Fig. 3

Patient distribution of postoperative pain scores 0–3, 3–6, and 6–24 h after surgery in patients with and without chronic pain. The pain score 3–6 h after surgery was significantly higher in the patients with chronic pain than in the patients without chronic pain. However, there was no significant difference in the pain scores 0–3 and 6–24 h after surgery between the two groups, although the patients with chronic pain tended to experience more pain than the patients without chronic pain at each time interval