Prolapsed lumbar discs ('slipped disc', 'herniated disc') account for less than five percent of all low-back problems, but are the most common cause of nerve root pain ('sciatica'). Ninety percent of acute attacks of sciatica settle with non-surgical management. Surgical options are usually considered for more rapid relief in the minority of patients whose recovery is unacceptably slow.
This updated review considers the relative merits of different forms of surgical treatments by collating the evidence from 40 randomized trials and two quasi-randomized controlled trials (5197 participants) on:
(i) Discectomy - surgical removal of part of the disc
(ii) Microdiscectomy - use of magnification to view the disc and nerves during surgery
(iii) Chemonucleolysis - injection of an enzyme into a bulging spinal disc in an effort to reduce the size of the disc
Despite the critical importance of knowing whether surgery is beneficial, only three trials directly compared discectomy with non-surgical approaches. These provide suggestive rather than conclusive results. Overall, surgical discectomy for carefully selected patients with sciatica due to a prolapsed lumbar disc appears to provide faster relief from the acute attack than non-surgical management. However, any positive or negative effects on the lifetime natural history of the underlying disc disease are unclear. Microdiscectomy gives broadly comparable results to standard discectomy. There is insufficient evidence on other surgical techniques to draw firm conclusions.
Trials showed that discectomy produced better outcomes than chemonucleolysis, which in turn was better than placebo. For various reasons including concerns about safety, chemonucleolysis is not commonly used today to treat prolapsed disc.
Many trials provided limited information on complications, but generally included recurrence of symptoms, need for additional surgery and allergic reactions (chemonucleolysis).
Many of the trials had major design weaknesses that introduced considerable potential for bias. Therefore, the conclusions of this review should be read with caution.
Future trials should be designed to reduce potential bias. Future research should explore the optimal timing of surgery, patient-centred outcomes, costs and cost-effectiveness of treatment options, and longer-term results over a lifetime perspective.