Table 4.

Correlation coefficient analysis between the operation time and postoperative pain level.

	Operation Time
	Co	p
Postoperative pain level (VAS)
Early period (POD < #3)	0.140	0.030 *
Late period (POD #3–7)	0.201	0.004 *
Total period (POD #0–7)	0.271	< 0.001 *

VAS, visual analog scale; POD, postoperative day; Co, correlation coefficient; * p < 0.05.