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This study compared sacral nerve stimulation (SNS) and pudendal nerve stimulation (PNS) for treating pelvic floor dysfunction by measuring their effects on the urethra and external anal sphincter during surgical implantation procedures. Researchers found that SNS required lower current amplitudes than PNS to achieve maximum urethral pressure changes and produced greater pressure changes per unit of electrical current applied. Nine participants underwent measurements during SNS lead implant surgery, with data showing SNS activates pelvic floor muscles more efficiently than PNS, likely due to closer proximity of electrodes to nerve targets.
Why it matters
These findings could help clinicians optimize neuromodulation therapy selection for patients with pelvic organ dysfunction, potentially improving treatment outcomes while using lower stimulation currents. The enhanced efficiency of SNS may reduce side effects and power consumption in implanted devices.
Understand the Science
⚠️ Preprint – Noch nicht peer-reviewed
Dieser Artikel wurde noch nicht von unabhängigen Experten begutachtet. Die Ergebnisse sind vorläufig und sollten mit Vorsicht interpretiert werden.
Introduction: Sacral neuromodulation (SNM) is a third line treatment for pelvic organ dysfunction. Pudendal nerve stimulation (PNS) uses SNM electrode leads in an off-label fashion to also treat pelvic dysfunction. Differences in how stimulation of these two nerve targets activates the urethra and external anal sphincter (EAS) may provide insights into the mechanisms of these therapies. Materials and Methods: During SNM lead implant surgeries, needle electrodes and a high-resolution manometry catheter were used to record EAS electromyography (EMG) and multi-segment urethra pressure, respectively. Intra-operative sacral nerve stimulation (SNS) was performed, and EMG and pressure data were analyzed to examine relationships between the responses and stimulation. Pressure data was then compared to previously collected PNS-evoked responses. Results: Nine participants had data recorded during a SNM lead implant surgery. The applied current threshold to activate the urethra was significantly higher than visual motor threshold (VMT; p = 0.04). The EAS threshold was higher but not significantly different from VMT (p = 0.06). Maximum urethra pressure changes during SNS were not different from PNS driven changes (p = 0.09). Current amplitudes required to elicit maximum changes in urethra pressure were lower for SNS than PNS (p = 0.01) and the maximum change in urethra pressure per mA of applied stimulation was higher for SNS than PNS (p = 0.005). Conclusion: This is the first work to compare muscle recruitment between SNS and PNS in humans. SNS has greater pelvic floor recruitment per step in current than PNS. Typical SNM leads are closer to the nerve target, which may contribute to this effect.