Effectiveness of Bupivacaine as Pre-emptive Pudendal Block among Patients Undergoing Vaginal Surgeries: A Systematic Review

Pre-emptive analgesia using pudendal nerve block (PNB) with bupivacaine is commonly used in clinical practice during perineal, pelvic floor or vaginal surgeries. However, its effectiveness is unclear. We conducted this review to synthesize short- and intermediate-term outcomes of pre-emptive analgesia using pudendal nerve block with bupivacaine. We searched the CENTRAL, PubMed, ClinicalTrials.gov, Google Scholar, and Open Grey from inception until April 2020. Randomized controlled trials (RCTs) of women who underwent perineal, pelvic floor or vaginal surgeries and received pre-emptive analgesia using a pudendal nerve block were included. Two authors independently screened, selected and performed data extraction as well as quality assessment on eligible trials. Disagreements were resolved via consensus. Data were narratively synthesized; when possible, data were pooled in RevMan 5 using the random-effects model. Four RCTs with a total of 349 participants were eligible for inclusion. We found evidence of improvement in postoperative pain scores; requirements for opioids, standardized mean difference (SMD): -0.89 (95% CI: -1.19, -0.59) and nonsteroidal anti-inflammatories SMD -1.04 (95% CI: -1.64, -0.43) in favor of the PNB versus control group. The risk ratio for adverse effects of postoperative nausea and vomiting, 0.42 (95% CI: 0.18, 0.99) favored PNB. There was no significantdifference between groups for the length of hospital stay, mean difference -0.82 (95% CI: -5.34, 3.69) and return to regular activity. We found limited evidence that pre-emptive pudendal block using bupivacaine improves postoperative pain and recovery in perineal, pelvic floor or vaginal surgeries. However, due to the heterogeneous nature of evidence, well-designed RCTs are required.