Comparison of Obturator Nerve Blockade and Neuromuscular Blockade

Comparison of Obturator Nerve Blockade and Neuromuscular Blockade for the Prevention of Adductor Spasm in Patients Undergoing Transurethral Resection of Bladder Tumors.

Patients diagnosed with posterolateral bladder tumors will be invited to participate in the study. Subjects will be randomized to receive an ultrasound-guided obturator block or a neuromuscular blocking agent after the induction of general anesthesia in an attempt to block the obturator reflex during surgery.

The purpose of this research is to compare the incidence of adductor spasm in patients undergoing general anesthesia with neuromuscular blocking agents versus obturator block. Transurethral resection of bladder tumor(s) (TURBT) is a commonly performed procedure to diagnose and treat bladder cancer. The obturator nerve is located lateral to the bladder wall in the pelvis prior to innervating the adductor muscles of the thigh. Depending on the location of the tumor(s), electrocautery or surgical stimulation may result in stimulation of the obturator nerve, resulting in adduction of the leg, which is called the adductor reflex or spasm. This may occur violently and unexpectedly, and result in bladder perforation, bleeding, or cancer dissemination.

Sixty subjects with be randomized to the obturator block or neuromuscular block arm upon enrollment, using randomized permutated blocks of six.

Comparing the incidence of adductor spasm in patients undergoing general anesthesia with obturator block.

Comparing the incidence of adductor spasm in patients undergoing general anesthesia with neuromuscular blocking agents.

Subjects allocated to the obturator block group will be monitored for the incidence of block and procedure-related adverse events. In addition to clinical observation, a Nerve Integrity Monitor (Medtronic) will be used to detect adductor spasm using continuous electromyography. Electrodes will be placed on the thigh to objectively detect and record instances of adductor spasm. One hour after arrival to post-anaesthesia care unit (PACU) or when discharge criteria are met (whichever comes first), repeat dynamometer measurements and TUG tests will be performed. Patients will be called 24-48 hours post procedure to inquire about falls or evidence of nerve injury, as well as patient satisfaction.

Subjects allocated to the neuromuscular block group will be monitored for the incidence of block and procedure-related adverse events. In addition to clinical observation, a Nerve Integrity Monitor (Medtronic) will be used to detect adductor spasm using continuous electromyography. Electrodes will be placed on the thigh to objectively detect and record instances of adductor spasm. One hour after arrival to PACU or when discharge criteria are met (whichever comes first), repeat dynamometer measurements and TUG tests will be performed. Patients will be called 24-48 hours post procedure to inquire about falls or evidence of nerve injury, as well as patient satisfaction.

Nerve Integrity Monitor will be used to detect adductor spasm and below are listed the numbers or patients with increased incidence of adductor spasm.

Based on TUG time measurements of patients below are the numbers of patients with an increased risk of falling.

Test the strength of subject's lower extremity muscles on the timed up and go (TUG) test and determine how many patients had increased leg weakness.

Inclusion Criteria: Patients ≥ 18 years of age Planned TURBT for unilateral or bilateral posterolateral bladder tumors Ability to understand and provide informed consent Exclusion Criteria: Patient refusal or inability to provide informed consent True allergy, not sensitivity, to local anesthetics True allergy, not sensitivity, Propofol True allergy, not sensitivity, general anesthetic agents Pregnancy Severe hepatic impairment Evidence of infection at or near the proposed needle insertion site Any sensorimotor deficit of the lower extremity, whether acute or chronic Inability to walk without assistance Lower extremity joint replacement surgery in the preceding six months

Soberon JR, Awoniyi CA, Perez MA, Vasilopoulos T, Canales BK. Obturator Nerve Blockade vs. Neuromuscular Blockade for the Prevention of Adductor Spasm in Patients Undergoing Transurethral Resection of Bladder Tumors: A Randomized Controlled Trial. Pain Med. 2021 Jun 4;22(6):1253-1260. doi: 10.1093/pm/pnaa448.