Does the outcome 2 months after lumbar disc surgery predict the outcome 12 months later?

Purpose: To assess the prognostic value of some preoperative and early post-operative indicators in the prediction of disability 14 months after lumbar disc surgery. Methods: Of 173 patients, who had participated in baseline measurements, 145 (84%) attended the 14-month follow-up. Before surgery the duration and intensity of pain was assessed. Follow-up questionnaires were completed during check-ups and included items on pain (VAS), Oswestry and Million disability indices, depression (BDS) and work status. Results: Two months after surgery average back pain was 67% lower and leg pain 70% lower than pre-operatively. The median Oswestry and Million disability indices were 14 and 15 at 2-months and remained low also at 14-months check-up. Further, the post-operative Oswestry and Million disability indices and BDS were highly associated with 14-month back and leg pain. Although the outcome of the patients was mostly good, 5% and 8% of them, respectively, reported severe pain at 2- and 14-month check-ups. Conclusions: As recovery following lumbar disc surgery occurred to a great extent during the first 2 months, the early post-operative outcome appears to be quite a reliable indicator of the postoperative outcome in 1-year follow-up. The strong association between pain and the disability indices allows us to conclude that both the Million and Oswestry indices are clinically useful instruments in the evaluation of outcome in these cases.