Purpose: We determined the utility of intraoperative data in predicting sacral neuromodulation outcomes in urgency urinary incontinence.
Materials and methods: Intraoperative details of sacral neuromodulation stage 1 were recorded during the prospective, randomized, multicenter ROSETTA trial, including responsive electrodes, amplitudes, and response strengths (motor and sensory Likert scales). Stage 2 implant was performed for stage 1 success on 3-day diary with 24-month follow-up. An intraoperative amplitude response score for each electrode was calculated ranging from 0 (no response) to 99.5 (maximum response, 0.5 V). Predictors for stage 1 success and improvement at 24 months were identified by stepwise logistic regression confirmed with least absolute shrinkage and selection operator and stepwise linear regression.
Results: Intraoperative data from 161 women showed 139 (86%) had stage 1 success, which was not associated with number of electrodes generating an intraoperative motor and/or sensory response, average amplitude at responsive electrodes, or minimum amplitude-producing responses. However, relative to other electrodes, a best amplitude response score for bellows at electrode 3 was associated with stage 1 failure, a lower reduction in daily urgency urinary incontinence episodes during stage 1, and most strongly predicted stage 1 outcome in logistic modeling. At 24 months, those who had electrode 3 intraoperative sensory response had lower mean reduction in daily urgency urinary incontinence episodes than those who had no response.
Conclusions: Specific parameters routinely assessed intraoperatively during stage 1 sacral neuromodulation for urgency urinary incontinence show limited utility in predicting both acute and long-term outcomes. However, lead position as it relates to the trajectory of the sacral nerve root appears to be important.
Keywords: implantable neurostimulators; overactive; percutaneous electrical neuromodulation; urinary bladder.