Hybrid Assistive Limb Intervention in a Patient with Late Neurological Deterioration after Thoracic Myelopathy Surgery due to Ossification of the Ligamentum Flavum

Abstract

Purpose We evaluated improvements in gait after using the Hybrid Assistive Limb (HAL®) exoskeleton robot in a patient with late-onset neurological deterioration of lower extremity function after undergoing thoracic spine surgery for a myelopathy due to ossification of the ligamentum flavum. Case Presentation A 70-year-old man participated in ten 20 min sessions of HAL intervention, twice weekly for five weeks. The effects of each HAL session were evaluated based on changes in performance on the 10 m walk test (10 MWT), lower limb kinematics quantified from motion capture, and the activation ratio of the gastrocnemius, measured before and after the intervention. Muscle activity was recorded using surface electromyography and synchronized to measured kinematics. The HAL intervention improved gait speed and step length, with an increase in the hip flexion angle during the swing phase and a decrease in the activation ratio of the gastrocnemius. The modified Ashworth scale improved from 1+ to 1 and International Standards for Neurological and Functional Classification of Spinal Cord Injury motor scores from 34 to 49. Conclusion Intervention using the HAL exoskeleton robot may be an effective method to improve functional ambulation in patients with chronic spinal disorders.

Feasibility of Neurorehabilitation Using a Hybrid Assistive Limb for Patients Who Underwent Spine Surgery

“…The results showed improvements in a series of clinical scales such as 10MWT, BI, GARS-M, and WISCI II. All participants showed improvements in gait ability that were similar to those of previous reports concerning the use of HAL for spine disorders such as SCI [ 8 – 14 ], SDAVF [ 41 ], and OPLL [ 18 – 22 , 26 ]. It is noteworthy that participants in our study underwent surgery for various reasons such as spinal cord tumor, vascular disease, and bone degenerative disease.…”

“…Another recent study demonstrated neuroplasticity induced by HAL treatment [ 16 , 17 ]. However, five case reports have focused on the efficacy of HAL therapy for postoperative thoracic ossification of the posterior longitudinal ligament (OPLL) [ 18 – 22 ]. These reports indicated that HAL was used as a last resort for gait recovery during the almost chronic phase of the postoperative state [ 21 , 22 ], and the authors recommended starting HAL-assisted training during the early stage following surgery.…”

“…However, five case reports have focused on the efficacy of HAL therapy for postoperative thoracic ossification of the posterior longitudinal ligament (OPLL) [ 18 – 22 ]. These reports indicated that HAL was used as a last resort for gait recovery during the almost chronic phase of the postoperative state [ 21 , 22 ], and the authors recommended starting HAL-assisted training during the early stage following surgery. Neurorehabilitation during the postoperative state is essential for returning to social activities and preventing disuse syndrome.…”

“…Neurorehabilitation during the postoperative state is essential for returning to social activities and preventing disuse syndrome. Based on the findings indicated by these five case reports [ 18 – 22 ], in addition to the reports demonstrating the efficacy of HAL training for SCI cases [ 8 – 14 ], we hypothesized that using HAL may facilitate early recovery after spine surgery. Therefore, we aimed to evaluate the safety and efficacy of HAL-assisted rehabilitation for spine disorder patients during the early postoperative period.…”

Muscular Activity Modulation During Post-operative Walking With Hybrid Assistive Limb (HAL) in a Patient With Thoracic Myelopathy Due to Ossification of Posterior Longitudinal Ligament: A Case Report

“…In previous studies on the application of HAL for postoperative gait rehabilitation of OPLL patients with thoracic myelopathy (10)(11)(12)(37)(38)(39), gait improvement is reported by comparing the state of the patient before starting and after finishing the entire robot-assisted intervention. However, this comparison hinders examination of the effect of the robot during the training per se, as well as how it differs from training without the robot.…”