Duplicate Inferior Vena Cava Scott McIntosh, MD, Robert Brautigam, MD, FACS, Ronald Gross, MD, FACS J Trauma. 2006;61:235. A nomalies of the inferior vena cava (IVC) are uncommon, occurring in approximately 0.2 to 3% of the population. 1,2 Duplicate IVC (DIVC) usually goes undetected. However, DIVC can pose an interesting challenge in some patients. We present the case of a 56-year old male motorcyclist in- volved in a high-speed motorcycle versus car collision. He suffered complex pelvic, acetabular, femur, and tibial fractures. A C-clamp was applied to stabilize his complex pelvic fracture. During our initial work-up, the C-clamp pelvic stabilizer precluded complete visualization of the infrarenal vasculature on computed tomography (CT) scan. An IVC filter was placed secondary to his extensive injuries and anticipated prolonged immobilization. After placement of a pelvic external fixator, a completed CT scan of the pelvis identified a DIVC (Fig. 1). The diameter of the second vessel was approximately half the diameter of the right-sided vena cava. De- ployment of a second filter was necessary to protect this patient from a pulmonary embolism (Fig. 2). Formation of the IVC is a complex process. During embryonic development, three pairs of veins (subcardinal, postcardinal, and supracardinal) develop during weeks 6 through 8 of gestation. Various segments of these vessels simultaneously coalesce and regress to form the renal veins, superior portions of the iliac veins, and the mature IVC. DIVC can arise if the left supracardinal vein fails to regress during normal embryonic development. 2 The abnormality normally goes undetected. However, a DIVC can be problematic in two specific situations: IVC filter placement and retroperitoneal operations. In patients with a DIVC who require IVC filters, one filter is normally deployed in each vessel, as was performed in our case. Cases have been reported where anatomy or obstruction prevents deploying two separate filters, e.g. small cali- ber or thrombus-containing vessel. In these situations, a suprarenal IVC filter has been used with success. This patient had his orthopedic injuries stabilized and remained in the hospital for 3 weeks before his discharge to a local rehabil- itation hospital in good condition. REFERENCES 1. Giordano JM, Trout HH. Anomalies of the inferior vena cava. J Vasc Surg. 1986;3:924 –928. 2. Mayo J, Gray R, St. Louis E, Grosman H, McLoughlin M, Wise D. Anomalies of the inferior vena cava. AJR. 1983;140:339 –345. Submitted for publication July 30, 2004. Accepted for publication April 12, 2006. Copyright © 2006 by Lippincott Williams & Wilkins, Inc. From the Division of Emergency Medicine, University of Utah Health Sci- ences Center (S.M.), Utah; the University of Connecticut School of Medicine, and the Department of Traumatology and Emergency Medicine, Hartford Hospital (R.B., R.G.), Hartford, Connecticut. Address for Reprints: Ronald I. Gross, Associate Director of Trauma, Hartford Hospital, 80 Seymour Street, PO Box 5037, Hartford, CT 06102; email: Rgross@harthosp.org. DOI: 10.1097/01.ta.0000224119.45955.88 Fig. 2. KUB showing both IVC filters in place. Fig. 1. IVC filter in place in primary IVC. Arrow indicates duplicate IVC. The Image of Trauma The Journal of TRAUMA  Injury, Infection, and Critical Care Volume 61 • Number 1 235