Controlled reshaping of nerve geometry

Abstract

The purpose of this study is the development of a nerve electrode that reshapes nerve geometry slowly and controllably. The flat interface nerve electrode (FINE) can reshape the nerve into an elongated oval and provide selective stimulation. However, the FINE'S ability to reshape nerve geometry quickly may cause acute nerve insult. The slowly closing flat interface nerve electrode (SC-FINE) is designed to increase the opening height to accommodate the nerve and initial swelling. Moreover, the SC-FINE controls the reshaping period to alleviate nerve compression injury. The SC-FINE is manufactured by combining the reshaping properties of the FINE and the controllable degradation of poly (DL lactic-co-glycolic) acid (PLGA). Bonding 50/50 or 65/35 PLGA to a stretched FINE increased the opening heights on average from .1 mm to 1.66 /spl plusmn/ 0.45 mm and 2.05 /spl plusmn/ 0.55 mm respectively. The addition of PLGA films controls the time course of closure over a period of 16 /spl plusmn/ 1 days and 14 to 16 hours for the 50/50 and 65/35 SC-FINEs respectively in vitro. An in vivo chronic experiment using 50/50 SC-FINEs implanted in 28 rats with an average opening height of 1.87 /spl plusmn/ 0.34 mm show that the reshaping periods in vivo are in vitro are similar.