Background and objective: Lumbar spinal stenosis (LSS) is a common spinal disorder that causes patients to assume a forward-trunk posture. Spinal alignment affects gait, muscle activity, and trunk-pelvis-limb coordination because the lumbar spine and muscles interact to allow load transfer between the lower back and pelvis during sagittal trunk movement. Therefore, we investigated the relationships among trunk and pelvic movement, swing toe clearance, and muscle coordination (isolated contraction ratios) of the stance limb during obstacle-crossing by patients with LSS.
Methods: Ten patients with LSS and ten control subjects were enrolled. All navigated an obstacle during walking. Kinematic data from the trunk and lower extremities were monitored using a three-dimensional motion analysis system. In addition, we measured the isolated contraction ratios of the gluteus medius (GMed) and vastus lateralis (VL) using surface electromyography.
Results: The normalized lead limb distance was significantly lower in the LSS group than in controls. The spine flexion angle when the swinging limb toe was above the obstacle was higher, but the pelvic anterior tilting angle was lower, in the LSS group. LSS patients also had a significantly lower isolated contraction ratio of the GMed in the trailing stance limb but a significantly higher VL.
Conclusions: Patients with LSS adapted a poor posture and their thoracic and spinal regions were hyperflexed with restricted pelvic obliquity. This created an inefficient gait, a shorter leading limb step, and less stable muscle coordination in the stance limb. Our findings may help healthcare professionals manage patients with LSS.
Keywords: Gluteus medius; lumbar spinal stenosis; muscle isolated contraction ratio; navigating obstacle; vastus lateralis.