to the pelvis and spine balance, appears to increased hyperextension of the lumbar spine. The con- be more predictive of spondylolisthesis progression. It dition primarily affects L5 (in 87% to 95% of patients) describes the obliquity of the sacrum to the pelvis and is and less frequently L4 (in up to 10%) and L3 (in up to measured on the lateral radiograph by the angle be- 3%). Spondylolisthesis represents a forward slippage of tween the line perpendicular to the middle of the sacral all or part of one vertebra on another and in children is plate and the line joining the middle of the sacral plate nearly always located between L5 and the sacrum. to the center of the acetabular axis (femoral heads) (Figure 5). This fixed angle is significantly larger in those patients with higher-grade deformities (when compared with those with low-grade slips and control 782 American Academy of Orthopaedic Surgeons

Orthopaedic Knowledge Update 8 Chapter 66 Pediatric Spinal Deformity subjects). Pelvic incidence has a strong correlation with Figure 5 Illustration showing how pelvic incidence in patients with spondylolisthesis the Meyerding classification; therefore, it may be used is determined by the angle between the line perpendicular to the middle of the sacral early to predict the ultimate severity of spondylolisthe- plate and the line joining the middle of the sacral plate to the center of the acetabular sis in early adolescence. axis. Pelvic incidence is significantly larger in patients with higher-grade deformities. The risk of progression in spondylolisthesis is great- and pedicle screws with hooks/rods over the lamina. est during the adolescent growth spurt, especially for When a patient with spondylolysis at L5-S1 or low- patients with dysplastic spondylolysis. Findings, such as a grade spondylolisthesis requires surgical treatment, a bi- vertical, dome-shaped sacrum, a trapezoidal L5, and a lateral posterolateral L5-S1 in situ fusion remains the kyphotic slip angle increase the risk for progression. gold standard, and it should be done early in patients with a dysplastic lesion because of the high propensity Asymptomatic patients with low-grade spondylolis- for progression. Patients with higher-grade spondylolis- thesis do not require treatment or activity restrictions. thesis may require fusion extending to L4. Postoperative Symptomatic patients will need to be counseled regard- brace immobilization may be used for comfort. These ing their disorder and temporarily curtail participation treatment options will successfully manage most adoles- in athletic activities. Ultimately, those participating in cent patients. high-risk sports are five times more likely to have an unfavorable clinical outcome. An acute spondylolysis Scheuermann’s Kyphosis may heal following the use of a thermoplastic lumbosac- ral orthosis worn full-time for 6 months, particularly if Scheuermann’s disease represents an exaggerated struc- the spondylolysis is unilateral. If the pars interarticularis tural kyphosis involving the thoracic spine. The primary defect is chronic, a brace can be used until the child is report of poor posture in the adolescent is commonly asymptomatic. Exercises that include hamstring stretch- accompanied by a dull, aching, midscapular, nonradiat- ing, pelvic tilts, and abdominal strengthening are begun ing discomfort. Physical examination demonstrates an when the patient is pain free. Athletic activities may increased, inflexible thoracic kyphosis, which is most ev- then be resumed with or without a low-profile antilor- ident during forward bending. A compensatory lumbar dotic brace. Should the symptoms recur after a return to hyperlordosis is common, but it remains debatable higher levels of activity, the following two options need whether this leads to an increased incidence of spondy- to be discussed: (1) discontinue the activity that pro- duces the symptoms or (2) proceed with surgical treat- ment to either repair the lytic defect or eliminate move- ment at the spondylolytic (or spondylolisthetic) segment by a single-level fusion. Surgical treatment options include repair of a spondylolytic defect, single-level (or two-level) fusions, and reduction of higher-grade spondylolisthesis defor- mities. The high-grade deformities are uncommon (1% of patients), yet much of the recent literature focuses on the treatment of these deformities. Options that have successfully been described in the recent literature in- clude partial reduction, decompression, and