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This scan shows annular tears and HIZ at posterior annulus of L45 and L5S1. The HIZ is likely to indicate a painful tear, can be confirmed on discography and visualized annuloplasty. Annular tears Image41 image42 Illustration of a Grade IV Annular tear. Annular tears can be graded per Adam's Classification. It can be visualized intradiscally and treated with bipolar Radiofrequency, laser, tissue sealants, and biologics that enhance tissue healing. Healing of a tear essentially depends on layers of annulus left to heal and depth of tear, blood supply and inflammatory response. An inflammatory membrane is identified in the epidural space containing granulation tissue and multiple nerves entering the disc through a grade V annular defect as seen from inside by an endoscope. Image 42 152

Image43 image44 Images above and below belong to a male 46, who had chronic back pain and with left sided occasional radiation. The severe back pain was due to trapped fragments in a chronic tear at L5S1. The chronic annular tear was demonstrated by discography at L5S1. Discography is integral part of the basic inside out technique used in treatment. Patient is an airline pilot and subsequent transforaminal access and surgery made him remain at work and not disqualified from work. Cimage45 Dilator seen over the posterior annular tear during access and subsequent treatment of annular tear. Removal of trapped fragments relieved patient. MRI non-conclusive in patient with annular tear and trapped fragments Image46 Image47 153

This sagittal MRI demonstrates two dark discs on T2 imaging, but does not show significant disc protrusion or the presence of an HIZ. It could be interpreted as \"normal.\" Positive discography and subsequent endoscopy identified a painful grade IV annular tear with trapped fragments. It also showed the inflammation at edge of the tear explaining pain generation. The annular tear is identified endoscopically and successfully treated with nuclectomy and thermal annuloplasty. Since the tear in this image indicates loss of multiple layers and expected to heal in 6-8 months. This duration may be shortened by use of PRF plug [unpublished data]. 2. Annular tear progressing to herniation 3. Image48 154

4. Image49 This MRI demonstrates an annular tear that progressed to in an eventual herniation. The patient had intermittent, but debilitating back pain at starting stage. Earlier definitive treatment of this condition with endoscopic discectomy would have mitigated the years of prolonged and debilitating symptoms. The patient progressed to herniation but without radiculopathy to start with. Back pain and sciatica later was constant. An extruded free fragment was found at surgery. Tears in annulus that are symptomatic are treated with visualized annuloplasty after cleaning of the tear. 155

Image50 image51 Cleaned tear and annuloplasty seen in images above. 156

Equipment The annular tear is treated with standard gore system, including needle, guide wire, dilator, cannula and various graspers. The cleaning of tear is done with help of hook. RF bipolar and laser may be used on edges of the tear. Use of curette is warranted if annular tear edges are collagenized, to clean and treat them. If collagenized it is more like debriding and freshening edges of the tear. Results Relief of Back pain in chronic nonhealing annular tear is very rewarding and a day care procedure. The post-operative healing of the annulus is a time- consuming process. Time frame varies as per the layers of annulus left to heal. The healing can be hastened by use of PRF plug.[unpublished data] Healing can be clinically monitored by using McKenzie for back and Gore sign for leg pain along recovery course. Advantages In patients with chronic debilitating back pain and non-conclusive standard images including MRI scans doing a discogram and endoscopy and visualize the nonhealing tear and treat by stitchless surgery under local anesthesia is a paradigm change in surgical philosophy. It is least invasive, precise, targeted way of treatment. Main advantages are precision diagnosis, predictable results, and least morbidity. In elderly age group with accompanying medical conditions procedure is possible without morbidity . Traditional thinking has not paid much attention to an annular tear, its healing and closure of the torn area. Since the tear may have a trapped 157

fragment healing may be prolonged and is associated with hardened annulus and collagenization of the edges. The portion of annulus that hardens also may undergo calcification or ossification thus making it into a osteophyte or a very hard to remove annulus. During surgery on the hard annulus we need to be cautious as the instruments may break if used improperly. We have thus seen an annular tear and its progression from leak, trapped fragments next would be a fragment herniating through the torn area. The DRG or nerve is primed by the cytokines inducing inflammation and mechanosensitivity that on mechanical compression results in more pain. If we follow the change in function of the relevant nerve over the life span of these changes it may be low back pain. Leg pain. Patchy leg pain. And summation of pain in time and space along lower limb. During recovery after intervention reversal in pain location and intensity order may be seen. If the change of collagenization and calcification or osteophyte formation is along lower or upper endplate of the disc space this can give claudication and is a target for treatment. 2.a Extraforaminal RT fragment removed from the patient. Image127 image128 158

