Evaluating the learning curve of single-port partial nephrectomy: A multi-institutional cohort analysis
Recommended Citation
Santangelo A, Silvani C, Stephens A, Considine J, Gishto R, Tinsley S, Aljoulani M, Valenzi FM, Vourganti S, Autorino R, Crivellaro S, Nelson RJ, Catanzaro M, Nicolai N, Montanari E, Salonia A, Montorsi F, Briganti A, Rogers C, Abdollah F. Evaluating the learning curve of single-port partial nephrectomy: A multi-institutional cohort analysis. Eur Urol 2026; 89:1.
Document Type
Conference Proceeding
Publication Date
3-1-2026
Publication Title
Eur Urol
Keywords
Urology & Nephrology
Abstract
Introduction & Objectives: In the evolving landscape of surgical technologies, single-port robot-assisted partial nephrectomy (SP-RAPN) represents an evolution in minimally invasive surgery with unique advantages for the patients at the cost of novel technical challenges. Existing evidence on SP-RAPN learning curves is limited to single-center or single-surgeon experiences. In this context, our aim is to evaluate the learning curve for SP-RAPN across multiple surgeons in terms of surgical time. Materials & Methods: We retrospectively analyzed data from 389 patients who underwent SP-RAPN across three U.S. centers (2019–2024). Surgery was performed by experienced multiport surgeons transitioning to the single-port platform. Only surgeons who performed > 20 cases were considered for the analysis. Patients with cM+ or cN+ disease were excluded. Learning curves for operative time (OT) were evaluated using cumulative sum (CUSUM) analysis and piecewise linear regression. CUSUM is a running sum of differences between OT of every single procedure and the median of all OTs. An upward (positive) slope in the CUSUM curve indicates a phase during which operative times are consistently longer than the overall median, reflecting the early learning phase . To account for inter-surgeon variability, a pooled CUSUM curve was generated by weighting individual surgeons' curves according to their case volume. A piecewise linear regression model was fitted to the CUSUM data to identify the inflection point of the learning curve. Davies test was used to assess the statistical significance of the change in slope of the CUSUM curve. Results: Our cohort included 295 SP-RAPN performed by 4 different surgeons. Median age at surgery was 62 years (IQR 52-70) and median tumor size was 3.2 cm (2.4-4.2). Aggregate median operative time was 155 min (IQR 126-203). The piecewise linear regression model effectively captured changes in OT performance across the learning curve (R² = 0.87). The change in slope (breakpoint) occurred at 58 cases (≈ 58.2 ± 2.1). In the first segment (cases 1–58), the slope was +19.8, whereas in the second segment it decreased to approximately −2.3 (a decline of 22.1 units, p < 0.01), indicating stabilization of operative times. Conclusions: Our analysis confirmed that SP-RAPN is a technically demanding procedure, even for experienced multiport surgeons, requiring a high case volume to achieve operative time stabilization.
Volume
89
First Page
1
