Literature References Supporting the Technique ENDOSCOPIC DISCECTOMY and SED Spine. 2004 Aug 15;29(16):E326-32. Percutaneous endoscopic lumbar discectomy for recurrent disc herniation: surgical technique, outcome, and prognostic factors of 43 consecutive cases. Ahn Y, Lee SH, Park WM, Lee HY, Shin SW, Kang HY. Divisions of Neurosurgery, Wooridul Spine Hospital, Seoul, Korea. ns-ay@hanmail.net STUDY DESIGN: A retrospective study of 43 consecutive patients who underwent percutaneous endoscopic lumbar discectomy for recurrent disc herniation. OBJECTIVES: To evaluate the efficacy of endoscopic discectomy for recurrent disc herniations and to determine the prognostic factors affecting surgical outcome. SUMMARY OF BACKGROUND DATA: Repeated open discectomy with or without fusion has been the most common procedure for a recurrent lumbar disc herniation. There have been no reports published on the feasibility and prognostic factors of the endoscopic discectomy for recurrent disc herniation. METHODS: The inclusion criteria were recurrent disc herniations at the same level, regardless of side, with a pain-free interval longer than 6 months after the conventional open discectomy. Posterolateral endoscopic laser-assisted disc excisions were performed under local anesthesia. RESULTS: The mean follow-up period was 31 months (24-39 months). Based on the MacNab criteria, 81.4% showed excellent or good outcomes. The mean visual analog scale decreased from 8.72 +/- 1.20 to 2.58 +/- 1.55 (P <0.0001). In our series, better outcomes were obtained in patients younger than 40 years (P = 0.035), patients with duration of symptoms of less than 3 months (P = 0.028), and patients without concurrent lateral recess stenosis (P = 0.007). CONCLUSIONS: Percutaneous endoscopic lumbar discectomy is effective for recurrent disc herniation in selected cases. The posterolateral approach through unscarred virgin tissue can prevent nerve injury and could preserve the spinal stability. Both foraminal and intracanalicular portions can be decompressed simultaneously. Neuroradiology. 2004 May;46(5):378-84. Epub 2004 Apr 22. Factors predicting excellent outcome of percutaneous cervical discectomy: analysis of 111 consecutive cases. Ahn Y, Lee SH, Lee SC, Shin SW, Chung SE. Department of Neurosurgery, Wooridul Spine Hospital, 47-4 Chungdam-dong Kangnam-gu, 135-100 Seoul, Korea. Percutaneous cervical discectomy (PCD) has been developed as an effective treatment option for soft cervical disc herniation. However, no prognostic study of this procedure has yet been made. The purpose of this study was to evaluate the surgical outcome of PCD and to determine the factors predicting excellent outcome. A retrospective review was performed of 111 consecutive patients who underwent PCD with a mean follow-up period of 49.4 months (range, 29-64 months). Under local anesthesia, a percutaneous anterior approach was followed by discectomy with microforceps and endoscopic Ho:YAG laser. The surgical outcomes of the 111 patients based on the Macnab criteria were excellent in 52 patients (46.9%), good in 37 (33.3%), fair in 9 (8.1%), and poor in 13 (11.7%), thereby indicating a symptomatic improvement in 88.3% of the patients. In this study, the two major factors predicting an excellent long-term outcome were the symptom of radiating arm pain (P = 0.02) and the location of lateral disc herniation (P < 0.02). Proper patient selection remains critical for the success of this minimally invasive procedure. Copyright 2004 Springer-Verlag Spine. 2003 Mar 15;28(6):573-81. Management of isthmic spondylolisthesis with posterolateral endoscopic foraminal decompression. Knight M, Goswami A. Spinal Foundation, Arbury Consulting Centre, Rochdale, United Kingdom. mknight@spinal-foundation.org STUDY DESIGN: Prospective evaluation of 24 consecutive patients with isthmic spondylolisthesis with chronic back, buttock, and leg pain treated by endoscopic foraminal decompression and followed for a minimum of 2 years. OBJECTIVES: To assess the efficacy of endoscopic foraminal decompression and mobilization of the exiting and transiting nerves, discectomy, ablation of osteophytes, and impinging pars as a means of treatment by the posterolateral approach. SUMMARY OF BACKGROUND DATA: Open decompression with or without fusion is a commonly accepted procedure for symptomatic isthmic spondylolytic spondylolisthesis in patients who fail to respond to conservative treatment. There is no published data on the outcome of endoscopic procedures for this condition. METHODS: Endoscopic foraminal decompression achieved with laser-assisted