Prospective multiple outcomes study of outpatient lumbar microdiscectomy: should 75 to 80% success rates be the norm?

Abstract

Object. The authors assessed the efficacy and outcomes of lumbar microdiscectomy performed on an outpatient basis by administering six questionnaires before and at five time points after surgery. The results were compared with those reported in literature in which the success rates vary between 70% and 80% and in excess of 90%. The authors use the methodology and data derived from their study to evaluate critically the relevance of these two categories of success rates. Methods. This is a prospective study of 212 consecutive, eligible patients who underwent outpatient microscopic discectomy for the treatment of lumbar disc herniation; no previous lumbar lesion had been treated. Data were collected from questionnaires given to the patients before and at five time points after surgery, including at a variable final follow-up examination (mean 2 years postoperatively). Data were collated and analyzed independently by individuals other than the operating surgeons. In both bi- and multivariate analyses, only two preoperative parameters were prognostically significant. The first factor was Workers' Compensation status, which had a negative effect on outcome. The second factor was patient age, which also had a negative effect and was linear with increasing age between 25 years and 56 years—that is, the ages most commonly encountered in cases of herniated disc. Successful outcome rates were as follows: leg pain relief according to a visual analog scale (VAS), 80%; back pain relief (VAS), 77%; Oswestry Low Back Disability Index, 78%; satisfaction with the results of surgery, 76%; return to normal daily activities, 65%; and return to work, 61%. Conclusions. The findings of this study support the evidence that lumbar microdiscectomy performed on an outpatient basis is a very safe and effective means of treating sciatic pain due to disc herniation. The authors believe that their outcome success rates of 75 to 80% are more realistic than those of 90% or more found in some reports.