Complications in Transurethral Resection of the Bladder Tumor: Using Nerve Stimulator with or Without Ultrasonography for Obturator Nerve Block: A Comparative Study

[Background]The use of ultrasonographic guide is a suggested way to ease the obturator nerve block procedure. Accordingly, in this study, the procedures by selective obturator nerve block with and without use of ultrasonographic guide were compared.[Methods]This interventional study was performed as an open-label randomized clinical trial among 50 consecutive subjects under surgery for intramural tumors of urinary bladder in a training hospital in 2016. The subjects were randomly assigned to be operated under spinal anesthesia accompanied with selective obturator nerve block (10 mL of 1.5% lidocaine adding 1:200000 epinephrine) with or without ultrasonographic guide. The outcomes were compared across the groups.[Results]There was no statistically significant difference between the onset time in group without guide (6.3 ± 2.2 minutes) and that in the guided group (5.9 ± 2.1 minutes). The time required for the nerve block (4.4 ± 1.3 minutes versus 1.7 ± 0.8 minutes) was significantly shorter (P = 0.001). There were less complications in the group with use of ultrasonographic guide showing significant difference (P = 0.01). The success rate in block was significantly higher in the group with ultrasonographic guide (100% versus 92%, P > 0.05).[Conclusions]Finally, according to the obtained results, it may be concluded that ultrasonography guidance would improve efficacy of obturator nerve block compared with conventional techniques.