Superficial peroneal neuromodulation of nonobstructive urinary retention induced by prolonged pudendal afferent activity in cats.

The purpose of this study is to determine whether superficial peroneal nerve stimulation (SPNS) can improve nonobstructive urinary retention (NOUR) induced by prolonged pudendal nerve stimulation (PNS). In this exploratory acute study using eight cats under anesthesia, PNS and SPNS were applied by nerve cuff electrodes. Skin surface electrodes were also used for SPNS. A double lumen catheter was inserted via the bladder dome for bladder infusion and pressure measurement and to allow voiding without a physical urethral outlet obstruction. The voided and postvoid residual (PVR) volumes were also recorded. NOUR induced by repetitive (4-13 times) application of 30-min PNS significantly ( P < 0.05) reduced voiding efficiency by 49.5 ± 16.8% of control (78.3 ± 7.9%), with a large PVR volume at 208.2 ± 82.6% of control bladder capacity. SPNS (1 Hz, 0.2 ms) at 1.5-2 times threshold intensity (T) for inducing posterior thigh muscle contractions was applied either continuously (SPNSc) or intermittently (SPNSi) during cystometrograms to improve the PNS-induced NOUR. SPNSc and SPNSi applied by nerve cuff electrodes significantly ( P < 0.05) increased voiding efficiency to 74.5 ± 18.9% and 67.0 ± 15.3%, respectively, and reduced PVR volume to 54.5 ± 39.0% and 88.3 ± 56.0%, respectively. SPNSc and SPNSi applied noninvasively by skin surface electrodes also improved NOUR similar to the stimulation applied by a cuff electrode. This study indicates that abnormal pudendal afferent activity could be a pathophysiological cause for the NOUR occurring in Fowler's syndrome and a noninvasive superficial peroneal neuromodulation therapy might be developed to treat NOUR in patients with Fowler's syndrome.