Outcome after microdiscectomy: results of a prospective single institutional study

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.

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.

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.

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.