Arthroscopic microdiscectomy: an alternative to open disc surgery.

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.

Red nucleus neurons of Bcl-2 over-expressing mice are protected from cell death induced by axotomy.

The Bcl-2 proto-oncogene regulates apoptosis and prevents cell death. We studied the effect of Bcl-2 gene over-expression on the survival of axotomized red nucleus (RN) neurons after unilateral hemisection at cervical segment 4/5 (C4/5) in mice. Seventy-five percent of RN neurons survived in Bcl-2 over-expressing mice 1 or 2 months after surgery compared with only 55% of RN neurons in wild-type mice. However, Bcl-2 gene over-expression does not prevent lesion-induced shrinkage of RN neurons.

A prospective, randomized study comparing the results of open discectomy with those of video-assisted arthroscopic microdiscectomy.

BACKGROUND: The usefulness of video-assisted arthroscopic microdiscectomy for the treatment of a herniated lumbar disc has been studied previously. In the current prospective, randomized study, the results of this procedure were compared with those of conventional open laminotomy and discectomy. METHODS: Sixty patients who had objective evidence of a single intracanalicular herniation of a lumbar disc caudad to the first lumbar vertebra were randomized into two groups consisting of thirty patients each; Group 1 was managed with open laminotomy and discectomy, and Group 2 was managed with video-assisted arthroscopic microdiscectomy. None of the patients had had a previous operation on the low back, and all had failed to respond to nonoperative measures. Analysis of the outcomes of both procedures was based on the patient's self-evaluation before and after the operation, the preoperative and postoperative clinical findings, and the patient's ability to return to a functional status. The patients were followed for nineteen to forty-two months postoperatively. RESULTS: On the basis of the patient's preoperative and postoperative self-evaluation, the findings on physical examination, and the patient's ability to return to work or to normal activity, twenty-eight patients (93 percent) in Group 1 and twenty-nine patients (97 percent) in Group 2 were considered to have had a satisfactory outcome. The mean duration of postoperative disability before the patients were able to return to work was considerably longer in Group 1 than in Group 2 (forty-nine compared with twenty-seven days). The patients in Group 1 used narcotics for a longer duration postoperatively. No neurovascular complications or infections were encountered in either group. CONCLUSIONS: Although the rate of satisfactory outcomes was approximately the same in both groups, the patients who had had an arthroscopic microdiscectomy had a shorter duration of postoperative disability and used narcotics for a shorter period. These findings suggest that arthroscopic microdiscectomy may be useful for the operative treatment of specific symptoms, including radiculopathy, that are caused by lumbar disc herniation, provided that patients are properly selected--that is, they must have a herniated disc at a single level as confirmed on imaging studies, have failed to respond to nonoperative management, have no evidence of spinal stenosis, and have a herniation not exceeding one-half of the anteroposterior diameter of the spinal canal. Moreover, the surgeon must be familiar with this technique and must have received training in its use.

Arthroscopic microdiscectomy and selective fragmentectomy.

A prospective outcome study to determine the efficacy and complications associated with posterolateral arthroscopic discectomy was initiated in April 1988. One hundred seventy-five patients with symptoms consistent with a lumbar disc herniation and correlative imaging studies were treated operatively, and 169 were available for followup evaluation. Fifty-nine patients with a central herniation or a nonmigrated sequestered fragment were treated using bilateral biportal posterolateral access, whereas 116 patients with radiographic evidence of a paramedial, foraminal, or extra-foraminal herniation were treated using the unilateral uniportal approach. The minimum duration of nonoperative management ranged from 3.5 to 28 months (average, 16 months), and all patients had a minimum of 24 months of postoperative followup. Outcome analysis indicated that 149 procedures were successful, whereas 20 (11.8%) procedures were failures because of persistent radicular symptoms that, in some cases, required open laminotomy. Complications associated with the procedures included one disc space infection, one transient peroneal neuropraxia, and four index extremity skin hypersensitivity. All of these complications resolved without sequelae, and there were no neurovascular complications directly related to the surgical approach.

Minimally invasive techniques in spinal surgery: current practice.

