The purpose of this study is to determine whether electrical pudendal nerve stimulation is more effective than pelvic floor muscle training with Transvaginal electrical stimulation in treating female stress incontinence.

Conservative therapy could be considered a choice of treatment for stress urinary incontinence (SUI) as it seems to have no side effects and causes significant and long-term improvement in symptoms. Pelvic floor muscle training (PFMT) and electrical stimulation are two commonly used forms of conservative treatment for SUI.

PFMT improves the structural support of the pelvis. However, many patients-especially women-have difficulty identifying and isolating their pelvic floor muscles (PFM) and are unable to perform the exercise effectively. Furthermore, patients who can identify the PFM often find that the required daily exercise routine is burdensome. Hence, the primary disadvantage of PFMT is lack of long-term patient compliance.

Electrical stimulation (ES) is a non-invasive, passive treatment that produces a muscle contraction. Transvaginal electrical stimulation (TES) has almost no side-effects and patient compliance in published reports is 70-85%. TES will result in PFM contraction by indirect nerve stimulation, mainly by polysynaptic reflex responses. The indirect stimulation and reflexive contraction may be the reason why the effect of electrical stimulation is not as good as that of PFMT when performed correctly.

By combining the advantages of PFMT and TES and incorporating the technique of deep insertion of long acupuncture needles, we 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) and contract the PFM. 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 PFM contraction, vaginal pressure and pelvic floor surface electromyogram in our previous study have proved that EPNS can exactly excite PN,contract the PFM and simulate PFMT. Our previous study has also proved that EPNS has a good therapeutic effect on female SUI. The purpose of this study is to compare the efficacy of EPNS to PFMT with TES in treating female SUI.

Inclusion Criteria:

• SUI history
• Positive stress test result
• Urodynamically confirmed SUI
• Postvoid residual urine volume <50ml

Exclusion Criteria:

• Urge incontinence (overactive bladder or detrusor overactivity incontinence)
• Neurogenic bladder