Comparison of Classic and Inguinal Obturator Nerve Blocks Applied for Preventing Adductor Muscle Contractions in Bladder Tumor Surgeries: A Prospective Randomized Trial.

PURPOSE: Obturator nerve block (ONB) has been performed in surgeries of transurethral resection of bladder tumors (TUR-BT) for the prevention of the development of obturator muscle contraction. Currently, classic and inguinal approaches are frequently being used. In the present study, we aimed to compare the success rate, performance speed, and complication risks of both approaches.

MATERIALS AND METHODS: Sixty-six patients who underwent TUR-BT under spinal anesthesia were randomly selected, and ONB was performed on the tumor location side using classic (n=33) or inguinal (n=33) approaches. Ten milliliters of 0.25% bupivacaine were administered using a peripheral nerve stimulator in both approaches. Two endpoints were defined in the study: Primary endpoint; the duration of the determination of the obturator nerve and number of interventions when each participant is assessed in at the end of the ONB procedure. Secondary endpoint;  development of contractions, and complications each participant is assessed during the TUR-BT and 24 hours after ONB. (Clinical Trial Registration Number: ACTRN12617001050347)Results: General anesthesia was applied to the five patients in the classic ONB group who detected diffuse or bilateral tumors. These patients were excluded from the study. Contractions developed in 4 patients in each group, no statistically significant difference was detected between the groups (14.3%, n=4 versus 12.1%, n=4) (P=1.00). No complications were detected in both groups during the TUR-BT and 24 hours after ONB.We found that the inguinal approach provided a statistically significant advantage regarding the number of punctures (1.9 ± 0.9 versus 1.5 ± 0.7) (P=.036), and duration of the procedure (99.1 ± 48.4 seconds versus 76.0 ± 31.9 seconds) (P=.029) compared with the classic approach.

CONCLUSION: Although complications and success rates were similar in both groups, the inguinal method may be a better approach because it is faster and requires fewer punctures.