Similar patient with left fragment. Image129 image130 Extraforaminal herniations involve the root coming from level above and so may have clinical presentation that is unusual. The fragments are seen to be collagenised and hard due to time taken in diagnosis and decision making.They are commonly diagnosed late. 159

2.b foraminal paracentral herniation A image131 B image132 C image133 160

**Patient presented with unilateral claudication, left foraminal paracentral herniation removed with full relief of the pain. C image134 Image135 Image136 161

Patient above presented with symptoms of bilateral claudication and had central herniation producing central stenosis. Central herniation removed by transforaminal access, and not midline posterior access. This was without stripping the multifidus muscle and weakening the annulus further. Sometimes a biportal access may help in central herniation. An annulectomy with medialization of annular access window is very helpful. Bendable hook and articulated graspers help in grabbing and removing the fragments. Common to see large central annular defect, that may take about 8-10 months to heal. This may present as lingering back pain during healing of annulus. 2c. Patient had unilateral radicular pain due to paracentral herniation. *image137 image138 2d.Central herniation seen in this patient was treated successfully. Annulus was very hard and collagenized. 162

Image139 image140 Upmigrated fragments: F. image141 163

Image142 Image143 Up migrated herniation was complicated due to severe medical co morbidities in this patient. The fragment is clearly seen going behind the body of L3. Patient was a high risk for anesthesia and was treated successfully with stitchless surgery under local anesthesia. Awake and Aware patient made surgery very safe. Access to area behind the body can be tricky. Up migrated fragment removal is easier than down migrated as we go in axilla and between roots that are live. In down migrated we may encounter the overhang of the facet and may need drilling of the facet undersurface or the lower pedicle to reach the fragment. Use of bendable hook most times over comes need for removal of bone. 164

HEAD 1 image144 fragment seen 2 image145 better view of the fragment. 3 Image146 165

4 Image147 5 Image148 6 Image149 166

7 Image150 8 Image151 9 167

Image152 Empty space behind L3 body and axilla seen after fragment removal. 10 Post aspect of body of L3 seen. . image153 Pink posterior aspect of the body of L3 11 168

Image154 12 Since lamina is less wide at L3 we can dock on the annulus very close to the midline and upper endplate at L34 disc. [lower endplate of L3 Body]. The access to fragment is possible without removal of bone. Image155 Totally decompressed epidural space and view through axilla of L3. Summary for up migrated cases: Search for the tear at upper end plate annulus junction. That will lead us to target. Using hook to mobilize and control over the irrigation will lead to proper hold and capture of the fragment. Awake aware surgery makes it safe. 169

Down migrated fragments G. image156 Image157 Large down migrated fragment at L5S1 is easy as entry for L5S1 is any way above crest and downwards directed. It may need under cutting of facet if hook is not effective. 170

H. image158 Image159 This shows a right sided periradicular fragment that was down migrated. Right S1 root is inflamed. Ablation, irrigation, excision and decompression helped in this patient. Use of hook to mobilize and free the root was mandatory. 171

2d ***Central HNP with large annular tear with subligamentous fragments Images160 161 162 163 172

164 165 Intraoperative PA and lateral discogram demonstrating a grade V annular tear. MRI seen again shows loss of concavity of the posterior annulus and a large central tear. 166 167 173

