Economic transition during robotic colorectal surgery implementation: reduced device costs and improved gross profit per hospital day.

Robotic colorectal surgery is associated with substantial device-related costs, but longitudinal economic changes during implementation remain incompletely understood. We evaluated temporal changes in perioperative and economic outcomes during robotic colorectal surgery implementation. This single-center retrospective study included 119 consecutive robotic colorectal resections performed between June 2024 and October 2025. Cases were divided into early (n = 60) and late (n = 59) eras for descriptive comparison. Continuous temporal trends were evaluated with adjustment for tumor location, energy platform, and primary surgeon. Median total device cost decreased from 57.3 × 10⁴ to 51.2 × 10⁴ Japanese yen (JPY) (p < 0.001), and total hospital stay decreased from 9.0 to 8.0 days (p = 0.008). Gross profit per case did not differ significantly between eras (100.5 vs. 105.5 × 10⁴ JPY, p = 0.6), whereas gross profit per hospital day increased from 11.0 to 12.9 × 10⁴ JPY/day (p < 0.001). In adjusted continuous analyses, advancing case sequence was associated with higher gross profit per hospital day (ratio per 10 cases, 1.030; 95% confidence interval, 1.018-1.042), shorter total hospital stay (0.961; 0.932-0.991), and lower total device cost (0.982; 0.976-0.989). Advancing case sequence was associated with lower device costs, shorter hospitalization, and higher gross profit per hospital day, while gross profit per case did not significantly differ between eras. These findings are consistent with improved hospital-day economic efficiency rather than increased per-case profitability and should be interpreted as temporal associations.