Institutional learning in single-port robot-assisted partial nephrectomy across RENAL complexity strata: a multicenter study

We examined institutional operative-time trends during single-port robot-assisted partial nephrectomy (SP-RAPN) adoption across RENAL complexity strata.

This retrospective six-center cohort included 408 procedures with available RENAL scores. Operative time was analyzed against institutional case sequence using center fixed-effects models, institution-clustered confidence intervals, and wild-cluster bootstrap tests.

For RENAL 4-9 tumors, slopes were negative at all six institutions. The pooled estimate was - 0.64 min/case (95% CI - 1.32 to 0.05; cluster-robust p = 0.063; bootstrap p = 0.059). Adjustment for RENAL score, tumor size, and access route reduced the estimate to - 0.53 min/case; further BMI and calendar-year adjustment reduced it to - 0.25 min/case. Among 19 RENAL 10-11 procedures at three institutions, one center-specific slope was negative and two were positive. The sequence-by-complexity interaction was + 0.14 min/case (95% CI - 1.00 to 1.28). Each additional RENAL point was associated with 4.90 more operative minutes and 1.89 more warm ischemic minutes. Complications occurred in 5/19 high-complexity and 34/389 low/intermediate-complexity procedures.

Operative time showed a consistent downward trend with institutional experience for RENAL 4-9 tumors, whereas center-specific trends varied in direction for RENAL 10-11 tumors. Higher complexity was associated with longer operative and warm ischemic times. These findings highlight the importance of considering tumor complexity when evaluating institutional adaptation to SP-RAPN.