A cadaver study evaluating intraluminal anomalies of the left common iliac vein.

OBJECTIVE: Intraluminal anomalies within the left common iliac vein, characteristic of iliac vein compression syndrome, are thought to result from compression by and pulsation of the overlying right common iliac artery. This cadaver study was designed to expand on the existing literature by surveying and photographing these spurs in addition to exploring whether certain factors, inherent to the cadaver, are associated with spur presence.

METHODS: Dissection to expose the aorta, inferior vena cava, and common iliac arteries and veins was performed in 51 cadavers. The spinal level at which the iliac vein confluence occurred was noted. The point at which the right common iliac artery crossed the left common iliac vein was examined for plaque presence. The overlying arterial structures were then transected to expose the venous system. The inferior vena cava was incised to facilitate observation into the mouth and full extent of the left common iliac vein. Spurs were photographed and documented. Statistical analysis was conducted to determine whether sex, body mass index, plaque presence, or level of the iliac vein confluence are associated with spur presence.

RESULTS: Spurs within the left common iliac vein were observed in 16 of 51 cadavers (31.4%). All spurs were located at the point that the right common iliac artery crossed the left common iliac vein. Utilizing the classification system established by McMurrich, 67% (n=10) of spurs were marginal and triangular; 25% (n=4) were columnar. One (6%) marginal, linear spur and one (6%) partially obstructed spur with multiple synechiae were observed. Among this population, males were 73% less likely to have a spur (OR=0.269; p=0.041). No significant relationship was found between plaque presence and spur presence (OR=0.933; p=0.824) and no significant differences were noted between body mass index and spur presence (x2 =1.752, p=0.625). Lastly, a significantly larger percent of spurs was found within cadavers with an iliac vein confluence located at the L5/S1 disc space (x2 =9.650; p=0.002).

CONCLUSIONS: Study findings show that spurs are more common when the confluence of the common iliac veins occurs at a lower spinal level. The level of the iliac vein confluence may be important in identifying patients at increased risk of venous disease. The findings also suggest that plaque within the right common iliac artery and BMI display no distinct relationship with spur presence. Further investigation is needed to understand exactly what factors lead to spur formation.