Preliminary results of the use of a two-stage treadmill test as a clinical diagnostic tool in the differential diagnosis of lumbar spinal stenosis.

This study assesses the ability of a two-stage treadmill test to distinguish stenotic from nonstenotic subjects by capitalizing on the postural dependency of stenotic symptoms. Forty-five subjects (26 stenotic, 19 nonstenotic) participated. An earlier onset of symptoms with level walking (p = 0.0009), increased total walking time on an inclined treadmill (p = 0.014), and prolonged recovery time after level walking (p = 0.001) were significantly associated with stenosis. Only one of four self-reported postural variables were significantly associated with stenosis. Linear discriminant analysis performed using the treadmill variables resulted in the correct classification of 76.9 and 94.7% of stenotic and nonstenotic subjects, respectively. Likelihood ratios for all treadmill variables were > 2.50, and < 2.00 for all self-report variables. A two-stage treadmill test may be useful in the differential diagnosis of lumbar stenosis, and clinical measurement of the postural nature of symptoms seems to be superior to subjects' self-reports.