Background and objectives Mastectomy has many potential sources of pain. Rhomboid intercostal block (RIB) is a recently described plane block. The primary hypothesis of the study is that ultrasound-guided RIB combined with general anesthesia would accelerate global quality of recovery scores of patients following mastectomy surgery. Secondary hypothesis is that RIB would reduce postoperative opioid consumption, pain scores, and the need for rescue analgesia.

Methods Patients aged between 18 and 70 years, with American Society of Anesthesiologists physical status I–II and scheduled for an elective unilateral modified radical mastectomy surgery with axillary lymph node dissection were enrolled to the study. Following endotracheal intubation, patients were randomly allocated into two groups. Patients in the first group (group R) received ultrasound-guided RIB with 30 mL 0.25% bupivacaine. In the control group (group C), no block intervention was applied. All patients received intravenous dexamethasone 8 mg, dexketoprofen trometamol 50 mg intraoperatively and tramadol 1 mg/kg 30 min before the end of surgery for postoperative analgesia. All patients received intravenous morphine patient-controlled analgesia device at the arrival to the recovery room.

Results The descriptive variables of the patients were comparable between group R and group C. Mean quality of recovery-40 score at 24 hours was 164.8±3.9 in group R and 153.5±5.2 in group C (mean difference 11.4 (95% CI 8.8 to 13.9; p<0.001). At 24th hour, median morphine consumption was 5 mg (IQR 4–7 mg) in group R and 10 mg (IQR 8–13 mg) in group C, p<0.001. Intraoperative fentanyl administration, pain scores and the need for rescue postoperative analgesia was similar between groups.

Conclusions In the current study, ultrasound-guided RIB promoted enhanced recovery and decreased opioid consumption after mastectomy surgery.

Trial registration number ACTRN12619000879167.