Pelvic Electrical Neuromodulation for the Treatment of Overactive Bladder Symptoms

Overactive bladder syndrome negatively affects the daily life of many people. First-line conservative treatments, such as antimuscarinics, do not always lead to sufficient improvement of the complaints and/or are often associated with disabling adverse effects leading to treatment failure. Electrical stimulation of the sacral nerves has emerged as an alternative and attractive treatment for refractory cases of bladder overactivity. Few theories attempted to explain its mechanism of action which remains elusive. It involves percutaneous posterior tibial nerve stimulation and more commonly sacral neuromodulation. For the latter, temporary sacral nerve stimulation is the first step. If the test stimulation is successful, a permanent device is implanted. The procedure is safe and reversible. It carries a durable success rate. The technique should be combined with careful followup and attentive adjustments of the stimulation parameters in order to optimize the clinical outcomes. This paper provides a review on the indications, possible mechanisms of action, surgical aspects and possible complications, and safety issues of this technique. The efficacy of the technique is also addressed

Percutaneous Nerve Evaluation Test Versus Staged Test Trials for Sacral Neuromodulation: Sensitivity, Specificity, and Predictive Values of Each Technique

Purpose InterStim device is an U.S. Food and Drug Administration approved minimal invasive therapy for sacral neuromodulation for lower urinary tract dysfunction. Before InterStim implantation, a trial with the appropriate screening tests is required to determine patient therapy eligibility. There are two different techniques for patient screening: percutaneous nerve evaluation (PNE) test and staged test. Few studies have reported success and failure rates for each technique. However, test sensitivity and predictive values of either test have not been studied. The aim of our study was to determine the sensitivity and specificity of each test and to establish a decision algorithm for the most appropriate testing method to be used as a screening test. Methods This cross-sectional study was conducted from August 2009 to February 2012 and included patients with lower urinary tract dysfunction who participated in the stimulation test trial. Patients underwent PNE as the first stimulation test, while those who encountered technical difficulty during PNE or electrode migration underwent staged testing. Results A total of 213 patients, including 172 female and 41 male subjects, underwent PNE. The patients’ diagnoses included refractory overactive bladder (47.9%), nonobstructive urinary retention (29.6%), and frequency urgency syndrome (22.1%). A total of 202 patients were screened with PNE and 10 patients with staged testing. Overall sensitivity of PNE was 87.3%, and it was 90% for staged test. PNE specificity was 98.5% as compared to 92.9% for staged test. Positive and negative predictive values for PNE were 99% and 82.1% and for staged test were 90% and 92.9%, respectively. Conclusions PNE test has high specificity and positive predictive value. We recommend PNE, a simple office-based, less expensive procedure as the first option for screening

Studies on the physiological and pharmacological aspects of the lower urinary tract in normal and following spinal lesion

The mechanisms implicated in voiding and continence are far from being settled in the normal as well as in neurogenic bladder dysfunction. Understanding these mechanisms is an essential step in the management of the bladder dysfunction secondary to neurological lesions. In the course of our studies, we demonstrated the existence of a fine coordination "synergism" between the several components of the lower urinary tract i.e., detrusor, proximal urethral muscle and periurethral striated muscles. This synergism is found to be responsible for adequate bladder emptying during voiding in the animal model with intact neural axis. The synergism between the bladder and its outlet is under the control of a higher centre in the brain stem and mediated through the spinal cord and peripheral nerves. The cause of failure of bladder emptying following a spinal lesion was shown to be a lack of synergism between the bladder and its outlet. An animal model for chronic multiple sclerosis-like disease was developed and proved to show a good urodynamic and neurological correlation with that found in the human afflicted with multiple sclerosis.The pharmacological investigation on the bladder and urethra shows that there is selective distribution of cholinergic, adrenergic and purinergic receptors along the individual layers of the smooth muscles of the urethra. On the other hand, the importance of the Calcium ions in the contractility of the detrusor muscle was also studied. The effect of some Calcium ions antagonists on the detrusor contractility was evaluated. They show selective inhibition on the detrusor contraction both in vivo and in vitro. The calcium antagonists may present a new treatment modality for controlling bladder instability

Sacral neuromodulation and refractory overactive bladder: an emerging tool for an old problem

Overactive bladder (OAB) syndrome negatively affects the daily life of many people. Conservative treatments, such as antimuscarinics, do not always lead to sufficient improvement of the complaints and are often associated with considerable side effects resulting in treatment failure. In the case of failure or intolerable side effects, sacral neuromodulation (SNM) and botulinum toxin intravesical injections are minimally invasive and reversible alternatives. Currently, both SNM and botulinum toxin injection have FDA approval for use in OAB patients. This mini-review attempts to provide an update on SNM as a second-line management of adults with refractory OAB, based on the available clinical evidence concerning the efficacy and safety

Sacral Neuromodulation in Patients With a Cardiac Pacemaker

The objective of this study was to describe our experience using sacral neuromodulation to treat urinary urgency, frequency, urge incontinence, and chronic urinary retention in patients with cardiac pacemakers. With the increasingly widespread use of InterStim for bladder function restoration, we are seeing more complex patients with multiple comorbidities, including cardiac conditions. Herein, we report 3 cases of individuals with cardiac pacemakers who underwent InterStim implantation to treat urinary conditions. This study is a case series of 3 patients with cardiac pacemakers who underwent sacral neuromodulation to treat refractory voiding dysfunction. The initial patient screening for InterStim therapy involved percutaneous nerve evaluation (PNE), in which a temporary untined lead wire was placed through the S3 foramen. Patients who did not respond to PNE proceeded to a staged implant. All patients in this study had a greater than 50% improvement of their urinary symptoms during the initial trial and underwent placement of the InterStim implantable pulse generator (IPG). Postoperative programming was done under electrocardiogram monitoring by a cardiologist. No interference was observed between the Inter-Stim IPG and the cardiac pacemaker. In this group of patients, sacral neuromodulation in the presence of a cardiac pacemaker appears to have been safe

Characterizing the transcutaneous electrical recruitment of lower leg afferents in healthy adults: implications for non-invasive treatment of overactive bladder

Abstract Background As a potential new treatment for overactive bladder (OAB), we investigated the feasibility of non-invasively activating multiple nerve targets in the lower leg. Methods In healthy participants, surface electrical stimulation (frequency = 20 Hz, pulse width = 200 μs) was used to target the tibial nerve, saphenous nerve, medial plantar nerve, and lateral plantar nerve. At each location, the stimulation amplitude was increased to define the thresholds for evoking (1) cutaneous sensation, (2) target nerve recruitment and (3) maximum tolerance. Results All participants were able to tolerate stimulation amplitudes that were 2.1 ± 0.2 (range = 2.0 to 2.4) times the threshold for activating the target nerve. Conclusions Non-invasive electrical stimulation can activate neural targets at levels that are consistent with evoking bladder-inhibitory reflex mechanisms. Further work is needed to test the clinical effects of stimulating one or more neural targets in OAB patients