Minimally invasive spinal surgery under arthroscopic or endoscopic magnification and illumination is emerging as an alternative, reliable method of treatment in a variety of spinal disorders. The operative techniques being used for discectomy and retrieval of herniated disc fragments or stabilization of unstable spinal motion segments are being utilized for visual diagnosis and debridement of infectious discitis and osteomyelitis transpedicular and transforaminal vertebral body biopsy, temporary diagnostic fixation of unstable lumbar motion segments, and transforaminal epidural steroid therapy.

Arthroscopic microdiscectomy: comparison of preoperative and postoperative imaging studies.

Forty-three patients with symptomatic lumbar disc herniations underwent paralumbar arthroscopic disc extraction by a uniportal or biportal approach and postoperative imaging studies. Thirty-one patients were subjected to immediate postoperative computed tomography (CT) at the operative site. The other 12 underwent magnetic resonance imaging (MRI at varying times postoperatively. Images obtained before and after surgery were magnified; the herniation area (H) and the spinal canal area (C) were measured by computerized digitization. The H/C ratio was calculated, and the percentage of canal clearance was obtained in each case. Immediate postoperative CT imaging in 16 of 18 patients with subligamentous and extraligamentous nonmigrated herniation showed a significant change in the external geometry of the annulus and canal clearance (75% to 100% canal clearance). Less compelling change in the postoperative CT images was unexpectedly seen with extraforaminal and foraminal herniations. This result may be attributable to limitations in our study methodology and not to inadequate decompression. Follow-up MRI on these patients within 8 weeks postoperatively did eventually show significant change in two cases that were initially not significant. This study confirms that the arthroscopic microdiscectomy technique effectively extracts herniated disc fragments and alters posterior annular contour, including removal of sequestered pieces.

Minimally invasive disc surgery. Nucleotomy versus fragmentectomy.

There is continued debate as to the optimum surgical management of a herniated disc with sciatica. There are proponents of conventional microdiscectomy as well as those who advocate minimally invasive approaches, including central disc decompression or nucleotomy as well as arthroscopic lumbar microdiscectomy and fragmentectomy. In this controversy (I), Dr. Gary Onik takes the position that central disc decompression is both safe and efficacious and may be the procedure of choice for recurrent disc herniations (II). Dr. Parvis Kambin takes the opposing position and advocates arthroscopically assisted fragmentectomy as the procedure of choice.

Arthroscopic discectomy of the lumbar spine.

Although open laminotomy remains an acceptable and, at times, necessary method of treatment for herniated intervertebral discs, spinal stenosis, and various intracanal spinal disorders, arthroscopic disc surgery is emerging as an alternative method of treatment for contained and nonmigrated sequestered herniated discs. Successful performance of arthroscopic disc surgery requires technical skill and a learning curve. Prudent patient selection, adherence to inclusion and exclusion criteria, and avoidance of entry into the spinal canal when possible will reduce the incidence of perineural and intraneural fibrosis and will ensure a satisfactory outcome. Although the incidence of complications has been acceptable, a satisfactory outcome ranging from 75% to 87% has been reported after arthroscopic microdiscectomy. In contrast to nuclear debulking procedures, the objective imaging confirmation of decompression of the nerve root may be shown by immediate postoperative computed tomography or magnetic resonance imaging studies.

History and current status of percutaneous arthroscopic disc surgery.

STUDY DESIGN: The relevant literature and the author's experience with the management of lumbar disc herniation is reviewed. OBJECTIVES: To describe the history of percutaneous arthroscopic discectomy, and to discuss the indications, the procedure's scientific validity, and its outcome. SUMMARY OF BACKGROUND DATA: In contrast to nuclear-debulking procedures, arthroscopic microdiscectomy is target-oriented and capable of retrieving the compressive elements in a carefully selected patient population. The insult to myoligamentous stabilizing structures and intracanalicular tissues is minimal. Extraction of herniated fragments not only can be demonstrated under arthroscopic visualization but also via postoperative imaging studies. METHODS: Search of the literature and the author's experience with arthroscopic disc surgery. RESULTS: Arthroscopic microdiscectomy has a learning curve. In properly selected patients, a successful outcome similar to macro- or microdiscectomy may be achieved. CONCLUSIONS: Proper patient selection is paramount to a successful outcome of arthroscopic disc surgery. Sequestered migrated herniations and large central herniations at L5-S1 in individuals with elevated iliac crests will require open surgery.

