- Email: [email protected]
Surgical treatment of lumbar disc herniation: MIS, endoscopic, and percutaneous techniques
Author's Accepted Manuscript
Surgical Treatment of Lumbar Disc Herniation: MIS, Endoscopic, and Percutaneous Techniques Junyoung Ahn BS, Vincent J. Rossi BS, BA, Robert A. Sershon MD, Ehsan Tabaraee MD, Kern Singh MD
www.elsevier.com/locate/enganabound
PII: DOI: Reference:
S1040-7383(15)00098-2 http://dx.doi.org/10.1053/j.semss.2015.08.006 YSSPS555
To appear in: Seminars in Spine Surgery
Cite this article as: Junyoung Ahn BS, Vincent J. Rossi BS, BA, Robert A. Sershon MD, Ehsan Tabaraee MD, Kern Singh MD, Surgical Treatment of Lumbar Disc Herniation: MIS, Endoscopic, and Percutaneous Techniques, Seminars in Spine Surgery, http://dx.doi.org/10.1053/j.semss.2015.08.006 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting galley proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Surgical Treatment of Lumbar Disc Herniation: MIS, Endoscopic, and Percutaneous Techniques Junyoung Ahn, BS1 Vincent J. Rossi, BS, BA2 Robert A. Sershon, MD3 Ehsan Tabaraee, MD4 Kern Singh, MD5 1
Research Fellow, Department of Orthopaedic Surgery, Rush University Medical Center, Chicago, IL, 60612 2
3
4
5
Medical Student, Rush Medical College, Chicago, IL, 60612
Resident, Department of Orthopaedic Surgery, Rush University Medical Center, Chicago, IL, 60612
Spine Fellow, Department of Orthopaedic Surgery, Rush University Medical Center, Chicago, IL, 60612
Associate Professor, Department of Orthopaedic Surgery, Rush University Medical Center, Chicago, IL, 60612
Correspondence: Kern Singh, MD Associate Professor Department of Orthopaedic Surgery Rush University Medical Center 1611 W. Harrison St, Suite #300 Chicago, IL 60612 Phone: 312-432-2373 Fax: 708- 492-5373 E-mail: [email protected] Conflicts of Interest and Source of Funding: No funds were received in support of this work. No benefits in any form have been or will be received from any commercial party related directly or indirectly to the subject of this manuscript. None of the authors have any conflict of interest. Prepared for: Seminars in Spine Surgery Acknowledgments: James J. Yue, MD of the Yale School of Medicine.
1
Abstract Lumbar disc herniation is one of the most common causes of low back pain and may be accompanied by numbness, weakness, tingling, and radiating pain in the legs. Majority of patients with radiculopathy secondary to lumbar disc herniation may be successfully treated with non-operative management including physical therapy, home exercise, counseling, and nonsteroidal anti-inflammatory medications. However, surgical management of lumbar disc herniation has also been demonstrated as an efficacious treatment modality. The purpose of this paper is to characterize the indications, techniques, outcomes, and the complications associated with the surgical treatment of lumbar disc herniation treated with minimally invasive techniques.
Indications The Spine Patient Outcomes Research Trial (SPORT) compared the outcomes between patients who underwent operative versus non-operative management of lumbar disc herniation.1,2 The 8-year results of the SPORT (both observational and randomized) demonstrated that surgical patients demonstrated greater improvements in pain and functional status while reporting greater overall satisfaction than non-operative patients.3 Previous studies have demonstrated the efficacy of non-operative management and significant improvements in pain, functional status, and overall satisfaction.1-4 However, patients with unrelenting pain despite conservative management may be candidates for surgery if magnetic resonance imaging (MRI) images correlate with their clinical presentation.5 Although the efficacy of the open microdiscectomy has been demonstrated, the potential for decreased tissue disruption, lower blood loss, shorter length of hospitalization, and decreased postoperative pain has driven substantial attention to minimally invasive techniques..6-9
2
Pre-operative Setup General anesthesia is typically utilized for this procedure. However, some surgeons may prefer spinal or epidural anesthesia. The patient is placed prone on a Jackson table with appropriate padding of the pressure points (Figure 1). Wilson frames or Andrews tables may be utilized to place the lumbar spine in the flexed position. This increases the ease of access to the interlaminar window. Minimally Invasive Lumbar Discectomy Technique A guide needle is introduced through the paraspinal muscles under fluoroscopic guidance to localize the desired disc space. Subsequently, a 1-2 cm incision is made approximately 1.5-2 cm lateral to the midline. Under lateral fluoroscopy, tubular dilators are introduced to expand the working corridor to the inferior-medial aspect of the lamina. The depth and the angle should carefully be monitored in order to avoid entry into the spinal canal through the interlaminar space. Sequential dilation is performed until an 18 mm tubular retractor is placed and secured as the surgical working channel (Figure 2). At this time, a lateral radiograph should be obtained to confirm the appropriate positioning of the working channel. When appropriate, a microscope may be brought into the surgical field for direct visualization through the tubular retractor. A hemilaminotomy is performed utilizing a combination of a burr and Kerrison rongeurs. Care should be taken to preserve at least 50% of the facet joint and at least 9 mm of the pars interarticularis. The hemilaminotomy is completed down to the level of the ligamentum flavum. A working passage is created with an angled curette. This step allows the passage of a Kerrison rongeur to detach the ligamentum flavum from the underside of the superior lamina. The ligamentum flavum is then resected inferiorly, often in a piecemeal fashion (Figure 3). Once the
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ligamentum flavum is resected, the traversing nerve root can be identified medially while the pedicle of the inferior adjacent vertebrae can be palpated. The herniated disc will often displace the traversing nerve root dorsally. Care should be taken to carefully retract the nerve root without excessive tension when attempting to directly visualize the intervertebral disc space. A vertical incision is created in the annulus fibrosus if no annular defect is present to extract the herniated disc material. A contralateral decompression may be performed by adjusting the tubular retractor medially (Figure 4). Any residual loose disc material is extracted utilizing pituitary rongeurs. Outcomes and Complications Previous studies have compared the surgical outcomes and the incidence of complications between minimally invasive (MID) and open techniques for lumbar discectomy. In a study by German et al. of 172 patients who underwent primary single-level lumbar discectomy, the authors demonstrated significantly decreases in blood loss, narcotic utilization, length of hospitalization, and requirement for hospital admission when compared to open microdiscectomy patients.10 A meta-analysis by Dasenbrock et al. of 6 randomized clinical trials demonstrated that both MID and open discectomy patients experienced significant and similar improvements in their leg pain as quantified by VAS scoring.11 The rate of incidental durotomy was greater in the MID patients. However, no difference was demonstrated in the overall complication rate between MID and open patients in these randomized clinical trials. A Cochrane systematic review by Rasouli et al. demonstrated similar primary outcomes (pain improvement, persistence of neurological deficits, and functional outcome) in MID patients as compared to the open discectomy patients.9 No differences were demonstrated in the incidence of thromboembolic disease, rate of incidental durotomy, post-operative narcotic
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utilization, and the Physical Health component summary of the SF-36 (Short-Form Health Survey) at 6-months between the MID and open discectomy patients. The incidence of recurrent disc herniation was greater in the MID patients while the risk of surgical site infections and urinary tract infections were decreased as compared to the open discectomy cohort.
