Variability of outcome after lumbar disc surgery.

ABSTRACT

STUDY DESIGN: A prospective, consecutive study of patients' outcome at three subsequent follow-up times after lumbar disc surgery. OBJECTIVES: To evaluate how consistent outcome remained in a group of patients after lumbar disc surgery. SUMMARY OF BACKGROUND DATA Despite similar results concerning the overall outcome, results in most studies show different prognostic factors for lumbar disc surgery at different follow-up times. A reason for this observation could be that patients shift to a different outcome group during the observation period. METHODS: Before surgery and at the three follow-ups (3, 12, and 28 months after surgery) the Low Back Outcome Score was calculated. Groups with favorable and unfavorable outcome were determined after each follow-up according to the scores. RESULTS: Ninety-eight patients were studied. Forty percent showed an unstable outcome at different follow-up times. For each follow-up, three prognostic factors were determined. No prognostic factor showed significance at all follow-up examinations. CONCLUSIONS: Patients whose outcome after lumbar disc surgery does not remain stable present a major problem in the calculation of prognostic factors.