Anterior Quadratus Lumborum Block Versus Erector Spinae Plane Block After Elective Cesarean Section

Cesarean section is the one of the most common surgical procedures. Inadequate pain management is associated with increased morbidity, costs, and maternal dissatisfaction. Furthermore, effective postoperative pain management enables mothers to care for their newborn infants. Systemic and neuraxial opioids are the cornerstone of postoperative pain management; however, opioids are associated with significant side effect such as respiratory depression, urine retention, constipation, and itching. To reduce the postoperative opioids requirement and subsequently their side effects, multimodal regimen is advice including neuraxial anesthesia, neuraxial morphine, regular administration of non-opioids analgesia (non-steroidal anti-inflammatory drugs and acetaminophen) and planned use of opioid for breakthrough pain. The addition of peripheral nerve blocks to the multimodal analgesic plan was found to reduced postoperative opioids requirement in non-obstetric procedures. Quadratus lumborum (QLB) and erector spinae plane (ESPB) blocks are relatively new techniques for peripheral nerve block and showed promising results in managing pain after Cesarean delivery. There are several types of QLB that had been described. Lateral (QLB1), posterior (QLB2), and anterior (QLB3) quadratus lumborum blocks been studied in cesarean delivery and were found to reduce opioids requirement when compared against placebo. Cadaver studies suggest that local anesthetic deposition at QLB1 diffuses mainly to the transversus abdominis muscle plane while, at QLB2, and at QLB3 spread may occur into the thoracic paravertebral space providing additional visceral pain control. ESPB can provide both visceral and somatic analgesia due to anterior spread to the paravertebral space. ESPB was found to reduce postoperative opioids requirement in comparison to transversus abdominis plane block and intrathecal morphine. To the best of our knowledge, there is no published data comparing the analgesic effect of QLB3 (anterior QL) and ESPB after elective cesarean delivery.