Endoscopic Microdiscectomy Interlaminar Approach12-16 Technique Under fluoroscopic guidance, a guide wire is advanced through the paraspinal musculature and onto the inferior aspect of the superior lamina-facet junction. The depth and the angle should be cautiously monitored during the advancement of the guide wire to avoid entry into the spinal canal. Via tactile feedback, appropriate positioning of the guide wire over the lamina should be confirmed with fluoroscopy. Next, a set of serial dilators is introduced until the desired width is achieved. A tubular retractor is placed over the final dilator or surgical sheath. In systems with a beveled sheath, the bevel opening is directed toward the ligamentum flavum. The endoscope may now be inserted. Flavectomy, laminotomy, and discectomy follow. A 3-5 mm incision is performed in the ligamentum and the beveled sheath is advanced through the interlaminar window. The sheath may be utilized to safely retract the nerve to provide a clear working window for the subsequent discectomy. If the osseous diameter of the interlaminar window does not facilitate direct access into the spinal canal through the ligamentum flavum, the opening may be expanded further utilizing a Kerrison rongeur or burr to resect the overlying laminar bone.
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Transforaminal Approach14,15,17-19 Technique The appropriate target level is localized utilizing a guide wire introduced under fluoroscopic guidance. The midline is marked on the anterior-posterior view and the posterior facet line is marked utilizing the lateral view. It is important to position the needle placement posteriorly to the posterior facet line, so as not to penetrate any visceral structures ventrally. A spinal needle is then advanced under fluoroscopy until contact is made with the lateral aspect of the facet joint. Lidocaine can be injected along the trajectory of the spinal needle to help decrease post-operative pain and better faciliate the passage of instruments. Subsequently, the needle is retracted and the bevel is advanced along the inferior half of the foramen until the posterior aspect of the disc is reached with the tip of the needle penetrating the annulus. It is important that the bevel never cross the medial boarder of the facet joint on the anterior-posterior view (Figure 5a-c).20-22 At this time, the needle is removed and a guide wire is advanced through the stylet. The stylet is then removed and an obturator is introduced over the guide wire through the foramen. A set of serial dilators is then introduced and a tubular retractor is placed over the final dilator or surgical sheath. The endoscope is placed for visualization (Figure 6).23 Occasionally, the foraminal diameter may not be large enough to allow entry into the canal. In these cases, the window must be expanded utilizing a burr or Kerrison rongeur. It is prudent to visualize the exiting nerve root prior to foraminal expansion. If the exiting nerve root is unable to be located, entry into the canal should be gained through the most caudal aspect of the foramen under direct visualization. Once within the canal, a vertical incision is made in the annulus fibrosus if no annular defect is present to extract the herniated disc material. Any residual loose disc material is
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extracted utilizing a pituitary rongeur, while care is taken to avoid damaging any surrounding neurovascular structures. Outcomes and Complications Endoscopic microdiscectomy (EMD) offers the potential advantages of smaller incisions, decreased blood loss, minimal tissue disruption, decreased post-operative pain, and shorter length of hospitalization as compared to open microdiscectomy. Clinical outcomes of primary EMD have been comparable to those of microscopic and open approaches for lumbar discectomy while maintaining a rate of symptomatic improvement in up to 90% of patients.12-17,19,24-27 These results include foraminal or extra-foraminal lumbar disc herniations.12,17,26 Significant clinical improvements as quantified by the North American Spine Score (NASS), Medical Outcomes Study Short Form-36 (SF-36) score, and Visual Analog Scale (VAS) score have been demonstrated following EMD.12-17,19,24-26 The benefit of EMD as compared to open microdiscectomy include shorter operative time, shorter length of hospitalization, and reduced costs associated with the operating room and anesthesia.13-17,24,26 Reduced tissue disruption following EMD has been attributed to its perioperative benefits including decreased intra-operative blood loss and decreased incidence of nerve root irritation as well as an expedited return to work.13-16,26,28 Negligible blood loss has been reported in several publications following EMD. A study by Wu et al. reported an average blood loss of 45 mL per operative level, while Ruetten et al. reported no appreciable blood loss in two studies.14-16 The authors further noted that blood loss did not differ between interlaminar and transforaminal approaches.14,15 Similarly, an intra-operative EMG study by Schick et al.28 reported on the potential protective effects of decreased regional tissue trauma. The authors
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demonstrated a decreased incidence of nerve root irritation and reduced intra-operative mechanically elicited activity in EMD patients as compared to open discectomy patients.28 The re-operation rates have been demonstrated as 3.0-12.0% in patients who undergo EMD.13-16,19,24,25 Ahn et al. demonstrated that positive prognostic factors in patients undergoing EMD were (1) age younger than 40 and (2) clinical symptoms lasting less than 3 months. However, concurrent lateral recess bony stenosis was demonstrated as a negative prognostic factor. In addition, the authors suggested that the technical challenges in decompressing this area may contribute to residual nerve compression.24 Other reported negative patient prognostic factors were Worker’s compensation status, personal injury cases, diabetes mellitus, and a greater comorbidity burden.19,25,26 The complication rates following EMD have been reported as 0-6.0% in recent studies.1317,19,24-26
Potential complications include iatrogenic neurologic deficits (secondary to injury to the
exiting nerve roots in the transforaminal approach), hematoma, discitis, and dural tears. However, catastrophic complications, such as cauda equina, have not been reported in recent literature.13-17,19,24-26 Percutaneous Lumbar Discectomy . Introduction Percutaneous lumbar discectomy is a minimally invasive surgical technique that achieves decompression via reduction of the intradiscal pressure. It is indicated for the treatment of a herniated nucleus pulposus that is contained by the annulus or posterior longitudinal ligament.29 The containment ensures that a communication exists between the central disc and the herniated fragment. The procedure is most efficacious for protruding fragments that are smaller in size.29
