The Radiographic Relationship of the Femoral Head, Inguinal Ligament, and Common Femoral Artery Bifurcation for Optimal Vascular Access

Introduction Common femoral artery (CFA) access is commonly used for endovascular interventions. Access site complications contribute to significant morbidity and mortality. This study characterizes the radiographic variability in the relationship of the femoral head, the inguinal ligament, and the CFA bifurcation, in order to identify the zone of optimal CFA access. Methods Human cadaver dissection of the inguinal ligament and CFA bifurcation was performed. The inguinal ligament and CFA bifurcation were marked with radiopaque pins and plain anteroposterior radiographs were obtained. Radiographic measurements of the femoral head length, the distance of the top of the femoral head to the inguinal ligament, and to the CFA bifurcation were obtained. Results were reported as percentage of femoral head covered by the inguinal ligament or the CFA bifurcation relative to the top of the femoral head. A heat map was derived to determine a safe access zone between the inguinal ligament and CFA bifurcation. Results Forty-five groin dissections (male=20, female=25) were performed in 26 cadavers. The mean overlap of the inguinal ligament with the femoral head was 11.2mm (range: -19.4mm to 27.4mm). There was no age (<85 vs ≥85) or sex-related differences. In 82.6% of cadaveric CFA exposures, there was overlap between the inguinal ligament and femoral head (mean 27.7%, range: -85.7% to 70.1%), with 55.6% having a >25% overlap. In 11.1% there was an overlap between the lower 3rd of the femoral head and the CFA bifurcation. Cumulatively, heatmap analysis depicted a >80% likelihood of avoiding the inguinal ligament and CFA bifurcation below the midpoint of the femoral head. Conclusion Significant variability exists in the relationship between the inguinal ligament, CFA bifurcation and the femoral head, suggesting the lack of a consistently safe access zone. The safest access zone in >80% of patients lies below the radiographic midpoint of the femoral head and the inferior aspect of the femoral head.