Three-dimensional motion patterns during active bending in patients with chronic low back pain.

Abstract

The three-dimensional motion patterns of chronic low back pain (LBP) patients were studied during active motions. To evaluate whether the motion patterns of coupling and asymmetry in chronic LBP patients differ from those in the normal population according to previous literature. There exists little data that correlates vertebral motion with LBP symptoms despite extensive research. Several studies have suggested that patterns of motion are sensitive indicators of spinal pathology, including coupled motion patterns and asymmetry of motion. In this study, 34 chronic LBP patients enrolled for an external fixation test performed active bending maneuvers, during which the three-dimensional intervertebral motions were measured continuously with an optoelectronic camera via markers attached to the percutaneous transpedicular screws. If a solid connection between each marker carrier and vertebrae was verified, the three-dimensional rotations of the vertebrae were analyzed with special reference to motion asymmetries and patterns of coupled motion. All data were compared to the normal values in the literature since the methodology is not possible in asymptomatic control subjects. Seven patients were removed from the analysis because of a loose screw-bone interface. In the remaining patients, three distinct patterns of motion were observed in each direction of movement. Significant differences in the extension-flexion ratio, the lateral bending asymmetry, and the coupled axial rotation-lateral bending ratio were found between the chronic LBP group and the normal literature values. Chronic LBP patients exhibited motion patterns altered from those of the normal population. Specific differences were observed in coupled axial rotation during lateral bending movement, in the symmetry between flexion and extension, and in the symmetry be tween right and left lateral bending.