Parviz Kambin

Consensus summary on 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.

History and current status of percutaneous arthroscopic disc surgery.

Study Design. The relevant literature and the authors 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 procedures 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 authors 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.

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.

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.

Nucleus pulposus pulmonary embolism. A case report.

Study Design This postmortem case report describes nucleus pulposus pulmonary embolism occuring 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.

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 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.

Annular protrusion: pathophysiology and roentgenographic appearance.

The degenerative changes of the lumbar spine in 100 patients with symptomatic low-back pain were reviewed using plain roentgenograms and computed tomographic scans in order to determine the relationship between degeneration and annular protrusion. Additionally, the lumbar spinal units of 25 fresh cadavers were roentgenographed, injected with a mixture of methylene blue and renografin-60, dissected, and studied. The state of degeneration of each of the intervertebral units of both groups was graded on a four-point scale based on the roentgenographic presence or absence of osteophytes and facet joint changes, and the intervertebral disc height. The degree of annular protrusion was measured by dividing the anteroposterior diameter of the intervertebral disc by the anteroposterior diameter of the vertebral plate as determined on the radiographic studies. In the clinical group, 39 intervertebral discs having Grade II and III degeneration exhibited a statistically higher annular/vertebral diameter ratio (A/V index) of 1.30 as compared to the normal invertebral discs, with an A/V index of 1.12 (P less than 0.001). The dissection of the disc spaces of the cadavers with radiographic evidence of disc space narrowing and marginal osteophytosis, Grade II and III degeneration, displayed significant interruption and tearing of the annular fibers and peripheral migration of collagenized nuclear fragments. In both the clinical and pathologic groups, there was a direct correlation between the size of the annular bulge, as indicated in the A/V index, and the degree of narrowing of the disc space. Therefore, this study indicated that annular protrusion is an intricate part of the degeneration process.

ROUTES AND INCIDENCE OF COMMUNICATION OF LUMBAR DISCS WITH SURROUNDING NEURAL STRUCTURES

Several authors have previously reported the complications resulting from contact between a diagnostic or therapeutte agent injected into an intervertebral disc and neural tissue, This study was undertaken to demonstrate the common routes by which, and frequency with whteh this corrtact occurs. Of 105 cadaveric imervertebral discs studies, 15 (14%) leaked. Of the discs that leaked, 27% demonstrated contact of injected dye with the adjacent spinal nerve. The high rate of leakage may be related to the age of the cadavers. Nonetheless, the contact between substances injected into an intervertebral disc and adjacent neural tissue during discography offers an alternate mechanism of pain reproduction in an incompetent disc, it also suggests that nontoxic agents should be used for discography and that intervertebral discs should be proved competent before chemonucteolysis.

History of Surgical Management of Herniated Lumbar Discs From Cauterization to Arthroscopic and Endoscopic Spinal Surgery

A review of the history of the surgical management of herniated lumbar discs as a common cause of sciatica is not complete without acknowledging the efforts of many investigators and researchers who have contributed to the understanding of the anatomy and origin of the sciatic nerve and lumbar intervertebral discs. In addition, the efforts of scientists and clinicians who have participated in developing the surgical management of disc herniation in the last seven decades should be recognized.