The Role of Preoperative Lower Extremity CT Angiography in Mandible Reconstruction: A Retrospective Cohort Analysis

Background: Preoperative computed tomography angiography (CTA) of the lower extremities is commonly performed before fibula free flap (FFF) harvest for mandibular reconstruction. While CTA is intended to improve harvest side safety, its actual impact on reconstructive decision-making and postoperative outcomes remains insufficiently characterized. Methods: In this retrospective, single-center cohort study, patients undergoing mandibular continuity resection between July 2012 and June 2023 who received preoperative lower extremity CTA were analyzed. CTA-derived vascular parameters, including plaque presence, three-vessel run-off, and a bilateral vascular anomaly score, were systematically assessed. Associations with fibula flap selection (yes/no) and postoperative outcomes were analyzed using logistic regression and non-parametric statistical methods. Discriminatory performance was evaluated by receiver operating characteristic (ROC) analysis, including a combined CTA-based multivariable model. Results: A total of 247 patients were included. CTA-derived parameters were strongly associated with the decision to perform a reconstruction with FFF, but showed no consistent association with postoperative outcomes such as revision surgery, flap loss, or length of hospitalization. After directional alignment of predictors, ROC analysis demonstrated moderate to good discrimination for individual parameters, including absence of plaque on any side (area under the ROC curve [AUC] 0.745) and the inverted bilateral vascular anomaly score (AUC 0.686). A combined multivariable CTA-based model integrating all vascular parameters achieved excellent discrimination for FFF selection (AUC 0.826). None of the CTA-derived variables independently predicted postoperative complications. Notably, FFF reconstruction was also performed in a small subset of patients despite the absence of three-vessel run-off, without an apparent increase in postoperative complications. Conclusion: Lower extremity CTA primarily serves as a preoperative decision-support tool guiding FFF selection rather than as a predictor of postoperative outcomes. CTA-based vascular assessment enables effective upstream risk stratification and supports individualized reconstructive planning in mandibular reconstruction.