A Comparison of Efficacies of Electrical Pudendal Nerve Stimulation Versus Transvaginal Electrical Stimulation in Treating Urge Incontinence

Electrical neuromodulation can be used to treat UUI refractory to medication. Electrical neuromodulation therapies include transvaginal or transanal electrical stimulation (TES), percutaneous tibial nerve stimulation (PTNS), sacral neuromodulation (SNM), and pudendal neuromodulation (PNM). TES is easily applicable but is sometimes intolerable for many patients due to discomfort, mucosal injury, and high-intensity stimulation necessary to obtain acceptable outcome. SNM with the InterStim device differs from TES by its continuous stimulation and close nerve contact. It has a high rate of success, but symptoms appear to recur almost immediately after discontinuation of the stimulation, and at least 20 % of patients initially tested do not respond to a test procedure. Its disadvantages included invasiveness, high cost of treatment, high surgical revision rate, device replacement required when battery runs out, and adverse events. PNM with the Interstim device or the Bion device can be used to treat UUI refractory to SNM, but this therapy also has the disadvantages similar to those of SNM. PTNS with needle electrodes is minimally invasive, demonstrates efficacy, and is easily applicable and well tolerated, but PTNS effects diminish over time after the end of treatment.

By combining the advantages of PTNS and PNM and incorporating the technique of deep insertion of long acupuncture needles, the investigators developed electrical pudendal nerve stimulation (EPNS). In EPNS, long acupuncture needles of 0.40 Х 100 or 125 mm were deeply inserted into four sacral points and electrified to stimulate the pudendal nerves (PN). CT transverse plane at the coccygeal apex has showed that the position of the lower needle tip is similar to where (adjacent to PN at Alcock's canal) the Bion device is implanted for chronic PN stimulation. Besides the radiographic evidence, simultaneous records of perineal ultrasonographic pelvic floor muscle contraction, vaginal pressure and pelvic floor surface electromyogram in our previous study have proved that EPNS can exactly excite PN. The purpose of this study is to compare the efficacies of EPNS versus TES in treating female UUI.