Efficacy of an implanted neuroprosthesis for restoring hand grasp in tetraplegia: a multicenter study

To evaluate an implanted neuroprosthesis that allows tetraplegic users to control grasp and release in 1 hand.

Multicenter cohort trial with at least 3 years of follow-up. Function for each participant was compared before and after implantation, and with and without the neuroprosthesis activated.

Tertiary spinal cord injury (SCI) care centers, 8 in the United States, 1 in the United Kingdom, and 1 in Australia.

Fifty-one tetraplegic adults with C5 or C6 SCIs.

An implanted neuroprosthetic system, in which electric stimulation of the grasping muscles of 1 arm are controlled by using contralateral shoulder movements, and concurrent tendon transfer surgery. Assessed participants' ability to grasp, move, and release standardized objects; degree of assistance required to perform activities of daily living (ADLs), device usage; and user satisfaction.

Pinch force; grasp and release tests; ADL abilities test and ADL assessment test; and user satisfaction survey.

Pinch force was significantly greater with the neuroprosthesis in all available 50 participants, and grasp-release abilities were improved in 49. All tested participants (49/49) were more independent in performing ADLs with the neuroprosthesis than they were without it. Home use of the device for regular function and exercise was reported by over 90% of the participants, and satisfaction with the neuroprosthesis was high.

The grasping ability provided by the neuroprosthesis is substantial and lasting. The neuroprosthesis is safe, well accepted by users, and offers improved independence for a population without comparable alternatives.