Outcomes from 871,441 Consecutive Surgical Procedures without Overlap or with Maximally Permissible Non-Concurrent Overlap

Objective: To isolate the impact of subsumed surgery (a shorter procedure completed entirely during overlapping non-critical portions of a longer antecedent procedure) on patient outcomes. Summary Background Data: The American College of Surgeons recently recommended the elimination of “concurrent surgery” with overlap during a procedure’s critical portions. Guidelines for non-concurrent overlap have been established, but the safety of subsumed surgery remains to be examined. Methods: All consecutive procedures from 2013 to 2021 within a multihospital academic medical center were included (n=871,441). Simple logistic regression was performed to compare postoperative events between patients undergoing non-overlap surgery (n=533,032) and completely subsumed surgery (n=11,319). Thereafter, coarsened exact matching was used to match patients with non-overlap and subsumed surgery 1:1 on CPT code, 18 demographic features, baseline health characteristics, and procedural variables (n=7,146). Exact-matched cases were subsequently limited to pairs performed by the same surgeon (n=5,028). Primary outcomes included 30-day readmission, ED visits, and reoperations. Results: Univariate analysis suggested that subsumed surgery had a higher 30-day risk of readmission (OR 1.55, P <0.0001), ED evaluation (OR 1.19, P <0.0001), and reoperation (OR 1.98, P <0.0001). When comparison was limited to the exact same procedure and patients were matched on demographics and health characteristics, there were no outcome differences between patients with subsumed surgery and non-overlapping surgery, even when limiting analyses to the same surgeon. Conclusions: Similar surgeries for similar patients result in similar outcomes whether there is completely subsumed or no overlap. Individual surgeons performing a specific procedure have no outcome differences with subsumed and non-overlapping cases.