THE OUTCOME OF REVISION DISCECTOMIES

Abstract

Revision discetomy is a procedure often assumed to give similar results to primary discectomy. There is no level one or level two evidence to support this view and no publications with pre and post surgical spine specific outcome measures.

This aim of this study was to evaluate the surgical outcomes of revision discectomies using standard spine instruments and to identify factors which influence the outcome. A prospective cohort study was performed between 1996 and 2004. A revision discectomy was defined as surgery at the same lumbar level as a previous discectomy with a minimum three month interval from the index surgery. Outcome measures were available for all 20 patients from the index primary discectomy. Questionnaires were given to the patients preoperatively and at 2 year follow-up. Among the outcomes measures used were the Oswestry Disability Index (ODI), the Low Back Outcome(LBO), and a Visual Analogue Score(VAS). 20 revision discectomies were performed on 11 males and 9 females, 7 at L4/5 and 13 at L5/S1. The mean age was 41(30–56) and the mean follow-up was 27(24–36) months. The preoperative ODI, LBO and VAS at the index primary discectomy averaged 54(22–82), 19(7–42) and 8(5–10) respectively. The preoperative ODI, LBO and VAS at the revision discectomy averaged 63(34–82), 18(1–46) and 8(1–10) respectively. The ODI, LBO and VAS all improved significantly at follow-up. The ODI averaged 27(2–66) (p< 0.05), the LBO averaged 47 (14–70) (p< 0.05) and the VAS 4(3–9) (p< 0.05). The outcome of revision discectomies is favourable, in this series the average improvement in ODI was 36 points, a clinically significant change. The risk factors which influence the outcome are preoperative ODI, preoperative VAS and Age (p< 0.05). Sex, preoperative LBO, duration between recurrent disc herniation, level of disc herniation and incidental durotomies were not predictive of outcome.