Optimizing Postoperative Analgesia After Perianal Abscess Surgery Using Ultrasound-Guided Pudendal Nerve Block Combined with Wrist-Ankle Acupuncture: A Randomized Controlled Trial

This prospective randomized controlled study investigated an innovative approach to postoperative pain management in patients undergoing perianal abscess surgery — a condition that often produces severe pain due to the rich innervation of the region. The trial assessed 120 patients divided into three groups: ultrasound-guided pudendal nerve block, wrist-ankle acupuncture, and combination treatment. The pudendal nerve block was performed bilaterally at the end of surgery, using 0.3% ropivacaine under ultrasound guidance to precisely localize the nerve in the pudendal canal. Wrist-ankle acupuncture involved subcutaneous needle insertion at lower zones 6 and 1 bilaterally, started 6 hours after surgery and maintained for 30 minutes daily for 7 consecutive days.

Results demonstrated significant superiority of the combination treatment across all assessed parameters. Visual analog scale pain scores were consistently lower in the combination group at all time points (6, 12, 24, 48, and 72 hours), with up to 40% reduction compared with the individual-treatment groups. Duration of analgesia was substantially prolonged in the combination group (12.8 ± 2.3 hours vs 8.5 ± 1.8 hours in the pudendal-block group and 6.2 ± 1.5 hours in the acupuncture group). The need for rescue analgesia was significantly lower in the combination group (15.0% vs 37.5% and 32.5% in the other groups).

Serum inflammatory markers — including C-reactive protein, interleukin-6, and tumor necrosis factor-alpha — showed smaller elevations in the combination group at 48 and 72 hours postoperatively, suggesting a synergistic anti-inflammatory effect. Sleep quality, assessed using the Pittsburgh Sleep Quality Index, improved significantly in the combination group, as did patient satisfaction. There were no differences in adverse-event incidence between groups, confirming the safety of the combined approach. Proposed mechanisms for the synergistic effects include targeted interruption of nociceptive transmission by the pudendal block, combined with systemic pain modulation by acupuncture through activation of endogenous analgesic pathways and release of natural opioids.

Wrist-ankle acupuncture may also influence the autonomic nervous system and reduce muscle spasm, complementing the regional block. The clinical implications are significant, offering a multimodal strategy that reduces opioid dependence and improves postoperative recovery. The approach is clinically feasible, with ultrasound-guided pudendal block becoming more accessible and wrist-ankle acupuncture being relatively simple to implement. Limitations include the single-center design and the relatively small sample, as well as the absence of MRI-based volumetric analysis of abscesses, which could have provided more precise stratification of disease severity.

The study represents an important contribution to postoperative pain medicine, demonstrating how integration of conventional regional anesthesia techniques with complementary therapies can yield substantial synergistic benefits for patients.