Microsoft Word - DR GORE SYSTEM book 2018 may

The tip is checked in AP and here it is lying exactly below the herniation [as visualized in MRI]. A cannula is now inserted over this dilator. IMPORTANT: The cannula always travels or glides over the dilator - it is never used alone. image110 image111 100

The beveled end of the cannula is seen here well. This open window at the end of the cannula helps in visualization of the dorsal structures inside the disc as the scope is 25 degrees. We are always looking up towards the posterior annulus, tear and fragment. The dorsal is taken as 12 o’clock. The cannula is pushed with the hand with small rotating movements over the dilator until we reach the annulus. The tapper is then threaded over the dilator and is used to tap the cannula inside the disc. The cannula is tapped until we reach the centre of the disc just below the posterior annulus in this patient. The tapping of the dilator and cannula is painful and in addition to use of lignocaine on annulus initially we ask the anesthetist to use sedation if needed at the stage of tapping. Image112 Image113 Image114 Image115 The open end of the cannula can be appreciated here in AP image lying just below the fragment ready to receive it. The tip of the cannula is seen in the lateral C arm image inside the disc in the posterior quadrant. Since we are sure about this lodgment of the cannula we can thus be sure of our targeting. 101

Up until now we have done surgery entirely under C arm images. The cannula is seen in the image below ready to receive the scope and at skin portal. Image116 image117 This shows ideal use of our set, the cannula is taking the scope inside, and the working channel accepts the grasper, which will aid the removal of the fragment. The image below is the first glimpse of base of the fragment. 12 o’clock is dorsal, 3 is towards the leg, 6 is ventral and 9 is towards the head. The axilla of the root is the 9 o’clock position. Image118 image119 The grasper is used to grab the fragment and remove it. The fragment is seen here. The procedure ends after doing tests of adequacy of the removal. Three important tests are: fragment is red at the tip due to epidural vascular reaction, it starts oozing through the tear so disc inside becomes red, and if we ask the patient who is awake to extend the spine, the normal pain that was present going down leg before surgery is relieved at this stage. Patient 102

may also cough and we check movement of free annular flaps and increased ooze with coughing. Image120 image121 The grasper inside the disc as is seen in the AP image is well appreciated as it is just below the fragment base. The image below shows the length of incision, [markings on the instrument are 10 mm apart] is 8 mm. This is minimally invasive transforaminal targeted fragmentectomy by stitchless access under local anesthesia. The skin is taped. Procedure is over. The patient is relieved of pain in real time without cutting any bone that may destabilize the spine and use of hardware. Image122 Image123 Image124 Before we close we use a platelet rich fibrin plug as shown image 123 to plug the original annular tear and the new opening in the annulus done for access, it is prepared from 15 cc of blood from patient with 10 minutes of centrifugation and 10 more minutes settling time. Our results have 103

been published and we get a better post-operative pain relief and less or almost nil recurrence as the annular openings are plugged by our Der1 plug. [*DERVAN is name of place where we started using it first in Walawalkar hospital, by team led by Drs Kohli, Nadkarni and Gore]. Literature on biological treatment of disc is evolving. IT is beyond scope of this book 1-19 Image125 Above shows the assembly of scope, light cable, HD camera, irrigation sets and proper covering camera head with of plastic cover to prevent irrigation fluid falling on it that may fog the lens. Image126 omit 104

B3 Variations in ACCESS We have 2 variations in basic access. Basic access is an inside out [green line] 25-35-degree angle. Or can be called as disc first. 0 1.Far lateral [blue line] 10-20 approach that uses the ventral aspect of the superior articular process facet as a fulcrum, to angle the trajectory, or 2. Transforaminal access from an “outside in” [red line] with blind facet under cutting at the start with fluoroscopy guidance. May be called as facet first. Image265 105

The Red line represents the outside in access which cuts the undersurface of the facet to get to the herniation, especially in extruded fragments. The Green line is the standard transforaminal access proposed by Yeung and Gore. (we graze the facet surface). The Blue arrow will be representing extreme lateral access. It is flatter and may go under the intertransverse ligament plane. All will land at same place in safe triangle, targeting the fragment directly versus indirectly but since the trajectory is different, structures seen may be little different. In the red line access, we must cut the facet to see more of epidural structures. In the green line we land inside disc, and after finishing our job inside and visualizing annular tear, we can access epidural structures by cutting annulus, by changing trajectory by levering against the ventral facet or with foraminoplasty. The Blue line trajectory represents the extreme lateral access which shows more epidural structures even at start of surgery. The “outside in” access does target the intracanal fragment directly after cutting the facet blindly and is practiced by experienced surgeons. The far lateral access to the epidural space targets the disc fragment directly. It is safer to visualize and enter the foramen and disc first under endoscopic visualization by inside out technique. Both these variations have evolved from the basic inside out technique. In outside in epidural bleed is a likely dampener and far lateral we need to cautious about ventral relations of the foramen namely lumbar plexus, those are motor roots and patient may not get pain on handling but land in motor deficit. Standardized inside out technique was first published by Yeung and Gore in 2001.Simultaneous change in understanding of the pain generators, pain 106

