Effects of passive back-support exoskeletons on physical demands and usability during patient transfer tasks

The objective of this study was to evaluate and compare the effects of three passive back-support exoskeletons (FLx ErgoSkeleton, V22 ErgoSkeleton, and Laevo V2.5) and patient transfer methods on physical demands in the low back and shoulders during patient transfer. Twenty professional caregivers (17 females and 3 males) performed a series of simulated patient transfer tasks between a wheelchair and a bed with three different patient transfer methods including the squat pivot, stand pivot, and scoot with two directions (wheelchair to bed and vice versa). The passive exoskeletons (FLx ErgoSkeleton, V22 ErgoSkeleton, and Laevo V2.5) significantly affected trunk postures (forward flexion and lateral flexion), shoulder postures (flexion and abduction), hand pull forces, muscle activities of erector spinae and middle deltoid (p-values < 0.01). The muscle activities of the erector spinae were significantly lower (up to 11.2%) with the FLx and V22 ErgoSkeletons compared to no exoskeleton condition (p-values < 0.002). However, the trunk and shoulder flexion angles with the passive exoskeleton use were greater (up to 77.3%) than those without the exoskeletons (p-values < 0.03). The biomechanical benefits and usability varied by passive exoskeleton designs (p-values < 0.01). The lower muscle activities of the erector spinae suggest that the back-support exoskeletons may be a viable intervention to reduce the low back strain during patient transfer tasks. More research would be needed to reduce the adverse effects of back-support exoskeletons on the postures such as increased trunk and shoulder flexions during patient handling.