Subject-controlled stimulation of dorsal genital nerve to treat neurogenic detrusor overactivity at home.

AIMS: To investigate the effects of subject controlled dorsal genital nerve (DGN) electrical stimulation on neurogenic detrusor overactivity (NDO) in subjects at home. METHODS: Subjects underwent a 5-day study at home with DGN stimulation. Stimulation was provided with surface electrodes placed either on the dorsal penile shaft in males and on or close to the clitoris in females. The days 1 and 5 were with no stimulation whereas days 2-4 were with stimulation. Two urodynamic studies were performed at the beginning and at the end of the study. A bladder diary was obtained. RESULTS: Eleven subjects with NDO and with urge incontinence were included. One subject stopped the protocol before the end of the 5-day trial and two did not undergo the second urodynamic study. The subjects showed a statistically significant increase in bladder capacities compared to baseline (P = 0.047). Mean volume per day voided significantly increased over the study within the subjects. Differences between day 1 and day 5 were statistically significant (P = 0.028). CONCLUSIONS: The feasibility and the globally positive outcomes of the study indicate that the stimulation of the dorsal genital nerve can be an option for the treatment of the NDO.

Dorsal genital nerve stimulation in patients with detrusor overactivity: a systematic review.

This study evaluates the outcome of trials to stimulate the dorsal genital nerve (DGN) in patients with lower urinary tract dysfunction. The aim of most studies was to suppress detrusor overactivity in patients with overactive bladder (OAB) syndrome by DGN stimulation. A literature search was performed using Pub Med, Web of Science, and Scopus databases (1980 to April 2012) for clinical trials of DGN stimulation in patients with detrusor overactivity. Seventeen studies were found in the literature. In the studies, different patterns of DGN stimulation were applied. The patterns were either continuous, conditional, or semi-conditional; on an acute or on a chronic basis. DGN stimulation lead to improvement of bladder capacity and reduction in urgency and/or incontinence episodes in many patients. The outcomes of conditional stimulation were comparable to continuous stimulation with respect to improvement of bladder capacity. The publications give evidence that DGN stimulation increases bladder capacity and suppresses involuntary detrusor contractions. Implantable DGN stimulation electrodes can open the way for more prolonged studies in larger patient groups to assess the effectiveness of chronic DGN stimulation in patients with OAB syndrome. Chronic DGN stimulation seems to be of value in the management of OAB syndrome.

Surgical access for electrical stimulation of the pudendal and dorsal genital nerves in the overactive bladder: a review.

PURPOSE: The anatomy of the pudendal nerve and its nerve branches, especially the dorsal nerve of the penis and clitoris (dorsal genital nerves), and the clinical application of electrical stimulation of these nerves in patients with overactive bladder syndrome and detrusor overactivity are reviewed. MATERIALS AND METHODS: A literature search was performed using the PubMed® database and reference lists of relevant studies to obtain articles concerning the anatomy as well as the electrical stimulation of the pudendal nerve and its nerve branches in patients with overactive bladder syndrome. RESULTS: According to the anatomy, electrical stimulation of the pudendal nerve and the dorsal genital nerves to suppress involuntary detrusor contractions is possible at several sites along their course from the sacral nerves to the penis or clitoris. The nerves are accessible by minimally invasive percutaneous methods. Stimulation of the pudendal nerve and dorsal genital nerves effectively increases bladder capacity, and inhibits involuntary detrusor contractions and overactive bladder symptoms. CONCLUSIONS: More clinically applied studies are recommended for stimulation of the dorsal genital nerves to assess its value and feasibility because most studies have been performed in an acute and experimental setting. The preferred type of electrode is not known, but if wire electrodes can be implanted and fixated well by a minimally invasive procedure, cuff electrodes are not necessary. Before deciding on continuous or conditional stimulation, chronic clinical studies are recommended because acute studies remain inconclusive. The feasibility of conditional stimulation depends on the availability of a reliable and clinically applicable detrusor activity sensor.

Rectal evacuation and antegrade colonic luminal transport by sacral anterior root stimulation in pigs.

PURPOSE: Electrical sacral anterior root stimulation with a selective anodal block may relieve difficulties with bowel evacuation by selective colorectal activation and anal sphincter suppression. This study compares rectal evacuation induced by anodal block with that induced by unselective stimulation. METHODS: The sacral anterior roots were stimulated with cuff electrodes in seven chloralose-anesthetized minipigs. Anodal block and unselective stimulation were applied in random order and compared by anorectal manometry and by the obtained colorectal evacuation. Evacuation was quantified scintigraphically after retrograde radioactive paste installation. RESULTS: Unselective stimulation evoked sphincter activation which obstructed rectal evacuation during the 30-second stimulation period, after which poststimulation evacuation occurred (mean, 13%; P < 0.05). Anodal block reduced the anal canal pressure by median 83% compared with unselective stimulation. With unrestrained evacuation, a different evacuation pattern (mean, 18%; P < 0.05) occurred within the first ten seconds of the stimulation period and evacuated volume was higher (P = 0.08). Colonic evacuation reached a mean of 17% with unselective stimulation and 11% with anodal block. CONCLUSION: Anodal block and unselective sacral root stimulation induce rectal evacuation and colonic luminal transport in pigs. However, anodal block may improve stimulation-induced defecation by enabling a near-physiologic defecation pattern.