bone and soft-tissue ablation was performed on 12 males and 12 females with an average age of 42.4 years (36-72 years) followed for an average period of 34 months (28-46 months). The average preoperative duration of symptoms was 6.1 years (3-9 years). RESULTS: One hundred percent cohort integrity was maintained at the final follow-up. Results were analyzed using the percentage change in Oswestry Disability Scores and in Visual Analogue Pain scores. Using a percentage change in Oswestry Disability Score of 50 or more plus VAP scores of 50 or more to determine good and excellent outcomes, 79% (19 out of 24) exceeded this value. CONCLUSION: Laser-assisted endoscopic foraminal decompression provides a minimalist means of exploring the extraforaminal zone, the isthmic defect, the foramen and its contents, the disc and the epidural space. It allows adequate resection with decompression and discectomy, without the need for open decompression and fusion, and targets the symptomatic level effectively in patients with Grade I-III isthmic spondylolisthesis. Hunan Yi Ke Da Xue Xue Bao. 2001 Aug 28;26(4):366-8. [Treatment of cervical disc herniation with percutaneous arthroscopic microdisectomy] [Article in Chinese] Wang WJ, Zhou JN, Yu JM. Department of Orthopaedics, Xiangya Hospital, Central South University, Changsha 410008, China. OBJECTIVE: To study the indications and efficacy of percutaneous cervical arthroscopic microdiscectomy (PCAD). METHODS: Twenty eight patients with cervical discs herniation or disorders received endoscopic spine surgery, 37 intervertebral cervical discs underwent partial nuclectomy or total nucleotomy; the efficacy and complication were evaluated in three months after operation. RELUT: Good/excellent results were obtained in 23/28(82.2%) cases according to MacNab criteria; no serious complication was found; the cervical stability did not decrease in most cases. CONCLUSION: PCAD is a safe, accuracy and rational method in diagnosing and treating herniated cervical disc and discogenic disorders. Spine. 2002 Apr 1;27(7):722-31. Comment in: Spine. 2002 Sep 15;27(18):2081-2; author reply 2081-2. Posterolateral endoscopic excision for lumbar disc herniation: Surgical technique, outcome, and complications in 307 consecutive cases. Yeung AT, Tsou PM. Arizona Orthopedic Surgeons, Phoenix, Arizona, USA. STUDY DESIGN: A retrospective review involving 307 consecutive cases of lumbar disc herniation managed by posterolateral endoscopic discectomy was conducted. OBJECTIVES: To describe a contemporary posterolateral endoscopic decompression technique for radiculopathy secondary to lumbar disc herniation; to evaluate the efficacy of the technique as it is applied to lumbar disc herniation including primary herniation, reherniation, intracanal herniation, and extracanal herniation; and to report outcome and complications. SUMMARY OF BACKGROUND DATA: The concept of percutaneous posterolateral nucleotomy was introduced in 1973. The development of the related equipment and technique had witnessed a slow and lengthy evolution. METHOD: A retrospective assessment of 307 patients was performed at least 1 year after their index operation. The outcome was graded according to a modified MacNab method. A patient-based outcome questionnaire also was incorporated into the study. RESULTS: The surgeon-performed assessment showed satisfactory results in 89.3% of the cases. The rate of response to the questionnaire was 91%. The responses indicated that 90.7% of the respondents were satisfied with their surgical outcome and would undergo the same endoscopic procedure again if faced with a similar herniation in the future. The poor outcome occurred in 10.7% of the primary group and 9.7% of the questionnaire group. The combined major and minor complication rate was 3.5%. CONCLUSIONS: The surgical outcome of posterolateral endoscopic discectomy for lumbar disc herniation is comparable with that for the traditional open transcanal microdiscectomy. Intracanal and extracanal herniations, reherniations, and incidental lateral recess stenosis can be addressed by the same approach. J Neurosurg Spine. 