Ultrasound Guided Posterior Quadratus Lumborum Block for Postoperative Analgesia in Gynecologic Surgery

Overview

The challenge to achieve adequate analgesia has led to the development of directed, multi-modal protocols specific to management of post-laparoscopy pain in effort to decrease the amount of additional administration of narcotic medication. While several non-opioid regiments have been found to be effective, opioid medications still play a significant role in early postoperative analgesia. Given the adverse side effects of narcotic medications, regional blocks utilizing local anesthetic agents and has been shown to improve overall pain control in this time period. Truncal abdominal nerve blocks are useful for pain control in abdominal and pelvic surgeries. More recently, the utilization of the quadratus lumborum (QL) block has effectively alleviated somatic and visceral pain in the upper and lower abdomen. The QL block provides analgesia spanning from the T4 to L1 dermatomal levels in the thoracolumbar plane to provide a broad sensory level analgesic effect. The approach involves injecting local anesthetic under ultrasound guidance into the plane posterior to the quadratus lumborum muscle and middle layer of thoracolumbar fascia. Given the utility of the QL block in controlling somatic pain, this study aims to determine whether the QL block is an effective analgesic adjunct in the control of postoperative pain period, specifically with regards to patients undergoing laparoscopic gynecologic surgery.

Prospective Cohort observational study. All patients that meet criteria for participation in this study will be screened: patients scheduled to undergo a laparoscopic hysterectomy for benign conditions by attending physicians in the division of Minimally Invasive Gynecologic Surgery. Based on surgeon's preference, and patient's consent, the patient is offered a QL block or not. Our aim is to follow the patient's pain scores post op and amount of oral pain medication used whether they received QL block or not. If the patient received the QL block then they will be considered part of the study arm. If the patient did not receive the QL block then they will be considered part of the control arm. The QL block is best thought of as a volume or compartment block in that volumetric spread of LA along the fascial plane is associated with efficacy in blocking the thoracolumbar nerves between T7-L1. It can be reasonably assumed that this compartment is the same across patients and is not affected by the amount of subcutaneous or central fat present in the obese patient. If a block is to be performed, the QL block will be performed using a 21G x 100mm Stimuplex needle under ultrasound guidance using a curvilinear probe. Subjects will be positioned in the semi-lateral position to facilitate access into the plane posterior to the quadratus lumborum muscle and middle layer of thoracolumbar fascia. The QL block will be administered via an in-plane approach and local anesthetic will be injected between the quadratus lumborum muscle and the middle layer of the thoracolumbar. The QL block will be in the operating room after induction prior to starting the scheduled surgical procedure. If the block is performed, it will include 20ml of 0.25% bupivacaine and 5ml of liposomal bupivacaine (Exparel) per side. The block will be done bilaterally therefore a total of 40ml of 0.25% bupivacaine and 10ml of liposomal bupivacaine (Exparel) will be administered.