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By decompressing the central portion of disc, the contained fragment will spontaneously reduce to relieve the impingement of neural structures. The technique of percutaneous discectomy has evolved since it was originally performed manually with forceps by Kambin et al.30 and Hijikata.31 Currently, two devices are commonly used. The methods vary in the mechanism of removing the disc material. Automated percutaneous lumbar discectomy (APLD) utilizes a Nucleotome (Clarus Medical, Minneapolis, MN) probe with suction to aspirate small fragments of nucleus pulposus into a lateral opening of the hollow probe. The specimen is then shaved off via a pneumatic inner cannula and aspirated with irrigation via the central bore. The other device available is the Dekompressor (Stryker Corp, Kalamazoo, MI). This device removes a predetermined amount of disc material via aspiration alone. The general techniques to enter the disc are similar between the two systems. Pre-operative set up Sedative anesthesia may be utilized for the procedure. The patient is positioned prone on the operative table. The proper level is identified using fluoroscopy. The operative field is then prepped and draped in the standard sterile fashion and local anesthetic is injected. Technique The technique will vary based upon the modality of percutaneous discectomy utilized, but each is similar in the approach to entering the disc space. The technique for automatic percutaneous lumbar discectomy (APLD) is described.29 A 2 mm incision is made approximately 5-10 mm from midline on the ipsilateral side of the pathology. The hollow metal sheath and trocar are inserted obliquely under fluoroscopy into the incision and advanced just anterior to the superior articular process towards the center of the disc. The sheath should be repositioned if the patient experiences radicular pain. Appropriate
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placement of the sheath and trocar is confirmed via fluoroscopy. The trocar is then removed leaving the sheath centered in the disc. The cannula and inner tapered sleeve are placed over the sheath and advanced until the outer annulus is contacted. The sleeve is then removed leaving the cannula resting against the posterolateral aspect of the outer annulus centered in the middle of the disc. The circular saw is then placed over the sheath and a small 2 mm circular incision is made in the annulus. This should be performed under fluoroscopic guidance to ensure the circular saw does not advance outside of the disc. The sheath and circular saw are then removed and the Nucleotome probe is inserted through the cannula. Once the probe is correctly positioned in the disc, the Nucleotome is activated and moved gently back and forth within the disc. When aspiration of the disc material ceases, the probe is rotated and the aspiration is repeated. Once no more disc material can be aspirated, the probe is removed through the cannula. The cannula is then removed. The incision is the appropriately closed and dressed. Outcomes and Complications Complications from percutaneous discectomy include infection, bleeding, discitis, vascular injury, and nerve root injury.32 Fractured probes requiring surgical removal have also been described.33 The method is limited to only contained herniations and disc levels above the L5-S1 disc due to interference of the iliac crest. Observational studies of APLD claim 67.5% to 76.0% success rates. 34-37 Randomized controlled trials comparing APLD to conventional discectomy or microdiscectomy have been conducted, but the results have been inconclusive.38,39 In a recent retrospective observational study, Liu et al. demonstrated no significant difference in outcomes between APLD versus
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microendoscopic discectomy with 76% and 84% of patients, respectively, demonstrating good or excellent outcomes according to the McNab criteria of decompression.40 Observational studies for Dekompressor have also demonstrated significant improvement in pain symptoms. Alo et al. demonstrated an average reduction in the pre-operative VAS score of 5.13 (65%) while 79% of patients were able to reduce their analgesic utilization.41 Amoretti et al. reported a greater than 70% reduction in the pre-operative VAS score in 72% of patients while 78% of patients were able to reduce or stop analgesic utilization.42 A randomized controlled trial performed by Erginousakis et al. compared Dekompressor versus conservative therapy. The study demonstrated a reduction in numerical visual scale (NVS) pain scores for the Dekompressor group and conservative therapy patients as 86% and 36%, respectively.43 Support of the effectiveness of percutaneous discectomy is limited to small observational studies. However, given the lack of conclusive randomized controlled trials detailing comparisons between percutaneous discectomy to other approaches, its utility as a method of minimally invasive discectomy is still up for debate.44 Conclusions Lumbar disc herniation is a common source of debilitating back and leg pain. When nonoperative modalities fail to resolve symptoms, surgical intervention can provide short and longterm improvement. Minimally invasive techniques have been associated with decreased blood loss, shorter hospitalization, decreased post-operative pain, and a decreased risk for surgical site infections when compared to traditional techniques. However, surgical options available for minimally invasive lumbar discectomy vary in their approach, equipment, and level of invasiveness. Yet, high quality studies comparing individual minimally invasive procedures are
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lacking. As such, the decision to proceed with a specific technique will often involve a compromise between patient preferences and surgeon experience.
References 1. Weinstein JN, Lurie JD, Tosteson TD, et al: Surgical vs nonoperative treatment for lumbar disk herniation: the Spine Patient Outcomes Research Trial (SPORT) observational cohort. J Am Med Assc 296:2451-9, 2006. 2. Weinstein JN, Tosteson TD, Lurie JD, et al: Surgical vs nonoperative treatment for lumbar disk herniation: the Spine Patient Outcomes Research Trial (SPORT): a randomized trial. J Am Med Assc 296:2441-50, 2006. 3. Lurie JD, Tosteson TD, Tosteson AN, et al: Surgical versus nonoperative treatment for lumbar disc herniation: eight-year results for the spine patient outcomes research trial. Spine 39:3-16, 2014. 4. Atlas SJ, Keller RB, Wu YA, et al: Long-term outcomes of surgical and nonsurgical management of sciatica secondary to a lumbar disc herniation: 10 year results from the maine lumbar spine study. Spine 30:927-35, 2005. 5. Peul WC, van Houwelingen HC, van den Hout WB, et al: Surgery versus prolonged conservative treatment for sciatica. New Engl J Med 356:2245-56, 2007. 6. German JW, Adamo MA, Hoppenot RG, et al: Perioperative results following lumbar discectomy: comparison of minimally invasive discectomy and standard microdiscectomy. Neurosurg Focus 25:E20, 2008.
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7. Lee P, Liu JC, Fessler RG: Perioperative results following open and minimally invasive single-level lumbar discectomy. J Clin Neurosci 18:1667-70, 2011. 8. Mathews HH, Long BH: Minimally invasive techniques for the treatment of intervertebral disk herniation. J Am Acad Ortho Arug 10:80-5, 2002. 9. Rasouli MR, Rahimi-Movaghar V, Shokraneh F, et al: Minimally invasive discectomy versus microdiscectomy/open discectomy for symptomatic lumbar disc herniation. Coch Rev 9:Cd010328, 2014. 10. Harrington JF, French P: Open versus minimally invasive lumbar microdiscectomy: comparison of operative times, length of hospital stay, narcotic use and complications. Min Inv Neursurg 51:30-5, 2008. 11. Dasenbrock HH, Juraschek SP, Schultz LR, et al: The efficacy of minimally invasive discectomy compared with open discectomy: a meta-analysis of prospective randomized controlled trials. J Neurosurg Spine 16:452-62, 2012. 12. Kim CH, Chung CK, Woo JW: Surgical Outcome of Percutaneous Endoscopic Interlaminar Lumbar Discectomy for Highly Migrated Disc Herniation. J Spin Dis Tech 25(5):E125-33, 2012. 13. Peng CW, Yeo W, Tan SB: Percutaneous endoscopic discectomy: clinical results and how it affects the quality of life. J Spin Dis Tech 23:425-30, 2010. 14. Ruetten S, Komp M, Merk H, et al: Full-endoscopic interlaminar and transforaminal lumbar discectomy versus conventional microsurgical technique: a prospective, randomized, controlled study. Spine 33:931-9, 2008. 15. Ruetten S, Komp M, Merk H, et al: Recurrent lumbar disc herniation after conventional discectomy: a prospective, randomized study comparing full-endoscopic interlaminar and transforaminal versus microsurgical revision. J Spin Dis Tech 22:122-9, 2009.
