Influences of nonspecific low back pain on three-dimensional lumbar spine kinematics in locomotion

Study Design. A three-dimensional kinematic analysis of lumbar spinal movem ents with an ultrasonic measuring system was used to distinguish patients w ith chronic low back pain from those without such pain. Objectives. To investigate the effects of chronic low back pain on the thre e-dimensional movements of the lumbar spine, and to identify variables that would allow discrimination among patients with chronic low back pain and c ontrol subjects. Summary of Background Data. To the authors' knowledge, no previous studies. have described or identified altered spinal and pelvic gait kinematics cau sed by nonspecific chronic low back pain in all anatomic planes. Methods. In this study, 34 participants with chronic low back pain and 22 s ubjects without such pain were monitored during treadmill gait. Data from t he measuring system operating at 30 Hz were low-pass filtered and normalize d to a percentage of the gait cycle. Results. Cross-correlations showed almost identical patterns of pelvic (S1) and thoracic (T12) movement curves in all anatomic planes between groups. No statistical group differences were detected for either pelvic or thoraci c oscillation amplitudes. However, Student's t test showed significantly hi gher coefficients of variation (P<0.01) in all anatomic planes of patients with chronic low back pain than in healthy control patients. Conclusions. The phasic patterns and angular spinal displacements of patien ts with nonspecific low back pain were shown to be within normal limits. Ho wever, the patients demonstrated higher degrees of stride-to-stride variabi lity, representing increased fluctuations in dynamic thoracic and pelvic os cillations. These findings, resulting in less than optimal gait patterns, m ust be considered in the rehabilitation of patients with chronic low back p ain.