Learning Curve Of Modified Miccoli Operation On Thyroid Space Occupying Lesion

Objective:To investigate the skills、effect and learning curve of modified Miccoli operation on thyroid space occupying lesion and provide guidance for surgeon who want to carry out the operation.Methods:A total of97patients diagnosed with thyroid solitary space occupying lesion were divided into six groups according to the surgical scequencing,which was group A (15cases),group B (15cases), group C (15cases), group D (15cases), group F (15cases), group F (22cases) and preoperative relative examinations were all considered benign lesions.All patients in six groups were treated by modified Miccoli operation and by the same surgeon who had rich experience in traditional open thyroid surgery,but had no experience of endoscopic thyroid surgery.All these operations were completed from May2010to March2012in our department. Genders,ages,tumor diameters,operative time,blood loss,time of total hospitalization, time of postoperative hospitalization,rate of complications were compared with statistical methods and related factors of the presence or absence of statistically significant differences about the observed indicators were analysed.Charts of the learning curve were drawn according to each patient’s operative time and each group’s mean operative time.Mathematical model of Wright’s learning curve was applied to design the learning curve function by which to calculate the number of cases that has stable operative time and minimum complications incidence.Results:Each operation of97cases was successful.No significant difference existed in clinical data (gender、age、tumor diametor) among the6groups(P>0.05).The operative time in group C(56.07±10.601min)、group D(50.57±9.146min)、group E(49.79±7.266min)、group F(51.00±7.942min) decreased significantly than that in group A(73.79±12.601min)、group B(74.36±8.697min) and there was significant difference (P<0.05);the operative time in group A and group B was similar(P>0.05) and so was it in group C、D、E、F(P>0.05).Time of posthospitalization in group C(3.43±0.756d)、group D(3.21±0.579d)、group E(3.57±0.756d)、group F(3.50±0.519d)was shorter than that in group A(4.14±0.949d)、group B(3.86±.535d) and there was significant difference (P<0.05); the time of posthospitalization in group A and group B was similar(P>0.05) and so was it in group C、D、E、F(P>0.05).There was no statistical significance in total hospitalization among group A(8.21±0.975d) group B(8.00±0.961d)、group C(8.07±0.917d)、group D(7.79±0.802d)、group E(8.36±0.633d)、group F(7.71±0.726d)(P>0.05) and there was no statistical significance in blood loss among group A(6.93±2.731ml)、group B(7.14±2.033ml) group C(6.07±3.452ml)、group D(6.93±2.200ml)、group E(6.29±2.016ml)、group F(7.14±2.381ml) too(P>0.05).The operative complications rate were20.0%(3/15) in group A,13.3%(2/15) in group B,0%(0/15) in group C,6.7%(1/15) in group D,0%(0/15) in group E,0%(0/22) in group F and there was no statistical significance between the6groups in operative complications rate (P>0.05).Intraoperative frozen pathology implied seven cases malignant and one case was converted to thyroid cancer surgery、cervical lymph node dissection,the other six cases were ended and were treated by open surgery some time later.The conversion rate was7.22%(7/97). No patient recurred after the following4to12months. Charts of the learning curve were drawn according to each patient’s operative time and each group’s mean operative time.The learning curve function was designed according to mathematical model of Wright’s learning curve.The function was Y;=98X-0.234in this study and the learning curve was determined28cases integrating charts of the learning curve.Conclusions:Modified Miccoli is a better effects,fewer traumas and safe operation as well as has a better cosmetic results on treating thyroid tumors.The learning curve is approximately28cases for a surgeon who have rich experiences in conditional open thyroid surgery, then surgical skill can aquire proficiency and operative time is basically stable.