Institutional proficiency and learning curves in robotic-assisted thoracoscopic surgery: a single-center retrospective analysis using the cumulative sum method.

Robot-assisted thoracoscopic surgery (RATS) has advanced the field of minimally invasive thoracic surgery. Its learning curve is reportedly shorter than that of video-assisted thoracoscopic surgery. However, few studies have examined how institutional proficiency evolves with the introduction of new surgeons and how this transition impacts surgical outcomes in RATS. This single-center retrospective study, conducted at a university hospital in Japan, included 154 patients who underwent RATS lobectomy between November 2018 and May 2024. The study population consisted of four thoracic surgeons at different stages of RATS experience. Operative metrics and learning curves were evaluated using the cumulative sum method. Trends in operating time, console time, blood loss, and non-console time were analyzed to assess surgeon-specific performance, and complications, if any, were recorded. The mean operating time was 206.5 min, console time was 153.3 min, and mean blood loss was 23.9 g. The lead surgeon demonstrated a typical upward convex learning curve, whereas subsequent surgeons showed smaller peaks. Non-console time increased during transitions between surgeons. Postoperative complications occurred in 13 patients, none of whom required conversion to thoracotomy. Mechanical malfunctions were noted in 11 cases and were resolved without significant delays. This study demonstrated that introducing new surgeons did not compromise institutional proficiency, indicating effective skill transfer. Optimizing training strategies to reduce early inefficiencies remains an important goal. In conclusion, structured training and workflow support may help maintain institutional proficiency during the expansion of RATS programs. Further prospective studies are recommended to validate training models and promote consistent surgical outcomes.