mechanism and pain carriers led to an evolution of philosophy from a general decompression to a refined “selective” decompression, ablation, and irrigation at the site of inflammation and compression. Yeung and gore have further published in 2011 about in vivo visualization of pain generators in painful degenerative lumbar spine. C: Instruments in GORE SYSTEM Currently available equipment in addition to appropriate graspers includes high resolution rod lens operating endoscopes in gore system, beveled cannula, trephine, bipolar RF electrode, side firing Holmium-YAG laser, and a diamond burr. Each tool has a unique role in performing special surgical tasks. Addition of a hook and flexible curette which can extend reach to epidural area and migrated fragments; makes removal of those fragments easier and possible at times without removal of bone. Image168 107

The gore system comprises of following instruments and they are essential to execute a dependable certain surgery for the back and leg pain. The equipment consists of Ca: Access to foramen equipment The access to foramen needs a 18g 25cm needle, a 41-cm guide wire, a 7- mm dilator, and a 7.6 mm cannula. Image169 Image170 108

The size of instruments has been specially matched for height and built of average patients. For large frame patients, this can work well. This is supplemented by mallet and tapper to introduce the dilator and cannula at proper level and position. The access equipment can be also used by traditional surgeons for foraminal access and isolating pain generators in hybrid surgery. Use of dilator can help in retracting the exiting nerve root and guard it during open facet removal in transforaminal lumbar interbody fusion surgery. [TLIF] Cb: Equipment for disc surgery The instruments needed for the disc surgery that involves targeting annular tear, accessing fragment that is herniated and migrated from D12 L1 to L5S1 and may be central, paracentral, foraminal and extraforaminal and migrated up or down; are graspers, forceps that open 90 degrees and mainly hook. Image171 109

Image172 image173 With advent of hook most migrated fragments can be mobilized accessed and removed without removal of bone. Graspers help in pushing and grabbing fragments needing removal. Judicious use of RF cautery helps in working on an annular tear or chronic non-healing tear and denervate it or 0 shrink it. 90 graspers help in working on firmer annulus and removal of fibrosed fragments. Image174 figure showing hook in plane between epidural space and annulus. 110

Image175 Figure showing hook teasing ligamentum flavum to expose nerve roots. Image176 Figure showing hook at work in epidural plane sweeping the floor. The hook changes approach to a migrated fragment, where we can access and remove the fragment without much removal of bone. It is multi directional in its work. The backbiter forceps change the basic surgical philosophy from push and grab to remove to grab and pull. This makes it easy to remove fragments. Image177 111

Cc: Instruments for canal stenosis surgery Canal stenosis needs an additional use of endoscope endochameleon to visualize different panorama in foramen and around tip of superior articular process. Canal stenosis gives symptoms due to hypertrophied tissue on and around the tip of superior articular process and on its medial and lateral surface. This tissue can be scraped by angled bendable curettes. We have a straight, left and right curette for the same. Endoscopic use of burr helps in removal of undersurface of the facet to improve the direct access and visualization of ligamentum flavum, epidural space and traversing root. Bendable graspers help around corners. Image239 The Addition of a curette helps in cutting the tip of SAP to expose hidden zone and deroof and decompress the DRG and axilla of the root in lateral canal. Once we have acknowledged the hypertrophy is of NONBONY tissue it is easy to appreciate that we just scrape it rather than excise or remove it by cutting bone. 112

Curette is seen on SAP [superior articular process] of the facet in fig. Image240 241 113

242 Curette under c arm seen working on SAP tip. Image243 Image244 114

D: Post op care after transforaminal interventions and Results Rest in bed upto 1 week. Or till soreness of back is present. Normally a 2 week rest is enough. Antibiotics are given for 3 days to 5 days as per age and medical condition. Oral and injectable anti-inflammatory may be needed for some days.If we do not leave behind any damaged devitalized tissue at end of surgery, then chance of discitis is low. Pre-and Post-op antibiotics may be considered for 24 hours and post op when patient morbidity dictates its use or when we are uncertain about asepsis and operative settings. A post-operative lumbar corset will make the patient feel more comfortable. The patient should be instructed to avoid bending, lifting, and twisting for 4- 6 weeks to allow the annulus to heal and to reduce the incidence of recurrent disc herniation from the foraminal access portal and from an annular defect of the disc herniation as well. Since we started using an annular plug incidence of recurrence has drastically reduced to almost nil. Physical therapy is helpful, but not required, but can be considered on an individual basis. Patients are instructed to use their pain as a guide after the 6-week period. Some patients return to work and limited activity as soon as one day after surgery. Post-operative delayed healing of annulus may give lingering back pain. Leg pain in post op period can be important concern, it is almost always inflammatory. This leg pain can be detected confirmed and treated by Gore sign and a distal block at ankle by use of sodium channel blockers, this is very effective. In patients recovering after foraminoplasty a preoperative counselling makes outcomes more acceptable. Preoperative counselling of patients in our set up has been very rewarding. 115

