Fig. 2. Postoperative pain scores based on the Children's Hospital of Eastern Ontario Pain Scale (CHEOPS, 0–10). F group = fentanyl group; F–P group = fentanyl–acetaminophen group. Pain scores recorded at 1, 6, 12, 24, 36, 48, 60, and 72 h after surgery did not show statistically significant differences between the two groups.