Use of the exercise treadmill to measure baseline functional status and surgical outcome in patients with severe lumbar spinal stenosis

Study Design. A prospective study of exercise tolerance of the treadmill before and after decompressive laminectomy in patients with severe lumbar spinal stenosis. Objectives. To determine whether treadmill testing provides useful information about baseline functional status and surgical outcome. Summary of Background Data. Historically, criteria for selecting patients for surgery and assessing postoperative outcome have been variable. Functional testing has not been used in a systematic fashion. Methods. Fifty patients with severe lumbar spinal stenosis underwent decompressive laminectomy. Preoperatively and 3 months postoperatively, functional capacity was assessed on an exercise treadmill. Time to first symptoms and total ambulation time were recorded. The examination was stopped at the onset of severe symptoms or after 15 minutes. Results. In the preoperative trial, mean time to first symptoms (± standard deviation) was 1.82 minutes (median, 0.58), and mean total ambulation time was 6.91 minutes (median, 5.22). In the postoperative trial, mean time to fist symptoms increased to 11.93 minutes (median, 15) and mean total ambulation time increased to 13.26 minutes (median, 15). There was significant improvement after surgery in both time to first symptoms (P < 0.001) and total ambulation time (P < 0.001). Conclusions. Exercise stress testing on a treadmill is a safe, easily administered, and quantifiable means of assessing baseline functional status and surgical outcome in patients with neurogenic claudication due to lumbar spinal stenosis. Treadmill testing provides objective evidence that surgery is beneficial in most cases and is helpful in guiding subsequent management of patients with residual symptoms.