D1 Dysesthesia in transforaminal surgery and foraminoplasty As with any surgery, there are the usual risks of infection, nerve injury, dural tears, bleeding, and scar-tissue formation. Transient dysesthesia, the most common postoperative complaint, occurs in approximately 2-5% of cases, and is almost always transient. Its cause remains incompletely understood and may be related to nerve recovery, operating adjacent to the dorsal root ganglion of the exiting nerve, furcal nerves or a small hematoma adjacent to the ganglion of the exiting nerve, as it can occur days or even weeks after surgery. There are also anomalous nerve fibers in the annular tissue which may be furcal nerves or nerves growing into an inflammatory membrane in the foramen [not the traversing or exiting nerve]. May show up in the surgical specimen without permanent effect on the patient, but may cause temporary dysesthesia. Using blunt techniques to dilate the annular fibers has limited surgical morbidity but dysesthesia cannot be avoided completely. It can occur even when there were no adverse intraoperative events and in cases where the continuous electromyography (EMG) and somato-sensory evoked potentials (SEP) did not show any nerve irritation. The more severe dysesthetic symptoms are like a variant of complex regional pain syndrome, but usually less severe, and without the skin changes. Post-operative dysesthesia is treated with transforaminal epidurals, sympathetic blocks, and use of Gabapentin [generic] as much as 1800-3200 mg/day. Gabapentin is FDA-approved for post-herpetic neuralgia, but effective in the treatment of neuropathic pain. 116

E: Advantages of stitchless surgery for lumbar spine under local anesthesia: 1. Muscle trauma: Even with smaller incisions specimens of posterior access have extensive scar formation of the dorsal column muscles. Erector spinae muscles are affected and deep short oligo segmental muscles which account for proprioception and fine tuning of segmental mobility too are affected. These muscles are grossly denervated. In stitchless spine surgery under local anesthesia we do not cut or denervate any muscle. We only bluntly dilate. Image245 117

2. In the transcanal approach, resection of lamina, ligamentum flavum, and annulus is necessary to reach the herniation, thus potentially destabilizing the spinal segment. Even after reaching the herniation site, inside the disc is unseen and we can’t see residual fragments. IN cases of central disc herniation, it may very easy to target and remove a central herniated contained protrusion or fragment by transforaminal access staying inside the disc. 3. Annular tears come in all sizes and shapes. Granulation tissue in annular defects (tears) can be visualized and ablated and closed using a RF electrode. Endoscopy can successfully identify and treat painful annular tears and is much more effective than the blind but image guided techniques of IDET and variations of surgical disc decompression. Image246 118

Image247 Image248 In patients with multilevel disc affection discography can be useful to distinguish and identify the symptomatic target. Image249 119

4. Selective nerve root block and epidurography is a pre-surgical trial that provides prognostic information. The imaging information by the contrast pattern outlined at the surgical site will be anatomical input. A favorable response is correlated with longer term favorable results of foraminal decompression, nerve ablation and disc decompression. Conditions such as foraminal osteophytes tethering the nerve, and lateral recess stenosis are often underestimated by traditional imaging. Surgery of discectomy can be combined with foraminal superior articular process decompression and ablation, making it more likely that the surgeon will be able to remove the source of pain and succeed. Image250 120

5. The Holmium-YAG laser, in a straight fiber or a reflected 90 degree fiber has the unique ability to divide shrink, ablate, and cut collagenous tissue and vaporize bone under endoscopic vision. This is extremely useful when the available surgical space is very tight and limited eg: L5S1 space with stenosis. 6. The foraminal approach is more versatile than the posterior approach, the more cephalad the herniation level. From T-10 to L-2, the foraminal posterolateral approach offers the greatest and most flexible access to the lumbar disc without the need for laminectomy. Case of D12 L1 disc herniation, who presented with erectile dysfunction. He was treated successfully and recovered fully by end of 7 months. These patients normally are detected in their urological or andrological assessment and imaging. Image251 121

Image252 Image253 ABOVE is D12L1 case BELOW is L12. Upper lumbar disc surgery is easier as the lamina is less wide and covers less of the disc. 7. 122

Image254 Image255 image256 Image257 123

Image258 8. Paradoxical effect of nucleus pulposus removal and post-operative instability needs attention. Annular fenestration as dilation of the annulus to cutting out an annular window has been studied wrt recurrences. In open surgery, we remove the hernia at its weakest point during a transcanal approach, weakening the annulus further and making it more susceptible for a recurrent herniation. 124

