Sagittal kinematics and imbalance of the spine and whole body during walking in late-onset Pompe disease

Late-onset Pompe disease (LOPD) is characterized by postural abnormalities mainly due to involvement of paraspinal lumbar and abdominal-pelvic muscles. Previous studies quantitatively analyzed static upright posture, spatial-temporal parameters, and kinematics of the lower limbs and trunk, considered as single bone segment. Sagittal plane analysis of the spine and whole body during walking has never been investigated in patients with LOPD. The aim of the study was to evaluate sagittal kinematics and imbalance of the spine and whole body in patients with LOPD by three-dimensional (3-D)-motion analysis using an appropriate marker set protocol and introducing innovative kinematic parameters. Seven siblings with LOPD were assessed by 3-D-stereophotogrammetry using the DB-total protocol, which allows to analyze sagittal alignment of whole body. Fourteen age-and sex-matched healthy subjects were used as controls. LOPD group showed a flattening of the spinal curvatures, with a head and neck posteriorization with respect to sacrum, a significant increase of concavity in Heel-S2-Nasion/C7 angles, a rear-position of upper limbs with respect to pelvis, a shorter pendular activity, and a trend of elbow extension during ambulation. Moreover, a significant increase of excursion range in most of sagittal parameters was found. The present study highlighted a specific pathological postural pattern, resembling "man falling backwards," which reveals a biomechanical compensation strategy of patients with LOPD to maintain the balance against the instability of the spinopelvic region, kinematically verified by increase of the excursion ranges. DB-total kinematic parameters might be useful for functional evaluation and for monitoring response to enzyme replacement therapy, rehabilitation project, and disease progression.