Textbook outcome-based performance assessment during transition to the da Vinci SP system in reduced-port robotic gastrectomy.

Although reduced-port gastrectomy with the da Vinci SP system offers a dedicated single-port platform, little is known about how an experienced robotic surgeon performs while changing platforms. We examined this transition by applying cumulative sum (CUSUM) analysis to textbook outcome (TO). We retrospectively analyzed 175 consecutive reduced-port robotic gastrectomies performed at a tertiary referral center from July 2021 through August 2025. The primary measure was TO, a composite of six perioperative requirements. Case-sequence performance was examined with CUSUM curves for TO and operative time. Among 175 patients, 164 achieved TO (93.7%; 95% CI, 89.1-96.5%) and 168 achieved adjusted TO (aTO; 96.0%); major complications occurred in 1.7%. The TO-CUSUM curve showed an apparent stabilization after approximately 60 cases, whereas operative-time CUSUM reached its observed nadir at case 107. The later period included more D2 dissections and complex procedures; the TO rate was 96.7% in the early period and 92.2% in the late period. During transition to the da Vinci SP platform, TO-based CUSUM provided a longitudinal description of perioperative quality as case selection and procedural complexity evolved. The distinct TO-CUSUM and operative-time CUSUM trajectories suggest that quality-related performance and procedural efficiency may evolve at different rates during platform transition.