9. Foraminoplasty: IN comparison to trans laminar decompression, there is less instability produced by foraminal decompression, as the articular surface area of the facet joints are preserved. More widening is achieved by transforaminal access in a case of stenotic lateral canal than by a medial facetectomy, which is known to add instability. 10. Transforaminal and translaminar endoscopy access inherently avoids excessive removal of ligamentum flavum in the interlaminar area. IT may be important to retain that barrier between dura and muscles in preventing scar formation. Newer studies about lateral ligamentum flavum favors it as main symptomatic portion in claudication. Since we land in foramen access to this portion is direct and simple. 11. Visualization has been touted as microscope being un-surpassed for visualization, emphasizing the 3-Dimensional capability of binocular vision, as the best visualized technique. For teaching purposes, the assistant can also see. With the new glass rod-lens endoscopes, however, it only requires side-by-side comparison of images to dispel the notion that visualization is inferior. While the microscope can give great visual detail, the endoscope can match the detail and with magnification as well. In a learning situation, the entire OR team can see what is happening on the video screen. 12. The advantage of the endoscope is the ability to place the lens and surgical instruments closer to the pathology, which requires less magnification for the same detail. The ability to manipulate the endoscope for viewing the pathology at slightly different angles and varied depths, the ability to manipulate normal and patho-anatomy, and the ability to 125

visualize the disc intradiscally as well as the foramen overcomes any concern about the lack of 3-Dimensional visualization. This happens in a awake and aware patient. Accomplished surgeons have also used the endoscope in all fields of surgery with no problems from the lack of 3- Dimension visualization namely laparoscopy and endourology. 13. When a surgeon limits his exposure, complications may arise because of unfamiliarity with the limited surgical view in both techniques and there is a learning curve. Once the learning barriers are overcome, however, surgeons who are competent in both techniques may prefer the posterolateral endoscopic disc surgery to microdiscectomy or micro-endo discectomy for selected herniations even though both approaches to the lumbar discs carry potential risk for injury or violation of blood vessels and spinal nerves. If we consider all these advantages stitchless surgery under local anesthesia through the foramen is a matter of choice by default. It can deliver better results with less of morbidity and complications. Whenever a discussion is centered on stitchless surgery under local anesthesia and micro discectomy traditionalists always bypass several issues. More precise diagnosis of pain generators, better correlation of image and symptoms, precise targeting of the pathology, possibility of doing surgery under local anesthesia and having patient awake and aware, surgery being stitchless, possibility of doing surgery to mitigate medical comorbidities, are inherent in transforaminal endoscopy. Even after ignoring these important advantages the discussion then only centers on decompression of nerve roots and approach related morbidity. The way 126

surgery is executed and why; is not given its due. The results being same or similar, it would be important to know how these results are achieved. It is not possible to ignore the morbidity with open surgery and limitation which medical comorbidities will have on choice of surgery. In patients with severe medical co morbidities only way we can offer pain relief is surgery under awake and aware status under local anesthesia. In studies, we should think of changed philosophy, clinical concerns, indications for surgery, advantages of transforaminal approach, location of disc fragment, complications, muscle damage, operative time, standardized patient-relevant outcomes, and sample size, allocation, and blinding where possible. A cost-effectiveness study should also be conducted to make a meaningful comparison. F: RESULTS: 1-9 F1 In studies prior to 1995, surgery was mainly under fluoroscopy and in later years visualized. Annular opening was done by blunt palpation. The scope did not have integrated instrument channels. Contraindications were sequestrations [1], calcified or narrow disc [2], cauda equina syndrome [3], previous same level surgery [4], instability [5], large extra ligamentous disc [6], high iliac crest [7], stenosis [8], Listhesis [9]. Over years we have overcome all contra indications except instability and central congenital canal stenosis. We may combine endoscopy with stabilization in instability and in congenital stenosis we may need interlaminar surgical access. In developmental stenosis, we can work with our system. Understanding of symptoms in stenosis was very primitive. 127

F2 Between 1995 to 2005. 10-22 spine endoscopy was in flux and evolving, YESS system received FDA approval in 1998. A study focusing on identification of pain generators 1991, and anatomy of foramen 1995 were published with studies supporting and validating these ideas. First prospective RCT was published by Hermantin et al in 1999 and a sound and strong base was created for taking these ideas further by adding many other complementary technologies like RF, laser and improvements in optics and electronics. We could deliver same or better results without any posterior midline access. It also established precision in the technique. The indications and inclusions changed to include sequestrations, prior surgery and even deficits. The exclusions narrowed. The reoperation rates were around 5% and complications low. The surgery did now essentially become intra and extradiscal. F3 After 2005 When spine endoscopy technologically matured producing relatively consistent results. The inclusion was a vast range of symptoms and degenerative conditions of an aging spine affecting the functional spinal unit. More studies addressed instability and failed back surgery syndrome with endoscopic transforaminal fusion and neuromodulation of the Dorsal root ganglion. Spine endoscopy was done in awake and aware patients thus extending its benefits to medically compromised patients. IN a 2006,7 study by LEE et al. 23,24,25 et al post op radiological evaluation concluded our surgery is less invasive procedure for the muscles and soft tissues of the back than 26 open microdiscectomy.2007 66 patients study was published by Sasani about far lateral herniations where our technique was effective in removal of total fragment and achieve a pain free status in majority. Following 2 studies 128

