Obturator Nerve Block in Transurethral Resection of Bladder Tumor: A Comparison of Ultrasound-guided Technique versus Ultrasound with Nerve Stimulation Technique.

BACKGROUND: Obturator nerve (ON) stimulation during transurethral resection of lateral and posterolateral bladder wall tumor under spinal anesthesia may lead to obturator reflex, adductor contraction, and leg jerking with complications such as bleeding, bladder perforation, or incomplete tumor resection. Our study was carried out to obtain successful block of ON using ultrasound (US)-guided technique with or without nerve stimulation in patients undergoing transurethral resection of bladder tumor (TURBT) under spinal anesthesia.

AIMS: The aim of the study was to compare the effectiveness of two different techniques in blocking ON and adductor spasm during TURBT.

SETTINGS AND DESIGN: Prospective, randomized, double-blind study.

SUBJECTS AND METHODS: Sixty patients with American Society of Anesthesiologists Status II and III scheduled to undergo TURBT for lateral and posterolateral bladder wall tumor were enrolled. Group I (US group, n = 30) patients received 5 ml of bupivacaine 0.5% each at anterior, and posterior division of ON under real-time US visualization and Group II (US-NS group, n = 30) received the same amount of bupivacaine 0.5% for each division using US-guidance with nerve stimulation-assisted technique. Motor block onset time, block success and performance time, ease of performance of block, and complications were measured besides assessing patient and surgeon satisfaction into two groups.

STATISTICAL METHODS USED: SPSS using two sample independent t -test and Pearson's Chi-square/Fisher's exact test.

RESULTS: Motor block onset was significantly faster in Group II (6.67 ± 2.40) than in Group I (12.39 ± 2.55). A success rate of 90% was achieved in Group II as compared to 76.7% in Group I with increased block performance time in Group II (4.47 ± 0.73 min) versus (2.10 ± 0.51 min) in Group I. A better patient and surgeon satisfaction were seen in Group II with combination of US and nerve stimulation technique. No complications were encountered.

CONCLUSION: We conclude that both techniques are safe and easy to perform; however, nerve stimulation as an adjunct to US results in a faster onset of block with a higher success rate.