Consensus summary of the diagnosis and treatment of lumbar disc herniation.

Clinicians must not simply decide that a patient with symptoms and a positive diagnostic test has a reason for a specific treatment, and likewise clinicians must not decide that a patient with symptoms and a negative test does not have a clinically important problem. We must also consider the sensitivity, specificity and predictive value of the diagnostic test and the individual characteristics of the patient. Treatment outcome depends on many factors. Point of service decisions vs population based decisions are obviously different. Each patient presents to the treating practitioner on a given day, at a given time, and it is this picture upon which a plan of care is formulated.

Transforaminal arthroscopic decompression of lateral recess stenosis.

The purpose of this study was to evaluate the feasibility and efficacy of arthroscopic decompression of lateral recess stenosis, determine potential associated complications, and present an alternative method to access the lateral recess of the lumbar spine. Forty patients were selected in whom the authors found clinical and computerized tomography evidence of lateral recess stenosis and sequestered foraminal herniations. All 40 were treated with a posterolateral arthroscopic technique, and 38 were available for this follow-up evaluation. A satisfactory result was obtained in 31 patients (82%). No neurovascular complications were encountered; however, other complications included an infection of the disc space in one patient and a causalgic-type pain in the involved extremity in four patients. The associated postoperative morbidity in this group of patients was minimal and resulted in rapid rehabilitation and return of patients to preoperative functioning level.

Diagnostic and therapeutic spinal arthroscopy.

Minimally invasive spinal surgery is an attractive alternative method for the diagnosis and treatment of a variety of spinal disorders. Minimal insult to the soft tissue structures results in rapid recovery and an early return to a functional level. Arthroscopic debridement of intervertebral disc infections, arthroscopic interbody fusion, diagnostic temporary fixation of lumbar motion segments, and intradiscal and pedicular access to the vertebral body for biopsy purposes are making inroads in the field of minimally invasive spinal surgery.

Nucleus pulposus pulmonary embolism. A case report.

STUDY DESIGN: This postmortem case report describes nucleus pulposus pulmonary embolism occurring in a human. OBJECTIVES: Clinical, pathologic, and pathogenetic features of the case are discussed. Reference is made to warnings in the literature stressing the importance of avoiding, during radiologic procedures, any possibility of intrathecal ingress of iodinated, ionic, hyperosmolar contrast material. SUMMARY OF BACKGROUND DATA: Various tissues have been implicated as pulmonary emboli in humans. Nucleus pulposus has been reported to embolize to spinal cord vessels in animals and humans and to embolize to the lungs in two animal species. This is the first report of nucleus pulposus pulmonary embolism in a human. METHODS: A patient with refractory low back pain was admitted for lumbar discography using diatrizoate meglumine, 52%, and diatrizoate sodium, 8%. Afterward, an ultimately fatal systemic reaction began, among the symptoms of which were spasmodic extensions of the lower back and legs. Postmortem examination was performed. RESULTS: Nucleus pulposus pulmonary emboli were seen microscopically on random lung sections. The lumbar vertebral column grossly featured acute herniations of disc material into vertebral marrow spaces; nucleus pulposus was identified microscopically in these areas. CONCLUSIONS: We speculate that the spasmodic back extensions imposed compressive forces on vertebrae, causing nucleus pulposus to be extruded into vertebral marrow sinusoids (thus creating emboli) and possibly causing these emboli to flow anteriorly into the anterior external vertebral plexus, which resulted in pulmonary emboli exclusively with no spinal cord emboli.

Mechanism research of cryoanalgesia.

