Effectiveness of Ultrasound-Guided Unilateral Subcostal Transverse Abdominal Plane Block Versus Conventional Systemic Analgesics for Postoperative Analgesia among Adult Patients Undergoing Open Cholecystectomy: A Prospective Cohort Study

Background: Postoperative pain after open cholecystectomy poses a significant challenge, with potential complications and extended hospital stays. Postoperative pain control is traditionally attained by the administration of opioids, which is associated with well-documented side effects. However, limited studies have evaluated the analgesic effect of the subcostal TAP block compared to the conventional systemic analgesics in open cholecystectomy. Objective: To assess the effectiveness of ultrasound-guided unilateral subcostal transverse abdominal plane block for postoperative analgesia among adult patients undergoing open cholecystectomy. Method: A prospective cohort study was conducted on 98 patients. Patients in the subcostal transverse abdominals plane block group (n = 49) received block with 20ml of 0.25% bupivacaine, while the non-block group (n = 49) received conventional systemic analgesics. The severity of pain, time to first rescue analgesic administration and total analgesic consumption were assessed 24 hours after surgery. An independent sample t test and a Mann-Whitney U test were used to compare symmetric and asymmetric data, respectively. Time to first rescue analgesic administration was analyzed using Kaplan-Meier survival curve, log rank test and cox-regression for covariates. Results: In total, 98 patients were analyzed with no dropouts. The severity of postoperative pain was lower in the subcostal transverse abdominals plane block group compared to the non-block group over the whole observation period (P<0.05). Median cumulative opioid consumption in morphine was 0 (0–5) vs. 25 (25–50) mg (P=0.0001) in the subcostal transverse abdominals plane block and non-block groups, respectively. Patients in the subcostal transverse abdominals plane block group had longer time to first rescue analgesia administration, with a median time of 12 hours, 95% CI: [10.997–13.003] compared to the non-block group, whose median time was 0.4hour,95%CI: [0.136- 0.664], with a p=0.001. Conclusions: Subcostal transverse abdominals plane lowers pain severity, total analgesia consumption, and prolongs time to the first analgesia request. Based on the above findings, we recommend its use for effective postoperative pain management in patients undergoing open cholecystectomy.