| Functional electrical stimulation (FES) is a means to restore lost function to neurologically impaired patients. One essential component of a FES system is the electrical charge delivery device or electrode. A peripheral nerve electrode delivers the electrical stimulation directly to the peripheral nerve. In this work, a novel class of peripheral nerve electrode, the reshaping nerve electrode, is introduced. The reshaping electrode applied a small, non-circumferential force to the nerve and exploits the natural plasticity of the body's tissues. The small force reshapes a peripheral nerve for intimate access to its entire axon population. Two reshaping electrode designs are presented. The stimulation selectivity and chronic safety of the reshaping nerve electrodes are presented.;The first electrode design is the slowly penetrating interfascicular nerve electrode (SPINE). The SPINE places small forces on elements perpendicular to the nerve to urge elements into the nerve, but between the fascicles. Acute experiments on the cat sciatic nerve show that the SPINE reshapes the nerve and rearranges the fascicles to place elements within the nerve, thus providing access to the central and surface axon populations. Stimulation results show that interfascicular stimulation selectively produces several different functions of sciatic nerve.;The second electrode design is the flat interface nerve electrode (FINE). The FINE is designed to slowly elongate the nerve and fascicles into flattened ovals. Acute experiments on the cat sciatic nerve show that the FINE reshapes the nerve and the fascicles. By aligning and flattening the fascicles, the FINE is able to selectively generate the functions of the sciatic nerve. The chronic safety of three FINEs that apply different forces to the rat sciatic nerve is examined. It is shown that a small force FINE, which applies the same or less force to the nerve than presently accepted nerve electrodes, can reshape the nerve and fascicles. This small force FINE does not cause changes in the physiology, histology, or blood-nerve barrier permeability of the rat sciatic nerve as compared to sham trials. |
