First assistant during metabolic and bariatric surgery often consists of either a resident, nurse practitioner (NP), or physician’s assistant (PA). While PA/NPs are typically consistent members of the bariatric team, residents are rotating members for whom operating serves additionally as a training experience. It is unclear whether and to what extent the inclusion of residents has upon surgical outcomes.


From the 2015-2017 MBSAQIP database, we identified patients who underwent weight loss surgery with either an NP/PA or Resident as a first assistant. Patient demographic characteristics, comorbidities, intraoperative practice patterns, complications, and thirty-day outcomes were compared between patients with Resident versus PA/NP first assistance.


Of 264,627 patients, 84,804 (32.05%) of procedures were performed with Resident first assistance. Operative length with Resident assistance was on average over 20 minutes longer (104.5 vs. 82.7 min, ROM=1.26, p<0.001). These had higher rates of unplanned ICU admission (0.83% vs. 0.67%, RR=1.24, p<0.001) and hospital readmission (4.48% vs. 3.85%, RR=1.16, p<0.001), more postoperative bleeding (0.53% vs. 0.42%, RR=1.24, p<0.001) and infection (1.52% vs. 1.38%, RR=1.11, p=0.003), and increased overall morbidity (6.06% vs. 5.19%, RR=1.17, p<0.001) corresponding to a number needed to harm of 114. On matched analysis, the relationship between resident assistance and poorer 30-day outcomes was preserved.


While training future surgeons is an important aspect of bariatric surgery, inexperienced trainees or shifting roles within a surgical team may confer increased surgical risks to patients. Strategies are needed to optimize patient safety while maintaining a robust resident experience.