Three-Dimensional in Vivo Anatomical Study of Female Iliac Vein Variations

To investigate female iliac vein variations by using the computed tomography angiography (CTA) three-dimensional (3 D) reconstruction technique.We retrospectively studied 1623 patients undergoing abdominal and pelvic CTA scanning for gynecological diseases from December 2009 to December 2018. Accurate digital 3 D models of the iliac vein were constructed using Mimics 19.0 software and used to study the morphology and variations. Variations in the common iliac vein (CIV), external iliac vein (EIV) and internal iliac vein (IIV) were classified as type I, abnormal number of veins; type II, abnormal communicating branches; or type III, other variations.The overall variation rates of the iliac vein and CIV were 51.57% (837/1623) and 20.33% (330/1623), respectively. The main type of CIV variation was type II. The main type I CIV variation was the absence of the CIV (98.15%), which mostly occurred on the right side (64.81%, 35/54). Type II CIV variation was the most common, with abnormal communicating branches between the left CIV and right IIV (81.78%, 211/258). The overall variation rates of the EIV and IIV were 36.66% (595/1623) and 49.60% (805/1623), respectively, mainly on the right side. The main type of variation was type I. Among them, the division of the IIV into two branches plus convergence with the ipsilateral EIV was the most common (22.98%, 373/1623).In this study, approximately half of the patients had iliac vein variations. The preoperative identification of iliac vein variation may reduce vascular injury in pelvic surgery.