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16. Wu X, Zhuang S, Mao Z, et al: Microendoscopic discectomy for lumbar disc herniation: surgical technique and outcome in 873 consecutive cases. Spine 31:2689-94, 2006. 17. Jang JS, An SH, Lee SH: Transforaminal percutaneous endoscopic discectomy in the treatment of foraminal and extraforaminal lumbar disc herniations. J Spin Dis Tech 19:338-43, 2006. 18. Ruetten S, Komp M, Merk H, et al: Use of newly developed instruments and endoscopes: full-endoscopic resection of lumbar disc herniations via the interlaminar and lateral transforaminal approach. Journal of neurosurgery. Spine 6:521-30, 2007. 19. Yeung AT, Tsou PM. Posterolateral endoscopic excision for lumbar disc herniation: Surgical technique, outcome, and complications in 307 consecutive cases. Spine 27:722-31, 2002. 20. Yue JJ: Figure 5a. Intraoperative fluoroscopic radiograph demonstrating access to the intervertebral disc space utilizing a cannula and flexible probe, 2014. 21. Yue JJ: Figure 5b.:Intraoperative fluoroscopic radiograph demonstrating access to the intervertebral disc space utilizing a cannula and flexible probe, 2014. 22. Yue JJ: Figure 5c. Intraoperative fluoroscopic radiograph demonstrating access to the intervertebral disc space utilizing a cannula and flexible probe, 2014. 23. Yue JJ: Figure 6. Intraoperative endoscopic image demonstrating the thecal sac and posterior aspect of the annulus, 2014. 24. Ahn Y, Lee SH, Park WM, et al: Percutaneous endoscopic lumbar discectomy for recurrent disc herniation: surgical technique, outcome, and prognostic factors of 43 consecutive cases. Spine 29:E326-32, 2004. 25. Kim CH, Chung CK, Park CS, et al: Reoperation rate after surgery for lumbar herniated intervertebral disc disease: nationwide cohort study. Spine 38:581-90, 2013.
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26. Lew SM, Mehalic TF, Fagone KL: Transforaminal percutaneous endoscopic discectomy in the treatment of far-lateral and foraminal lumbar disc herniations. J Neurosurg 94:216-20, 2001. 27. Yeung AT, Yeung CA: Advances in endoscopic disc and spine surgery: foraminal approach. Surg Tech Int 11:255-63, 2003. 28. Schick U, Dohnert J, Richter A, et al: Microendoscopic lumbar discectomy versus open surgery: an intraoperative EMG study. Eur Spine J 11:20-6, 2002. 29. Onik G, Helms CA, Ginsburg L, et al: Percutaneous lumbar diskectomy using a new aspiration probe. AJR Am J Roentgenol 1137-40, 1985. 30. Kambin P, Brager MD: Percutaneous posterolateral discectomy. Anatomy and mechanism. Clin Orthop Relat Res 145-54, 1987. 31. Hijikata S: Percutaneous nucleotomy. A new concept technique and 12 years' experience. Clinical orthopaedics and related research 1989:9-23, 1989. 32. Golovac S: Percutaneous lumbar discectomy. Neuroimaging Clin N Am 20:223-7, 2010. 33. Domsky R, Goldberg ME, Hirsh RA, et al: Critical failure of a percutaneous discectomy probe requiring surgical removal during disc decompression. Reg Anesth Pain Med 31:177-9, 2006. 34. Bonaldi G: Automated percutaneous lumbar discectomy: technique, indications and clinical follow-up in over 1000 patients. Neuroradiology 45:735-43, 2003. 35. Degobbis A, Crucil M, Alberti M, et al: A long-term review of 50 patients out of 506 treated with automated percutaneous nucleotomy according to Onik for lumbar-sacral disc herniation. Acta Neurochir (Wien) 92:103-5, 2005. 36. Onik G, Mooney V, Maroon JC, et al: Automated percutaneous discectomy: a prospective multi-institutional study. Neurosurgery 26:228-32; discussion 32-3, 1990.
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37. Teng GJ, Jeffery RF, Guo JH, et al: Automated percutaneous lumbar discectomy: a prospective multi-institutional study. J Vasc Interv Radiol 8:457-63, 1997. 38. Chatterjee S, Foy PM, Findlay GF: Report of a controlled clinical trial comparing automated percutaneous lumbar discectomy and microdiscectomy in the treatment of contained lumbar disc herniation. Spine 20:734-8, 1995. 39. Haines SJ, Jordan N, Boen JR, et al: Discectomy strategies for lumbar disc herniation: results of the LAPDOG trial. J Clin Neurosci 9:411-7, 2002. 40. Liu WG, Wu XT, Guo JH, et al: Long-term outcomes of patients with lumbar disc herniation treated with percutaneous discectomy: comparative study with microendoscopic discectomy. Cardiovasc Intervent Radiol 33:780-6, 2010. 41. Alo KM, Wright RE, Sutcliffe J, et al: Percutaneous lumbar discectomy: one-year follow-up in an initial cohort of fifty consecutive patients with chronic radicular pain. Pain Pract 5:116-24, 2005. 42. Amoretti N, David P, Grimaud A, et al: Clinical follow-up of 50 patients treated by percutaneous lumbar discectomy. Clin Imaging 30:242-4, 2006. 43. Erginousakis D, Filippiadis DK, Malagari A, et al: Comparative prospective randomized study comparing conservative treatment and percutaneous disk decompression for treatment of intervertebral disk herniation. Radiology 260:487-93, 2011. 44. Ong D, Chua NH, Vissers K: Percutaneous Disc Decompression for Lumbar Radicular Pain: A Review Article. Pain Pract (In Press)
Figure Legends Figure 1. Photograph demonstrating prone positioning of a patient on open frame Jackson table.
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Figure 2. Tubular retractor image demonstrating the visualization of the inferior-medial aspect of the L4 lamina. Figure 3. Tubular retract image demonstrating the visualization of the thecal sac following resection of the ligamentum flavum. Figure 4. Tubular retractor image demonstrating the medialization of the working channel for contralateral decompression. Figure 5.a-c. Intraoperative fluoroscopic radiograph demonstrating access to the intervertebral disc space utilizing a cannula and flexible probe. Reprinted with permission by James J. Yue (20,21,22). Figure 6. Intraoperative endoscopic image demonstrating the thecal sac and posterior aspect of the annulus. Reprinted with permission by James J. Yue (23).
