Grants We Funded

Abstract
Upper extremity loss is a life-altering event that can have devastating physical, psychosocial, and economic consequences for an amputee. Unfortunately, standard prostheses tend to be passive devices that provide little functional recovery beyond basic grasping. Acknowledging these limitations, researchers have explored the concept of a surgically integrated, biocompatible robotic prosthesis driven by an amputee's own severed nerves. Turning this concept into reality requires the development of a Regenerative Peripheral Nerve Interface (RPNI). This interface is a physical construct connecting nerve to machine allowing for the translation of natural human-driven electrical impulses into deliberate prosthetic movements. Our laboratory has developed an RPNI in the rat model consisting of a neurotized muscle graft with an applied electrode that can transduce and potentially harness electrophysiological signals for downstream control of a prosthetic device. We have demonstrated both the viability and durability of this interface, with ongoing studies focused on high-fidelity signal acquisition. Moving forward, we must consider the distinct tissue environment of a human residual limb to which we must adapt this construct. Our current rat model involves the use of whole muscles as grafts. In humans, however, there is no practical source of whole muscles for constructing multiple RPNIs without causing significant donor site morbidity. In contrast, ample muscle is present for harvest as partial muscle grafts. As such, we propose to investigate the novel use of partial muscle grafts for in vivo RPNI fabrication in the rat model. We will define key architectural characteristics of these muscle grafts that would optimize RPNI viability and functionality. Determining these features will help guide future construction of an RPNI suitable for humans.

Biography
Dr. Shoshana Woo is a resident in the Integrated Plastic Surgery Residency Program at the University of Michigan (Ann Arbor, MI). She obtained her Bachelor of Science degree in Molecular, Cellular, and Developmental Biology at Yale University (New Haven, CT). Dr. Woo completed her medical school training at Duke University, where she performed clinical research in geriatric psychiatry supported by the 2007-2008 Ewald W. Busse NIMH Research Fellowship, as well as clinical research in reconstructive plastic surgery. As a current plastic surgery resident at the University of Michigan, she discovered an interest the development of a regenerative peripheral nerve interface (RPNI) that would permit a seamless surgical integration between an amputee’s residual limb and a neuroprosthetic device. As a recipient of the 2013-2014 Plastic Surgery Foundation Research Fellowship award, she will investigate the muscle graft component of this interface in the rat model, which will guide future RPNI construction in humans.