Outcome after surgical treatment for lumbar spinal stenosis: the lumbar extension test is not a predictive factor.

Study Design. A prospective clinical study. Objectives. To investigate the predictive value of the lumbar extension test for outcome after surgical treatment of lumbar spinal stenosis (LSS). Summary of Background Data. Studies have indicated that aggravation of the symptoms from LSS by extension of the lumbar spine has predictive value for the outcome after decompression. The aim of this study was to investigate this theory in a larger group of patients. Methods. One hundred forty-six consecutive patients surgically treated for LSS were included in the study. The clinical condition was recorded before surgery and at 3, 6, 12, and 24 months after surgery using 3 different scoring systems: Swiss Spinal Stenosis Questionnaire, Neurogenic Claudication Outcome Score, and Oswestry Disability Index. The group of patients with preoperative aggravation of the symptoms by the lumbar extension test, (positive extension test), was compared with the group of patients without aggravation by the test, (negative extension test). Results. Before surgery, patients with a positive extension test scored significantly worse on all disability scoring systems than patients with a negative test. However, the extension test itself had no prognostic value for the overall outcome after lumbar decompression. Using regression models with the 2-year Oswestry Disability Index as dependent variable, only before surgery self-reported health and age were found to have prognostic significance. Conclusion. The lumbar extension test has no predictive value for the outcome after surgical treatment of LSS.