Hybrid Assistive Limb Treatment for the Shoulder and Elbow Joints Enabled Recovery from Chronic-Phase Severe C5 Palsy Following Cervical Spine Surgery

Postoperative C5 palsy is a common complication of cervical spine surgery. Inadequate recovery from C5 palsy can result in significant impairment of activities of daily living. However, no effective treatment has been established for persistent cases. In the present report, we describe a novel therapeutic approach using the Hybrid Assistive Limb (HAL) in a patient with severe, prolonged postoperative C5 palsy. The patient was a 46-year-old man who developed severe right C5 palsy following cervical spine surgery performed 41 months earlier. Despite undergoing conventional rehabilitation, no improvement was observed, and the muscle strength of the right deltoid and biceps remained at manual muscle testing (MMT) grade 2. HAL training, using both shoulder and elbow devices, was initiated at our institution. Training was conducted once weekly for a total of 106 sessions over 21 months. At baseline, the right shoulder range of motion was limited to 50° in flexion and 35° in abduction. With HAL-assisted training, flexion improved to 150° and abduction improved to 95° by the final (106th) session and further increased to 165° and 170°, respectively, at long-term follow-up. Deltoid strength, assessed using handheld dynamometry, increased from 3.5 Nm/kg at baseline to 28.5 Nm/kg after training. In this case, a long-term therapeutic program incorporating shoulder and elbow HAL training successfully improved severe and prolonged postoperative C5 palsy to a functionally useful level. This case highlights the potential effectiveness of HAL therapy for treatment-resistant postoperative C5 palsy.