To compare the efficacy of ultrasound (US) guided Obturator nerve block versus Pericapsular Nerve Group (PENG) block in preventing adductor spasm in patients undergoing transurethral resection of postero-lateral bladder mass under spinal anaesthesia: a prospective, randomised, single blinded, controlled clinical study.

After approval by the Institute Ethics Committee, the eligibility criteria (inclusion and the exclusion) will be adhered to strictly for selection of study population. Written informed consent will be obtained from the patients undergoing elective trans-urethral resection of posterolateral bladder mass surgery under spinal anaesthesia after explaining the study protocol to them.

The patients will be assessed for medical and surgical history, general and systemic examination, airway examination and investigations such as complete blood picture, renal function test, liver function test and coagulation profile.

On the day of surgery, in the preoperative area, baseline vitals such as Heart rate (HR), Mean arterial pressure (MAP), and Oxygen saturation (SpO2) will be noted. The patients will be randomly allocated to one of the two groups. Based on the number chosen and the allotted group, patients will be randomly divided into Group P and Group O. The patient will then be taken into the operation theatre and standard ASA monitors will be connected. After noting down the baseline vitals in the operation theatre, spinal anesthesia will be given, and the level of the sensory and motor blockade will be noted. The onset of sensory blockade will be assessed by the appearance of tingling and numbness sensation and the maximum level of sensory blockade will be assessed using pin prick test. The motor blockade will be assessed using the Modified Bromage scale.

After achieving adequate sensory and motor blockade, under all aseptic precautions, Group P will receive ultrasound (US) guided PENG block with 20 mL of 0.5% Bupivacaine and Group O will receive US guided obturator nerve block with 20 mL of 0.5% Bupivacaine.

Intraoperatively, presence of adductor jerk will be noted by the surgeon and the anesthesiologist. The patient will be followed up for 6 hours postoperatively and quadriceps muscle strength by MRC medical grading at postoperative 0, 2, 4, 6 hours and return to Grade 5 will be documented. Complications like perforation of the bladder, conversion to general anaesthesia due to failure of the block and hypotension, bradycardia, low back ache, post dural puncture headache and urinary retention due to spinal anaesthesia will be noted. Any adverse event before, during and after the procedure will be treated appropriately.