Variability of outcome after lumbar disc surgery

Study Design. A prospective, consecutive study of patients' outcome at thre e subsequent follow-up times after lumbar disc surgery. Objectives. To evaluate how consistent outcome remained in a group of patie nts after lumbar disc surgery. Summary of Background Data. Despite similar results concerning the overall outcome, results in most studies show different prognostic factors for lumb ar disc surgery at different follow-up times. A reason for this observation could be that patients shift to a different outcome group during the obser vation period. Methods. Before surgery and at the three follow-ups (3, 12, and 28 months a fter surgery) the Low Back Outcome Score was calculated. Groups with favora ble and unfavorable outcome were determined after each follow-up according to the scores. Results. Ninety-eight patients were studied. Forty percent showed an unstab le outcome at different follow-up times. For each follow-up, three prognost ic factors were determined. No prognostic factor showed significance at all follow-up examinations. Conclusions. Patients whose outcome after lumbar disc surgery does not rema in stable present a major problem in the calculation of prognostic factors.