Surgery for lumbar disc prolapse.

BACKGROUND: Surgical investigations and interventions account for as much as one third of the health care costs for spinal disorders, but the scientific evidence for most procedures is still unclear.

OBJECTIVES: The primary rationale for surgery for disc prolapse is to relieve nerve root irritation or compression due to herniated disc material. Claims of the merits of alternative surgical procedures are made without clear evidence about clinical outcomes. The objective of this review was to assess the effects of surgical interventions for the treatment of lumbar disc prolapse.

SEARCH STRATEGY: We have searched the Cochrane Controlled Trials Register, Medline, Embase, Biosis, Dissertation Abstracts, Index to UK Thesis, and reference lists of the retrieved articles. We have also sought trials from expert spinal surgeons and other health workers by direct contact. All data found up to 31/12/99 are included.

SELECTION CRITERIA: Randomised and quasi-randomised trials of the surgical management of lumbar disc prolapse.

DATA COLLECTION AND ANALYSIS: Two reviewers assessed trial quality and extracted data from published papers. Additional information was sought from the authors if necessary.

MAIN RESULTS: Twenty-seven trials have now been found. There were methodological weaknesses in many of the trials. Sixteen of the 27 trials were of some form of chemonucleolysis. Eleven trials compared different surgical techniques, although only one of these compared surgical discectomy with conservative management. Surgical discectomy produced better clinical outcomes than chemonucleolysis with chymopapain, and chemonucleolysis produced better clinical outcomes than placebo. Three trials showed no difference in clinical outcomes between microdiscectomy and standard discectomy. A recent trial suggests that an inter-position gel covering the spinal dura after discectomy may reduce scar formation, although both this trial and two others failed to show any definite improvement in clinical outcomes. Three trials of percutaneous discectomy provided moderate evidence that it produces poorer clinical outcomes than standard discectomy or chymopapain. We found no published randomised trials of laser discectomy.

REVIEWER'S CONCLUSIONS: Chemonucleolysis is more effective than placebo and it is less invasive, but less effective than surgical disectomy. Surgical discectomy for carefully selected patients with sciatica due to lumbar disc prolapse provides faster relief from the acute attack than conservative management, although any positive or negative effects on the lifetime natural history of the underlying disc disease are unclear.