Introduction

Bladder cancer is the sixth most common cancer in men in the United States (1). Transurethral resection of bladder tumour (TUR-BT) is an initial diagnostic and therapeutic procedure for non-muscle invasive bladder cancer (NMIBC). The most common complications related to tumour resection include minor bleeding and irritative symptoms in the early postoperative period. The major complications, including uncontrolled haematuria and bladder perforation, may occur in approximately 5% of cases (2). The obturator nerve is located near the inferolateral bladder wall, and it arises from the anterior rami of the second, third and fourth lumbar nerves, descends through the psoas major and emerges from the psoas major medial border. The nerve then crosses into the pelvis at the level of the sacroiliac joint. At this point, it courses close to the wall of the bladder (3). TUR-BT of bladder tumours localized close to the lateral side of the bladder may stimulate the obturator nerve and trigger the adductor contraction approximately the rate of 20%, causing possible inadvertent bladder perforation or an incomplete resection due to hindrance of the tumour resection (4). Spinal anaesthesia combined with obturator nerve blockade in the obturator canal may be effective in preventing adductor spasm (5). Various strategies are recommended to prevent undesirable adductor contractions due to obturator nerve stimulation. For instance, the incidence of obturator nerve stimulation can be reduced by attention to technical strategies, decreasing the intensity of energy, avoiding overdistention of the bladder, and using anaesthetic paralysis or giving general anaesthesia during the resection of lateral wall localized tumours to decrease an obturator reflex response (4,6,7). Meta-analyses comparing bipolar and monopolar TUR-BT have reported no statistically significant differences between bipolar and monopolar TUR-BT in terms of obturator reflex and bladder perforation rates (8,9).
Most of the bladder cancers (70–75%) were NMIBC during the initial diagnosis. Tumour recurrence is more common for NMIBC. Nearly 30% of patients have tumour recurrence within the first 3 months of having TUR-BT, and 50% of patients have a recurrent tumour at the 1-year follow-up (10). The major causes of recurrent tumour have been reported to be residual tumour tissue due to incomplete resection or inability to obtain adequate muscle tissue during TUR-BT (11). The obturator reflex that occurs during the TUR-BT may increase the risk of incomplete resection of the tumour, inability to sample the muscle tissue or tumour dissemination via bladder perforation.
In this study, we aimed to investigate the effect of obturator nerve blockade on oncological outcomes in patients undergoing TUR-BT for lateral wall localized NMIBC.