RESULTS: No patient converted to open operation, no patient died, without myasthenia crisis occurring, and no incision infected in both group. The blood loss volume of control group and study group were 30.6±21.1ml and 46.7±34.2ml, without significant difference (p=0.115). There was no significant difference between pulmonary complications of control group (23.5%, 4/17) and of study group (25.0%, 3/12) (p=0.810). The ICU stay of control group and study group were 0.4±0.8 days and 0.3±0.8 days, there was no significant difference (p=0.945). The hospital stay of control group and study group were 8.2±4.1 days and 9.8±4.7 days, there was no significant difference (p=0.325). There was also no significant difference of hospital costs between control group and study group (14402.0±2317.2￥, 15449.3±3292.9￥, p=0.302).