Quantification of similarities in recruitment properties of monopolar and tripolar configurations

Nerve cuff electrodes have been shown to be safe and capable of effecting selective and controlled activation of select segments of a peripheral nerve. This selectivity has been shown using a cuff with four equally spaced tripole electrodes employing twelve contacts and twelve lead wires. With present technology, constructing a twelve contact, twelve lead wire nerve cuff is not feasible for safe chronic implementation in a human. In the study presented here, the authors evaluate the monopolar configuration for its simplified and reduced number of contacts and lead wires. Based on the similarity of current flow patterns between monopolar and tripolar configurations, the recruitment characteristics should be similar. Both the overlap between monopolar and tripolar configurations and the repeatability of each configuration was measured. A statistical difference was not found between monopolar and tripolar configurations nor was a statistical difference found for the repeatability of each configuration. Based on these findings the authors conclude that a four contact monopolar cuff electrode can be used in place of a twelve contact tripolar cuff electrode