posterior lumbosacral fixation; additional anterior column sup- port; and even in situ posterolateral fusion followed by cast immobilization. Partial (or complete) reduction and instrumentation should be undertaken only by experi- enced spine surgeons (see chapter 45 for more in-depth information regarding the treatment of adult patients with spondylolisthesis). Direct repair of spondylolytic defects in patients without spondylolisthesis is usually reserved for those patients with defects at L4 or L3. Defects that occur at L5 can be effectively treated by single-level in situ L5-S1 fusion. If a direct repair is considered, preopera- tive MRI should be done to rule out adjacent disk pa- thology. A variety of techniques have been described, in- cluding screws across the pars defects, compression wires from transverse process to the spinous process, pedicle screws with wires around the spinous process, American Academy of Orthopaedic Surgeons 783

Pediatric Spinal Deformity Orthopaedic Knowledge Update 8 lolysis. Mild scoliosis is present in 15% of patients, but Danielsson A: Back pain and function 23 years after fu- the neurologic examination is almost always normal. sion for adolescent idiopathic scoliosis: A case control study. Part II. Spine 2003;28:E373-E383. Radiographic features of Scheuermann’s disease in- clude kyphosis exceeding 45°, with the apex usually in This is a study of 142 patients who had posterior spinal fu- the middle to lower thoracic spine. If the exaggerated sion and instrumentation using Harrington rods at a minimum kyphosis is mild, then other accompanying features 20-year follow-up; these patients were compared with 100 age- must be recognized to differentiate Scheuermann’s dis- and sex-matched control subjects. Patients with scoliosis had ease from postural kyphosis. These include anterior significantly more degenerative disk changes and lumbar pain wedging of three or more adjacent vertebrae in the api- than control subjects (65% versus 47%, respectively). How- cal region, end plate irregularities, and narrowing of disk ever, only 25% of patients who underwent fusion had daily spaces. Schmorl’s nodes (herniation of the disk into the pain, and there were no differences in back function or gen- vertebral end plate) are occasionally present. Hyperex- eral health-related quality of life. Patients who underwent fu- tension lateral radiographs are also helpful in differenti- sion also reported pain over their iliac crest incisions when it ating Scheuermann’s disease from postural kyphosis be- was made separately. cause the apical region in patients with Scheuermann’s disease will remain relatively inflexible. Preoperative Dobbs M, Lenke LG, Szymanski DA, et al: Prevalence MRI can be used to rule out disk herniation if neces- of neural axis abnormalities in patients with infantile id- sary. iopathic scoliosis. J Bone Joint Surg Am 2002;84:2230- 2234. Nonsurgical treatment consists of exercises and brac- ing. Although exercises can help alleviate thoracic and This multicenter study analyzed 46 consecutive patients lumbar discomfort, they will not result in improvement between 1992 and 2000 with infantile idiopathic scoliosis and a of the kyphosis. Bracing has been reported to be effec- curve magnitude greater than or equal to 20°. Ten of the 46 tive in improving moderate deformity, but lack of pa- patients (21%) had evidence of neural axis abnormalities on tient compliance is a primary limitation. MRI. Eight of these 10 patients had neurosurgical treatment of these abnormalities. Surgical indications include large deformities (> 70°), curve progression, persistent pain despite non- Kuklo TR, Lenke LG, Graham EJ, et al: Correlation of surgical treatment, and, most importantly, genuine cos- radiographic, clinical, and patient assessment of shoul- metic concerns of the patient. Over the past 15 years, der balance following fusion versus nonfusion of the anterior release followed by posterior instrumentation proximal thoracic curve in adolescent idiopathic scolio- and fusion has been most commonly used. However, re- sis. Spine 2002;27:2013-2020. cent reports documenting the success of posterior fusion alone, particularly with the use of threaded 4.8-mm In this retrospective review of 112 patients who underwent compression rods, may obviate the need for additional surgical treatment for a double thoracic curve pattern, the au- anterior surgery. Progressive localized kyphosis above thors evaluated T1 tilt, clavicle angle, coracoid