Introduction: Effective opioid-sparing postoperative analgesia often requires a multimodal approach, which may include regional nerve blocks. The objective of this randomized controlled trial is to determine whether a pudendal nerve block is associated with improved postoperative pain control and decreased opioid consumption compared to a sham injection at the time of vaginal pelvic reconstructive surgery (PRS).
Methods: In this randomized, double-blind, placebo controlled trial, we enrolled women undergoing benign vaginal PRS at a single academic institution. Exclusion criteria included patients with a diagnosis of chronic pelvic pain, inability to receive non-narcotic analgesia, or any concurrent abdominal procedure. Patients were randomized to receive a transvaginal pudendal nerve block (9mL 0.25% bupivacaine + 1mL 40mg/mL triamcinolone) or a sham injection (10mL normal saline) at the conclusion of surgery. The injection syringe was wrapped by pharmacy to blind the surgeon. Postoperatively, all patients received routine care. Primary endpoints were visual analog pain scores (VAS) and postoperative opioid requirement, measured in the post-anesthesia recovery unit (PACU) and on post-operative days (POD) 1 and 4. A power calculation determined 60 patients were required to show a mean difference of 20mm on a 100mm VAS. Opioid administration was standardized as morphine milligram equivalents (MME), and VAS scores were compared with Wilcoxon-Mann-Whitney analysis.
Results: We randomized 71 patients: 36 pudendal block and 35 sham injection. The study groups were well matched with no differences in baseline characteristics or type of surgery performed. Pelvic organ prolapse repairs were the most common procedures (n=63, 87.5%). There was no difference in anesthetic dose or operative time between groups. Pain scores were equivalent between groups in the PACU (mean VAS 53.1 block vs 56.4 sham, p=0.517) and on POD 4 (mean VAS 26.7 block vs 35.5 sham, p=0.131). On POD 1, the intervention group did report less pain than the sham group (mean VAS 29.2 vs 42.5, p=0.047). Patients who received a pudendal block took fewer opioid medications than those in the sham group at all time points, but this difference did not meet statistical significance (PACU 5 vs 7.8 MME, POD1 7.5 vs 11.25 MME, POD4 7.5 vs 21.25 MME, all p>0.05).
Conclusions: Pudendal nerve block resulted in decreased pain reported in the immediate postoperative period and less opioid use, though not statistically significant. Pudendal block may be an additional tool for non-narcotic perioperative analgesia with vaginal PRS.
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