Impact of hospital volume and surgeon volume on robot-assisted partial nephrectomy outcomes: a multicentre study

Objective To assess the impact of hospital volume (HV) and surgeon volume (SV) on perioperative outcomes of robot-assisted partial nephrectomy (RAPN). Patients and Methods All consecutive patients who underwent a RAPN from 2009 to 2015, at 11 institutions, were included in a retrospective study. To evaluate the impact of HV, we divided RAPN into four quartiles according to the caseload per year: low HV (<20/year), moderate HV (20-44/year), high HV (45-70/year), and very high HV (>70/year). The SV was also divided into four quartiles: low SV (<7/year), moderate SV (7-14/year), high SV (15-30/year), and very high SV (>30/year). The primary endpoint was the Trifecta defined as the following combination: no complications, warm ischaemia time (WIT) <25 min, and negative surgical margins. Results In total, 1 222 RAPN were included. The mean (SD) caseload per hospital per year was 44.9 (26.7) RAPNs and the mean (SD) caseload per surgeon per year was 19.2 (14.9) RAPNs. The Trifecta achievement rate increased significantly with SV (69.9% vs 72.8% vs 73% vs 86.1%; P < 0.001) and HV (60.3% vs 72.3% vs 86.2% vs 82.4%; P < 0.001). The positive surgical margins (PSM) rate (P = 0.02), length of hospital stay (LOS; P < 0.001), WIT (P < 0.001), and operative time (P < 0.001), all decreased significantly with increasing SV. The PSM rate (P = 0.02), LOS (P < 0.001), WIT (P < 0.001), operative time (P < 0.001), and major complications rate (P = 0.01), all decreased significantly with increasing HV. In multivariate analysis adjusting for HV and SV (model 3), HV remained the main predictive factor of Trifecta achievement (odds ratio [OR] 3.70 for very high vs low HV; P < 0.001), whereas SV was not associated with Trifecta achievement (OR 1.58 for very high vs low SV; P = 0.34). Conclusion In this multicentre study HV and SV both greatly influenced RAPN perioperative outcomes, but HV appeared to have a greater impact than SV.