The effect of combined pudendal nerve and spermatic cord block or caudal epidural block on postoperative analgesia after posterior urethroplasty: a randomized trial

Abstract Background Postoperative pain management remains a significant challenge for patients undergoing posterior urethroplasty (PU). In a previous study, we proposed a novel technique of combined pudendal nerve (PN) and spermatic cord (SC) block to manage pain after PU. The present trial was conducted to test the hypothesis that this technique is effective for pain control after PU and provides longer-lasting analgesia than caudal epidural block (CB). Methods Sixty patients undergoing PU were randomized into two groups: Group NB received combined PN and SC block, and Group CB received CB. General anesthesia with a laryngeal mask was performed. The primary outcome was the postoperative analgesic duration, and the secondary outcomes included the Numeric Rating Scale (NRS) scores for pain and the number of patients with different motor scores of the lower limb at 3, 6, 12, and 24 h postoperatively. Results Two patients in Group CB were withdrawn due to block failure. The postoperative analgesic duration was statistically longer in Group NB compared with Group CB (mean difference [95% confidence interval], 115.78 min [17.80, 213.75]; P = 0.021). The NRS scores for pain at 12 and 24 h after surgery were statistically lower in Group NB compared with Group CB. Group NB had statistically more patients with motor score 0 at 3 h postoperatively than Group CB. Conclusions PN combined with SC block is an effective technique for postoperative analgesia in PU. This technique can achieve a longer duration of analgesia and lower pain scores, especially 12 h after surgery, than a CB. Trial registration This study was registered in the Chinese Clinical Trial Register (registration no. ChiCTR2100042971, registration date on 2/2/2021).