Efficacy of a pubic superior ramus approach versus a distal approach for obturator nerve block in transurethral bladder tumor resection: a randomized controlled trial.

OBJECTIVE: This study aimed to compare the clinical efficacy and safety of a modified pubic superior ramus (PSS) approach for pericapsular nerve group block against the conventional distal technique in obturator nerve blockade during transurethral resection of bladder tumor (TURBT), with a focus on preventing intraoperative obturator nerve reflex. METHODS: We conducted a prospective, randomized, single-blind trial involving 70 patients scheduled for TURBT under general anesthesia. Participants were randomly assigned to one of two groups: Group P (n = 34) received ultrasound-guided obturator nerve block via the pubic superior ramus approach, while Group O (n = 34) underwent blockade via the distal approach. The primary outcome measures were the incidence and severity of obturator nerve reflex. Secondary outcomes encompassed block performance time and success rate, postoperative pain profiles (assessed by VAS scores), recovery quality, perioperative inflammatory biomarker levels, hemodynamic fluctuations, functional recovery metrics, as well as long-term bladder function and oncological outcomes evaluated at 6 and 12 months postoperatively. RESULTS: Group P demonstrated significantly faster onset and greater reduction in adductor muscle strength at all measured time points (P < 0.05), with shorter block performance times (175.5 ± 34.2 vs. 223.7 ± 39.6 seconds, P < 0.001) and fewer needle passes (P < 0.001). While the incidence of the obturator reflex was similar between the groups, Group P had superior postoperative analgesia with lower pain scores, reduced morphine consumption (15.2 ± 4.8 vs. 24.5 ± 6.1 mg, P < 0.001), and a longer time to first analgesia. The quality of recovery scores was significantly greater in Group P at 24 and 48 hours (P < 0.001), along with an attenuated systemic inflammatory and neurochemical stress response (e.g., IL-6, Substance P, and c-Fos), improved hemodynamic stability, faster quadriceps recovery, and better short- and long-term bladder function. At the 12-month follow-up, Group P exhibited superior urodynamic parameters (Qmax and PVR, P < 0.01) and a trend towards lower tumor recurrence (94.1% vs. 85.3% recurrence-free survival, P = 0.218). CONCLUSION: Compared with the distal approach, the pubic superior ramus approach for obturator nerve block provides more efficient blockade and superior multidimensional perioperative benefits, making it an optimal technique for TURBT within enhanced recovery protocols.