height differ- or below the fusion can be avoided if the implant ex- ence, trapezius length, first rib-clavicle height difference, shoul- tends from the second thoracic vertebra proximally to der asymmetry as measured by soft-tissue shadows on one level beyond the first lordotic lumbar disk space in- radiographs, and the translation of the structural curves. They feriorly and if the correction is not excessive (> 50%). reported that the clavicle angle was the best preoperative pre- dictor of postoperative shoulder balance. Annotated Bibliography Lenke LG, Betz RR, Harms J, et al: Adolescent idio- Idiopathic Scoliosis pathic scoliosis: A new classification to determine extent of spinal arthrodesis. J Bone Joint Surg Am 2001;83: Asher M, Min Lai S, Burton D, Manna B: The reliability 1169-1181. and concurrent validity of the Scoliosis Research Society-22 patient questionnaire for idiopathic scoliosis. This study introduced the new scoliosis classification, Spine 2003;28:63-69. which includes the following three components: curve type, lumbar spine modifier, and a sagittal thoracic modifier. The Asher M, Min Lai S, Burton D, Manna B: Scoliosis Re- authors who developed the new system and seven randomly search Society-22 patient questionnaire: Responsiveness selected surgeons from the Scoliosis Research Society then to change associated with surgical treatment. Spine tested its reliability. The interobserver and intraobserver cap 2003;28:70-73. of values for the components of the classification were ana- lyzed and demonstrated good interobserver and intraobserver These two studies confirm the reliability and validity of reliability. the SRS-22 questionnaire when compared with the SF-36. The authors conclude that the SRS-22 is responsive to changes in Liljenqvist UR, Allkemper T, Hackenberg L, Link TM, the postoperative period. Steinbeck J, Halm HF: Analysis of vertebral morphol- ogy in idiopathic scoliosis with use of magnetic reso- 784 American Academy of Orthopaedic Surgeons

Orthopaedic Knowledge Update 8 Chapter 66 Pediatric Spinal Deformity nance imaging and multiplanar reconstruction. J Bone or juvenile idiopathic scoliosis. The authors concluded that Joint Surg Am 2002;84:359-368. convex epiphysiodesis together with Luque trolley instrumen- tation may slow down or improve progressive infantile or ju- The authors analyzed the morphology of the thoracic pedi- venile idiopathic curves. cles in 307 vertebrae using MRI in multiplanar reconstruction. Maximum intravertebral deformity at the apex of the curve Richards BS: Delayed infections following posterior spi- was noted, with transverse endosteal width of the apical pedi- nal instrumentation for the treatment of idiopathic cles between 2.3 to 3.2 mm on the concavity and 3.9 to 4.4 mm scoliosis. J Bone Joint Surg Am 1995;77:524-529. on the convexity. Ten patients (average age, 25 months) with delayed treat- Merola AA, Haher TR, Brkaric M, et al: A multi-center ment of deep wound infections were observed after undergo- study of the outcomes of the surgical treatment of ado- ing posterior instrumentation for adolescent idiopathic scolio- lescent idiopathic scoliosis using the Scoliosis Research sis. The authors reported that the patients usually had Society (SRS) Outcome Instrument. Spine 2002;27:2046- drainage from the wound, fluctuance, and mildly elevated 2051. erythrocyte sedimentation rates and were treated using instru- mentation removal, primary wound closure, and short-term This multicenter study measured outcomes following sur- administration of antibiotics. The authors also discuss the im- gical treatment of adolescent idiopathic scoliosis in 242 pa- portance of longer culture incubation to identify the infectious tients. Outcome categories included improvement from preop- organisms. erative pain, general self-image, function from back condition, and level of activity. Overall, the patients were satisfied with Richards BS, Sucato DJ, Konigsberg DE, Ouellet JA: the results of surgery. The authors concluded that preoperative Comparison of reliability between the Lenke and King pain is typically present in patients with adolescent idiopathic classification systems for adolescent idiopathic scoliosis scoliosis, and it improves significantly following surgical treat- using radiographs that were not premeasured. Spine ment. 2003;28:1148-1157. Newton PO, Betz R, Clements DH, et al: Anterior tho- Four surgeons analyzed 50 radiographs that had not been racoscopic instrumentation: A matched comparison to premeasured and assigned a classification using both the King anterior open instrumentation and posterior open in- and the Lenke classification. The intraobserver and interob- strumentation. 