Biomechanical Evaluation of Back-Support Exoskeletons during Patient Transfers

Abstract

The purpose of this study was to investigate the effects of three back-support exoskeletons (FLx ErgoSkeleton, V22 ErgoSkeleton, Laevo V2.5) and patient transfer methods (Squat pivot, stand pivot, scoot) on the musculoskeletal loading and self-reported usability measures during patient transfers between a bed and a wheelchair. In a repeated-measures laboratory study, 20 experienced caregivers (17 females and 3 males) performed a series of 24 bed-to-wheelchair transfer tasks (2 directions × 4 exoskeleton conditions × 3 patient transfer methods). The trunk flexion and lateral flexion angles, bilateral hand pull forces, and muscle activities of the erector spinae were significantly different by exoskeleton conditions and patient transfer methods (p’s < 0.01). The usability measures were significantly affected by exoskeleton designs (p’s < 0.01). There were significant two-way interaction effects on the trunk flexion and lateral flexion angles and muscle activities of the erector spinae (p’s < 0.01). For the squat pivot method, three back-support exoskeletons showed the largest reduction of erector spinae muscle activities (47.4 to 83.5% reference voluntary contractions) compared to no exoskeleton. This indicated the effects of exoskeleton conditions on the trunk postures and erector spinae muscle activities depended on the patient transfer method. More research could be needed to improve the trunk postures and usability of back-support exoskeletons suitable for patient handling.