Robot-assisted partial nephrectomy: continued refinement of outcomes beyond the initial learning curve

Abstract

Objectives: To evaluate trends in peri-operative outcomes of 250 consecutive cases beyond the initial learning curve (LC) of robot-assisted partial nephrectomy (RAPN) among multiple surgeons. Patients and Methods: A multi-institutional database was used to evaluate trends in patient demographics (e.g. age, gender, comorbidities), tumour characteristics (e.g. size, complexity) and peri-operative outcomes (e.g. warm ischaemia time [WIT], operating time, complications, estimated blood loss [EBL], trifecta achievement) in consecutive cases 50–300 (n = 960) from 2008 to 2016 among four experienced surgeons. Trends in outcomes were assessed using multivariable regression models adjusted for demographic and tumour-specific variables. Outcomes for cases 50–99 were compared with those for cases 250–300. Results: In the study period RAPN was increasingly performed in patients with larger tumours (β = 0.001, P = 0.048), hypertension (odds ratio [OR] 1.003; P = 0.008) diabetes (OR 1.003; P = 0.025) and previous abdominal surgery (OR 1.003; P = 0.006). Surgeon experience was associated with more trifecta achievement (OR 1.006; P < 0.001), shorter WIT (β = −0.036, P < 0.001), less EBL (β = −0.154, P = 0.009), fewer blood transfusions (OR 0.989, P = 0.024) and a reduced length of hospital stay (β = −0.002, P = 0.002), but not with operating time (P = 0.243), complications (P = 0.587) or surgical margin status (P = 0.102). Tumour size and WIT in cases 50–99 vs 250–300 were 2.7 vs 3.2 cm (P = 0.001) and 21.4 vs 16.2 min (P < 0.001), respectively. Conclusion: Refinement of RAPN outcomes, concomitant with the treatment of a patient population with larger tumours and more comorbidities, occurs after the initial LC is reached. Although RAPN can consistently be performed safely with acceptable outcomes after a small number of cases, improvement in trifecta achievement, WIT, EBL, blood transfusions and a shorter hospitalization continues to occur up to 300 procedures.