Objectives: Sacral neuromodulation (SNM) is theorized to alter the neural pathways that mediate bladder and urethral sensation. We hypothesize that SNM affects current perception thresholds (CPTs) of afferent sensory nerve pathways.
Materials and methods: Eight women were enrolled and completed pre and postoperative testing. A CPT device was used to measure CPT at 5 Hz (C-fibers), 250 Hz (Aδ-fibers), and 2000 Hz (Aβ-fibers) on the urethra and bladder prior to and one month after SNM. Index finger readings at 2000 Hz served as controls.
Results: SNM had the greatest effect on the bladder at 250 and 2000 Hz, suggesting reduced bladder sensitivity. Significant changes in CPT were seen in the bladder at 2000 Hz with a decrease in sensitivity (p = 0.033). CPT testing was well tolerated, and no adverse events were identified.
Conclusions: With a measurable change in CPT values for Aδ-fibers and Aβ-fibers, these findings suggest that SNM modulates large myelinated afferent fibers in the bladder. Notably, little or no changes were found in the C-fiber CPT measurements. More research is needed with a larger sample size to determine the significance of these findings.
Keywords: Neuroanatomy; neuromodulation; overactive bladder.
© 2014 International Neuromodulation Society.