Annular defect is identified after removing the degenerative nucleus. The nerve and dura are protected by an intact PLL between the annular defect and epidural space, shielding the nerve. The tear can open and close with the patient's breathing or coughing during surgery. Note mildly inflamed disc annulus and blue stained nucleus material. Thermal modulation is done with a bipolar cautery to ablate the inflammatory and disc tissue and partially contract the hole in the annulus. After thermal modulation, a valve-like flap would open and close the hole. Discectomy specimen contained 4 grams of soft, degenerative nucleus pulposus. MRI scan showing altered outline of the disc especially posterior annulus is taken as an important sign for symptomatic patients.IN several patients the outline may remain unaltered but on relevant discography and in vivo visualization a more appropriate and precise solution can emerge. Surgery does not need general anesthesia, blood transfusion, or skin sutures. It is done under local anesthesia with conscious sedation. Only small adhesive skin strips are needed to close the skin. Any bleeding generally very minor, from the incision site will stop by the time the patient is becomes supine and then brought to the recovery room. 174

1. Discitis Image259 image260 Discitis is one of the best indications for transforaminal access and treatment. It has greater approach related surgical morbidity with the traditional median and even paramedian posterior approach, especially at 175

L5-S1. The pathology is most times localized to disc. Traditional empirical use of 6 or more weeks of IV antibiotics and rest with no active treatment and hoping for recovery is obsolete. We can enter the disc and drain and debride. The surgery is least morbid and can be done under local anesthesia with some conscious sedation. Caution: Disc annulus is extremely soft and extreme caution is warranted while entering and handling disc tissue, as accidental transgressing limits of disc is a distinct possibility. Use of copious amount of irrigation is mandatory. Large localized abscess can also be drained, and tissue diagnosis confirmed. Abscesses can be aspirated or removed, irrigated. Discitis can also be chemical in nature when it is seen as a flare up after surgery. The inflamed disc needs rest, local support for the back and prolonged use of anti-inflammatory medication. Clinically diagnosis and management is helped by routine use of ESR,CRP, pro calcitonin estimation and seeing a trend as time passes. Post-operative care: Pain normally subsides within a week or so. The patient can be mobilized with pain as guide. Use of lumbar support helps in mobilisation. In discitis the bacterial enzymes may be active to make a clean distinction at nucleus and annulus plane. This cleavage helps in total removal of infected avascular nucleus. 176

CHANGES IN POSTERIOR STRUCTURES: anterior or posterior facet capsule and ligamentum flavum. inflammation and mechanical compression: 1. Fact pain and denervation: Facet joints are formed by inferior articular process of upper and superior articular process of lower vertebra. This is a synovial joint. The lumbar facet joint is commonly at 45 to the coronal or sagittal plane. It undergoes 0 changes of degeneration. The posterior capsule and tissue and its inflammation and later hypertrophy is commonly associated with facet pain and is felt as paraspinal back pain. Facet joint is supplied by medial branch of dorsal ramus of same level along its lateral aspect and branch of level above on medial aspect so while treating facet nerve supply we need to address level same and above to cover both lateral and medial capsule. Degenerative Facet undergoes same changes as osteoarthrosis, where we have erosion of the cartilage and synovial hypertrophy. Some joints may have synovial effusion. In joints with micro instability cyst formation is seen. The cyst can be symptomatic depending on its location. It is common to see a cyst in foramen compressing DRG or dorsal root. The joint space is commonly around 2 mm. The appearance of facet in instability is larger joint space “open facet sign”. Facet pain sometimes is known to be referred to lower limbs. 177

Clinical presentation Facet related back pain manifests as pain felt paraspinally. It is well localized, sharp and always increases with extension 92 and rotation of the spine. Commonly it does not radiate. It may be associated with difficulty in extension after prolonged stooped posture or siting in flexion. Generally seen at age around 60 years. Commonly pain is bilateral. This pain may be treated by a facet and peri facet injection of anti- inflammatory or local anesthetic. This may mask pain substantially and for long duration. As non-fusion solution for further changes in facet; a denervation of the degenerated facet is possible. This is accomplished by accessing medial branch of dorsal ramus on the transverse process lateral to facet and ablating it under local anesthesia. The awake and aware patient can confirm a real-time change in pain location and intensity. Same GORE SYSTEM instruments can be used for facet denervation, RF cautery to ablate the nerve is main instrument, used at two levels and generally bilaterally so total 4 spots and stitchless and under local anesthesia. Image below shows needle placed over the likely location of the medial branch of dorsal ramus. Visualized denervation is preferred as MEDIAL branch of dorsal ramus may be under mammilo-accessory ligament inside a tunnel along upper cephalad border of the transverse process. 178

