Efficacy of ultrasound-guided obturator nerve block in transurethral surgery

Background: During transurethral resection surgery (TUR), accidental stimulation of the obturator nerve can cause violent adductor contraction, leading to serious intraoperative complications. General anesthesia with muscle relaxation is currently the preferred technique for TUR surgery. Spinal anesthesia combined with obturator nerve block has also been used for TUR surgery in geriatric population. Blind, anatomical methods for identifying the obturator nerve are often unsatisfactory. Therefore, we conducted this prospective study to validate the efficacy of ultrasound-guided obturator nerve block (USONB) during TUR procedures. Methods: Eighteen male patients undergoing TURP surgery under spinal anesthesia were included in the study. Bilateral USONB with maximum 20 ml of 1% lidocaine per patient was performed. An independent observer was present to monitor any adduction movements during the operation and to record patient and surgeon satisfactions. Results: In all patients, obturator nerve was visualized from the first attempt, requiring an average of 4.3 min for blocking of each side. USONB was successful (97.2%) in preventing an adductor spasm in all except one patient. Patient′s and surgeon′s satisfaction were appropriate. In all patients, adductor muscle strength recovered fully within 2 h following the surgical procedure. Conclusions: USONB is safe and effective during TUR surgery. It provides optimal intra-and postoperative conditions.