Learning curve analysis of transvaginal natural orifice transluminal endoscopic hysterectomy

BACKGROUND: No data are available to assess the learning curve for transvaginal natural orifice transluminal endoscopic hysterectomy for non-prolapsed uteri in benign gynecologic diseases. The lack of exposure to transvaginal natural orifice transluminal endoscopic hysterectomy during training, in addition to a poorly defined learning curve, further deters interested physicians from applying this technique to daily practice. The aim of this study was to evaluate the learning curve and perioperative outcome of transvaginal natural orifice transluminal endoscopic hysterectomy by an experienced endoscopist. METHODS: A total of 240 cases of transvaginal natural orifice transluminal endoscopic hysterectomies with or without adnexectomy for various benign gynecologic diseases were included. Demographic data and various perioperative parameters were reviewed from the prospectively collected database. Operative time was set as a surrogate marker for surgical competency. The learning curve was evaluated using the cumulative sum method. RESULTS: The overall mean operative time (OT) was 76.5 min ± 22.4. Four unique phases of the learning curve were derived using cumulative sum analysis: the mean OT of phase I (the initial learning curve of 20 cases) was 86.3 ± 23.7 min, phase II (acquisition of competence of 80 cases) was 71.0 ± 21.4 min, phase III (proficiency and plateau of 80 cases) was 76.0 ± 20.4 min, and phase IV (post-learning in which more challenging cases were managed) was 81.3 ± 23.6 min. No major complications were encountered. One case in phase III converted to laparoscopy due to difficulty in performing anterior colpotomy. CONCLUSION: Our data demonstrated four distinct phases of the learning curve of transvaginal natural orifice transluminal endoscopic hysterectomy. In a well-trained endoscopist, surgical competence in transvaginal natural orifice transluminal endoscopic hysterectomy can be reached after 20 cases. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1186/s12893-019-0554-0) contains supplementary material, which is available to authorized users.