Learning curve and perioperative outcomes of four-port assistant-independent robot-assisted total laparoscopic hysterectomy according to uterine size

To evaluate the learning curve and perioperative outcomes of four-port assistant-independent robot-assisted total laparoscopic hysterectomy (RA-TLH) according to surgeon experience and retrieved tissue weight. Between July 2020 and October 2025, 486 RA-TLH procedures were performed. One case with a retrieved tissue weight of 7,141 g was excluded as the only case exceeding 3,000 g. The remaining 485 cases were classified into five groups according to retrieved tissue weight: <250 g, 250-<500 g, 500-<750 g, 750-<1,000 g, and 1,000-<3,000 g. Learning curves were evaluated using cumulative sum analysis of console time. Four novice surgeons demonstrated biphasic learning curves, with inflection points at the 15th, 17th, 18th, and 37th cases. For retrieved tissue weights < 500 g, console time was significantly longer during the first 20 cases than during cases 21-40, with no significant difference thereafter. For cases ≥ 500 g, console time did not differ significantly among experience groups. However, heavier cases were preferentially assigned to experienced surgeons. In this single-center experience, novice surgeons demonstrated learning-curve inflection points between 15 and 37 cases. For cases < 500 g, console time decreased significantly after approximately 20 cases. Four-port assistant-independent RA-TLH was feasible in selected patients with very large uteri, including those with retrieved tissue weights 1,000-<3000 g, when performed by experienced robotic surgeons. These findings should be interpreted in light of selective case allocation and the retrospective single-center design.