Perioperative outcome
The average operative times was 249 minutes for the low-, mid- and
high-volume groups, at 270 minutes, 260 minutes and 227 minutes,
respectively (P < 0·001). Although there was no significant
difference in operative time between the low- and mid-volume groups,
that of the high-volume group was significantly shorter than that of the
low-and mid-volume groups (P < 0·001). Among the 1405
patients, the average intraoperative blood loss was 196 ml; the values
were 218 ml, 197 ml and 179 ml in the low-, mid- and high-groups,
respectively (P = 0·005). There was no significant difference between
the mid-volume group and the low- and high-volume groups, but blood loss
in the high-volume group was significantly less than that in the
low-volume group (P = 0·001).