Risk management and regulations for lower limb medical exoskeletons: a review

Abstract

Gait disability is a major health care problem worldwide. Powered exoskeletons have recently emerged as devices that can enable users with gait disabilities to ambulate in an upright posture, and potentially bring other clinical benefits. In 2014, the US Food and Drug Administration approved marketing of the ReWalk™ Personal Exoskeleton as a class II medical device with special controls. Since then, Indego™ and Ekso™ have also received regulatory approval. With similar trends worldwide, this industry is likely to grow rapidly. On the other hand, the regulatory science of powered exoskeletons is still developing. The type and extent of probable risks of these devices are yet to be understood, and industry standards are yet to be developed. To address this gap, Manufacturer and User Facility Device Experience, Clinicaltrials.gov, and PubMed databases were searched for reports of adverse events and inclusion and exclusion criteria involving the use of lower limb powered exoskeletons. Current inclusion and exclusion criteria, which can determine probable risks, were found to be diverse. Reported adverse events and identified risks of current devices are also wide-ranging. In light of these findings, current regulations, standards, and regulatory procedures for medical device applications in the USA, Europe, and Japan were also compared. There is a need to raise awareness of probable risks associated with the use of powered exoskeletons and to develop adequate countermeasures, standards, and regulations for these human-machine systems. With appropriate risk mitigation strategies, adequate standards, comprehensive reporting of adverse events, and regulatory oversight, powered exoskeletons may one day allow individuals with gait disabilities to safely and independently ambulate.

Systematic Review on Wearable Lower-Limb Exoskeletons for Gait Training in Neuromuscular Impairments

“…Studies found that misalignment due to suboptimal fitting can increase the metabolic cost and discomfort of the wearer producing pain, injuries [56,57] and augment the risk of bone fractures [58,59]. Therefore, the structure of the exoskeleton has to be able to adapt to the anthropometry of the users [60].…”

“…Despite the fact that, in general, studies show that wearable exoskeletons are safe devices, these results may not be fully representative. According to He et al [58], studies tend to omit relevant details when reporting adverse events, differ on the inclusion/exclusion criteria, and do not report explicitly whether adverse events occurred. In the study by van Herpen et al [59], the authors reported the occurrence of two cases of bone fractures during training with exoskeleton and provided instructions for handling accidental situations such as an unexpected shut down of the control system of the exoskeleton.…”

“…Although results show that wearable exoskeletons are generally safe devices [136], there is always the risk of unforeseen serious adverse events [59]. Thus, more efforts are needed to develop adequate standards and regulations to have a better understanding of the adverse events and risks of using wearable exoskeletons [58].…”

Advanced technology for gait rehabilitation: An overview

“…76 Bone mineral density should be assessed before proceeding to training with robotic devices to avoid such accidents. 77 While adverse effects are transitory and mainly due to lack of individual adjustments, the beneficial effects of technologically assisted gait training can be seen even after one single session. For example, one session of training on TM with FES on dorsi and plantar flexors increases the peak of anterior ground reaction force and of integral ground reaction force in post-stroke users.…”

Development of a Compact Lower-Limb Exoskeleton for Walking Assistance: A Case Study

“…In recent years, the lower-limb exoskeleton, or \wearable robot" as it is known, has substantially evolved and been an effective means to provide paraplegic and hemiplegic individuals with the ability to walk upright. [5][6][7][8][9][10][11][12] A lot of studies about the lower-limb exoskeletons have been developed to assist the impaired populations. Several commercial devices including Rewalk TM ; 13,14 Ekso TM ; 15,16 HAL r ; [17][18][19][20] and Indego TM ; [21][22][23][24][25] are on the market.…”