MEASUREMENT OF EXERCISE TOLERANCE ON THE TREADMILL IN PATIENTS WITH SYMPTOMATIC LUMBAR SPINAL STENOSIS - A USEFUL INDICATOR OF FUNCTIONAL STATUS AND SURGICAL OUTCOME

A prospective study of patients with neurogenic claudication and lumba r spinal stenosis was undertaken to determine whether measurement of e xercise tolerance on the treadmill would be useful in defining baselin e functional status and response to surgical treatment. Twenty patient s with an average age of 73 years, all of whom had intractable neuroge nic claudication and radiographically confirmed severe lumbar spinal s tenosis, were studied. Lumbar decompressive laminectomy was performed in all patients. Preoperatively and 2 months postoperatively, quantita tive assessment of ambulation was conducted on a treadmill at 0 degree s ramp incline at two different speeds: 1.2 mph and the patient's pref erred walking speed. The following information was recorded: time to f irst symptoms, time to severe symptoms, and nature of symptoms (leg pa in, back pain, or generalized fatigue). The examination was stopped af ter 15 minutes or at the onset of severe symptoms. In the preoperative 1.2-mph trial, the mean time to first symptoms was 2.68 minutes (medi an 1.31) and the mean time to severe symptoms was 5.47 minutes (median 3.42). In the postoperative trial at the same speed, 13 patients (65% ) were able to walk symptom free for 15 minutes. The mean time to firs t symptoms was 11.12 minutes (median 15) and the mean time to severe s ymptoms was 11.81 minutes (median 15). Similar findings were recorded in the preferred walking-speed trials. There were no complications fro m the treadmill testing procedure. These findings indicate that exerci se stress testing on a treadmill is a safe, easily administered, and q uantifiable means of assessing baseline functional status and outcome following laminectomy in patients with symptomatic lumbar spinal steno sis.