Quadratus Lumborum II Block vs Conventional Therapy Alone For Laparoscopic Sleeve Gastrectomy

The QL 2 block is a novel fascial plane block recently described by Blanco and colleagues in which local anesthetic is deposited adjacent to the antero-lateral aspect of the quadratus lumborum muscle. This results in posterior spread of local anesthetic through the middle layer of the thoraco-lumbar fascia, which theoretically communicates with the paravertebral space resulting in potentially longer-lasting and denser analgesia than wound infiltration. Like the more commonly used transversus abdominis plane (TAP) block, the QL 2 block targets the anterior rami of T7-T12, ilioinguinal, iliohypogastric, and the lateral cutaneous branches of L1-L3. The QL 2 block derives from the TAP block, which is also a fascial plane block that is commonly used to treat pain following surgery involving the anterior abdominal wall. However, the QL block's more posterior location has recently been shown to provide a longer lasting and more profound analgesic effect than the TAP block, possibly by communicating with the paravertebral space. Although the TAP has been shown to be effective in a variety of surgical procedures involving an anterior abdominal wall incision including laparoscopic bariatric surgery the QL 2 block has until now, not been studied in the context of bariatric surgery. Conventional therapy has consisted of surgical infiltration of the incision ports with bupivacaine 0.25%. The study team proposes a study to compare the analgesic effects of the QL 2 block with conventional therapy, consisting of surgical wound infiltration, for postoperative analgesia following laparoscopic gastric sleeve gastrectomy.