The sciatic nerves of rabbits were frozen at different temperatures (-20 degrees C, -60 degrees C, -100 degrees C, -140 degrees C, and -180 degrees C). The morphology and function of the frozen nerves were examined with light microscopy (hematoxylin and eosinophilin stain and a histochemical thiocholine method) and electron microscopy. The function of the nerve after freezing was assessed using short latency somatosensory evoked potentials, sensory conduction velocity, and electromyogram at various intervals after freezing. There were no changes in morphology or function of nerves cryolesioned at -20 degrees C. The nerve fibers cryolesioned at -60 degrees C showed signs of freezing degeneration and lost their conductive function although, these nerves all recovered. Approximately half of nerve fibers cryolesioned at -100 degrees C showed Wallerian degeneration, and although the time to remyelination was delayed, nerve regeneration was still complete. At -140 degrees C and -180 degrees C the nerve fibers showed immediate necrosis, with destruction of basal membranes and proliferation of collagen fibers. The results explained the mechanism of cryoanalgesia. Our study demonstrates that cryo-temperatures lower than -140 degrees C will cause permanent alterations in nerve morphology and function, whereas warmer temperatures do not result in permanent nerve damage and are therefore not likely to provide long-term analgesia to patients.

Development of degenerative spondylosis of the lumbar spine after partial discectomy. Comparison of laminotomy, discectomy, and posterolateral discectomy.

STUDY DESIGN: The development of degenerative spondylosis after successful operative decompression of the affected nerve root was prospectively evaluated in a comparative case series of 100 patients with a herniated lumbar nucleus pulposus. OBJECTIVES: The objective of this study was to compare the relative incidence of degenerative spondyloarthrosis after successful posterior laminotomy and discectomy and posterolateral extradural discectomy for decompression of a compromised lumbar nerve root. SUMMARY OF BACKGROUND DATA: The relationship between the radiographic appearance of degenerative spondylosis and prior operative procedures has been controversial and at times contradictory. The posterior operative approach with a partial discectomy has been associated with a significant incidence of postoperative degenerative spondylosis and intraneural and perineural fibrosis, complications that may be minimized, or perhaps even eliminated, with the posterolateral evacuation of the offending intervertebral disc fragment. METHODS: Each patient had: 1) not responded favorably to nonoperative treatment, 2) a persistent radiculopathy, 3) correlative imaging studies with no preoperative spondyloarthrosis and 4) minimum 2-year follow-up. Fifty patients were treated by posterior laminotomy and discectomy and fifty were treated by a posterolateral extradural discectomy. Postoperative spondylosis was graded based on the radiographic presence or absence of osteophytes, the intervertebral disc height, the vertebral body alignment and the facet joint changes. RESULTS: At an average postoperative follow-up of 65 months, the incidence of a one grade increase in degenerative spondylosis was 80% of the laminotomy and discectomy patients as compared to 39% of the posterolateral discectomy patients. CONCLUSIONS: The increased incidence of spondyloarthrosis with the posterior approach suggests that minimally invasive posterolateral extradural procedures should be considered for the decompression of a compromised lumbar nerve root.

The infra-aortic arteries of the spine: their variability and clinical significance.

The infra-aortic spinal arteries caudal to the aortic bifurcation were studied in 20 perinatal and adult cadavers to determine their import relative to extraforaminal approaches to the lower lumbar discs as well as their probable involvement in certain cases of radiculomedullary ischemia. Analysis of these specimens indicated that, despite considerable variation, the arteries to the L4-L5 and L5-S1 intervertebral foramens generally were not related to the disc dorsolateral zones where lateral surgical approaches are best accomplished. Also, the frequency in which the fourth as well as the fifth lumbar and all sacral segmental vessels were dependent on the posterior division of the hypogastric artery may help explain how spinal cord ischemia could occur in individuals with vulnerable cord vascular patterns and/or spinal arteriopathy after interruption of hypogastric artery blood flow during pelvic operations.

Arthroscopic microdiscectomy versus nucleotomy techniques.

Arthroscopic microdiscectomy represents an alternative method of treatment for herniated lumbar disc and its associated radiculopathy. In contrast to nucleotomy procedures that allow for only central evacuation of the nuclear mass, in arthroscopic microdiscectomy, the emphasis is placed on evacuation of the posterior collagenized fragments, which are responsible for mechanical compression of the nerve roots. Over a period of 10 years, 250 patients with unremitting sciatica due to herniated nucleus pulposus have been treated at the Graduate Hospital through a posterolateral approach via a 6.5-mm cannula. Our overall successful results have been 87.5%, and we have not encountered any neurovascular or other serious complications.