Impact of Structural Anomalies and Anatomical Variations on Operative Time in Abdominal Surgery-Systematic Review

Prolonged operative time is associated with increased surgical complications, resource utilization, and cost. While factors such as surgeon experience and patient habitus are well recognized, the impact of anatomical anomalies and variations remains poorly quantified. This systematic review evaluates the influence of abdominal structural anomalies and anatomical variations on operative time. Following PRISMA 2020 guidelines, a search of PubMed (2000-2025) identified 82 eligible studies. Operative-time impact was assessed using added operative time relative to reference benchmarks. The unit of analysis was the procedure-level observation. Observations were stratified by procedure category and surgical complexity and summarized using median added operative time and range. Among procedure-level observations with available benchmarks, 13 of 14 (92.9%) structural anomalies, 48 of 54 (88.9%) situs inversus cases, and 10 of 11 (90.9%) other anatomical variants demonstrated increased operative time relative to baseline. Structural anomalies were associated with larger median increases, particularly in colorectal procedures, whereas anatomical variations demonstrated a more heterogeneous effect across procedural systems. Higher-complexity procedures, including pancreatic operations, showed greater absolute increases in operative time. Preoperative identification of anatomical differences was associated with attenuation of operative delays. Structural anomalies are frequently associated with increased operative duration, whereas anatomical variations demonstrate a more variable and context-dependent effect. The magnitude of operative time impact is influenced by procedural complexity and preoperative planning. Incorporating anatomical variability into surgical planning may reduce avoidable operative delays and improve operative efficiency.