Quadratus Lumborum Block vs Transversus Abdominis Plane Block for Post-cholecystectomy Analgesia

Overview

In laparoscopic cholecystectomy, overall pain is a conglomerate of three different and clinically separate components: incisional pain (somatic pain) due to trocar insertion sites, visceral pain (deep intra abdominal pain), and shoulder pain due to peritoneal stretching and diaphragmatic irritation associated with carbon dioxide insufflation. Moreover, it has been hypothesized that intense acute pain after laparoscopic cholecystectomy may predict development of chronic pain (e.g., postlaparoscopic cholecystectomy syndrome). Without effective treatment, this ongoing pain may delay recovery, mandate inpatient admission, and thereby increase the cost of such care. Recently, the uses of peripheral axial blocks that deliver local anesthetic into the transversus abdominis fascial plane have become popular for operations that involve incision(s) of the abdominal wall. Thus, the Transversus Abdominis plane (TAP) block has been shown to reduce perioperative opioid use in elective abdominal surgery, including open appendicectomy, laparotomy, and laparoscopic cholecystectomy. However, the efficacy of the TAP block is reportedly only reliable in providing analgesia below the umbilicus. The ultrasound-guided subcostal transversus abdominis (STA) block is a recently described variation on the TAP block which produces reliable supraumbilical analgesia. Deposition of local anesthetic in this plane has shown to block dermatomes T6 to T10 with an occasional spread to T12. This variant will be discussed in our study. Currently, the Quadratus Lumborum block (QL block) is performed as one of the perioperative pain management procedures for all generations (pediatrics, pregnant, and adult) undergoing abdominal surgery. The local anesthetic injected via the approach of the posterior QL block ( QL 2 block ) can more easily extend beyond the TAP to the thoracic paravertebral space or the thoracolumbar plane, the posterior QL block entails a broader sensory-level analgesic and may generate analgesia from T7 to L1. Use of posterior QL block in laparoscopic cholecystectomy has not been investigated before and it is the variant that will be discussed in our study.

The aim of this study is to compare the analgesic efficacy of ultrasound guided posterior quadratus lumborum block and subcostal transversus abdominis plane block in laparoscopic cholecystectomy. The primary outcome will be assessment of postoperative opioid analgesic requirements. The secondary outcomes will include assessing intraoperative analgesic requirements, stress of trocar insertion and insufflation, postoperative visual analogue scale (VAS), length of stay at post-anesthesia care unit (PACU), time of first request to analgesia, incidence of nausea, and vomiting. The study will hypothesize that quadratus lumborum block will be more superior than or equal to transversus abdominis block because it could cover all the dermatome segments from caudally L1 to cranially till T6 segments as the drug is expected to travel from the QL to the higher paravertebral spaces.