Image27 draw a artist impression image28 Images: Facet joint changes Image34 omit Pain referred from facet joints Image35 179

surgical philosophy The facet pain is diagnosed and treated by injections masking the pain. If the pain is severe and is the dominant cause of back pain initially an injection can be given at location of medial branch along the transverse process and lateral wall of pedicle junction.to confirm the source of pain. Once confirmed by more than 75% relief of pain denervation of the facet is done by ablating medial branch of dorsal ramus along the groove between the transverse process and the lateral wall of pedicle. The location of the nerve is constant but in some it may be covered by mammilo accessory ligament, so a visualized ablation is preferred as blind access may miss the nerve. Image shows the medial branch of dorsal ramus our anatomical target. 180

image36 The percutaneous access is at point of intersection of line bisecting the transverse process and the lateral pedicle line. Total surgery for one level facet pain generator will involve targeting 4 points namely L45 and L34 for L45 facet pain. Illustration below shows the target points for left L45 joint. 1 is at level of L45 orange line and 2 is at L34. 2 is shown by an arrow with blue head. image37 181

a. Cases Facet denervation case showing use of probe to mobilize the medial branch before it is ablated. Image38 b. Equipment for facet denervation Gore system Needle, guidewire, dilator cannula is used. The target is base of the transverse process, lateral wall of pedicle and the medial branch of dorsal ramus and reached under fluoroscopic guidance. After visualization the nerve, Use of RF cautery to ablate the nerve is recommended. Use of laser is also possible. To mark the nerve and make targeting easy any radio opaque and pigment dye can be used in first step of injection of local anesthetic. The dye is seen in images to spread along the nerve. In all surgeries scope remains same. Same camera light source is used. Shorter cannula is preferred. 182

c. Results 49 In our previous study reported , Patients having positive response to medial branch blocks with and without steroid were studied. 10 percent partially regressed at one-year follow-up, but none were worse. None requested, nor received repeat denervation in the first year. Pre- and post- op VAS score decreased from 6.2 to 2.5 and Oswestry scores decreased from 48 to 28. No patient was worse. Duration of pain relief lasted over one year in the two year follow up period with ablation of nerves near the transverse process lateral to the mammillary body. All were satisfied with their decision to have the surgery even if some of the initial relief began to fade with time. d. Advantages Advantages of facet denervation surgery in degenerated symptomatic facet joints is surgery under local anesthesia, stitchless, can be done as day care, does not involve fusion, can be done in aged patients with medical co morbidities, results can be forecast depending on relief with facet blocks, can be repeated and staged. Patient can know the relief almost immediately and there are no added morbid outcomes unlike open surgeries and fusion. It can also form a part of the hybrid surgery that includes decompression in foramen and transpedicular stabilization, where added negation of facet pain can relieve most of the relevant back pain immediately. Summary: nerve supply of posterior facet capsule and joint can be targeted for facet related back pain. Facet pain that is known to increase on extension. target is medial branch of dorsal ramus. 183

CHNAGES ON front OF THE FACET CAPSULE ETC. in foramen etc 2 Assessing claudication: Anterior capsule and soft tissue covering the joint may undergo changes of hypertrophy, and added calcification ossification, and together with hypertrophied ligamentum flavum cause symptoms of claudication by compression of the DRG and exiting or traversing root affecting its microcirculation. This symptom complex of claudication, inability to walk long distance or stand for a long time is seen in later age and can be very bothersome as quality of life is affected. Various assessment methods exist for diagnosis of severity of claudication. Neurogenic claudication outcome score has been proposed by Weiner et al. it includes following 1,2,3 Claudication commonly results from compression of the DRG and surrounding tissues by the unyielding walls of the canal in foraminal area. It can result over long term in neurological deficit. Affection of sacral roots may result in detrusor underactivity and should be assessed by post void urine residue estimation by ultrasound, uroflowmetry. Urodynamic studies may be needed for ruling out bladder neck obstructions or prostatic causes is important in male patients. Our threshold of PVR is 60 ml in a female and 100 in a male patient, where we counsel patient about likelihood of post- operative retention and need for long term catherization. US measurement of PVR is simple and noninvasive. Routine and unnecessary catheterization may be prevented, which may reduce incidence of urinary infection, and shorten hospital stay and reduce expenditures. 5-15 Claudication due to instability can be assessed by on dynamic images. Assessment instruments: 184