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Surgical Treatment of Lumbar Disc Herniation: MIS, Endoscopic, and Percutaneous Techniques Junyoung Ahn BS, Vincent J. Rossi BS, BA, Robert A. Sershon MD, Ehsan Tabaraee MD, Kern Singh MD
www.elsevier.com/locate/enganabound
PII: DOI: Reference:
S1040-7383(15)00098-2 http://dx.doi.org/10.1053/j.semss.2015.08.006 YSSPS555
To appear in: Seminars in Spine Surgery
Cite this article as: Junyoung Ahn BS, Vincent J. Rossi BS, BA, Robert A. Sershon MD, Ehsan Tabaraee MD, Kern Singh MD, Surgical Treatment of Lumbar Disc Herniation: MIS, Endoscopic, and Percutaneous Techniques, Seminars in Spine Surgery, http://dx.doi.org/10.1053/j.semss.2015.08.006 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting galley proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Surgical Treatment of Lumbar Disc Herniation: MIS, Endoscopic, and Percutaneous Techniques Junyoung Ahn, BS1 Vincent J. Rossi, BS, BA2 Robert A. Sershon, MD3 Ehsan Tabaraee, MD4 Kern Singh, MD5 1
Research Fellow, Department of Orthopaedic Surgery, Rush University Medical Center, Chicago, IL, 60612 2
3
4
5
Medical Student, Rush Medical College, Chicago, IL, 60612
Resident, Department of Orthopaedic Surgery, Rush University Medical Center, Chicago, IL, 60612
Spine Fellow, Department of Orthopaedic Surgery, Rush University Medical Center, Chicago, IL, 60612
Associate Professor, Department of Orthopaedic Surgery, Rush University Medical Center, Chicago, IL, 60612
Correspondence: Kern Singh, MD Associate Professor Department of Orthopaedic Surgery Rush University Medical Center 1611 W. Harrison St, Suite #300 Chicago, IL 60612 Phone: 312-432-2373 Fax: 708- 492-5373 E-mail: [email protected] Conflicts of Interest and Source of Funding: No funds were received in support of this work. No benefits in any form have been or will be received from any commercial party related directly or indirectly to the subject of this manuscript. None of the authors have any conflict of interest. Prepared for: Seminars in Spine Surgery Acknowledgments: James J. Yue, MD of the Yale School of Medicine.
1
Abstract Lumbar disc herniation is one of the most common causes of low back pain and may be accompanied by numbness, weakness, tingling, and radiating pain in the legs. Majority of patients with radiculopathy secondary to lumbar disc herniation may be successfully treated with non-operative management including physical therapy, home exercise, counseling, and nonsteroidal anti-inflammatory medications. However, surgical management of lumbar disc herniation has also been demonstrated as an efficacious treatment modality. The purpose of this paper is to characterize the indications, techniques, outcomes, and the complications associated with the surgical treatment of lumbar disc herniation treated with minimally invasive techniques.
Indications The Spine Patient Outcomes Research Trial (SPORT) compared the outcomes between patients who underwent operative versus non-operative management of lumbar disc herniation.1,2 The 8-year results of the SPORT (both observational and randomized) demonstrated that surgical patients demonstrated greater improvements in pain and functional status while reporting greater overall satisfaction than non-operative patients.3 Previous studies have demonstrated the efficacy of non-operative management and significant improvements in pain, functional status, and overall satisfaction.1-4 However, patients with unrelenting pain despite conservative management may be candidates for surgery if magnetic resonance imaging (MRI) images correlate with their clinical presentation.5 Although the efficacy of the open microdiscectomy has been demonstrated, the potential for decreased tissue disruption, lower blood loss, shorter length of hospitalization, and decreased postoperative pain has driven substantial attention to minimally invasive techniques..6-9
2
Pre-operative Setup General anesthesia is typically utilized for this procedure. However, some surgeons may prefer spinal or epidural anesthesia. The patient is placed prone on a Jackson table with appropriate padding of the pressure points (Figure 1). Wilson frames or Andrews tables may be utilized to place the lumbar spine in the flexed position. This increases the ease of access to the interlaminar window. Minimally Invasive Lumbar Discectomy Technique A guide needle is introduced through the paraspinal muscles under fluoroscopic guidance to localize the desired disc space. Subsequently, a 1-2 cm incision is made approximately 1.5-2 cm lateral to the midline. Under lateral fluoroscopy, tubular dilators are introduced to expand the working corridor to the inferior-medial aspect of the lamina. The depth and the angle should carefully be monitored in order to avoid entry into the spinal canal through the interlaminar space. Sequential dilation is performed until an 18 mm tubular retractor is placed and secured as the surgical working channel (Figure 2). At this time, a lateral radiograph should be obtained to confirm the appropriate positioning of the working channel. When appropriate, a microscope may be brought into the surgical field for direct visualization through the tubular retractor. A hemilaminotomy is performed utilizing a combination of a burr and Kerrison rongeurs. Care should be taken to preserve at least 50% of the facet joint and at least 9 mm of the pars interarticularis. The hemilaminotomy is completed down to the level of the ligamentum flavum. A working passage is created with an angled curette. This step allows the passage of a Kerrison rongeur to detach the ligamentum flavum from the underside of the superior lamina. The ligamentum flavum is then resected inferiorly, often in a piecemeal fashion (Figure 3). Once the
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ligamentum flavum is resected, the traversing nerve root can be identified medially while the pedicle of the inferior adjacent vertebrae can be palpated. The herniated disc will often displace the traversing nerve root dorsally. Care should be taken to carefully retract the nerve root without excessive tension when attempting to directly visualize the intervertebral disc space. A vertical incision is created in the annulus fibrosus if no annular defect is present to extract the herniated disc material. A contralateral decompression may be performed by adjusting the tubular retractor medially (Figure 4). Any residual loose disc material is extracted utilizing pituitary rongeurs. Outcomes and Complications Previous studies have compared the surgical outcomes and the incidence of complications between minimally invasive (MID) and open techniques for lumbar discectomy. In a study by German et al. of 172 patients who underwent primary single-level lumbar discectomy, the authors demonstrated significantly decreases in blood loss, narcotic utilization, length of hospitalization, and requirement for hospital admission when compared to open microdiscectomy patients.10 A meta-analysis by Dasenbrock et al. of 6 randomized clinical trials demonstrated that both MID and open discectomy patients experienced significant and similar improvements in their leg pain as quantified by VAS scoring.11 The rate of incidental durotomy was greater in the MID patients. However, no difference was demonstrated in the overall complication rate between MID and open patients in these randomized clinical trials. A Cochrane systematic review by Rasouli et al. demonstrated similar primary outcomes (pain improvement, persistence of neurological deficits, and functional outcome) in MID patients as compared to the open discectomy patients.9 No differences were demonstrated in the incidence of thromboembolic disease, rate of incidental durotomy, post-operative narcotic
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utilization, and the Physical Health component summary of the SF-36 (Short-Form Health Survey) at 6-months between the MID and open discectomy patients. The incidence of recurrent disc herniation was greater in the MID patients while the risk of surgical site infections and urinary tract infections were decreased as compared to the open discectomy cohort.