70th Annual Meeting Proceedings. Rose- server reliability of the King classification were 83.5% and mont, IL, American Academy of Orthopaedic Surgeons, 68.0%, respectively. These values were similar when only the 2003. Lenke curve types were analyzed; however, when the com- plete classifications were assigned (curve type, lumbar modi- This multicenter study compared three treatment ap- fier, and thoracic sagittal modifier), there was fair intraob- proaches (thoracoscopic, open anterior, and posterior) for pa- server and interobserver reliability (65.0% and 55.5%, tients with right thoracic curves. The radiographic and func- respectively). tional outcomes were similar for the three approaches; however, the patients who had thoracoscopic anterior instru- Sucato DJ, Duchene C: The position of the aorta rela- mentation and fusion had longer surgical times. tive to the spine: A comparison of patients with and without idiopathic scoliosis. J Bone Joint Surg Am 2003; Ouellet JA, LaPlaza J, Erickson M, Birch JG, Burke S, 85:1461-1469. Browne R: Sagittal plane deformity in the thoracic spine: A clue to the presence of syringomyelia as a Axial T1-weighted MRI scans of the thoracic and lumbar cause of scoliosis. Spine 2003;28:2147-2151. spine were compared for normal control subjects and patients with right idiopathic scoliosis. The aorta was positioned more Thirty patients with scoliosis and documented evidence of laterally and posteriorly to the vertebral bodies in patients syringomyelia were compared with 54 patients with adolescent with idiopathic scoliosis, which was in line with a well-placed idiopathic scoliosis and a normal MRI. The authors analyzed vertebral body screw and would be in jeopardy of a laterally the lateral radiographs for the presence or absence of Dickson misplaced left pedicle screw. apical lordosis. Apical lordosis was seen in 97% of patients with adolescent idiopathic scoliosis and normal MRI scan, Sucato DJ, Elerson E: A comparison between the prone whereas only 25% of patients with syringomyelia-associated and lateral position for performing a thoracoscopic an- scoliosis had apical lordosis. terior release and fusion for pediatric spinal deformity. Spine 2003;28:2176-2180. Pratt R, Webb JK, Burwell RG, Cummings SL: Luque trolley and convex epiphysiodesis in the management of The technique of an anterior thoracoscopic release using a infantile and juvenile idiopathic scoliosis. Spine 1999;24: regular endotracheal tube is described, with ventilation of 1538-1547. both lungs with lower tidal volumes. The patient is positioned prone. When compared with patients who underwent this pro- The authors reported 5-year follow-up of patients in whom cedure in the lateral position (double lumen endotracheal either a Luque trolley alone or a Luque trolley together with a tube for single-lung ventilation), the anesthesia preparation convex epiphysiodesis was used to treat progressive infantile American Academy of Orthopaedic Surgeons 785

Pediatric Spinal Deformity Orthopaedic Knowledge Update 8 time and the delay between the anterior and posterior proce- normal respiration or lung growth, which is caused by a rare dure were both shorter and there were fewer respiratory com- condition of multiple fused ribs and congenital scoliosis. plications (in 0 versus 14.8% of patients). Kim YJ, Otsuka NY, Flynn JM, et al: Surgical treatment Suk SI, Kim WJ, Lee SM, Kim JH, Chung ER: Thoracic of congenital kyphosis. Spine 2001;26:2251-2257. pedicle screw fixation in spinal deformities: Are they re- ally safe? Spine 2001;26:2049-2057. In this study, 26 patients were retrospectively reviewed. The authors found a low rate of pseudarthrosis even without This study analyzed 462 patients who had 4,604 thoracic routine augmentation of the fusion mass if instrumentation screws placed to treat spinal deformity. Neurologic complica- was used. They report that although gradual correction of ky- tions directly related to the screws occurred in four patients phosis occurs with growth in patients younger than 3 years of (0.8%), one of whom had transient paraparesis and three had age with type II and type III deformities after posterior fusion, dural tears. The authors concluded that thoracic pedicle screw it appears to be unpredictable. fixation is safe when treating