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We can also use FLS25 proposed as fukushima scale. 186

Pathology and imaging: The progression of degeneration leads to changes in facet joints getting inflamed, anterior facet capsular and soft tissue gets hypertrophied. This hypertrophy in medial and lateral aspect of facet is better appreciated by coronal oblique mri pics and is better tackled by transforaminal stitchless surgery under local anesthesia as we can directly 4 reach the target. The coronal oblique images in plane of the facet show the ligamentum flavum that directly causes symptoms, situated lateral to medial pedicle line. We go around the tip of sap from lateral to medial in canal and decompress the roof of DRG. Local anesthesia helps by making this solution safe and precise and available to medical compromised patients too. Anatomy On X-ray The structural change is mainly in upper part of the foramen in plane of the lamina and body. If we consider the 3 planes in coronal plane as under: plane between orange lines is PEDICLES, plane between orange and yellow is body lamina plane or foraminal plane[sagittal] and is important in stenosis, however between yellow and green is disc plane. Down pointing red arrow: red line is plane of facet where changes around anterior tip of sap may be causative of the symptoms. 187

image178 pedicles Stenosis plane Disc plane image179 pedicles Stenosis plane Disc plane 188

In the sagittal plane; plane between lower orange line and yellow line is the stenosis plane and is bound by body and lamina and is unyielding in stenosis. Normally the superior articular process [SAP] of the lower vertebra is below this plane. With collapse of a degenerated disc the SAP starts encroaching on the stenosis plane and create further compression of the nerve. This also may be associated with bulging of ligamentum flavum in inter laminar area. IT is very important to note that we have the MOBILE facet joint anterior surface in the lower corner of this stenosis plane and contributes to stenosis by tissue hypertrophy. This tissue may get calcified or ossified. It may have an osteophyte anteriorly over lower endplate of the cephalad vertebra. The bone never grows after age of skeletal maturity or hypertrophies. Bony hypertrophy is a misnomer and is used by traditional surgeons to justify their cutting the bone. In stenosis plane the real changes are occurring in oblique PLANE of the facet as marked by a RED line below image and not in disc plane. The MRI in cross section in plane of disc may be totally IRRELEVANT for understanding this change except changes along lower endplate level of cephalad vertebra where osteophytes are noted that may form over lower endplate of cephalad vertebra and push the traversing nerve dorsally and or exiting nerve against the pedicle above. 189

image180 Fallacy of the assessment above is the plane of imaging does not match the pathology plane of the facets. The red arrow points out how it should be. Changes around anterior surface of facet and in ligamentum flavum leads to stenosis and its symptoms of claudication. The lateral ligamentum flavum causes vascular compression and involvement around dorsal root ganglion. The dorsal root ganglion can get compressed from all sides due to unyielding walls of the canal [bony] and added fibrosed calcified annulus or hypertrophied anterior facet tissue. Imaging studies and concepts about these changes are not mature as of date. We need coronal oblique images to understand full impact of changes in ligamentum flavum mainly the lateral ligamentum flavum that is lateral to medial pedicle line. 190

image181 Brown border of the pedicle and superior articular process. Red line is lower border of upper vertebra, tip of SAP normally lies below red line. IN collapsed disc, SAP may over ride in upper foramen. Yellow is the exiting nerve and may have its drg in the foramen at L45, may be involved in claudication due to compression by unyielding walls of the root canal, hypertrophied tissue in upper foramen over tip of SAP, and extension movement of back bending of facet joint may allow the sap to compress the drg and root further. There could be annular change over lower endplate level of upper vertebra with osteophyte formation. This may further push the exiting as well as traversing nerve. 191

