Chronic implementation of the flat interface nerve electrode

The Flat Interface Nerve Electrode (FINE) is a novel peripheral nerve electrode that reshapes the nerve into an ovoid geometry. Compared to cylindrical electrodes, this allows more contacts to be placed around the nerve, and moves deep fibers closer to the neural surface. Acute experiments have previously demonstrated that it is possible to selectively activate groups of fibers within individual fascicles using the FINE. In this study, the ability to achieve subfascicle level selectivity in a chronic setting has been investigated. A FINE was implanted on the right sciatic nerve of 6 cats, and selectivity measurements were made every 2 weeks. Subfascicle level selectivity was attainable throughout the implant period, but only in some of the fascicles tested. It is hoped that refinements in the electrode design may lead to more consistent selectivity across different nerve geometries.