Cumulative Sum Analysis of Learning Curve Process for Vaginal Natural Orifice Transluminal Endoscopic Surgery Hysterectomy.

STUDY OBJECTIVE: This study aimed to evaluate the learning curve of vaginal natural orifice transuminal endoscopic surgery (vNOTES) hysterectomy in expert minimal invasive and vaginal surgery team. DESIGN: This is a cohort study on a retrospective analysis. SETTING: Department of Obstetrics and Gynecology of Cannizzaro Hospital in Catania Italy. PATIENTS: First 50 women underwent vNOTES hysterectomy between February 2021 and February 2022. INTERVENTION: vNOTES hysterectomy performed by a team with optimal skills in laparoscopic and vaginal surgery. MEASUREMENT AND MAIN RESULTS: Primary outcome was surgical time. Secondary outcomes were intraoperative and postoperative complications, length of hospitalization, and first 24-hour postoperative pain. All patients underwent hysterectomy for benign indications: 27 fibromatosis, 13 metrorrhagia, and 10 precancerous. Concomitant procedures have been bilateral adnexectomy in 35 cases and bilateral salpingectomy in 15 cases. The median age was 51 years (range, 42-64). Median body mass index was 26 kg/m2 (range, 21-42). The median operative time was 75 minutes (range, 40-110). The median hospital stay was 2 days (range, 1-4). There was 1 intraoperative adverse event (bladder lesion) and 1 postoperative grade 3 complication (hemoperitoneum). The median visual analog scale score for pain assessment during the first 24 hours after surgery was 3 (range, 1-6). The experience in our surgical center with the first 25 vNOTES hysterectomies showed an accumulation of initial experience in the first 5 cases with stable operating time and a gradual reduction of mean operating time in the subsequent 17 surgeries. The learning curve plotted by cumulative sum analysis shows 3 phases: phase 1 of competence (cases 1-5), phase 2 of proficiency (cases 6-26), and phase 3 of mastering the procedure (after the 31st case) with the management of more complex cases. CONCLUSION: vNOTES hysterectomy is a feasible and reproducible approach for benign indications with a short learning curve and low rate of perioperative complications. For a team skilled in minimally invasive surgery, 5 cases are required to rich competence and 25 to rich proficiency in vNOTES hysterectomy. Mastering phase, with the introduction of more complex cases, should be addressed after 30 surgeries.

Localization in Structured Environments with UWB Devices without Acceleration Measurements, and Velocity Estimation Using a Kalman-Bucy Filter.

In this work, a novel scheme for velocity and position estimation in a UWB range-based localization system is proposed. The suggested estimation strategy allows to overcome two main problems typically encountered in the localization systems. The first one is that it can be suitable for use in environments where the GPS signal is not present or where it might fail. The second one is that no accelerometer measurements are needed for the localization task. Moreover, to deal with the velocity estimation problem, a suitable Kalman-Bucy filter is designed and it is compared, experimentally, with a particle filter by showing the features of the two algorithms in order to be used in a localization context. Additionally, further experimental tests are carried out on a suitable developed test setup in order to confirm the goodness of the proposed approach.