Table 1.

Comparison of baseline data between two groups (x̅ ± s, n)

Group	n	Gender		Average age (years)	Operation time (min)	Body mass index (kg/m2)	ASA rating		Clinical staging
		Male	Female				Grade I	Grade II	Phase I	Phase II
Observation group	38	26	12	58.15±7.31	180.69±32.36	23.91±1.05	10	28	25	13
Control group	37	24	13	59.76±8.06	178.27±35.92	24.13±1.12	11	26	27	10
χ2/t		0.107		0.907	0.307	0.878	0.108		0.455
P		0.744		0.368	0.760	0.383	0.742		0.500