Test-retest reproducibility of the exercise treadmill examination in lumbar spinal stenosis.

OBJECTIVE: To provide further validation of the treadmill test by assessing its "test-retest" reproducibility. PATIENTS AND METHODS: In this prospective study, 28 patients with severe lumbar spinal stenosis underwent exercise treadmill testing, first at a walking speed of 1.2 mph and then at the patient's preferred walking speed. All patients had a second treadmill examination or "retest." No treatment intervention was performed between the initial test and the retest. Time to first symptoms (TFS) and total ambulation time (TAT) were measured. Differences between the baseline examination and the retest examination were assessed by using the concordance correlation coefficient (CCC) as well as graphically. RESULTS: There was good reproducibility between baseline test and retest results for all 4 end points: 1.2 mph, TFS (CCC = 0.90); 1.2 mph, TAT (CCC = 0.89); preferred walking speed, TFS (CCC = 0.98); and preferred walking speed, TAT (CCC = 0.96). The median difference between trials was not significantly different from zero for any of the 4 outcomes. CONCLUSIONS: Exercise treadmill testing has good test-retest reproducibility. There was no learning phenomenon associated with the test procedure. The study further validates the clinical utility of exercise treadmill testing in patients with lumbar spinal stenosis and neurogenic claudication.

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 on 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 first 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). CONCLUSION: 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.

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 lumbar spinal stenosis was undertaken to determine whether measurement of exercise tolerance on the treadmill would be useful in defining baseline functional status and response to surgical treatment. Twenty patients with an average age of 73 years, all of whom had intractable neurogenic claudication and radiographically confirmed severe lumbar spinal stenosis, were studied. Lumbar decompressive laminectomy was performed in all patients. Preoperatively and 2 months postoperatively, quantitative assessment of ambulation was conducted on a treadmill at 0 degree ramp incline at two different speeds: 1.2 mph and the patient's preferred walking speed. The following information was recorded: time to first symptoms, time to severe symptoms, and nature of symptoms (leg pain, back pain, or generalized fatigue). The examination was stopped after 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 (median 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 first symptoms was 11.12 minutes (median 15) and the mean time to severe symptoms was 11.81 minutes (median 15). Similar findings were recorded in the preferred walking-speed trials. There were no complications from the treadmill testing procedure. These findings indicate that exercise stress testing on a treadmill is a safe, easily administered, and quantifiable means of assessing baseline functional status and outcome following laminectomy in patients with symptomatic lumbar spinal stenosis.