Colon emptying induced by sequential electrical stimulation in rats.

Electrical stimulation could be used to induce colon emptying. The present experiments were performed to establish a stimulation pattern to optimize the stimulation parameters and to test neural involvement in propulsion induced by electrical stimulation. Colon segments were sequentially stimulated using rectangular pulses. The resulting propulsive activity displaced intraluminal content in consecutive propulsion steps. The propulsion steps differed in displacement latency, distance, and velocity along the stimulated colon. Increasing the pulse duration or amplitude resulted in a decrease of the latency. Increasing the stimulation amplitude doubled the displacement distance. The frequencies tested in the present study did not affect propulsion. Inhibition of cholinergic and nitrergic pathways inhibited propulsion. Electrical stimulation can induce colonic propulsion. Motor differences are present along the descending colon. The most suitable combination of pulse parameters regarding colon stimulation is 0.3 ms, 5 mA, 10 Hz. Neural circuits are involved in propulsion when using these values.

Different pulse shapes to obtain small fiber selective activation by anodal blocking--a simulation study.

The aim of this study was to investigate whether it is possible to reduce a charge per pulse, which is needed for selective nerve stimulation. Simulation is performed using a two-part simulation model: a volume conductor model to calculate the electrical potential distribution inside a tripolar cuff electrode and a human fiber model to simulate the fiber response to simulation. Selective stimulation is obtained by anodal block. To obtain anodal block of large fibers, long square pulses (> 350 micros) with a relatively high currents (1-2.5 mA) are usually required. These pulses might not be safe for a long-term application because of a high charge per pulse. In this study, several pulse shapes are proposed that have less charge per pulse compared with the conventional square pulse and would therefore be safer in a chronic application. Compared with the conventional square pulse, it was possible to reduce the charge with all proposed pulse shapes, but the best results are obtained with a combination of a square depolarizing pulse and a blocking pulse. The charge per pulse was up to 32% less with that pulse shape than with a square pulse. Using a hyperpolarizing anodal prepulse preceding a square pulse, it was not possible to block nerve fibers in a whole nerve bundle and to obtain reduction of a charge per phase. Reduction of the charge could be achieved only with spatially selective blocking. The charge per phase was larger for the combination of a hyperpolarizing anodal prepulse and a two-step pulse than for the two-step pulse alone.

Neuroprostheses to treat neurogenic bladder dysfunction: current status and future perspectives.

BACKGROUND: Neural prostheses are a technology that uses electrical activation of the nervous system to restore function to individuals with neurological or sensory impairment. INTRODUCTION: This article provides an introduction to neural prostheses and lists the most successful neural prostheses (in terms of implanted devices). CURRENT TREATMENT: The article then focuses on neurogenic bladder dysfunction and describes two clinically available implantable neural prostheses for treatment of neurogenic bladder dysfunction. Special attention is given to the usage of these neural prostheses in children. FUTURE TREATMENT: Finally, three new developments that may lead to a new generation of implantable neural prostheses for bladder control are described. They may improve the neural prostheses currently available and expand further the population of patients who can benefit from a neural prosthesis.

Electrical stimulation for the treatment of bladder dysfunction: current status and future possibilities.

Electrical stimulation of peripheral nerves can be used to cause muscle contraction, to activate reflexes, and to modulate some functions of the central nervous system (neuromodulation). If applied to the spinal cord or nerves controlling the lower urinary tract, electrical stimulation can produce bladder or sphincter contraction, produce micturition, and can be applied as a medical treatment in cases of incontinence and urinary retention. This article first reviews the history of electrical stimulation applied for treatment of bladder dysfunction and then focuses on the implantable Finetech-Brindley stimulator to produce bladder emptying, and on external and implantable neuromodulation systems for treatment of incontinence. We conclude by summarizing some recent research efforts including: (a) combined sacral posterior and anterior sacral root stimulator implant (SPARSI), (b) selective stimulation of nerve fibers for selective detrusor activation by sacral ventral root stimulation, (c) microstimulation of the spinal cord, and (d) a newly proposed closed-loop bladder neuroprosthesis to treat incontinence caused by bladder overactivity.