3.1. The Main Outcome Measures
CPSP, NRS, pain
The incidence of CPSP was assessed by the number of positive cases of CPSP (NRS ≥ 1 and 3 months postoperatively). The intensity of CPSP can be indirectly assessed by the scores of the effects of pain on daily life and the level of pain treatment measures [The effect of pain on daily life had four grades: grade A (no effect), grade B (mild effect), grade C (moderate effect), and grade D (severe effect).The level of pain treatment measures had four grades: grade A (no treatment measures), grade B (rest or reduced activity), grade C (self-medication), and grade D (treatment at a hospital).