Hybrid assistive limb (HAL) treatment for patients with severe thoracic myelopathy caused by ossification of the posterior longitudinal ligament (OPLL) in postoperative acute phase

Abstract

The purpose of this study was to clarify the safety and feasibility of rehabilitation using the robot suit hybrid assistive limb (HAL) for severe thoracic myelopathy due to ossification of the posterior longitudinal ligament (OPLL). Eight patients (mean age, 60.9 years) in the postoperative acute or subacute phases who presented with severe gait disturbance before surgery and underwent posterior decompression with instrumented fusion for thoracic ossification of the posterior longitudinal ligament (T-OPLL) were included in this study. Treatment using HAL (about 60 min per session, 2–3 times a week, 10 sessions in total) was started on mean postoperative day 27.5. Gait speed, step length, and cadence for each session were measured with the 10-m walking test. The American Spinal Injury Association (ASIA) motor score (lower extremities) and Walking Index for Spinal Cord Injury (WISCI) II were also evaluated at baseline and after 10 sessions. In addition, the Japanese Orthopaedic Association (JOA) score was calculated over time after surgery. Ten sessions of HAL treatment were completed in all patients. No serious adverse events related to the locomotor treatment with HAL were noted. Gait speed, step length, and cadence improved over time. Compared with baseline values, WISCI-II and ASIA motor score (lower extremities) after 10 sessions improved. The JOA score improved over time after surgery. Treatment using HAL can be performed in the early postoperative period without severe adverse events in patients with T-OPLL and severe gait disturbance.