The influence of familiarity between the surgeon and their assistant on patient outcomes: a prospective observational cohort study.

Background: The inverse relationship between increased surgical team familiarity and reduced operative time is established, but its effect on patient outcomes remains uncertain.

Materials and methods: A prospective cohort study including operations by attending surgeons between 1 November 2020 and 31 December 2021 across fourteen surgical departments from four French university hospitals. Surgical team familiarity was measured as the cumulative number of previous operations performed by the same dyad of attending and assisting surgeons. Composite of adverse events within 30 days of surgery encompassed major surgical complication, unplanned reoperation, extended ICU stay, and death. We used multivariable generally estimated equations to model the association between patient outcomes and surgical team familiarity, using a logarithmic function. The model considered the clustering of operations within surgeons.

Results: Our analysis included 8546 operations by 1109 surgical team dyads, involving 45 attending surgeons and 369 assisting surgeons. We observed a significant inverse association between surgical team familiarity and composite adverse events odds ratio [OR] 0.92 (95% confidence interval [95% CI] 0.87-0.98), major surgical complications OR 0.93 (95% CI 0.88-0.99), and unplanned reoperations OR 0.88 (95% CI 0.78-0.99), with non-significant trends observed for extended ICU stays OR 0.88 (95% CI 0.75-1.04) and deaths OR 0.87 (95% CI 0.74-1.03). Within the first 15 collaborations, this was illustrated by a reduction in the occurrence of composite adverse events from 23.0% (95% CI 22.1%-24.0%) to 16.5% (95% CI 14.1%-18.8%), major surgical complications from 21.3% (95% CI 20.3%-22.2%) to 15.3% (95% CI 13.0%-17.5%), unplanned reoperations from 8.8% (95% CI 8.6%-9.1%) to 5.2% (95%CI 4.2%-6.1%), extended ICU stays from 4.3% (95% CI 4.1%-4.5%) to 3.1% (95% CI 2.0%-4.1%), and deaths from 2.3% (95% CI 2.1%-2.5%) to 1.4% (95% CI 0.9%-1.8%).

Conclusions and relevance: This study emphasizes that heightened familiarity among surgical teams is associated with a significant reduction in major adverse events. Building stable operating room teams should be a management priority to enhance patient outcomes.