Nerve-Muscle Graft Chamber and micro-channel arrays tor interface to peripheral nerves for prosthesis control.
This research effort consists of two sub-projects with the goal to develop a small implantable device for achieving bi-directional communication with the amputated nerves in a prosthesis user’s residuum. The nerve-muscle graft chamber (NMGC) is a small implanted device which contains one or more electrically isolated chambers (ca. 20mm l x 4mm h x 4mm w ) that can be filled with muscle or cutaneous tissue. The electrical activities of the components of a compound peripheral nerve that in the intact limb sub-served different motor functions can be separated by mechanically dividing the nerve and placing each isolated nerve segment into apposition with a small piece of muscle tissue in each of the separate chambers of the NMGC. For example, the muscle filled chambers can be ganged together in a modular design so that a single implanted device containing three chambers would interface to motor nerve fascicles that provide prosthesis command signals for three different motor functions. For a mixed peripheral nerve that is known to contain cutaneous fascicles as well as motor fascicles, an additional compartment could be added that contains cutaneous tissue. This would be done to provide an appropriate target for regenerating cutaneous nerve fibers to prevent the cutaneous axons from competing with regenerating motor nerve fibers and errantly taking up residence in the muscle tissues. Also, by provide cutaneous target tissue, regenerating sensory afferent nerve fiber are less likely to result in the formation of potentially painful neuromas.
The second sub-project aims to develop a micro-channel array into which peripheral nerve fibers will grow into. Because the micro-channels are on the order of 100 to 200 um I.D., only a small number of nerve fibers will be present in an individual micro-channel. This can potentially provide greater separation of axons by their functionality. Such separation by function is important when seeking to provide cutaneous and proprioceptive feedback by means of direct electrical activation of the sensory components of the interfaced peripheral nerves.