“Robotic fatigue?” – The impact of case order on positive surgical margins in robotic-assisted laparoscopic prostatectomy

Purpose: Multiple robotic-assisted surgeries are often performed within a single operating day; however, the impact of this practice on patient outcomes has not been examined. We aim to determine whether outcomes for robotic-assisted laparoscopic prostatectomy (RALP) differed when performed sequentially. Materials and methods: A multi-institutional, retrospective cohort study was conducted involving a total of 8 academic centers between years 2015 and 2018. Participants were adult males undergoing RALP for localized prostate cancer on operative days in which 2 RALP cases were performed sequentially by the same resident-attending team. The primary outcome of the study was presence of positive surgical margin (PSM). Secondary outcomes were lymph node yield, operative time, and estimated blood loss. The primary analysis was a random effects meta-analysis model for PSM. Results: Overall, 898 RALP cases (449 sequential pairs) were included in the study. There was no significant difference in PSM rate (27.2% vs. 30.3%, P= 0.338) between first and second case groups, respectively. Utilizing random effects meta-analysis, the second case cohort had no increased risk of PSM (OR _0.761.23_1.97, P= 0.40). Higher blood loss was noted in the second case cohort (186.7 ml vs. 221.7 ml, P = 0.002). Additionally, factors associated with PSM were increasing prostate specific antigen, higher percent tumor involvement, extraprostatic extension, and seminal vesicle invasion. Conclusion: Case sequence was not associated with PSM, lymph node yield, or operative time for RALP. Disease specific factors and institutional experience are associated with increased risk for positive surgical margin which can aid providers in scheduling of patients.