of 2008 and 2009 by Ruetten 27,28 compared TFE [transforaminal endoscopy] and MLD [micro lumbar discectomy] one for standard virgin untreated herniations and one for recurrences. The clinical results were equal to microsurgical technique. TFE had reduced traumatization. Study concluded that full-endoscopic surgery [includes interlaminar FE] is a sufficient and safe supplementation and alternative to microsurgical procedures.IN 2009 study 29 from Lee DY et al. for recurrent disc herniation, PELD [percutaneous endoscopic lumbar discectomy] had advantages in terms of shorter operating time, hospital stay, and disc height preservation. There was a brief mention of annular closure technology for prevention of recurrence that was achieved in interlaminar access by annular sealing mainly in percutaneous interlaminar FE. Another study in 2009 demonstrated that FE 30 can be day care surgery and achieved similar results. IN 2010 in a systematic review of heterogeneous 1 randomized controlled trial, 7 non- randomized controlled trials and 31 observational studies showed eight trials [rct and nrct]did not find any statistically significant differences in leg pain reduction between the transforaminal endoscopic surgery group (89%) and the open microdiscectomy group (87%); overall improvement (84 vs. 78%), re-operation rate (6.8 vs. 4.7%) and complication rate (1.5 vs. 1%), respectively. There has been a detailed review of evolution of disc surgery 31 in 2011 by Postachini. 32 IN 2013 a study comparing learning curve of MLD and FE it was found it is steep but not hard to master. There is a recent French instructional course on disc surgery 2013 by A. Blamoutier. This study has done Comparison 33 between microdiscectomy and full endoscopy. Ruetten et al. reported no 129

difference in terms of lumbar or radicular pain, or Oswestry or North American Spine Society (NASS) pain or neurology scores at 2 years’ follow- 34 up. Gotfryd and Avanzi and Nellensteijn performed systematic literature reviews. The former compared SD [standard discectomy], MD [micro or micro lumbar discectomy] and endoscopy (MED and FE). Endoscopy and MED were preferable to SD in terms of hospital stay and bleeding but not of clinical result. The latter assessed efficacy in FE and MED, they concluded that there was no difference between the techniques in terms of pain, complications or recurrence. Three randomized controlled trials (Hermantin, Krappel, and Mayer ] and three retrospective studies (Kim, Lee, and Lee ) compare TFE and MD. Taken together, this is Level 4 and 5 evidence that transforaminal endoscopy is not superior to microdiscectomy for back pain (n = 154), leg pain, (one randomized trial, one nonrandomized; n = 100) or patient satisfaction (one randomized trial; n = 60) and very low quality evidence that there is no difference in function or general improvement (three randomized trials, three non randomised trials ; n = 1,169) at any time point. There is Level 4-5 evidence from two randomized controlled trials (n = 80)that there is no difference in the proportion of people who return to work one further randomized controlled trial [70] (n = 60) measured return to work in days but does not report sufficient detail to estimate the between- group difference. There is Level 5 evidence from two randomized controlled trials and three non-randomised studies (n = 1,109) that operative time is not different; mean operative time was 55.2 min for TFE and 60.3 min for MD. Level 5 evidence suggests that there is no difference in length of hospital 35 stay (n = 154) or rate of complications (n = 1,056). There is Level 5 130

evidence from three randomized controlled trials (total n = 160) of no difference in reoperation rate, but low quality evidence that TFE results in more reoperations when two non randomised, retrospective studies (total n = 1,129) are included (OR; 1.69, CI 1.06–2.71). One randomized controlled trial (n = 40) reported that TFE may be more expensive than MD. IN our hands, we had success rate of around 92%. We had our share of complications of discitis initially during first 4 years of work [out of 18 years] of 1.5%. We also had about 1.5 % dysesthesia. There were about 3-4% where we were not able to make a difference to the pain and other symptoms of significant degree. Rare complications were psoas hematoma in patients on antiplatelet agents, but we did not have nerve injury or dural or vascular injuries. F4 Evolution post 2015 1. About anatomy: Nerves and blood vessels are fixed and protected by transforaminal ligaments and/or corpora transverse ligaments. Important to note veins running through Kambin's triangle. Lateral zones of foramen are filled with nerves and blood vessels needs more caution to handle. 36 2. High-quality randomized controlled trials are required to study the efficacy and cost-effectiveness of PTED. 37 1. More Work is now reported from all over the world. Indian study of first 100 cases by an advanced beginner is presented by Dr Mahesha K. The low complication rate is important advantage. Transforaminal approach alone is sufficient in majority of cases, although 16% of cases required 131

