Which parameters predict sacral neuromodulation outcomes?

Some parameters that are usually assessed intraoperatively during stage 1 sacral neuromodulation appear to be of little use in predicting acute and long-term outcomes in urgency urinary incontinence, reveals a study.

“However, lead position as it relates to the trajectory of the sacral nerve root appears to be important,” the researchers said.

In the prospective, randomized, multicentre ROSETTA trial, the researchers recorded intraoperative details of sacral neuromodulation stage 1, as well as responsive electrodes, amplitudes, and response strengths (motor and sensory Likert scales). Stage 2 implant was conducted for stage 1 success on a 3-day diary with 24-month follow-up.

The researchers then calculated an intraoperative amplitude response score for each electrode, ranging from 0 (no response) to 99.5 (maximum response, 0.5 V). They also identified the predictors for stage 1 success and improvement at 24 months using stepwise logistic regression confirmed with least absolute shrinkage and selection operator and stepwise linear regression.

Of the 161 women with intraoperative data, 139 (86 percent) achieved stage 1 success, which did not correlate with the number of electrodes generating an intraoperative motor and/or sensory response, average amplitude at responsive electrodes, or minimum amplitude-producing responses.

However, a best amplitude response score for bellows at electrode 3, compared with other electrodes, correlated with stage 1 failure, a lower reduction in daily urgency urinary incontinence episodes during stage 1, and strongly predicted stage 1 outcome in logistic modeling.

Participants with electrode 3 intraoperative sensory response demonstrated lower mean reduction in daily urgency urinary incontinence episodes at 24 months than those with no response.