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Burke et al. Plast Aesthet Res 2022;9:48 https://dx.doi.org/10.20517/2347-9264.2022.26 Page 5 of 9

Figure 3. Intraoperative RPNI creation. This patient underwent implantation of four RPNIs, one each for the radial and median nerve and
two for the ulnar nerve. RPNI: Regenerative peripheral nerve interface.

[15]
peripheral nerves through the RPNI . In fact, even in patients with proximal amputations, fascicular
RPNIs can be created and utilized to capture signals for intrinsic finger movements. For instance, distinct
RPNIs that facilitated individual finger movements were identified in a patient with a shoulder-level
amputation .
[9]

Human trials have also demonstrated that patients with RPNIs have long-term stability of RPNI signals for
highly accurate, continuous control of prosthetic finger movements . Experimental tasks were designed to
[9]
test the accuracy of prosthetic control. These tasks were completed by patients with high accuracy on day 0
[9]
(96%-100%) up to day 300 (96%-100%) . It should be noted that signal amplitudes and SNR remained
unchanged over time without the need for recalibration of the original control algorithm. This is a
significant advancement and major benefit due to the fact that other existing strategies of prosthetic control
require frequent recalibrations for accurate, reliable control [19-23] . For example, powered prostheses
controlled using surface EMG often require daily recalibrations, and even multiple recalibrations during the
same day, due to changes in electrode impedance, position, and motion artifacts throughout the day. Even
as the user becomes more experienced using the device, the need for frequent recalibration cannot be
eliminated . The outcomes from clinical trials in humans have helped establish the reliability, stability, and
[19]
durability of RPNIs in signal transduction for intuitive neuroprosthetic control.

REGENERATIVE PERIPHERAL NERVE INTERFACES FOR SENSORY FEEDBACK
Despite the advancements in modern robotic technology, prosthetic users still primarily rely on visual
[24]
feedback to improve the function and control of their prosthetic device . Lack of sensory feedback is a
major limitation to reestablishing the full functionality of the natural limb. Restoring tactile sensation and
proprioception would relieve the cognitive burden of relying solely on visual cues to monitor motor
commands. In addition, the restoration of the sense of touch would provide tremendous psychological
benefits and give individuals a sense of prosthetic embodiment .
[25]