spinal deformity. Klemme WR, Polly DW, Orchowske JR: Hemivertebral Weinstein SL, Dolan LA, Spratt KF, Peterson KK, excision for congenital scoliosis in very young children. Spoonamore MJ, Ponseti IV: Health and function of pa- J Pediatr Orthop 2001;21:761-764. tients with untreated idiopathic scoliosis. JAMA 2003; 289:559-567. Six children (average age, 19 months) underwent anterior- posterior hemivertebra excision. Correction was maintained In this prospective natural history study, 117 patients with with plaster immobilization for 3 months. The authors reported untreated scoliosis were compared with 62 age- and sex- that excellent improvements in the curves were obtained and matched control subjects. The minimum follow-up was 50 maintained at a minimum 2-year follow-up. years, and multiple parameters were evaluated. The probabil- ity of survival was similar between the two groups, however, McMaster MJ, Singh H: The surgical management of the incidence of shortness of breath and chronic back pain congenital kyphosis and kyphoscoliosis. Spine 2001;26: were greater in patients with scoliosis. 2146-2154. Congenital Spinal Deformities In this study, 65 patients with congenital kyphosis or ky- phoscoliosis were treated with spine arthrodesis. The authors Basu PS, Elsebaie H, Noordeen MH: Congenital spinal concluded that all patients with type I or type III congenital deformity: A comprehensive assessment at presentation. kyphosis or kyphoscoliosis should be treated using posterior Spine 2002;27:2255-2259. arthrodesis before age 5 years and before the kyphosis ex- ceeds 50°. If the kyphosis does not reduce to less than 50°, an A series of 126 consecutive patients with congenital spinal anterior release and arthrodesis using strut grafting is needed deformity were assessed for incidence of intraspinal anomaly. before posterior arthrodesis can be done. This incidence was found in 37% of patients (26% of patients had cardiac defects and 21% had urogenital anomalies). The Ruf M, Harms J: Hemivertebra resection by a posterior authors concluded that MRI and echocardiography should be approach: Innovative operative technique and first re- an essential part of the evaluation of patients with congenital sults. Spine 2002;27:1116-1123. spinal deformity. In this retrospective study, 21 consecutive patients with Campbell RM, Hell-Vocke AK: Growth of the thoracic congenital scoliosis were treated with hemivertebra resection spine in congenital scoliosis after expansion thoraco- using a posterior approach only with transpedicular instru- plasty. J Bone Joint Surg Am 2003;85:409-420. mentation. Early surgery is recommended to avert severe local deformities, to prevent secondary structural changes, and to Expansion thoracoplasty consists of osteotomizing fused avert extensive fusions. ribs on the concavity of the spine followed by expansion of the chest cage using a vertical, expandable prosthetic titanium rib Sink EL, Karol LA, Sanders J, et al: Efficacy of periop- implant. The authors reported that longitudinal growth of the erative halo-gravity traction in the treatment of severe spine was achieved using this technique, likely providing addi- scoliosis in children. J Pediatr Orthop 2001;21:519-524. tional volume for growth of the underlying lungs. Perioperative halo traction was used in 19 patients, includ- Campbell RM, Smith MD, Mayes TC, et al: The charac- ing those with congenital scoliosis. The technique improved bal- teristics of thoracic insufficiency syndrome associated ance and frontal and sagittal alignment. No neurologic compli- with fused ribs and congenital scoliosis. J Bone Joint cations occurred. Surg Am 2003;85-A:399-408. Sturm PF, Chung R, Bormze SR: Hemivertebra in This landmark article introduces and defines thoracic in- monozygotic twins. Spine 2001;26:1389-1391. sufficiency syndrome, the inability of the thorax to support This is a report on two monozygotic female twins with tho- racic hemivertebrae that led to scoliosis. 786 American Academy of Orthopaedic Surgeons

