High-frequency blockade of the pudendal nerve using transcutaneous, capacitively coupled electrical stimulation

After spinal cord injury (SCI), external urethral sphincter (EUS) hyperreflexia often develops which can lead to an inability to properly empty the bladder. Short of catheterization and irreversible surgery, few options exist for managing this condition. High-frequency electrical stimulation can produce a reversible block of peripheral nerve conduction, and has been proposed as a way to block unwanted EUS contractions. We investigated the feasibility of a new stimulation technique using transcutaneous, capacitively coupled electrodes to produce a conduction block of the pudendal nerve (PN). Adhesive surface electrodes were placed over subcutaneous “pickup” electrodes which were connected to nerve cuffs or hook electrodes on the PNs in three isoflurane anesthetized cats. A portion of the current delivered to the surface electrodes is captured by the subcutaneous electrode and routed to the target nerve. Using this “stimulus router system” (SRS), high-frequency stimulation produced graduated blockade of EUS contractions elicited by proximal lowfrequency stimulation of the pudendal nerve. The SRS requires no implanted electronics and may aid in the management of EUS dysfunction after SCI.