Invasive neural interfaces: the perspective of the surgeon

Abstract

Background: By implanting electrodes inside peripheral nerves, amputee's intentions are picked up and exploited to control novel dexterous sensorized hand prostheses. Under the pretext of presenting surgical technique and clinical outcomes of the implant of invasive peripheral neural interfaces in a human amputee, this article critically comments, from the point of view of the surgeon, strengths and weaknesses of the procedure.

Materials and methods: Four multielectrodes were implanted in the medial and ulnar nerves of a young volunteer, which, following a car-crash, had a left transradial amputation. Both nerves were approached with a single incision in the medial aspect of the upper arm. Four weeks later, the electrodes were removed.

Results: Even if the trauma and the postamputation plastic processes altered the anatomy, electrodes were proficiently implanted with an overall success of 66%. Looking at the procedure from the surgeon's viewpoint unveils few still open issues. Electrodes weaknesses were related to the absence of stabilizing structures, the cable transit through the skin, the implant angle, and the unproven magnetic resonance imaging compatibility. Future investigations are needed to definitely address the better anesthesia, number and sites of incisions, the nerves to implant, and the convenience of performing epineural microdissection.

Conclusions: Invasive neural interfaces developmental process almost completely relies on the efforts of bioengineers and neurophysiologists; however, the surgeon is responsible for intra and perioperative factors. Therefore, he deserves to play a major role also at the stage of specifying the requirements, to satisfy the requisites of a safe, stable, and long-lasting implant.

Keywords: Amputees; Hand prostheses; Invasive neural interface; Peripheral nerves; Upper limb surgery.