Objective:To evaluate the operative time

blood loss

conversion rate toopen surgery

and operative complications formodi-fied Miccoli mode endoscopic thyroidectomy at different stages

under different surgical conditions and with diffrent techniques

in order to explore the learning curve of modified Miccoli mode endoscopic thyroidectomy and its influence factors.Methods:Clinical data of 362 operative cases of benign thyroid tumore performed between June 2005 and June2008 by a single doctor were reviewed.The patients were sequentially divided into three groups

with 30 cases in each group(without considering the size and site of the mass).The operative time

blood loss

conversion rate to open surgery and operative complications were compared between the three groups.Results:The op-erative time in group A

group B and group C were(104.3±29.6)min

(79.5±21.9)min

and(73.67±17.6)min

respectively.There were significant differences in operative time

between the three groups.2 patients in group A converted to open surgery for blood loss

and 1 patient had a temporary injury of recurrent laryngeal nerves.There were significant differences blood loss between the three groups.The influencing factors were as follows.The operative time for the masses of 2 to 4 centimeters was significantly shorter than that for the masses of shorter than 1 centimeter or longer than 5 centimeters.The size cased the same difference for the blood loss.The operative time for the masses in the middle and upper part was significantly shorter than the masses in other parts

the site also did bring about sig-nificant differences in blood loss.The technique of constructing cavity

imaging and ultrasonic calpel to stop bleeding had obvious impact on operative time and blood loss.The operative time for radical thyroidectomy was longer than than for partial thyroidectomy

while 2 pa-tients had a temporary injury of recurrent laryngeal nerves after the adical thyroidectomy.The significant differences in blood loss were found.Conclusion:The learning curve of the modified Miccoli mode endoscopic thyroidectomy requires approximately 30 cases to achieve more proficiency.Advanced technology and equipment

proper choice of patients and simple way of operation can passivate the learning curve of this kind.