Endoscopic Microdiscectomy Interlaminar Approach12-16 Technique Under fluoroscopic guidance, a guide wire is advanced through the paraspinal musculature and onto the inferior aspect of the superior lamina-facet junction. The depth and the angle should be cautiously monitored during the advancement of the guide wire to avoid entry into the spinal canal. Via tactile feedback, appropriate positioning of the guide wire over the lamina should be confirmed with fluoroscopy. Next, a set of serial dilators is introduced until the desired width is achieved. A tubular retractor is placed over the final dilator or surgical sheath. In systems with a beveled sheath, the bevel opening is directed toward the ligamentum flavum. The endoscope may now be inserted. Flavectomy, laminotomy, and discectomy follow. A 3-5 mm incision is performed in the ligamentum and the beveled sheath is advanced through the interlaminar window. The sheath may be utilized to safely retract the nerve to provide a clear working window for the subsequent discectomy. If the osseous diameter of the interlaminar window does not facilitate direct access into the spinal canal through the ligamentum flavum, the opening may be expanded further utilizing a Kerrison rongeur or burr to resect the overlying laminar bone.
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Transforaminal Approach14,15,17-19 Technique The appropriate target level is localized utilizing a guide wire introduced under fluoroscopic guidance. The midline is marked on the anterior-posterior view and the posterior facet line is marked utilizing the lateral view. It is important to position the needle placement posteriorly to the posterior facet line, so as not to penetrate any visceral structures ventrally. A spinal needle is then advanced under fluoroscopy until contact is made with the lateral aspect of the facet joint. Lidocaine can be injected along the trajectory of the spinal needle to help decrease post-operative pain and better faciliate the passage of instruments. Subsequently, the needle is retracted and the bevel is advanced along the inferior half of the foramen until the posterior aspect of the disc is reached with the tip of the needle penetrating the annulus. It is important that the bevel never cross the medial boarder of the facet joint on the anterior-posterior view (Figure 5a-c).20-22 At this time, the needle is removed and a guide wire is advanced through the stylet. The stylet is then removed and an obturator is introduced over the guide wire through the foramen. A set of serial dilators is then introduced and a tubular retractor is placed over the final dilator or surgical sheath. The endoscope is placed for visualization (Figure 6).23 Occasionally, the foraminal diameter may not be large enough to allow entry into the canal. In these cases, the window must be expanded utilizing a burr or Kerrison rongeur. It is prudent to visualize the exiting nerve root prior to foraminal expansion. If the exiting nerve root is unable to be located, entry into the canal should be gained through the most caudal aspect of the foramen under direct visualization. Once within the canal, a vertical incision is made in the annulus fibrosus if no annular defect is present to extract the herniated disc material. Any residual loose disc material is
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extracted utilizing a pituitary rongeur, while care is taken to avoid damaging any surrounding neurovascular structures. Outcomes and Complications Endoscopic microdiscectomy (EMD) offers the potential advantages of smaller incisions, decreased blood loss, minimal tissue disruption, decreased post-operative pain, and shorter length of hospitalization as compared to open microdiscectomy. Clinical outcomes of primary EMD have been comparable to those of microscopic and open approaches for lumbar discectomy while maintaining a rate of symptomatic improvement in up to 90% of patients.12-17,19,24-27 These results include foraminal or extra-foraminal lumbar disc herniations.12,17,26 Significant clinical improvements as quantified by the North American Spine Score (NASS), Medical Outcomes Study Short Form-36 (SF-36) score, and Visual Analog Scale (VAS) score have been demonstrated following EMD.12-17,19,24-26 The benefit of EMD as compared to open microdiscectomy include shorter operative time, shorter length of hospitalization, and reduced costs associated with the operating room and anesthesia.13-17,24,26 Reduced tissue disruption following EMD has been attributed to its perioperative benefits including decreased intra-operative blood loss and decreased incidence of nerve root irritation as well as an expedited return to work.13-16,26,28 Negligible blood loss has been reported in several publications following EMD. A study by Wu et al. reported an average blood loss of 45 mL per operative level, while Ruetten et al. reported no appreciable blood loss in two studies.14-16 The authors further noted that blood loss did not differ between interlaminar and transforaminal approaches.14,15 Similarly, an intra-operative EMG study by Schick et al.28 reported on the potential protective effects of decreased regional tissue trauma. The authors
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demonstrated a decreased incidence of nerve root irritation and reduced intra-operative mechanically elicited activity in EMD patients as compared to open discectomy patients.28 The re-operation rates have been demonstrated as 3.0-12.0% in patients who undergo EMD.13-16,19,24,25 Ahn et al. demonstrated that positive prognostic factors in patients undergoing EMD were (1) age younger than 40 and (2) clinical symptoms lasting less than 3 months. However, concurrent lateral recess bony stenosis was demonstrated as a negative prognostic factor. In addition, the authors suggested that the technical challenges in decompressing this area may contribute to residual nerve compression.24 Other reported negative patient prognostic factors were Worker’s compensation status, personal injury cases, diabetes mellitus, and a greater comorbidity burden.19,25,26 The complication rates following EMD have been reported as 0-6.0% in recent studies.1317,19,24-26
Potential complications include iatrogenic neurologic deficits (secondary to injury to the
exiting nerve roots in the transforaminal approach), hematoma, discitis, and dural tears. However, catastrophic complications, such as cauda equina, have not been reported in recent literature.13-17,19,24-26 Percutaneous Lumbar Discectomy . Introduction Percutaneous lumbar discectomy is a minimally invasive surgical technique that achieves decompression via reduction of the intradiscal pressure. It is indicated for the treatment of a herniated nucleus pulposus that is contained by the annulus or posterior longitudinal ligament.29 The containment ensures that a communication exists between the central disc and the herniated fragment. The procedure is most efficacious for protruding fragments that are smaller in size.29
