Genital Nerve Stimulation - GNS - for Treatment of Non-neurogenic OAB

Pelvic organ dysfunctions are complex and difficult to treat. These conditions affect a substantial portion of the population, especially with increasing age. The two most frequent pelvic dysfunctions are the idio-pathic overactive bladder (IOAB) and erectile dysfunction (ED).

In pelvic dysfunctions, sacral nerve stimulation was the first technique for pelvic nerves stimulation that typically involves electrical stimulation of the nerve via a dorsal transformational technique of implantation. SNS evolved as a widely used treatment for OAB but does not completely resolve symptoms in the majority of patients. Because PNS reach more "sphincter-vesico-anal" fibers than SNM, PNS has been proposed for patients who have failed to respond to sacral neuromodulation. The good effects of PNS in neurogenic and in some non-neurogenic disorders. However, the implantation of a lead to the PN is not easily accomplished and the risk for lead migration with implantation below the pelvic floor is increased. So there is definitively a need for a more suitable alternative for selective stimulation within the pelvic cavity, a method that cannot only be reserved for experts in this field but for all gynecologists dealing with patients suffering from functional disorders of the bladder in daily clinical practice. The stimulation of the dorsal nerve of the pe-nis/clitoris - GNS - emerges as a very attractive alternative that might result in great outcomes for controlling urinary and fecal disorders.

Because part of the DNP lies superficially to the skin outside the pelvis, this nerve can be stimulated using surface electrodes attached to the overlying skin of the penis or close to the clitoris. This application is however limited, due to intolerance to required high stimulation amplitude. Surface electrodes have limitations such as difficulties in proper daily placement and issues related to hygiene as well as a lack of acceptance in some patients. Implanted electrodes are more suitable. However, implanted electrodes in the penis or near the clitoris, must endure the mechanical stress of penile erections and external pressure, carrying the risk of the cable/electrode breaking or being dislocated.

The GNS consists of a two-step procedure with a preoperative non-surgical test-phase and a final surgical implantation of the neuroprothesis. In contrast to the classical technique of transcutaneous lead electrode implantation for sacral or pudendal nerve stimulation, the GNS-test-phase does not require any interventional procedure: because the genital nerves are located just few millimeter below the skin, test-stimulation can be achieved using skin surface or needle electrodes. Stimulation is achieved using a battery powered hand-held stimulator . The effect of the stimulation can be tested by the patient in their daily, home and professional environment, or at the practice under urodynamic testing, or if required other electro-physiological testing. After confirmation of the effectiveness of GNS, implantation of a permanent neuroprothesis can be planned. The procedure is performed either under general or spinal anesthesia or using only local anesthesia with IV-sedation as in the classical tension-free vaginal tape procedure (TVT). Because the GNS does not require two surgical procedures for both the test- and the final-implantation but rather only one for the final implantation, the presented protocol allows considerable cost reduction in comparison to the usual procedures for sacral or pudendal nerve stimulation.