either percutaneous interlaminar approach or combined approach in his hands. The procedure has a learning curve, but it is acceptable with adequate preparations as reported by him. Learning curve is a matter 38 of concern as the radiation during learning is likely to be heavy. Both surgeon and the patient are likely to be exposed to higher doses of radiation. An algorithmic approach and line drawing is advised to shorten 39 this phase of learning. Radiation exposure during surgery is a matter of concern and newer ideas to use ultra sound guidance over fluoroscopy is promising as reported in this study. In patients with medical 40 comorbidities its effective. Positive effect of endoscopy is, also, evident in better quality of life of those patients one year after the procedure 41 supported by this study. There are newer indications and applications now possible due to maturity of this methodology. Surgery in adolescents we have a better minimally invasive surgical method with less trauma, less blood loss, early function recovery, less effect on lumbar spinal stability and so on. The short-term outcomes are similar to open disc 42 surgery. Surgery at TL junction Transforaminal endoscopic discectomy and foraminotomy can be used as a safe yet minimally invasive technique for the treatment of lumbar radiculopathy in the setting of a thoracolumbar disc herniation if the location forms a part of sagittal curve of lumbar spine. 43 In case of lumbar canal stenosis easy, safe, and effective minimally invasive surgery for patients is possible. 44 This study has added new dimensions to treatment of discogenic back pain. IN case of discogenic back pain patients showed only inflammatory response and membrane at annulus tear tissues or no annulus tear but 132

adhesion and inflammatory granuloma among the intracanal annulus fibrous, posterior longitudinal ligament and ventral dural sac or both changes. Concordant pain is triggered by touching the inflammation with the probe. The success rate (excellent and good) of patients with both causes is much higher than individual causes (P < 0.05). The whole success rate was 75.8%. Study reported high satisfaction and negligible complications 45 IN down migrated herniations many endoscopic surgeons use the radiologic characteristics of foramen to choose the most appropriate approaching technique by drilling pedicle bone coming in way. we propose use of hook avoiding any bony drilling. 46 Lateral stenosis can be safely treated with less invasive, effective and safe 47 surgery as we are landing and working in foramen anyway. Outside in access TESSYS well tolerated by patients and is a better approach than open disc surgery48 . Listhesis In lumbosacral radiculopathy reduced iatrogenic instability and achieving symptom control is possible in select patients. 49 Fusion thru foramen the working triangle is a relatively large area. The safe zone, just superior to the lower pedicle, is free of nerve structures. By utilizing the superior border of the pedicle, the disc space can be accessed 50 within this safe zone without risk of injury to the nerves. Endoscopy in failed fusion for foraminal decompression of previously fused segments and resection of displaced interbody cages appears to have excellent outcomes. Personal experience tells us peek is a polymer and can be easily removed with use of laser. Transforaminal endoscopic discectomy and foraminotomy for the treatment of lumbar radiculopathy in the setting of previous instrumented lumbar fusion is effective too. 51 133

In Difficult L5S1 with high iliac crest above the mid L5 pedicle in lateral xray foraminoplasty may be considered for transforaminal access of L5-S1 disc herniation. Conventional transforaminal access can be utilized with ease in low iliac crest cases where the iliac crest is below the mid-L5 pedicle 52 0 We can also utilize the 25 angle of the scope to overcome an oblique landing on S1 endplate. In recurrences or revisions after previous open surgery there is an advantage of avoiding old scar tissue, a short operation time, less 51, 53 trauma, and rapid postoperative recovery. B4: interlaminar surgery at L5S1 The anatomical difficulty in accessing L5S1 foramen can be over come by 1. Transiliac surgical access or 2 Interlaminar Access. Gore system can be used for L5S1 interlaminar surgery with same instruments additionally a circular round cannula. Since Interlaminar window in L5S1 is widest it is easy to enter. The paraspinal posterior near midline entry with needle, guide wire, dilator and then blunt cannula is little difficult during stage of dilating tight paraspinal muscles, it can be more discomforting and painful. Entry thru ligamentum flavum needs a proper handling of the dilator and use of fluoroscopic monitoring. It may be difficult even interlaminar way to go for central herniations at L5S1. Images of interlaminar surgery with same instruments: 134

B5: Adequacy of surgery In case of transforaminal surgery landing is entirely blind and under fluoroscopy and surgical visualization is limited so it is important to establish adequate surgery for the relevant target. We confirm adequacy of surgery by several points 1. When a fragment is removed tip is normally red due to its epidural exposure. 2. Annular tear once free of fragments will start oozing making inside of the disc red. 3. If we ask patient to cough or raise shoulders annular flaps will move and tear may close. 4. Use hook to sweep epidural plane, and both superior and inferior notch in foramen. 5. Match amount of disc removed with image to confirm that it matches. 6. In acute cases patient gets relief of pain after removal of the main fragment. 7. Use indigo carmine to color the acidic symptom causing fragment and its adequate removal. 8. In migrated fragments using hook to pull them towards us makes it easy . 9. In case of adgesions using hook to gently mobilise and open up tissue plains works. 10. In case of stenosis there is a scope to develop better criteria of adequacy yet. 135

