Ultrasound-Guided Transversalis Fascia Plane Block Versus Transmuscular Quadratus Lumborum Block for Post-operative Analgesia in Inguinal Hernia Repair

Regional blocks as a part of multimodal analgesia can improve pain control in the postoperative period. The transversalis fascia plane (TFP) block can block the proximal portions of the T12 and L1 nerves, while the main advantage of the Quadratus Lumborum (QL) block is the possible extension of the local anesthetic beyond the transversus abdominis plane (TAP) plane spreading into the thoracic paravertebral space and anesthetizing both the lateral and anterior cutaneous branches from T7 to L1. the aim of this study is to compare effectiveness of ultrasound-guided transversalis fascia plane block to trans-muscular quadratus lumborum block in providing postoperative analgesia in patients undergoing unilateral inguinal hernia repair.

This prospective randomized controlled study will include 50 patients (25 in each group) of American Society of Anesthesiologist (ASA) I and II physical status who will undergo unilateral inguinal herniorrhaphy under general anesthesia. The investigators hypothesize that ultrasound-guided trans-muscular quadratus lumborum block will be more effective than ultrasound guided transversalis fascia plane block in providing postoperative analgesia in these type of patients. Randomization will be done by a computer-generated random numbers. Patients will be blinded to the study groups. All patients will undergo a thorough pre anesthetic check-up and will be premedicated with metoclopramide 10 mg intravenously. In the operation theatre, an 18-gauge intravenous (IV) catheter will be placed and monitoring devices will be attached which will include electrocardiograph (ECG) using (GE-Datex Ohmeda 5 lead ECG cable), pulse oximetry (SpO2) using (GE- Datex Ohmeda adult finger spO2 sensor), non-invasive blood pressure (NIBP) using (GE-Datex Ohmeda NIBP cuff, adult double tube with bag). Emergency drugs and equipment will be ready and prepared. Numeric pain rating scale will be explained clearly to all patients before conduction of anesthesia. Anesthesia will be induced with fentanyl (2 mcg/kg) and propofol (1.5-2.5 mg/kg) and atracurium besylate (0.5 mg/Kg). An endotracheal tube will be inserted, and controlled ventilation will be adjusted to maintain normocapnia. Anesthesia will be maintained with sevoflurane at 1% and boluses of atracurium (0.1 mg/Kg) every 30 min. All patients will be given 1 g intravenous paracetamol, together with 4 mg ondansetron 10 min prior to the end of surgery for postoperative nausea and vomiting prophylaxis. The patients will be classified into two equal groups; Group QL (n=25) and group TF (n=25). All blocks will be performed on patients, following general anesthesia induction and endotracheal tube insertion, under guidance of a digital ultrasonic diagnostic imaging system (Mindray®, china), using a low frequency (2-6 MHz) curvilinear probe and a 100-150-mm short-bevel echogenic needle. Before ultrasound scanning, the operator will wear sterilized gown and gloves following routine scrubbing, flank skin will be prepared by antiseptic solution and fenestrated drape and dressings will be used for all procedures. After surgical disinfection of ipsilateral flank and protection of the ultrasound probe with a sterile ultrasound probe cover, sterile gel will be applied prior to scanning. After skin closure, inhalational anesthesia will be discontinued and reversal of muscle relaxation with atropine (0.02 mg/Kg) and neostigmine (0.05 mg/Kg) will be administered IV after return of patient's spontaneous breathing. Patient will then be transferred to post anesthesia care unit (PACU) for complete recovery and monitoring. In the PACU; rescue analgesia in the form of intravenous nalbuphine (in 5 mg increments) will be given for a numerical pain score more than 4 in the immediate postoperative period. The block will be considered a failed block if the patient required more than one 5mg dose of nalbuphine in the first hour postoperatively. In the ward; rescue analgesia will be given in the form of intravenous nalbuphine (in 5 mg increments) and repeated if needed every half an hour with a maximal dose of 60 mg in 24 hours.