Stimulation of the deep perineal nerve elicits bladder contractions

Spinal cord injury (SCI) eliminates voluntary control of bladder function. This study examined the ability to elicit and sustain bladder contractions with deep perineal nerve (DP) stimulation in 3 cats. The DP was stimulated at 2, 10, 20, 33, and 40 Hz over a range of bladder volumes before and after SCI. DP stimulation elicited bladder contractions pre- and post-spinal transection and was dependent on bladder volume and stimulation frequency. Bladder contractions were only evoked above a threshold bladder volume, which decreased post-spinalization. Both pre- and post-transection, bladder contractions were evoked at stimulation frequencies (2 Hz - 40 Hz), however frequencies of 20 Hz or greater were more effective at sustaining contractions. Post-transection, stimulation frequencies of 33 Hz or greater evoked greater bladder pressures than lower frequencies. Stimulation of the proximal, but not distal DP after DP-transection elicited contractions, demonstrating that the response was afferent mediated. Neural prostheses able to evoke sustained bladder contractions could restore bladder control and provide substantial clinical benefit to individuals with SCI.