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By decompressing the central portion of disc, the contained fragment will spontaneously reduce to relieve the impingement of neural structures. The technique of percutaneous discectomy has evolved since it was originally performed manually with forceps by Kambin et al.30 and Hijikata.31 Currently, two devices are commonly used. The methods vary in the mechanism of removing the disc material. Automated percutaneous lumbar discectomy (APLD) utilizes a Nucleotome (Clarus Medical, Minneapolis, MN) probe with suction to aspirate small fragments of nucleus pulposus into a lateral opening of the hollow probe. The specimen is then shaved off via a pneumatic inner cannula and aspirated with irrigation via the central bore. The other device available is the Dekompressor (Stryker Corp, Kalamazoo, MI). This device removes a predetermined amount of disc material via aspiration alone. The general techniques to enter the disc are similar between the two systems. Pre-operative set up Sedative anesthesia may be utilized for the procedure. The patient is positioned prone on the operative table. The proper level is identified using fluoroscopy. The operative field is then prepped and draped in the standard sterile fashion and local anesthetic is injected. Technique The technique will vary based upon the modality of percutaneous discectomy utilized, but each is similar in the approach to entering the disc space. The technique for automatic percutaneous lumbar discectomy (APLD) is described.29 A 2 mm incision is made approximately 5-10 mm from midline on the ipsilateral side of the pathology. The hollow metal sheath and trocar are inserted obliquely under fluoroscopy into the incision and advanced just anterior to the superior articular process towards the center of the disc. The sheath should be repositioned if the patient experiences radicular pain. Appropriate
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placement of the sheath and trocar is confirmed via fluoroscopy. The trocar is then removed leaving the sheath centered in the disc. The cannula and inner tapered sleeve are placed over the sheath and advanced until the outer annulus is contacted. The sleeve is then removed leaving the cannula resting against the posterolateral aspect of the outer annulus centered in the middle of the disc. The circular saw is then placed over the sheath and a small 2 mm circular incision is made in the annulus. This should be performed under fluoroscopic guidance to ensure the circular saw does not advance outside of the disc. The sheath and circular saw are then removed and the Nucleotome probe is inserted through the cannula. Once the probe is correctly positioned in the disc, the Nucleotome is activated and moved gently back and forth within the disc. When aspiration of the disc material ceases, the probe is rotated and the aspiration is repeated. Once no more disc material can be aspirated, the probe is removed through the cannula. The cannula is then removed. The incision is the appropriately closed and dressed. Outcomes and Complications Complications from percutaneous discectomy include infection, bleeding, discitis, vascular injury, and nerve root injury.32 Fractured probes requiring surgical removal have also been described.33 The method is limited to only contained herniations and disc levels above the L5-S1 disc due to interference of the iliac crest. Observational studies of APLD claim 67.5% to 76.0% success rates. 34-37 Randomized controlled trials comparing APLD to conventional discectomy or microdiscectomy have been conducted, but the results have been inconclusive.38,39 In a recent retrospective observational study, Liu et al. demonstrated no significant difference in outcomes between APLD versus
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microendoscopic discectomy with 76% and 84% of patients, respectively, demonstrating good or excellent outcomes according to the McNab criteria of decompression.40 Observational studies for Dekompressor have also demonstrated significant improvement in pain symptoms. Alo et al. demonstrated an average reduction in the pre-operative VAS score of 5.13 (65%) while 79% of patients were able to reduce their analgesic utilization.41 Amoretti et al. reported a greater than 70% reduction in the pre-operative VAS score in 72% of patients while 78% of patients were able to reduce or stop analgesic utilization.42 A randomized controlled trial performed by Erginousakis et al. compared Dekompressor versus conservative therapy. The study demonstrated a reduction in numerical visual scale (NVS) pain scores for the Dekompressor group and conservative therapy patients as 86% and 36%, respectively.43 Support of the effectiveness of percutaneous discectomy is limited to small observational studies. However, given the lack of conclusive randomized controlled trials detailing comparisons between percutaneous discectomy to other approaches, its utility as a method of minimally invasive discectomy is still up for debate.44 Conclusions Lumbar disc herniation is a common source of debilitating back and leg pain. When nonoperative modalities fail to resolve symptoms, surgical intervention can provide short and longterm improvement. Minimally invasive techniques have been associated with decreased blood loss, shorter hospitalization, decreased post-operative pain, and a decreased risk for surgical site infections when compared to traditional techniques. However, surgical options available for minimally invasive lumbar discectomy vary in their approach, equipment, and level of invasiveness. Yet, high quality studies comparing individual minimally invasive procedures are
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lacking. As such, the decision to proceed with a specific technique will often involve a compromise between patient preferences and surgeon experience.
References 1. Weinstein JN, Lurie JD, Tosteson TD, et al: Surgical vs nonoperative treatment for lumbar disk herniation: the Spine Patient Outcomes Research Trial (SPORT) observational cohort. J Am Med Assc 296:2451-9, 2006. 2. Weinstein JN, Tosteson TD, Lurie JD, et al: Surgical vs nonoperative treatment for lumbar disk herniation: the Spine Patient Outcomes Research Trial (SPORT): a randomized trial. J Am Med Assc 296:2441-50, 2006. 3. Lurie JD, Tosteson TD, Tosteson AN, et al: Surgical versus nonoperative treatment for lumbar disc herniation: eight-year results for the spine patient outcomes research trial. Spine 39:3-16, 2014. 4. Atlas SJ, Keller RB, Wu YA, et al: Long-term outcomes of surgical and nonsurgical management of sciatica secondary to a lumbar disc herniation: 10 year results from the maine lumbar spine study. Spine 30:927-35, 2005. 5. Peul WC, van Houwelingen HC, van den Hout WB, et al: Surgery versus prolonged conservative treatment for sciatica. New Engl J Med 356:2245-56, 2007. 6. German JW, Adamo MA, Hoppenot RG, et al: Perioperative results following lumbar discectomy: comparison of minimally invasive discectomy and standard microdiscectomy. Neurosurg Focus 25:E20, 2008.
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7. Lee P, Liu JC, Fessler RG: Perioperative results following open and minimally invasive single-level lumbar discectomy. J Clin Neurosci 18:1667-70, 2011. 8. Mathews HH, Long BH: Minimally invasive techniques for the treatment of intervertebral disk herniation. J Am Acad Ortho Arug 10:80-5, 2002. 9. Rasouli MR, Rahimi-Movaghar V, Shokraneh F, et al: Minimally invasive discectomy versus microdiscectomy/open discectomy for symptomatic lumbar disc herniation. Coch Rev 9:Cd010328, 2014. 10. Harrington JF, French P: Open versus minimally invasive lumbar microdiscectomy: comparison of operative times, length of hospital stay, narcotic use and complications. Min Inv Neursurg 51:30-5, 2008. 11. Dasenbrock HH, Juraschek SP, Schultz LR, et al: The efficacy of minimally invasive discectomy compared with open discectomy: a meta-analysis of prospective randomized controlled trials. J Neurosurg Spine 16:452-62, 2012. 12. Kim CH, Chung CK, Woo JW: Surgical Outcome of Percutaneous Endoscopic Interlaminar Lumbar Discectomy for Highly Migrated Disc Herniation. J Spin Dis Tech 25(5):E125-33, 2012. 13. Peng CW, Yeo W, Tan SB: Percutaneous endoscopic discectomy: clinical results and how it affects the quality of life. J Spin Dis Tech 23:425-30, 2010. 14. Ruetten S, Komp M, Merk H, et al: Full-endoscopic interlaminar and transforaminal lumbar discectomy versus conventional microsurgical technique: a prospective, randomized, controlled study. Spine 33:931-9, 2008. 15. Ruetten S, Komp M, Merk H, et al: Recurrent lumbar disc herniation after conventional discectomy: a prospective, randomized study comparing full-endoscopic interlaminar and transforaminal versus microsurgical revision. J Spin Dis Tech 22:122-9, 2009.
