An Ultrasound-Guided Interfascial Injection Approach Versus an Ultrasound-Assisted Nerve Stimulating Approach of Obturator Nerve Block: A Randomized Clinical Trial

Background The majority of bladder cancer patients are elderly and have various comorbidities, increasing the risk of complications following general anesthesia. Spinal anesthesia with a selective obturator nerve block (ONB) is an alternative to general anesthesia for transurethral resection of bladder tumor (TURBT); however, incomplete ONB can cause adductor muscle spasm. The objective of this study was to assess if the ultrasound-guided interfascial injection approach is compatible with the blind nerve stimulating technique for ONB in bladder cancers undergoing TURBT. Methodology A total of 50 ONBs were performed for TURBTs under spinal anesthesia and were divided into two groups, that is, ONB with nerve stimulation control group (group RD1) and an experimental ultrasound-guided interfascial injection group (group RD2). During TURBT surgeries, one urology assistant determined obturator reflex grade (I-IV) at 15 minutes after injection completion in both groups. Results A success rate of 88% was achieved in group RD1 compared to 76% in group RD2, which was clinically significant. Three cases failed to achieve complete ONB in group RD1, and six cases in group RD2 failed to achieve complete ONB. One case in group RD1 and two cases in group RD2 exhibited grade II obturator re­flex during the surgery. Conclusions Ultrasound-guided interfascial injection approach was inferior to the ultrasound-guided nerve stimulating technique for ONB at the inguinal crease; hence, we recommend using both ultrasound and nerve stimulators for ONB.