Three-dimensional gait analysis reveals dynamic alignment change in a patient with dropped head syndrome: A case report.

Dropped head syndrome (DHS) is a cervical kyphotic deformity caused by apparent weakness of the neck extensor muscles. We often encounter patients whose symptoms, including impaired forward vision and neck pain, deteriorate while walking. This is the first report of a case of dynamic spinal alignment change in a patient with DHS during walking using three-dimensional gait analysis. A 78-year-old Japanese woman complained of impaired forward vision and neck pain while walking. Her radiograph showed severe cervical kyphosis. C2-C7 SVA was +74 mm and C7-S1 SVA was -18.4 mm. The patient attempted to compensate to improve forward vision through lumbar hyperlordosis. We analyzed the gait motion of the patient by using three-dimensional (3D) motion and wireless surface electromyographic analysis systems to measure two systems synchronously. The patient walked continuously for as long as possible. We calculated dynamic SVA from the 3D motion analysis. Her head drop deformity gradually progressed and interfered with her forward vision while walking. Cervical SVA gradually increased from 75 to 85 mm. Thoracic SVA, Lumbar SVA and Whole spine SVA were initially decreased because of compensatory lumbar hyperlordosis, but ultimately increased, suggesting decompensation by the time she had finished walking. EMG activity of the bilateral trapezius muscles gradually reduced, which reflected the disturbance of maintaining her posture. Previous static evaluation could not prove the dynamic change of spinal alignment and EMG activity during walking. By introducing 3D gait analysis, we could evaluate dynamic spinal alignment of a patient with DHS.