Learning curve for endoscope holder in endoscopic thyroidectomy via complete areola approach: a prospective study

Endoscopic thyroidectomy via complete areola approach (ETCAA) is becoming the preferred choice of some patients due to the perfect cosmetic result. Endoscope holder plays an important role in the procedures. Research on the learning curve is helpful in training of endoscope holder and improvement of the whole procedure. This prospective study investigated 100 consecutive patients who underwent ETCAA performed by a single experienced surgeon and a single inexperienced endoscope holder. Patients were equally divided into ten groups chronologically. One-way analysis of variance, Student-Newman-Keuls test, and Pearson Chi square test were used to analyze statistical significance for clinical data. The correlativity between the operative time and the case number, the endoscope holding score and the case number, the operative time and the interval of neighboring procedures, the endoscope holding score and the interval of neighboring procedures were analyzed with linear regression analysis. The mean operative time was 96.30 +/- A 13.10 min, and the mean endoscope holding score was 74.65 +/- A 14.08. There were significant differences among the mean operative time (P < 0.0001) and the mean endoscope holding score (P < 0.0001). Multiple comparison revealed that the mean operative time of group 7, 8, 9, 10 were shorter than group 4, 5, 6, meanwhile the mean operative time of group 4, 5, 6 were shorter than group 1, 2, 3. Moreover, the mean endoscope holding score of group 7, 8, 9, 10 were higher than group 4, 5, 6, and the mean endoscope holding score of group 4, 5, 6 were higher than group 1, 2, 3. Linear regression analysis showed negative correlation between the operative time and the case number (r = -0.746, P < 0.0001), positive correlation between the endoscope holding score and the case number (r = 0.765, P < 0.0001), positive correlation between the operative time and the interval of neighboring procedures (r = 0.777, P = 0.008), and negative correlation between the endoscope holding score and the interval of neighboring procedures (r = -0.809, P = 0.005). A specific learning curve for endoscope holder in ETCAA does exist. The initial 30 cases composed the infancy of the learning curve, and the endoscope holder could expect a learning curve of approximately 60 cases in order to achieve proficiency. Increasing the operating frequency would help shorten the learning curve.