Quadratus Lumborum Block for Post-Cesarean Analgesia

Overview

Most women having planned cesarean section receive spinal anesthetic for the procedure. Typically, spinal opioids are administered during the same time as a component of multimodal analgesia to provide pain relief in the 16-24 hr period postoperatively. However, spinal opioids are frequently associated with adverse effects such as nausea, pruritus, sedation and occasionally respiratory depression. The quadratus lumborum (QL) block is a regional analgesic technique which blocks T5-L1 nerve branches and has an evolving role in postoperative analgesia for lower abdominal surgeries and is a potential alternative to spinal opioids. There is some evidence that it may provide visceral along with somatic pain relief. It is a simple and safe technique that has been studied in lower abdominal surgeries, but has not been studied for pain relief after cesarean section. If found effective, it will have the advantage of a reduction in opioid associated adverse effects while providing similar quality of analgesia. This block has evolved from the previously known transversus abdominis plane block. We propose to undertake a study that will compare the relative efficacy of QL block with local anesthetic to spinal morphine. We will also study if it provides any incremental benefit when administered in addition to spinal morphine.

This will be a randomized controlled double blinded trial. Seventy five female patients belonging to American Society of Anesthesiologists status 1-3, age 18-45 yrs undergoing elective caesarean delivery will be included in this prospective study. After obtaining informed consent, they will be randomized to one of the three groups by a computer-generated randomization. All patients will receive standard spinal anesthetic. They will be randomized to one of the three groups (n=25 per group). Groups 1 and 3 will receive intrathecal morphine in addition to the spinal anesthestic. Group 2 will receive equal volume of saline added to the intrathecal mixture. Ultrasound guided Quadratus Lumborum block will be done. Following negative aspiration, 25 mL of Ropivacaine 0.5% (Groups 2 and 3), or the same amount of saline (Group 1) will be injected in each side. All patients will receive routine postoperative analgesia, including analgesics and oral morphine. All patients will be assessed postoperatively by a blinded investigator at 6, 12 and 24h post-operatively.