2001 Apr;94(2):216-20. Transforaminal percutaneous endoscopic discectomy in the treatment of far-lateral and foraminal lumbar disc herniations. Lew SM, Mehalic TF, Fagone KL. Division of Neurosurgery, University of Vermont, Burlington 05405, USA. Sean.Lew@vtmednet.org OBJECT: Far-lateral (extraforaminal) and foraminal disc herniations comprise up to 11% of all herniated intervertebral discs. Operative management can be technically difficult, and the optimum surgical treatment remains controversial. Accessing these lateral disc herniations endoscopically via a percutaneous transforaminal approach offers several theoretical advantages over the more traditional procedures. The object of this study was to assess the safety and efficacy of treating patients with far-lateral and foraminal disc herniations via a percutaneous transforaminal endoscopic approach. METHODS: A retrospective analysis was performed of 47 consecutive patients who underwent surgery via this approach. All procedures were performed after induction of a local anesthetic on an outpatient basis. Outcome was measured with Macnab criteria and by determining a patient's return-to-work status. The median follow-up period was 18 months (range 4-51 months). Excellent or good outcome was obtained in 40 (85%) of 47 patients. Of the 38 patients working before the onset of symptoms, 34 (90%) returned to work. Five patients (11%) experienced poor outcomes and subsequently underwent open procedures at the same level. Of the 10 recipients of Workers' Compensation, Macnab criteria indicated a significantly worse outcome (70% excellent or good), but an excellent return-to-work status was maintained (90%). There were no complications. CONCLUSIONS: Transforaminal percutaneous endoscopic discectomy is safe and efficacious in the treatment of far-lateral and foraminal disc herniations. Mt Sinai J Med. 2000 Sep;67(4):283-7. Arthroscopic microdiscectomy: an alternative to open disc surgery. Kambin P, Savitz MH. Department of Orthopedic Surgery, Allegheny University Hospitals, MCP-Hahnemann School of Medicine, Philadelphia, PA, USA. OBJECTIVE: To assess minimally invasive spinal surgery under endoscopic magnification and illumination (arthroscopic microdiscectomy) as a reliable alternative to open microsurgery for most herniated lumbar discs. METHOD: A total of 600 cases are evaluated retrospectively in terms of patient selection and technique. One series of 300 operations was performed by a key academician in the development of arthroscopic microdiscectomy. A second series of 300 patients was treated by a neurosurgeon in private suburban practice. RESULTS: In terms of patients self-evaluation, satisfactory outcome rates of 85-92% were realized. The patients considered brief intravenous anesthesia and same-day scheduling preferable to general anesthesia and hospitalization needed for open laminotomy and discectomy. Fewer than 2% of the cases required a second surgery. CONCLUSION: The authors are of the opinion that advantages include: (1) one-hour operative time, (2) negligible blood loss, (3) avoidance of significant scarring in the spinal canal, and (4) anterolateral fenestration of the annulus for continuing relief of intradiscal pressure and nerve root decompression. Mt Sinai J Med. 2000 Sep;67(4):278-82. Percutaneous microdecompressive endoscopic cervical discectomy with laser thermodiskoplasty. Chiu JC, Clifford TJ, Greenspan M, Richley RC, Lohman G, Sison RB. California Center for Minimally Invasive Spine Surgery, Thousand Oaks, USA. OBJECTIVE: To study the surgical outcome of outpatient percutaneous microdecompressive endoscopic cervical discectomy with lower energy laser for shrinkage of disc material (thermodiskoplasty). METHOD: Since 1994, 200 patients with herniated cervical discs have presented at the authors' clinic, with unilateral radicular pain. The diagnosis was confirmed by MRI or CT, and EMG. RESULTS: At an average follow-up of 25 months, 94.5% of the cases had good-to-excellent results. Eleven patients (5.5%) remained symptomatic, with persistent neck and upper extremity pain associated with paresthesias. There were no significant postoperative complications. Average time before returning to work was 10 days. CONCLUSIONS: Percutaneous microdecompressive endoscopic cervical discectomy with laser thermodiskoplasty has proven to be a safe and efficacious minimally invasive procedure. J Neurosurg Spine. 