Shetty, Shreya

Injections of local anesthetic in the fascial planes around the quadratus lumborum muscle (QL blocks) are performed for postoperative pain control after abdominal surgeries. Multiple approaches of injecting anesthetic in and around the QL have been reported (anterior, posterior, transmuscular, intramuscular and lateral QL blocks). These techniques vary in terms of ease of administration and extent of analgesia. The extent of the anesthetic spread from this ultrasound‐guided procedure is influenced by the fascial layers surrounding the QL. A limited number of studies on small samples using varying amounts of anesthetic have left open questions regarding the extent of spread of local anesthetic and the best approach. This study evaluates the local anesthetic spread of two ultrasound‐guided lateral QL block approaches that have proven effective in controlling postoperative pain. A methylene blue‐dyed saline solution (40mL per QL block) is injected into fresh frozen cadavers (n=10). With the patient in supine position, the needle tip is placed at either (1) the anterolateral border of the QL deep to the transversalis fascia or (2) anterior to the transversus abdominus muscle superficial to its aponeurosis. Anatomic dissection of the injection plane is then performed to determine the extent of spread of the dyed saline. We hypothesize that the continuity between the transversalis fascia and the anterior layer of the thoracolumbar fascia (anterior to the QL) facilitates the cranial spread of the anesthetic under the lateral arcuate ligament to the endothoracic fascia. This would explain our observed analgesic effect past the umbilical region to dermatomes in the epigastric region (T7–T8). Understanding how QL fascial planes facilitate anesthetic spread will enable intraoperative administration of these blocks to be tailored to specific procedures and facilitate post‐operative recovery after abdominal operations. Improved methods of intraoperative pain management may reduce post‐operative opioid use and support the medical community in addressing the opioid epidemic in the United States. This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal .