Surgical anatomy of the common iliac veins during para-aortic and pelvic lymphadenectomy for gynecologic cancer

OBJECTIVE: Compression of the left common iliac vein between the right common iliac artery and the vertebrae is known to be associated with the occurrence of left iliofemoral deep vein thrombosis (DVT). In this study, we described the variability in vascular anatomy of the common iliac veins and evaluated the relationship between the degree of iliac vein compression and the presence of DVT using the data from surgeries for gynecologic cancer. METHODS: The anatomical variations and the degrees of iliac vein compression were determined in 119 patients who underwent systematic para-aortic and pelvic lymphadenectomy during surgery for primary gynecologic cancer. Their medical records were reviewed with respect to patient-, disease-, and surgery-related data. RESULTS: The degrees of common iliac vein compression were classified into three grades: grade A (n=28, 23.5%), with a calculated percentage of 0%-25% compression; grade B (n=47, 39.5%), with a calculated percentage of 26%-50% compression; and grade C (n=44, 37%), with a calculated percentage of more than 50% compression. Seven patients (5.9%) had common iliac veins with anomalous anatomies; three were divided into small caliber vessels, two with a flattened structure, and two had double inferior vena cavae. The presence of DVT was associated with the elevated D-dimer levels but not with the degree of iliac vein compression in this series. CONCLUSION: Although severe compression of the common iliac veins was frequently observed, the degree of compression might not be associated with DVT in surgical patients with gynecologic cancer. Anomalous anatomies of common iliac veins should be considered during systematic para-aortic and pelvic lymphadenectomy in the gynecologic cancer patients.