Outcome after microdiscectomy: results of a prospective single institutional study.

Background: Although lumbar microdiscectomy is one of the most frequently performed spinal procedures, little consensus exists in the literature regarding results. Whereas retrospective reports boast success rates as high as 98%, prospective studies are less sanguine with statistics in the 73-77% range.

Methods: Prospective single-institution outcome study of all patients undergoing virgin unilateral single-level microdiscectomies by study surgeons November 1990 to March 1992. Outcome determined by patient-reported responses to mail questionnaire or phone interview by a disinterested party.

Results: There were 374 patients operated on, average age 42.4 years with mean length of symptoms 9.4 months, and 31.5% were Workman's Compensation cases. Total complication rate was less than 4%, and follow-up was accomplished for 86% of the patients. Overall success rate was 74% using a strict combination of patient-reported pain relief, work status not affected, absence of narcotic use, and satisfaction with the procedure. Using a multivariate logistic regression analysis, only Workman's Compensation claim and length of symptoms (>6 months) were related to success, with a positive outcome in 86% of non-Compensation patients with brief symptoms contrasting with 29% in Compensation cases of greater than 6 months duration.

Conclusions: A prospective analysis of the frequency of success after microdiscectomy yields results lower than anticipated based on retrospective studies and finds success related to the non-anatomic factors of length of symptoms and Workman's Compensation claims.