# Regenerative Peripheral Nerve Interface for Restoring Individual Finger Movement in People with Upper Limb Amputations

> **NIH NIH R01** · UNIVERSITY OF MICHIGAN AT ANN ARBOR · 2020 · $451,219

## Abstract

Project Summary/Abstract
There are approximately 50,000 people in the US with complete amputation of the hand, and many more with
debilitating partial hand amputations. Treatments have not changed substantially since the body powered hook
was invented during the civil war. While electrical signals from residual muscle can provide some function,
every amputee is missing muscles, and therefore missing a variety of important functions. Attempts to record
these signals from the nerves have suffered from low amplitude, low longevity, or both. Recently our group has
demonstrated a novel method for obtaining signals from independent nerve fascicles in rats and NHPs, which
we call the Regenerative Peripheral Nerve Interface (RPNI). Multiple dissected residual nerve branches are
each placed in a 1x3 cm free muscle graft. The small muscle grafts degenerate, regenerate, revascularize, and
reinnervate utilizing natural biologic processes. Upon completion of this regenerative process, the neurotized
free muscle graft then amplifies a 5 μV cuff ENG into a >250 μV EMG signal. Most recently, we have replicated
these results in 3 humans with upper limb amputation, routinely recording signals above 100 μV that
correspond to individual finger movements. Our long-term goal is to provide intuitive high fidelity control of
individual prosthetic fingers and enable naturalistic sensory feedback. The objective of the present application,
which represents our proposed next step, is a pilot clinical trial of safety and bidirectional prosthetic
control efficacy using the RPNI in 6 subjects. Our team includes the original developers of the RPNI
concept, Drs. Cederna and Kung, who have since placed human RPNI implants in 65 patients for the control of
neuroma pain. The team also includes two engineers, Drs. Chestek and Gillespie with complementary
expertise in neural signal processing and prosthetic control. Dr. Chestek also has extensive experience in
neuroprosthetic human clinical trials. Three specific aims have been constructed to address independent
aspects of safety and efficacy of RPNis in humans during a 5 year study. In Aim 1, 6 participants will be
implanted with multiple grafts on each severed nerve, following by indwelling EMG electrodes in a later
procedure. Multiple validated instruments will be used to monitor pain and other potential adverse events
during this process. In Aim 2, we will evaluate the amplitude, specificity, and longevity of the result neural
signals for up to 12 months. In Aim 3, we will quantitatively determine whether enhanced finger control
ultimately enables higher performance on tasks of daily living and embodiment with the prosthetic limb. The
results of these aims will provide critical safety and efficacy data, and strongly motivate a larger, perhaps
pivotal clinical trial across multiple years, using a wireless implantable neural recording device for EMG.

## Key facts

- **NIH application ID:** 9963422
- **Project number:** 5R01NS105132-03
- **Recipient organization:** UNIVERSITY OF MICHIGAN AT ANN ARBOR
- **Principal Investigator:** Cynthia Anne Chestek
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $451,219
- **Award type:** 5
- **Project period:** 2018-07-15 → 2023-06-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9963422

## Citation

> US National Institutes of Health, RePORTER application 9963422, Regenerative Peripheral Nerve Interface for Restoring Individual Finger Movement in People with Upper Limb Amputations (5R01NS105132-03). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/9963422. Licensed CC0.

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