Abstract
Quantitative evaluation of gait characteristics was conducted in patients with lumbar spinal stenosis (LSS). Our method utilized a miniature three-dimensionalinertialsensor attached on the upper trunk of a subject during a clinical walk test. Six LSS subjects (age 66±3 years) participated in this study. Measurements before surgery and at three months after surgery were compared. Gait capability was examined by the six-minute walk test, with the patient walking back and forth a 30-meter straight corridor in a hospital. First, gait parameters were estimated from the sensor output, including step counts, cadence and mean step lengths. Furthermore three-dimensional rotation angles of the upper trunk were calculated to illustrate postural sway features. Time-variable characteristics that express pain or intermittent claudication were evaluated by the path length and range of postural sway trajectory during walking. Experimental results showed remarkable changes in posturalperturbation over time before surgery. Walk distance and duration were improved after surgery. Analysis of postural sway revealed reduced anterior-posterior sway range after surgery, with maintenance of upper body steadiness and smooth walking. The proposed inertia sensor used in combination with the conventionalcl inicalwal king test may be usefulfor evaluating the therapeutic effects in LSS patients in terms of gait kinematic characterization.