1999 Oct;91(2):151-6. Endoscopic transpedicular thoracic discectomy. Jho HD. Center for Minimally Invasive Innovative Microneurosurgery, Department of Neurological Surgery, University of Pittsburgh School of Medicine, Pennsylvania, USA. hdjho@neuronet.pitt.edu OBJECT: To minimize the invasiveness and maximize the adequacy of the decompressive procedure in thoracic discectomy, a 70 degrees endoscope was adapted to perform transpedicular thoracic discectomy. METHODS: A posterior transpedicular approach was performed via a 2-cm transverse skin incision, aided by an operating microscope or a 0 degrees lens endoscope. Using a 70 degrees lens endoscope, discectomy was performed after obtaining direct visualization of the ventral aspect of the spinal cord dura mater. This surgical technique has been used in 25 patients. There were 12 men and 13 women whose ages ranged from 29 to 74 years (median 46 years). Thirteen patients experienced myelopathy, with or without radiculopathy, 10 presented with radiculopathy, and two patients suffered from segmental pain. The follow-up period ranged from 4 to 60 months (median 27 months). In 12 of 13 patients with myelopathy, excellent improvement was shown postoperatively. In the remaining patient, symptoms recurred after she was injured in a motor vehicle accident 3 months postsurgery. In nine of 10 patients with radiculopathy, pain resolved completely. In the one patient with right-sided hypochondral pain and in the two patients with segmental pain, no relief was obtained despite excellent discectomy results demonstrated on postoperative magnetic resonance images. The average length of hospital stay was overnight. CONCLUSIONS: The use of a 70 degrees lens endoscope through a transpedicular route has made thoracic discectomy comparable with cervical or lumbar discectomy in terms of minimal surgical invasiveness, recovery time, and complexity of the procedure. Orthopade. 1999 Jul;28(7):615-21. [Transforaminal endoscopic microdiscectomy. Indications and short-term to intermediate-term results] [Article in German] Haag M. Orthopadische Abteilung, Universitatskliniken Freiburg. 101 patients with lumbar disc herniation were treated by transforaminal endoscopic microdiscectomy between 5/94 and 6/97. Caused by technical problems the procedure could not be successfully completed in 3 patients. They must be excluded from the presented study as 9 others, who were lost for follow up. So 89 patients were followed with a median follow-up time of 28 months (15-56 months). 69 patients (78%) were satisfied. 16 patients needed a second operation. In 11 of these 16 patients it was done by an open procedure, in 5 by transforaminal endoscopic microdiscectomy again. 4 of these 5 patients showed a good or satisfying result. As in open procedures the most important prognostic factor is a promptly disappearing radicular leg pain. Only 6 of 61 patients with a radicular leg pain disappearing within one week were reoperated, but 10 of 28, who showed a leg pain persisting longer than one week postoperatively. Neurol Res. 1999 Jan;21(1):39-42. A special device for endoscopic surgery of lumbar disc herniation. Destandau J. Department of Neurosurgery, Hopital Bagatelle, Talence, France. We studied the use of an endoscopic technique for lumbar discectomy, the most frequent operation in spinal surgery. Minimal invasive procedures are cost effective and allow earlier resumption of activities, work and sports. Endoscopic procedures have become more frequent in surgery but rarely for spinal surgery. It is sometimes used in the disc itself but not in the spinal canal. The goal of this operation is to reach the disc herniation in the spinal canal through a small incision, using a special device with an endoscope. It is composed of three tubes: one for the endoscope, one for aspiration and the largest one for classical surgical instruments. A protected space is created at one end of the tubes by a special part of the device which looks like a speculum; there is also an included nerve retractor. One hundred patients were operated during the year 1993. In a follow-up, 91 patients were evaluated using Prolo's criteria. The results could be classified as excellent in 78 patients, good in nine and poor in four. Complications were rare: two discitis, four recurrences, one failure. This technique allows a smaller incision, less trauma to lumbar muscles, better identification of deep structures, soft manipulation and better release of neural structures, perfect hemostasis and no drain. Early post-operative mobilization is easy and special wound dressing allows immediate shower and intensive re-education. These excellent results must be confirmed by long term studies; nevertheless this minimal invasive technique can be considered as a safe and effective treatment of the lumbar disc herniation. Surg Neurol. 