Impact of the Percentage of Overlapping Surgery on Patient Outcomes: A Retrospective Cohort Study of 87,000 Surgical Cases.

Objectives: The primary objective of this study was to analyze the relationship of percentage of surgical overlap with patient outcomes to determine if a detrimental level of overlap exists.
Background: Overlapping surgery is defined as 1 attending physician supervising 2 or more operative cases simultaneously, without the critical portions of the cases occurring concurrently. To date, no study has examined the relationship of percent overlap, or the percentage of 1 case that is spent overlapping with another, to outcomes, efficiency, safety, and complications.
Methods: This study is a retrospective cohort study conducted at a large tertiary referral center. The primary outcomes of interest included operative duration, in-hospital mortality, 30-day readmission, and patient safety indicators (PSIs). The Cochran-Armitage test for trend was used to evaluate the outcomes of interest. P values of ≤0.05 were considered statistically significant.
Results: A total of 87,426 cases were included in this study. There were 62,332 cases without overlap (Group 0), 10,514 cases with 1% to 25% overlap (Group 1), 5303 cases with 26% to 50% overlap (Group 2), 4296 cases with 51% to 75% overlap (Group 3), and 4981 cases with >75% overlap (Group 4). In-hospital mortality decreased as overlap increased ( Ptrend <0.0001). Operative time increased with increasing overlap ( Ptrend <0.0001) while readmission rates showed no statistical significance between groups ( Ptrend =0.5078). Rates of PSIs were lower for Groups 1, 2, and 3 (1.69%, 2.01%, and 2.08%) when compared to Group 0 (2.24%). Group 4 had the highest rate of PSIs at 2.35% ( P =0.0086).
Conclusion: Overlapping surgery was shown to have reduced in-hospital mortality and similar PSI and readmission rates when compared to nonoverlapping cases. Operative time was shown to increase in overlapping surgeries when compared to nonoverlapping surgeries. The results from this study indicate that the percentage of surgical overlap does not detrimentally affect most patient outcomes, especially with overlap of <75%.
Competing Interests: The authors report no conflicts of interest.
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