E: Contraindications of transforaminal interventions: There are no contraindications to treat an annular tear by endoscopic clearing and removing trapped nuclear fragment. Endoscopic removal of disc herniation is only limited by the accessibility of endoscopic instruments to the herniation site. The location of the disc herniation, the extent of the extrusion and sequestration, and the experience level of the surgeon are vital considerations for patient selection. Some patients with high iliac crests, horizontal L5-S1 disc spaces or a flat back or degenerative scoliosis make surgical access through the foramen difficult. Contraindications thus are relative and depend MAINLY on the anatomic factors involved. Unstable spine can be a relative contraindication as endoscopy alone cannot address the issue of added instability. We can isolate the pain generators and then separately tackle the instability. Central bony stenosis may be taken as a main contraindication as the causative tissue may be bone or lying dorsal to dural sac and we cannot access this by transforaminal way. H: Summary moving towards symptom and pathology directed intervention and away from fusion More precise diagnosis of pain generators, better correlation of image and symptoms, precise targeting of the pathology, possibility of doing surgery under local anesthesia and having patient awake and aware, surgery being stitchless, possibility of doing surgery to mitigate medical comorbidities, are inherent in transforaminal endoscopy. Our ability to precisely detect and confirm neuralgia, treat knee, heel and other localized leg pain by integrating it in common thread of neuralgia, importance of nerve supply of the 136

functional spinal unit and its relevance with special reference to facet denervation is also a part of our philosophy. The discogenic back pain is now easily detected and addressed by intradiscal access and it should be possible to solve this major issue affecting the working age patients. Sciatica arising from disc herniations and all its variants in all medical status is treatable by stitchless surgery under local anesthesia. Claudication in stable spine can be addressed by decompression of roof of foramen and in unstable spine better pain isolation can judge real need for mechanical stabilization and its possible execution through foramen. The way surgery is executed and why must be given its due as this is a significant shift from traditional image guided surgery with heavy emphasis on stabilization. Since we can now isolate the pain generators and know about location of DRG in most foramina we need to overcome the long-held belief that stopping motion can relieve pain. It is proven that only total removal of pain generating interface can relieve pain and in fusion it may be this removal not only stabilization that relieves pain. In case of dynamic deformities stopping mobility may be effective in reducing the nerve stretch and stop the symptoms. Clinically it is now important to distinguish what is causing the symptoms, excess mobility or pain generating inflamed interface. In the former fusion may be indicated but the incidence and prevalence does not seem to be very high. Landmark study from NEJM has concluded that fusion does not add any value in decompression for stenosis. This randomized study of 247 lumbar spinal stenosis patients including spondylolisthesis, showed no clinical benefit long after fusion surgery. Decompression plus fusion had higher costs 137

not clinical benefits at 2 years. The natural history of untreated degenerative spondylolisthesis is benign and not been correlated with progression of slip or clinical symptoms. Validated and reliable imaging studies to identify signs 54 of instability are lacking adding to uncertainty . 138

Chapter 3: Applications: Further refinement Anterior changes in DISC 1. annular tear 2. tear with herniation 2a. extraforaminal 2b. foraminal paracentral 2c. paracentral 2d. central herniation 3. discitis Posterior changes in facet and canal 1. facet pain and denervation 2. assessing claudication 2a. image analysis in claudication 3. illustrative cases in stenosis 4a. failed back surgery 4b. soft tissue central canal stenosis 4c. foraminal osteophytosis 4d. facet cysts 5a. Listhesis stable: anterior bridging 5b. unstable spine and hybrid surgery 6.summary and new advances: sneha set 139

ANTERIOR CHANGE target is posterior annulus of disc. mainly causing pain: inflammation plus mechanical compression A Anterior change: disc annular tear-leak-chemical radiculitis- later fragment trapped in tear chronic non-healing- chronic back pain - herniation- sciatica 1. ANNULAR TEAR: A normal disc has normal structure and function, whereas aging disc has reduced diffusion affecting nutrition of the disc. 26,27,28,29 A degenerated disc irrespective of calendar age is characterized by symptomatic “structural failure”. Annular tear is the basic structural failure in degenerating disc. This becomes symptomatic. Tear can be in posterior or postero lateral annulus and has dual nerve supply somatic and sympathetic, SO pain may manifest in back [post] and or along leg [post lateral]. Central area normally correlates to area under Posterior Longitudinal Ligament. As central tear falls in area supplied by the axial branches we have only back pain. The pain changes to leg pain when posterolateral corner of the annulus is torn and inflamed, and somatic nerves and root is involved. Posterolateral tear and symptoms can exist in absence of central annular changes and symptoms. The tear may leak and cause inflammation around adjoining nerve root or DRG. Physiologically, the inflammation gives rise to mechano-sensitization of the nerve roots and DRG. This chemical involvement and inflammation can manifest as knee [L5] and heel [S1] pain to start with and can be 140

