Rhomboid Intercostal Block for Postoperative Analgesia in Mastectomy: A Prospective, Randomized Controlled Trial

Abstract Background: Postoperative pain following mastectomy remains a significant concern, often requiring high-dose opioids that may lead to adverse effects. The rhomboid intercostal block (RIB) is a novel ultrasound-guided fascial plane block shown to reduce pain in thoracic and breast surgeries. This study aimed to evaluate the effectiveness of RIB in reducing postoperative opioid consumption and pain scores in patients undergoing mastectomy. Materials and Methods: In a randomized, double-blind trial, 28 patients (American Society of Anesthesiologists [ASA] I–II, aged 19–60 years) were randomized 1:1 to receive either general anesthesia with RIB (Group A) or general anesthesia alone (Group B). The sample size was based on prior data demonstrating opioid reduction with RIB undergoing mastectomy. The primary outcome was total morphine consumption within 24 h postoperatively. Secondary outcomes included pain scores at multiple time points and intraoperative fentanyl use. Data were analyzed using appropriate statistical tests based on data distribution, with a significance level of P < 0.05. Results: Group A demonstrated significantly lower morphine consumption in the first 24 h postoperatively (1.71 ± 0.99 mg vs. 10 ± 1.30 mg; P < 0.001). Pain scores were significantly reduced in Group A across all time points (1st, 3rd, 6th, 12th, and 24th h; P < 0.001). Intraoperative fentanyl requirements were also significantly lower in Group A (125 µg vs. 225 µg; P < 0.001). No significant differences in side effects were observed between groups. Conclusion: RIB significantly reduces postoperative opioid requirements and pain intensity in mastectomy patients and may serve as a valuable adjunct in enhanced recovery pathways for breast surgery.