Urethral sphincter EMG-controlled dorsal penile/clitoral nerve stimulation to treat neurogenic detrusor overactivity

Abstract

The goal of this study was to investigate whether real-time external urethral sphincter (EUS) EMG-controlled dorsal genital nerve (DGN) stimulation can suppress undesired detrusor bladder contractions in patients with both neurogenic detrusor overactivity (NDO) and detrusor sphincter dyssynergia (DSD). Detrusor pressure (Pdet) and EUS EMG were recorded in 12 neurogenic patients who underwent two filling cystometries. The first one was without stimulation and was intended to confirm the NDO and DSD and to set the EMG detection threshold. The second one was with real-time EMG-controlled stimulation of DGNs. Two detection methods were analyzed to detect bladder contractions. The first method was a Kurtosis-scaled root mean square (RMS) detector and was used on-line. The second was a simple RMS detector and was used off-line. Of 12 patients included, 10 patients showed both NDO and DSD. In nine of these ten patients relevant EMG concomitant to detrusor activity was detected and stimulation could suppress at least one detrusor contraction. The second filling compared to the first one showed an increase of 84% in bladder capacity (p = 0.002) and a decrease of 106% in Pdet (p = 0.002). Nine false-positive detections occurred during the ten fillings with electrical stimulation. The mean increases of both time and Pdet between stimulation and bladder contraction onsets for method 1 were 1.8 s and 4 cmH2O and for method 2 were 0.9 s and 2 cmH2O, respectively. This study shows that EUS EMG can be used in real time to detect the onset of a bladder contraction. In combination with DGN stimulation has been shown to be feasible to suppress undesired bladder contractions and in turn to increase bladder capacity in subjects with both NDO and DSD.