Orthopaedic Knowledge Update 8 Chapter 66 Pediatric Spinal Deformity Suh SW, Sarwark JF, Vora A, et al: Evaluating congeni- Papagelopoulos PJ, Klassen RA, Peterson HA, et al: tal spine deformities for intraspinal anomalies with mag- Surgical treatment of Scheuermann’s disease with seg- netic resonance imaging. J Pediatr Orthop 2001;21:525- mental compression instrumentation. Clin Orthop 2001; 531. 386:139-149. In this study, 41 children with congenital spinal deformities Twenty-one patients with kyphotic deformities of 50° or underwent MRI. Evidence of intraspinal anomalies were visi- greater underwent posterior compression instrumentation. ble for 31% of the patients, including tethered cord, syringo- Seven patients also had anterior release. The authors con- myelia, and diastematomyelia. The authors recommend MRI cluded that the use of the posterior procedure by itself pro- as part of the initial evaluation, even in the absence of clinical vided significant correction, thereby avoiding the development findings. of any secondary deformity in most patients. Spondylolysis and Spondylolisthesis Poolman RW, Been HD, Ubags LH: Clinical outcome and radiographic results after operative treatment of Grzegorzewski A, Kumar SJ: In situ posterolateral spine Scheuermann’s disease. Eur Spine J 2002;11:561-569. arthrodesis for grades III, IV, and V spondylolisthesis in children and adolescents. J Pediatr Orthop 2000;20:506- In this study, 23 patients underwent combined anterior and 511. posterior fusion of their kyphotic deformities. On extended follow-up, thoracic kyphosis significantly increased, which was This study reports on 21 patients who underwent in situ thought to be caused primarily by removal of the posterior im- posterolateral L4-S1 fusions to treat severe spondylolisthesis, plant. This occurred despite solid fusions being shown at the followed by pantaloon cast for 4 months. The authors report time of implant removal. Use of the SRS-22 questionnaire satisfactory results using this technique. showed only fair outcomes after surgical intervention, leading the authors to question the indications for surgery. Hanson DS, Bridwell KH, Rhee JM, Lenke LG: Corre- lation of pelvic incidence with low and high-grade isth- Stotts AK, Smith JT, Santora SD, et al: Measurement of mic spondylolisthesis. Spine 2002;27:2026-2029. spinal kyphosis: Implications for the management of Scheuermann’s kyphosis. Spine 2002;27:2143-2146. In this study, pelvic incidence, a fixed angle in an individ- ual, was reported to be significantly higher in patients with In this study, a broad range of intraobserver and interob- low-grade and high-grade isthmic spondylolisthesis when com- server differences occur in the measurement of thoracic ky- pared with control subjects and correlated significantly with phosis in patients with Scheuermann’s disease. the Meyerding grades of severity. Classic Bibliography Lenke LG, Bridwell KH: Evaluation and surgical treat- ment of high-grade isthmic dysplastic spondylolisthesis. Blount WP, Schmidt AC: The Milwaukee brace in the Instr Course Lect 2003;52:525-532. treatment of scoliosis. J Bone Joint Surg 1957;39:693. The authors reported that high-grade isthmic dysplastic Cook S, Asher M, Lai S-M, Shobe J: Reoperation after spondylolisthesis should be treated surgically with appropriate primary posterior instrumentation and fusion for idio- central and foraminal decompressions at the L5-S1 level, fol- pathic scoliosis: Toward defining later operative site lowed by lumbosacral fusion. Partial reduction (to improve pain of unknown cause. Spine 2000;25:463-468. the slip angle) provides less risk to the L5 nerve root than complete reduction. Anterior and posterior fusion at L5-S1 Metha MH: The rib-vertebra angle in the early diagnosis appears to provide the best long-term results. between resolving and progressive infantile scoliosis. J Bone Joint Surg Br 1972;54:230-243. Scheuermann’s Kyphosis Nachemson AL, Peterson L-E: Effectiveness of treat- Johnston CE, Sucato DJ, Elerson E: Correction of ado- ment with a brace in girls who have adolescent idio- lescent hyperkyphosis with posterior-only threaded rod pathic scoliosis: A prospective, controlled study based compression instrumentation. 38th Annual Scoliosis Re- on data from the Brace Study of the Scoliosis Research search Society Meeting Manual. Quebec, Canada, Scolio- Society. J Bone Joint Surg Am 1995;77:815-822. sis Research Society, 2003, p 121. Weinstein SL, Ponseti IV: Curve progression in idio- In this study, threaded 4.8-mm posterior compression rods pathic scoliosis. J Bone Joint Surg Am 1983;65:447-455. were used to treat 14 patients with thoracic kyphosis (average kyphosis, 78.6° preoperatively). Anterior release was not per- formed. Correction to 40° was maintained 2.5 years postopera- tively. The authors concluded that anterior spinal fusion is not necessary when kyphosis is corrected using this technique. American Academy of Orthopaedic Surgeons 787