Table 1. Demographic data.

Value are presented as mean ± standard deviation, median (P₂₅-P₇₅) or number (%).

Group C, saline infiltration group; group L, 0.1% ropivacaine infiltration group; CND, central neck dissection.

^a)Mann-Whitney U test was used and expressed as median (P₂₅-P₇₅) because of abnormal distribution.