1998 Jun;49(6):588-97; discussion 597-8. Endoscopic transforaminal lumbar discectomy and reconfiguration: a postero-lateral approach into the spinal canal. Ditsworth DA. Division of Neurosurgery, Cedars-Sinai Medical Center, Los Angeles, California, USA. BACKGROUND: In the past, minimally invasive procedures (chemonucleolysis, laser, automated percutaneous discectomy, percutaneous manual nucleotomy, arthroscopy) have been largely confined to intradiscal work. This study represents cases of working channel, transforaminal spinal endoscopy performed using an endoscope which, because of its small size and flexibility, can bend up to 90 degrees (depending on the guiding cannula), and pass completely through the foramen into the spinal canal (truly transforaminal, as opposed to just going through part of the foramen and into the disc), to directly remove free fragments and reconfigure disc, relieving root and dural displacement at all lumbar levels. METHODS: The records of 533 patients who had outpatient, minimally invasive operations performed over a 6-year period (ending in 1995) by this author were analyzed. Of these, 110 had small scope transforaminal procedures, forming the basis of this study. RESULTS: An independent observer followed the 110 patients who had endoscopic transforaminal procedures for 2 or more years. Using MacNab's criteria, the success rate (excellent or good) was 95% in the 75 patients with disc presenting lateral to the dura-"lateral presenting,"-and 83% in the 35 patients not presenting disc for direct removal-"non-lateral presenting" (i.e., dura in the pathway)-making an overall success rate of 91%. One patient who developed discitis was the only complication. CONCLUSION: Guideable endoscopes small enough to pass completely through the foramen allow percutaneous surgery to include non-contained disc herniations and even some migrated free fragments, depending on the location. The percutaneous transforaminal endoscopic technique can be an effective, safe approach for disc removal through the foramen, especially in cases where the disc presents itself for direct removal. Orthopade. 1997 Mar;26(3):280-7. [Endoscopic treatment of intervertebral disk displacement. Percutaneous transforaminal access to the epidural space. Indications, technique and initial results] [Article in German] Stucker R, Krug C, Reichelt A. Abteilung Orthopadie des Universitatsklinikums Freiburg i. Br. The authors report their experiences with the percutaneous transforaminal approach to the epidural space. 85 patients were treated endoscopically for non-contained lumbar herniated discs. Very good and good results of 20 patients (learning curve) were obtained in 65%. However, reoperation rate was 25% versus 3% for the last 65 patients. The first 50 patients were treated under local anaesthesia, the last 35 patients under general anaesthesia. Operative technique is described in detail. Laser application in the epidural space is helpful for tissue ablation and to obtain hemostasis. No complications were observed. The main advantages of this new minimal invasive technique are, besides reduced morbidity, less epidural scarring and removal of the sequestered tissue under visual control while retaining disc tissue in the intervertebral space. Thus, the disadvantages of open nucleotomy with possible instability and abundant scarring may be avoided. J Neurosurg. 1994 Jun;80(6):1039-45. Comment in: J Neurosurg. 1994 Oct;81(4):639-40. J Neurosurg. 1994 Oct;81(4):640-1. Same-day microsurgical arthroscopic lateral-approach laser-assisted (SMALL) fluoroscopic discectomy. Savitz MH. Department of Surgery, Good Samaritan Hospital, Rockland County, New York. The 2-year experience of one neurosurgeon with Kambin's orthopedic instruments and frame for arthroscopic microdiscectomy is reported. Arthroscopy using a unilateral approach and monoportal technique is a valuable adjunct to fluoroscopic monitoring. One hundred patients underwent same-day microsurgical arthroscopic lateral-approach laser-assisted (SMALL) fluoroscopic discectomy. In addition, suspected spinal tumors in three patients were treated by biopsy and infection of the disc space was drained in one. A prototype operating discoscope was employed for delivery of the neodymium:yttrium-aluminum-garnet laser beam to assist with hemostasis. Seventy-five "ideal" cases were identified that exhibited the following features: 1) up to a 6-month history of unilateral sciatica symptoms, which responded to bed rest; 2) mechanical signs of nerve root irritation when the patient was erect; 3) computerized tomography or magnetic resonance imaging studies interpreted as showing one protruding or prolapsed disc without extrusion; 4) no segmental spondylosis at the level of a herniated nucleus pulposus; 5) no motor weakness; 6) no prior disc surgery; 7) no obesity; and 8) no diabetes mellitus. Twenty-five "nonideal" cases failed to meet one or more of the above criteria. Good outcome