The Impact of Pudendal Nerve Injection in Vaginal Surgery: A Secondary Analysis

Evidence regarding the effect of pudendal nerve blockade during vaginal surgery is conflicting. Previous studies compared pudendal nerve blockade to either normal saline placebo injection or no injection, demonstrating small or no difference in pain outcomes. Studies investigating nerve blocks at the time of vaginal surgery have not evaluated the effect of infiltration of the space around the pudendal nerve.

The aim of the study was to determine whether intraoperative pudendal nerve injection (bupivacaine or normal saline) will result in improved pain scores and satisfaction compared with patients who receive no pudendal injection.

We performed a secondary analysis of 2 randomized controlled trials investigating postoperative pain after vaginal reconstructive surgery, comparing the outcomes of the following 3 groups: control (no pudendal injection), intervention (bilateral pudendal nerve blockade), and placebo (bilateral normal saline pudendal injections). The primary outcome was postoperative pain scores. Secondary outcomes were opioid use, patient satisfaction, and postoperative complications. Linear mixed effects models were applied to outcomes, and treatment effects with 95% confidence intervals were estimated at each time point from the model.

One hundred four patients who underwent vaginal surgery were included: 36 pudendal nerve block, 35 normal saline pudendal injection, and 33 no injection. The groups were well-matched. Linear mixed effects models demonstrated no significant differences between treatment groups for postoperative pain severity scores, opioid use, and patient-reported satisfaction at each time point.

Normal saline injection and no injection seem to have no clinically meaningful difference in effect, and either could reasonably serve as control for pudendal blockade during vaginal surgery.