Restoring hand grasping for patients with a complete tetraplegia with selective epineural stimulation: a parsimonious thus relevant clinical approach.

Only four men participated, all with C4 complete tetraplegia and no eligibility for tendon transfer, so the findings cannot be generalized beyond this small group. The experiment lasted less than a month, so performance optimization was not possible. The electrodes were removed between day 28 and day 30 because of short-term device regulations, so long-term safety, durability, and benefit were not tested. Several grasping phases required a passive orthosis or human aid, and three participants needed a passive orthosis, so the contribution of stimulation alone cannot be separated. P1 and P2 used an orthosis, human aid, or both for grab, hold, and release, while P3 used a wrist brace depending on task. P4 had residual wrist extensor strength of 2/5, so his results may reflect that residual movement as well as stimulation. Execution times were not a valid indicator of functional improvement because participants were only asked to finish within 180 seconds, not to move quickly. Fatigue was assessed in only P3 and P4 over two sessions, and one P4 tablet recording was too noisy to report. The study used an external stimulator and cables through the skin, not a fully implanted system. The authors state that they could not explore all possibilities of the nerve stimulation approach because the investigation time was limited. The authors state that no scale currently objectively quantifies task reliability and safety.

The study was funded by Région Occitanie Grant, EIT Health Grant, and EIC PathFinder. The report does not state author competing interests.

Do not read this as proof that the system works for most people with complete tetraplegia. It was four men, under one month, and tasks often required a passive orthosis or human aid.