detected by GORE SIGN. 30,31 It may resolve naturally over time; without need of intervention. In chronic non-healing tear many times requires removal of the embedded trapped nuclear fragments in the annulus to allow that torn annulus to heal restoring the barrier between nucleus and nerve supply; and relief of symptoms of back and leg pain. The weakened annulus may allow a subsequent herniation of a fragmented nucleus through this tear. 32,33,34,35,36. This may result in sciatica due to inflamed and mechanically compressed nerve root. The DRG “mini brain” lies at top of a conceptual solid cone. This lies in foramen at L45, just outside at L34 and just inside at L5S1. The base of cone is the dermatome. Idea of dermatome as clinically indicative of definitive supply by the root is more than 100 years old and has many inaccuracies. So instead of diagnosing pain based on dermatomal maps alone; I palpate the nerve. Palpation of nerve and elicitation of tenderness is better form of detection of its inflammation in early chemical stages of mechano sensitized nerve manifesting as sciatica. [gore sign] In mechano sensitization of the nerve GORE SIGN is the ONLY objective way to identify and monitor sciatica. It can be used to integrate other common painful entities namely knee pain and heel pain in sciatic “neuralgia”. 37-47 Back pain may be felt in axial skeleton and perceived vertical or horizontal. We have commonly seen horizontal spread of pain associated with L5S1 disc related cause. It is commonly associated with chronic nonhealing central posterior annular tear with trapped nuclear fragments in the tear. This pain from trapped fragments and not only leak may not centralize on extension 141

in McKenzie test and may also have associated leg pain with a tender deep peroneal nerve at sinus tarsi [L5] or sural[S1]. This is detected by gore sign. Axial discogenic back pain can be easily differentiated from paraspinal, well localized facet related pain, facet pain increases with extension. Discogenic pain is central either vertical or horizontal. This pain in patient with good annular integrity reduces on extension of the back in prone lying position; that is basis of McKenzie’s method MDT of mechanical diagnosis and treatment 50. In sciatica, due to mechanical compression by a fragment pain does not centralize. In post- operative, period major part of the pain is relieved and remaining pain centralizes as annulus closes and heals over time. This forms basis of post-operative McKenzie exercises to make annulus more strong and painless. In case of discogenic back pain disc outline may not significantly change as the fragment is intra annular. The usual concavity of the posterior annular wall may HOWEVER change to a flat appearance. Sub annular access and use of hook can make us tease out the trapped fragment and make the tear clean and so heal. We access the tear endoscopically inside of the annulus, tear starts from inside and leads to outer wall, we need to know texture of the trapped nuclear fragment and the tear walls. The fragment can also be associated with an endplate fracture fragment and needs surgical excision as it does not fully resolve naturally even over long time. 51 to 58 The surgery related to anterior[to dural sac] changes in posterior annulus is essentially surgery of interpedicular part plus foraminal and extra foraminal part of the annulus and reaction of its nerve and vascular supply. 142

Anatomy and access Image39 Access to tear in black demarcated rectangle: working rectangle. The area of posterior annulus accessed by transforaminal targeting is area between two pedicles. This can be projected as a working rectangle on the posterior annulus; normally we access half of it on one side, in mono portal. Length of this working rectangle is interpedicular distance that is about 24 mm at D12L1 and up to 36 mm at L5S1. The working rectangle can be bound by endplates of the related disc as side walls and lateral border is medial pedicle line at related disc. Working rectangle as a concept helps in better mental visualization. The up migrated fragments are closer to upper border, and down migrated to lower border of the rectangle. Due to more width of the vertebral body, this rectangle is wider at L5S1 and as the lamina too is wider; access through foramen also needs an entry at skin more away from midline in lower lumbar spine. In most cases of L5S1 since entry is oblique above the iliac crest our trajectory may be directed towards endplate of S1 143

and needs proper understanding of this anatomy. Working rectangle also makes us aware of the small size of our operative field that is in square millimeters and not large. Imaging Annular tear is leak on discography or can be a tear with a trapped fragment of the nucleus or a High Intensity Zone in an MRI. Discography ideally must be done by treating surgeon as its interpretation may significantly vary if done by non-surgeon. Discography in cases of back pain with suspected tear is done not only for evocation of pain but also for understanding changed morphometry of the symptomatic disc and differentiate only leak or a associated trapped intra annular fragment. Images will guide us to the location of the tear. In some patients tear and leak is the only pathology and patient needs a better assessment for predictable results. Surgical Philosophy Annular tear with leak is treated with local anti-inflammatory including, PRP and or steroids injected intradiscally. Injection inside disc is reported to cause later calcification of the disc reported only from Japanese population. Trapped Fragment if found is removed and tear is cleaned. Reaching ventral to the symptomatic posterior annulus but remain intradiscal is important to work safely. Annular tears with discogenic lumbar pain as determined by discography, both positive and false negative 144

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