MP8-15 ELECTRICAL STIMULATION OF THE SPINAL DORSAL ROOT INHIBITS REFLEX BLADDER CONTRACTION AND EXTERNAL URETHRA SPHINCTER ACTIVITY: IS THIS HOW SACRAL NEUROMODULATION WORKS?

You have accessJournal of UrologyUrodynamics/Incontinence/Female Urology: Basic Research I1 Apr 2015MP8-15 ELECTRICAL STIMULATION OF THE SPINAL DORSAL ROOT INHIBITS REFLEX BLADDER CONTRACTION AND EXTERNAL URETHRA SPHINCTER ACTIVITY: IS THIS HOW SACRAL NEUROMODULATION WORKS? Jian Ren, Daniel Chew, and Nikesh Thiruchelvam Jian RenJian Ren More articles by this author , Daniel ChewDaniel Chew More articles by this author , and Nikesh ThiruchelvamNikesh Thiruchelvam More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2015.02.282AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES Sacral neuromodulation (SNM) is used to treat detrusor overactivity (DO). Human and animal experiments suggest that SNM mechanisms may be linked to afferent pathways in the spinal root and possibly a supra-sacral spinal loop. Using a rat model, we aimed to confirm the inhibitory effect of dorsal spinal root (afferent) stimulation using SNM parameters, and test if bilateral stimulation is more effective than unilateral stimulation. External urethral sphincter (EUS) electromyography (EMG) is also used with cystometrogram (CMG) to verify the correlation between parasympathetic and pudendal nerve stimulation. METHODS 18 Female Sprague-Dawley rats were tested following urethane anesthesia. Via urethral catheterization, the bladder was infused with normal saline evoked rhythm bladder reflex contraction (BRC). EUS EMG was recorded using bipolar fine needle electrodes, which were placed in the muscle just 1–2mm apart from the EUS at 3 and 9 o'clock. L6 spinal nerves were dissected and stimulated using SNM stimulation parameters; stimulation was commenced when rhythmic BRC was achieved. L6 was tested to mimic S3 in the human. RESULTS L6 stimulation was effective in inhibiting BRC. L6 unilateral dorsal root (DR) stimulation: 200uA (10Hz, 0.1ms) was used as the initial intensity and effectively inhibited the BRC in five rats. Lower intensities were tested without success. L6 unilateral ventral root (VR) stimulation: stimulation caused bladder contraction in three rats. L6 bilateral DR stimulation: in five rats, the lowest effective intensity that could inhibit BRC was identified using the sequential stimulation pattern (50uA-100uA-150uA-200uA). When stimulated bilaterally, 50% intensity was required to cause inhibition as compared to unilateral stimulation. EUS EMG recording: there was a strong association between strong EUS EMG activities and bladder contraction (98.7%, 74 in 75 contractions). When the bladder contraction was inhibited effectively by L6 DR stimulation, a considerable reduction of the EUS EMG activities was also found. CONCLUSIONS L6 DR stimulation using SNM parameters that are used in human clinical practice abolished BRC. Bilateral L6 DR stimulation allowed a 50% reduction in stimulation intensity to provide a similar BRC block. Abolishing BRC also appeared to result in a reduction in EUS EMG. We postulate that SNM abolishes DO by acting on the DR but the association of simultaneous reduced EUS activity remains unclear. © 2015 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 193Issue 4SApril 2015Page: e78 Advertisement Copyright & Permissions© 2015 by American Urological Association Education and Research, Inc.MetricsAuthor Information Jian Ren More articles by this author Daniel Chew More articles by this author Nikesh Thiruchelvam More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...