Preemptive Ultrasound guided Modified Thoracoabdominal nerve block via perichondrial approach (M - TAPA) vs oblique subcostal transversus abdominis plane block for postoperative analgesia in patients undergoing laparoscopic cholecystectomy under general anaesthesia - A Randomised controlled trial

Laparoscopic cholecystectomy (LC) is a frequently performed surgery as the gold standard in the treatment of symptomatic gallstone disease. Despite the introduction of a  minimally invasive approach, cholecystectomy can cause significant postoperative pain owing to multifactorial factors.  Acute postoperative pain is the most common cause of patient discomfort during the period after LC and is the most common cause of readmission after discharge. Poorly controlled postoperative pain impairs the quality of recovery, increasing the risk of postoperative pulmonary complications as risk factor for the formation of chronic pain. It was observed that the abdominal pain following LC mostly originates from the incision area, and the remaining part consists of visceral and referred pain. Multimodal analgesia, including opioids is used to limit pain following LC. Treatment with opioids might cause side effects for example postoperative nausea and vomiting, constipation, respiratory depression. Oblique subcostal transverse abdominis plane block (OSTAP) provides a wide range of analgesia from T7 – T12, is effective for 6 – 18h postoperatively, however it requires multiple injections to achieve complete analgesia. Modified thoracoabdominal nerve block through perichondrial approach (M – TAPA)  is a newer technique which has received increasing attention due to its wide range of analgesic coverage of the trunk (that is T5 – T12)  with a single puncture per side and has been  reported to provide a long acting effect. M – TAPA offers blocking both anterior and lateral cutaneous branches of the thoracoabdominal nerves, surpassing the limitations of conventional techniques such as transversus abdominis plane block. We hypothesize that M – TAPA block would be more effective than OSTAP block for controlling postoperative pain, considering its range of efficacy and long term durability.