Safety and risk management of powered exoskeleton for spinal cord injury

Abstract

The usage of powered exoskeletons has been reported to benefit gait reconstruction in patients with spinal cord injury (SCI). However, few studies have reported on the aspects of safety. We investigated and observed rehabilitation using exoskeleton, and performed a risk analysis for safer exoskeletons. First, we reviewed reports on adverse events and found a high incidence of skin troubles and device malfunctions but a low incidence of falls. It suggests the usefulness of support from human helpers. Second, gait training using two types of exoskeletons was performed at a rehabilitation center. The falling of a paraplegic patient with an exoskeleton was prevented by the contact assistance and supervision of two physical therapists, thus confirming that safety was dependent on human support. On the other hand, the specific themes of rehabilitation using exoskeletons were also found, such as unstable walking, behaviors suggesting psychological and physical fatigue in physical therapists, and problems of fitting and usability. Finally, the risk assessment results indicated the engineering protective measures to multiple hazards reduced the risk score, but some unavoidable risks, such as falls, remained without the human supports. The development of safer exoskeletons requires comprehensive risk reduction measures through engineering protection and human support which assumed the usage of patients with SCI and their helpers.