Effectiveness and Safety of a Modified Technique of Transvesical Obturator Nerve Block to Avoid Adductor Contractions during Transurethral Resection of Bladder Tumors

<b><i>Introduction:</i></b> The aim of the study was to evaluate the effectiveness of a modified transvesical obturator nerve block (ONB) in the prevention of obturator nerve reflex and consecutive bladder perforations (BPs) during transurethral resection of bladder tumors (TURBTs). <b><i>Materials and Methods:</i></b> A retrospective analysis of all patients resected in 2014–2015 due to a bladder tumor of the lateral walls, including a follow-up period until December 2018, was performed. Two groups were defined: in the first group, all patients underwent TURBT with a modified transvesical ONB. The second group underwent conventional TURBT with intermittent resection. Primary endpoints were the rates of adductor contractions and BPs. <b><i>Results:</i></b> Ninety-four out of 1,145 resected patients presented with tumors on the lateral wall of the bladder and a complete dataset including a long-term follow-up. Thirty-six patients were treated in the ONB group, and 58 patients comprised the control group. The median age in the 2 groups was 70.8 and 71.8 years in the first and second groups, respectively. Adductor spasms were reported in 8.33 versus 25.86% (<i>p</i> = 0.057) and perforation in 2.78 versus 17.24% (<i>p</i> = 0.047) in groups 1 and 2, respectively. After a median follow-up of 32.5 months, there was no significant difference in recurrence rates (52.78 vs. 51.72%, <i>p</i> = 0.672). In a subgroup analysis, lower perforation rates were recorded for the ONB group in patients with tumors &#x3c;3 cm (0/30 vs. 8/46, <i>p</i> = 0.076) and in patients with unifocal tumors (0/12 vs. 5/23, <i>p</i> = 0.141). <b><i>Discussion/Conclusion:</i></b> The simplified approach of transvesical ONB demonstrated in this study appears to be an inexpensive, safe, effective, and simple-to-use technique.