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Surgery for lumbar disc prolapse.

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 searched the Cochrane Controlled Trials Register, Medline, Embase, Biosis, Dissertation Abstracts, Index to UK Thesis, and reference lists of the retrieved articles up to March 1997 and we corresponded with experts.


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 were found. There were methodological weaknesses in many of the trials. Sixteen of the 27 trials were of some form of chemonucleolysis. Ten 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. Three trials failed to show a significant reduction in scar formation or improved clinical outcomes by inserting an inter-position membra ne to cover the spinal dura after discectomy. 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.