THE DIAGNOSTIC VALUE OF A TREADMILL TEST IN PREDICTING LUMBAR SPINAL STENOSIS

Abstract

Introduction: Lumbar spinal stenosis is a frequent indication for spinal surgery. The predictive quality of treadmill testing and MRI for diagnostic verification is not yet clearly defined. The aim of our study was to assess correlations between treadmill testing and MRI findings in the lumbar spine.

Methods: Patients with lumbar spinal stenosis who had been admitted for surgical treatment by means of decompression with or without stabilisation were prospectively examined. We included patients with lumbar spinal stenosis as defined by clinical symptoms like low back and/or leg pain, which increased when walking, and by the area of the dural sac examined by MRI. We excluded patients with clinically manifest peripheral arterial disease, polyneuropathy or musculoskeletal impairments compromising the ability to walk. Treadmill tests were performed using the standardized testing protocoll by Deen at a speed of 0.5 m/sec without inclination. After the onset of symptoms (pain, weakness or dysaesthesia), each patient decided when to end the test.

The area of the dural sac and neuroforamina was examined with MRI for the narrowest spinal segment. ODI and VAS were used for clinical assessment.

Results: 25 patients were included with a median age of 67 years (Interquartile range IQR 60–72 yrs). In the narrowest spinal segment the median area of the dural sac was 91mm2 (IQR 67–135 mm2). The median ODI was 66 percent (IQR 64–72 percent). The median walking distance in the treadmill test was 70 m (IQR 30–130 m). The distance reached in the treadmill test correlated with the area of the dural sac (Spearman’s rho=0.53) and ODI (rho=0.51), but not with the area of the neuroforamina and VAS.

Discussion: The treadmill test helps objectifying pre- and postsurgical clinical complaints and verifying a lumbar spinal stenosis by creating a situation of dynamic strain. Moreover, the treadmill test lets the patient experience his own physical limits and enables the examiner to attain a replicable postoperative assessment. The distance reached in the treadmill test predicts the grade of stenosis in MRI but has a limited diagnostic importance for the level of clinical symptoms in lumbar spinal stenosis.