Table 1.

Demographics of the three groups

Item	Group R2	Group R4	Group R6	P value
Sex, male/female	22/18	24/16	23/17	0.903
Age, years	45 ± 10	43 ± 10	45 ± 8	0.442
Height, cm	164 ± 9	165 ± 8	164 ± 8	0.892
Weight, kg	62 ± 10	61 ± 11	60 ± 9	0.668
Operation time, min	18 ± 5	18 ± 4	18 ± 4	0.782