Effects of Adjuvant Dexmedetomidine in Dorsal Penile Block for Penile Prosthesis Implantation

Inflatable penile prosthesis (IPP) surgery is the gold standard treatment for medication-refractory erectile dysfunction. While satisfaction rates are high, post-operative pain and narcotic requirement remain a concern. Intraoperative dorsal penile nerve block (DPNB) with long-acting local anesthetic can improve analgesia. Recent studies on peripheral nerve blocks in other fields have demonstrated prolonged analgesia and minimal adverse effects with blocks containing local anesthetic and dexmedetomidine. This retrospective study aimed to evaluate the effect of DPNB for IPP surgery with and without dexmedetomidine on postoperative analgesia. This is a single institution retrospective IRB-approved study of patients undergoing IPP surgery with preoperative DPNB and without dexmedetomidine. The DPNB used in the 2019 control group utilized 0.25% bupivacaine, while the 2020–2021 intervention group also included 70 µg dexmedetomidine. The primary outcome was pain scores at post-operative hours 0, 2, 6, 12, 18, and 24, while secondary outcomes were intraoperative and postoperative narcotic use, intraoperative hypotension (IOH), (MAP < 60 for > 5 minutes or requiring intervention), and intraoperative bradycardia, (HR < 50 for > 1 minute). 98 patients met inclusion criteria, 32 in the control group and 66 in the intervention group. 24-hour pain scores were significantly lower in the intervention group (1.1 vs 3.8, 1.6 vs 3.9, 3.1 vs 4.9, 2.4 vs 4.3, 2.9 vs 5.3, 2.3 µg vs 4.4 µg; p < 0.05). Postoperative narcotic requirement was lower for the intervention group (46 vs 65, P < 0.05). Adverse effects (IOH and bradycardia) occurred in 16 intervention cases, each mild and brief. Intraoperative DPNB with local anesthetic and dexmedetomidine can safely improve immediate post-operative analgesia and decrease opioid consumption in the first 24 hours. This type of combination DPNB may be useful for other penile and scrotal surgeries, requiring prospective randomized study.