rates were not substantially different in the two groups, success being judged in part by patient satisfaction. Complete success was evidenced in two-thirds of cases by early return to work, but improvement was also determined by increased mobility and a reduction in pain medication from narcotic to analgesic agents. Three patients underwent repeat surgery (laminotomy), but only one improved. Two years has provided sufficient clinical experience to determine that a percutaneous endoscopic procedure under neuroleptanalgesia may become a significant surgical alternative. Vestn Ross Akad Med Nauk. 1994;(7):53-5. [Microsurgical and endoscopic laser diskectomy in osteochondrosis of the lumbar spine] [Article in Russian] Musalatov KhA, Brovkin SV, Aganesov AG, Silin LL. Experimental studies have revealed that a pulse surgical laser based on alumo-yttrium garnet with neodymium ensures bloodless diskectomy and evaporation of a pulposus nucleus in the volume sufficient for decompression of the intervertebral disk. Biomechanical studies of spinal resistance following puncture endoscopic laser decompression of the intervertebral disk (PELDID) and microsurgical laser diskectomy (MLD) have demonstrated that these surgical interventions fail to disturb the stability of the spinal portion operated on. A total of 75 patients with radicular syndrome were operated on with the proposed procedures: 32 with PELDID and 43 with MLD. The subsequent studies have shown that 69 (92%) patients returned to previous work at week 7 and 5 (6.7%) at week 9 of postoperation. The major manifestation of radicular syndrome--leg pain--was eliminated in 100% after MLD and in 96.9% after PELDID. J Neurosurg. 1993 Feb;78(2):216-25. Comment in: J Neurosurg. 1993 Aug;79(2):309-10; author reply 310-1. J Neurosurg. 1993 Aug;79(2):310; author reply 310-1. J Neurosurg. 1993 Dec;79(6):967-8. J Neurosurg. 1993 Dec;79(6):968-9; author reply 969-70. J Neurosurg. 1994 Dec;81(6):965-6. Percutaneous endoscopic discectomy: surgical technique and preliminary results compared to microsurgical discectomy. Mayer HM, Brock M. Department of Neurosurgery, Universitaetsklinikum Steglitz, Freie Universitaet Berlin, Germany. Percutaneous endoscopic discectomy is a new technique for removing "contained" lumbar disc herniations (those in which the outer border of the anulus fibrosus is intact) and small "noncontained" lumbar disc herniations (those at the level of the disc space and occupying less than one-third of the sagittal diameter of the spinal canal) through a posterolateral approach with the aid of specially developed instruments. The technique combines rigid straight, angled, and flexible forceps with automated high-power suction shaver and cutter systems. Access can thus be gained to the dorsal parts of the intervertebral space where the disc herniation is located. Percutaneous endoscopic discectomy is monitored using an endoscope angled to 70 degrees coupled with a television and video unit and is performed with the patient under local anesthesia and an anesthesiologist available if needed. Its indication is restricted to discogenic root compression with a minor neurological deficit. Two groups of patients with contained or small noncontained disc herniations were treated by either percutaneous endoscopic discectomy (20 cases) or microdiscectomy (20 cases). Both groups were investigated in a prospective randomized study in order to compare the efficacy of the two methods. The disc herniations were located at L2-3 (one patient), L3-4 (two patients), or L4-5 (37 patients). There were no significant differences between the two groups concerning age and sex distribution, preoperative evolution of complaints, prior conservative therapy, patient's occupation, preoperative disability, and clinical symptomatology. Two years after percutaneous endoscopic discectomy, sciatica had disappeared in 80% (16 of 20 patients), low-back pain in 47% (nine of 19 patients), sensory deficits in 92.3% (12 of 13 patients), and motor deficits in the one patient affected. Two years after microdiscectomy, sciatica had disappeared in 65% (13 of 20 patients), low-back pain in 25% (five of 20 patients), sensory deficits in 68.8% (11 of 16 patients), and motor deficits in all patients so affected. Only 72.2% of the patients in the microdiscectomy group had returned to their previous occupation versus 95% in the percutaneous endoscopic discectomy group. Percutaneous endoscopic discectomy appears to offer an alternative to microdiscectomy for patients with "contained" and small subligamentous lumbar disc herniations.