Image182 IN coronal view in MRI the yellow outline of superior articular process and pedicle that is circular is seen clearly. The tissue marked forms [dorsal] roof of the kambin’s triangle. Deroofing from ventral access is the key to relief in cases of lumbar canal stenosis. Dorsal deroofing as practiced by open midline access gives added instability begetting more surgery. Interlaminar decompression may be more of indirect decompression and may not reach the relevant area over DRG causing symptoms. 192

Coronal MRI pics can show the anatomy of ligamentum flavum well and the upward pushing tip of SAP towards the DRG. 193

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Image below is coronal oblique image for visualizing full extent of ligamentum flavum. This shows that ligament in its lateral part is attached to upper pedicle and forms part of the roof of the dorsal root ganglion. There is A DISTINCT SUBARTICULAR PORTION WHICH FORMS SIGNIFICANT PART. There is no evidence to say medial aspect of facet tissue is causing symptoms directly. Image183 The nerve root is always medial and inferior to the pedicle so lies below this portion of the ligamentum flavum. In adult human beings since bone can never grow after age of skeletal maturity all talk about “bony hypertrophy” is untenable. The soft tissue hypertrophy that may be calcified or part 195

ossified is present in and around roots giving symptoms of claudication in canal stenosis. Decompression of interlaminar portion of ligamentum flavum may be helping by indirect decompression of the dural sac and root in patients undergoing traditional decompression. It is almost impossible for a traditional surgeon to reach relevant part of the ligamentum as shown by blue arrow in image above as this is closer to foramen and dorsal root ganglion than interlaminar area. This is best accessed through foramen. Image184 Left hand is pedicle of L4 right is L5. Index finger left is inferior articular process of L4, right index is superior articular process of L5. Thumb of left is body posterior surface of L4 right thumb is body posterior surface of L5. Disc lies between both thumbs shown as brown IVD intervertebral disc. Facet is 196

shown as blue [inferior] and black outline [superior]. Tissue hypertrophy location is shown by a star in image above and below. Only movement in this facet and SAP area occurs as 1. Disc collapses and the SAP starts going cephalad crossing its normal level denoted by red line indicating the lower border of L4 and tip of SAP of L5. 2. SAP moves in flexion extension movement at facet and stimulation of soft tissue hypertrophy and further narrowing of the upper part of intervertebral foramen is likely with nerve compression. This partly explains increased claudication on extension of the spine. 3. There can be osteophytes at area denoted by left thumb nail. Image185 Cadaver specimen matching the illustration above. 197

 * Indicates a capsular and intra foraminal ligament. This needs special attention in decompression or clearance of the foramen in cases of stenosis. Image186 Specimen highlighting same capsular and facetal ligament. The blunt hook is under the facet and the spatula is in the facet joint Nerve lies in a groove under the pedicle just cephalad to the tip of the blunt hook. We have cut the specimen in sagittal plane at medial pedicle line so the anatomy when seen from medial aspect that is canal side shows our landing point during transforaminal surgery. It is easier to appreciate tip of hook in lower foramen, SAP tip not crossing lower border of upper vertebra, nerve 198

below pedicle, capsular and foraminal ligament and ligamentum flavum covering upper ventral aspect of the joint. 2A: IMAGE ANALYSIS in LUMBAR CANAL STENOSIS TRADITIONAL Foraminal and extraforaminal stenosis A thorough study of pre-operative imaging and attention to details of the anatomy and its alterations and altered physiology can help in extending application of our philosophy to canal stenosis. VENTRAL view of canal image213 In cases of lumbar canal stenosis L5–S1 level showing nerve root compression by the ligamentum flavum (LF) in the subarticular zone (black arrow with white line inside a blue demarcated area) and foraminal zone (solid black arrow). Legend: Dura dura mater, L5 L5 nerve root, S1 S1 nerve root, E extraforaminal zone, F foraminal zone, S subarticular zone, C central canal. LF is ligamentum flavum in the axilla as seen from ventral aspect in the 199