Ultrasound-guided pudendal nerve block in patients undergoing open hemorrhoidectomy: a double-blind randomized controlled trial

Purpose In this double-blind randomized trial, we aimed to compare the postoperative pain, complications, and length of hospital stay in patients undergoing open hemorrhoidectomy under spinal anesthesia with or without the pudendal nerve block. Methods Patients undergoing Milligan-Morgan hemorrhoidectomy under spinal anesthesia were randomized to undergo a pudendal nerve block or no intervention. Postoperative pain on the visual analogue scale (VAS) at 6, 12, 24, and 48 h; opioid administration; and length of hospital stay were recorded and analyzed. Results Over the study period, 49 patients were included and 23 randomized in the treatment arm. No differences in terms of age, gender, and preoperative risk factors were noted between groups. The pain on the VAS at 6, 12, 24, and 48 h was 2.8 vs. 4.6 ( p = 0.046), 3.4 vs. 4.7 ( p = 0.697), 1.4 vs. 3.1 ( p = 0.016), and 1.0 vs. 2.1 ( p = 0.288) in the treatment and control groups respectively. No differences in opioids use or complications were noted. Length of hospital stay was 1.2 vs. 1.8 days respectively ( p = 0.046). No complications directly associated to the pudendal nerve block were observed. Multivariate analysis revealed that the pudendal nerve block was an independent factor reducing the postoperative pain. Conclusions The ultrasound-guided pudendal nerve block in patients undergoing open hemorrhoidectomy under spinal anesthesia showed a statistically significant reduction in postoperative pain and length of hospital stay. The proposed technique appeared to be safe and feasible and may be recommendable in patients undergoing open hemorrhoidectomy. Trial registration ClinicalTrials.gov Identifier: NCT04251884