Characterizing pelvis dynamics in adolescent with idiopathic scoliosis.

摘要

STUDY DESIGN: Pelvic dynamic analysis in adolescents with idiopathic scoliosis (AIS). OBJECTIVE: To examine and characterize pelvis dynamics in AIS. SUMMARY OF BACKGROUND DATA: Although studies have examined spine and pelvis postural differences between female adolescents with and without scoliosis much is still unknown about the dynamics of pelvis in trunk-pelvic interaction and how the type of scoliosis compromises pelvic mobility consequently affecting the overall dynamics of the trunk-pelvis kinematic chain. METHODS: A total of 25 female AIS (18 right thoracic: RT and 7 right thoracic-left lumbar: RTLL) and 12 controls were recruited. Reflective markers were placed on the trunk and pelvis and their trajectories were recorded using a 5-camera motion capture system. Three trials were carried out, one for each of the various trunk-pelvis movements (flexion/extension, lateral bend, and axial rotation on either side) performed by the subjects. RESULTS: Pelvic alignment in the 3 planes were significantly different for all movement types (P < 0.001), with distinct differences in pelvic sagittal tilt and transverse plane rotation, particularly during lateral bending and axial rotation in patients with RT and LL curves (P = 0.035, P = 0.006, respectively). A majority of the patients from the 2 scoliotic groups had the pelvis rotated to the side of the major curve (right). Although RT subjects had similar dynamic pelvic responses as the controls, the RT-LL patients had relatively more pelvic sagittal tilt during lateral bending and axial rotation toward the major curve. CONCLUSION: In AIS, the initial three-dimensional alignment of the pelvis (sagittal and frontal tilt, transverse plane rotation) plays an essential role in dictating the biomechanics of the pelvis for any movement type. A spatial concurrency in pelvic alignment was noted wherein a change in 1 parameter will affect the remaining 2. Increased pelvic sagittal tilt in the RT-LL subjects was substituted by more pelvic rotation in the RT subjects during trunk flexion/extension. Differences in pelvic dynamics in AIS are not evident in discrete parameters, for example, total ranges-of-motion but more so in its biomechanics during the movement, which in turn is dictated by the initial alignment of the pelvis.