Simple cuff electrodes, because they are easily fabricated, easily implanted, and highly reliable. have been the workhorse electrodes for most of the clinically applied neural prostheses in spite of their """"""""off- on"""""""" characteristics. While electrodes that permit graduated neural activation would yield better control, they cannot now be fabricated in the form of a safe and practical cuff. This limitation has recently been overcome by investigators at Case Western Reserve University (CWRU), who have demonstrated selective activation of nerves in animals with a self- wrapping spiral cuff electrode of patented design. The CWRU electrodes are now fabricated one-at-a-time in a laborious, time consuming series of manual operations whose output is small and whose product is unreliable and non reproducible to fully realize the benefits of CWRU's innovation, an improved, mass-producible version must be developed. Such an electrode is the subject of Spire's proposal. Specifically, the proposed work would target fabrication of a spiral cuff electrode for restoration of bladder control in pediatric spinal cord injury patients. Ion beam assisted deposition (IBAD) will be used to place a thin, highly adherent, conducting film on silicone rubber substrates and standard semiconductor processing techniques (photolithography) used to define electrodes in it. This approach will allow reliable, repeatable production of the spiral cuff electrode design and make possible designs with smaller features and more stimulating surfaces. Prototype cuffs will be manufactured in the proposed research period. The prototype electrodes will then be tested in acute and chronic animal models. In a continuation effort, we would further refine the fabrication process and test the electrodes in extensive, longterm animal studies.
