Efficacy Of Quadratus Lumborum II Block 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. 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.

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.

The QL 2 group will receive 15 mL bupivacaine 0.25% on both sides for a total of 30 mL once the surgery is done but prior to extubation under ultrasound guidance.

Conventional therapy consists of the injection of 30 mL of bupivacaine 0.25% directly into the incision sites by the surgeon at the end of the procedure.

The amount of opioid consumption (in mg IV morphine equivalents) during and after procedure (100mcg fentanyl= 10mg morphine) (1.5mg dilaudid=10mg morphine)

Inclusion Criteria: Patients scheduled to undergo laparoscopic gastric sleeve gastrectomy 18-65 years of age BMI> 35 kg/m2. Exclusion Criteria: Contraindications to administration of local anesthesia (e.g. local anesthetic allergy) Contraindication/allergy to acetaminophen or ketorolac History of substance abuse or chronic opioid use Coagulopathy Patients receiving systemic anticoagulation Local infection ASA 4

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