The role of the assisting surgeon in cholecystectomy - a population-based cohort study

Abstract Introduction Reducing cholecystectomy-related complications is critical for improving surgical outcomes. An often overlooked factor is the role of the assistant surgeon, with previous studies showing conflicting results. This study aimed to describe team composition across Sweden and investigate whether the presence of an assistant surgeon influences complication rates and procedure time. Method A population-based cohort study was conducted using GallRiks data, including all patients who underwent cholecystectomy between January 1, 2006, and December 31, 2023. Analyses were performed using generalized estimating equations and mixed-effects models. Result A total of 208,318 cholecystectomies were included: 128,631 (61.7%) elective and 79,687 (38.3%) acute, performed at 91 centers by 3,052 surgeons. Of these, 108,384 (52%) were performed without an assistant, and 99,943 (48%) with an assistant. At public hospitals (university, regional, county) approximately 50% of procedures were unassisted, compared to 70% at private clinics. Procedures without an assistant were associated with fewer intraoperative complications (acute: OR 1.64; 95%CI 1.45–1.84; elective: OR 1.58; 95%CI 1.04–2.42), including bile duct injuries, and shorter operating times (acute: mean difference – 21.84; 95%CI -22.56-21.11; elective: mean difference -19.96 minutes; 95%CI -22.04- -17.88). A similar trend was observed for postoperative complications (acute: OR 1.18; 95%CI 1.11–1.25; elective OR 1.57; 95%CI 1.28–1.91). Discussion Cholecystectomies without an assistant surgeon are common in Sweden. While shorter operative times and lower complication rates likely reflect simpler cases that do not require additional assistance, the frequent absence of assistants may limit hands-on training opportunities for junior surgeons.