Learning Curve Analysis of Transvaginal Natural Orifice Adnexal Surgery

Study Objective This study was designed to evaluate the learning curve of transvaginal natural orifice surgery (NOS) for adnexal tumors based on the type of procedure (adnexectomy or cystectomy). Design Retrospective cohort study. Setting Tertiary-care university hospital. Patients One hundred thirty-six women with adnexal tumors. Interventions A series of 136 consecutive transvaginal NOS for adnexal tumor were performed between April 2011 and June 2016. Eighty-five patients (62.5%) had undergone cystectomy, and 51 patients (37.5%) had undergone adnexectomy. Measurements and Main Results The transvaginal NOS procedures included vaginal, endoscopic, single-port access techniques and were divided into 2 categories: adnexectomy and cystectomy. Operating time was electronically recorded and was defined as the time from the creation of a posterior colpotomy incision until the complete closure of the posterior colpotomy opening. The average operating time for the cystectomy and adnexectomy groups was 42.7 and 37.7 minutes, respectively (p = .015). The learning curve was analyzed using the cumulative summation method and showed that 36 cases were needed to achieve proficiency in transvaginal NOS for ovarian cystectomy. However, there was no significant cut-off point to determine the number of patients who had undergone adnexectomy. Conclusion A well-trained gynecologic endoscopist can achieve surgical proficiency in transvaginal NOS cystectomy after 36 cases. It is suggested that the surgical transvaginal NOS procedure should begin with adnexectomy rather than with cystectomy to avoid initial technical challenges.