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16. Wu X, Zhuang S, Mao Z, et al: Microendoscopic discectomy for lumbar disc herniation: surgical technique and outcome in 873 consecutive cases. Spine 31:2689-94, 2006. 17. Jang JS, An SH, Lee SH: Transforaminal percutaneous endoscopic discectomy in the treatment of foraminal and extraforaminal lumbar disc herniations. J Spin Dis Tech 19:338-43, 2006. 18. Ruetten S, Komp M, Merk H, et al: Use of newly developed instruments and endoscopes: full-endoscopic resection of lumbar disc herniations via the interlaminar and lateral transforaminal approach. Journal of neurosurgery. Spine 6:521-30, 2007. 19. Yeung AT, Tsou PM. Posterolateral endoscopic excision for lumbar disc herniation: Surgical technique, outcome, and complications in 307 consecutive cases. Spine 27:722-31, 2002. 20. Yue JJ: Figure 5a. Intraoperative fluoroscopic radiograph demonstrating access to the intervertebral disc space utilizing a cannula and flexible probe, 2014. 21. Yue JJ: Figure 5b.:Intraoperative fluoroscopic radiograph demonstrating access to the intervertebral disc space utilizing a cannula and flexible probe, 2014. 22. Yue JJ: Figure 5c. Intraoperative fluoroscopic radiograph demonstrating access to the intervertebral disc space utilizing a cannula and flexible probe, 2014. 23. Yue JJ: Figure 6. Intraoperative endoscopic image demonstrating the thecal sac and posterior aspect of the annulus, 2014. 24. Ahn Y, Lee SH, Park WM, et al: Percutaneous endoscopic lumbar discectomy for recurrent disc herniation: surgical technique, outcome, and prognostic factors of 43 consecutive cases. Spine 29:E326-32, 2004. 25. Kim CH, Chung CK, Park CS, et al: Reoperation rate after surgery for lumbar herniated intervertebral disc disease: nationwide cohort study. Spine 38:581-90, 2013.
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26. Lew SM, Mehalic TF, Fagone KL: Transforaminal percutaneous endoscopic discectomy in the treatment of far-lateral and foraminal lumbar disc herniations. J Neurosurg 94:216-20, 2001. 27. Yeung AT, Yeung CA: Advances in endoscopic disc and spine surgery: foraminal approach. Surg Tech Int 11:255-63, 2003. 28. Schick U, Dohnert J, Richter A, et al: Microendoscopic lumbar discectomy versus open surgery: an intraoperative EMG study. Eur Spine J 11:20-6, 2002. 29. Onik G, Helms CA, Ginsburg L, et al: Percutaneous lumbar diskectomy using a new aspiration probe. AJR Am J Roentgenol 1137-40, 1985. 30. Kambin P, Brager MD: Percutaneous posterolateral discectomy. Anatomy and mechanism. Clin Orthop Relat Res 145-54, 1987. 31. Hijikata S: Percutaneous nucleotomy. A new concept technique and 12 years' experience. Clinical orthopaedics and related research 1989:9-23, 1989. 32. Golovac S: Percutaneous lumbar discectomy. Neuroimaging Clin N Am 20:223-7, 2010. 33. Domsky R, Goldberg ME, Hirsh RA, et al: Critical failure of a percutaneous discectomy probe requiring surgical removal during disc decompression. Reg Anesth Pain Med 31:177-9, 2006. 34. Bonaldi G: Automated percutaneous lumbar discectomy: technique, indications and clinical follow-up in over 1000 patients. Neuroradiology 45:735-43, 2003. 35. Degobbis A, Crucil M, Alberti M, et al: A long-term review of 50 patients out of 506 treated with automated percutaneous nucleotomy according to Onik for lumbar-sacral disc herniation. Acta Neurochir (Wien) 92:103-5, 2005. 36. Onik G, Mooney V, Maroon JC, et al: Automated percutaneous discectomy: a prospective multi-institutional study. Neurosurgery 26:228-32; discussion 32-3, 1990.
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37. Teng GJ, Jeffery RF, Guo JH, et al: Automated percutaneous lumbar discectomy: a prospective multi-institutional study. J Vasc Interv Radiol 8:457-63, 1997. 38. Chatterjee S, Foy PM, Findlay GF: Report of a controlled clinical trial comparing automated percutaneous lumbar discectomy and microdiscectomy in the treatment of contained lumbar disc herniation. Spine 20:734-8, 1995. 39. Haines SJ, Jordan N, Boen JR, et al: Discectomy strategies for lumbar disc herniation: results of the LAPDOG trial. J Clin Neurosci 9:411-7, 2002. 40. Liu WG, Wu XT, Guo JH, et al: Long-term outcomes of patients with lumbar disc herniation treated with percutaneous discectomy: comparative study with microendoscopic discectomy. Cardiovasc Intervent Radiol 33:780-6, 2010. 41. Alo KM, Wright RE, Sutcliffe J, et al: Percutaneous lumbar discectomy: one-year follow-up in an initial cohort of fifty consecutive patients with chronic radicular pain. Pain Pract 5:116-24, 2005. 42. Amoretti N, David P, Grimaud A, et al: Clinical follow-up of 50 patients treated by percutaneous lumbar discectomy. Clin Imaging 30:242-4, 2006. 43. Erginousakis D, Filippiadis DK, Malagari A, et al: Comparative prospective randomized study comparing conservative treatment and percutaneous disk decompression for treatment of intervertebral disk herniation. Radiology 260:487-93, 2011. 44. Ong D, Chua NH, Vissers K: Percutaneous Disc Decompression for Lumbar Radicular Pain: A Review Article. Pain Pract (In Press)
Figure Legends Figure 1. Photograph demonstrating prone positioning of a patient on open frame Jackson table.
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Figure 2. Tubular retractor image demonstrating the visualization of the inferior-medial aspect of the L4 lamina. Figure 3. Tubular retract image demonstrating the visualization of the thecal sac following resection of the ligamentum flavum. Figure 4. Tubular retractor image demonstrating the medialization of the working channel for contralateral decompression. Figure 5.a-c. Intraoperative fluoroscopic radiograph demonstrating access to the intervertebral disc space utilizing a cannula and flexible probe. Reprinted with permission by James J. Yue (20,21,22). Figure 6. Intraoperative endoscopic image demonstrating the thecal sac and posterior aspect of the annulus. Reprinted with permission by James J. Yue (23).
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