blunt traumatic infrarenal aortic injuries are rare , with a few case reports in the literature . a more common occurrence is an intimal flap which may form after blunt injury to the aorta , and most of these will resolve with anticoagulation alone [ 1 , 2 ] . blunt aortic injury which initially presents as an intimal flap ( grade i ) may progress and evolve into an intramural hematoma ( grade ii ) or a pseudoaneurysm ( grade iii ) . aortic intimal flap progressing to dissection or pseudoaneurysm is an occurrence identified in 2% or less of the patients , and the majority of these occur in the thoracic aorta [ 1 , 2 ] . this article presents the case of a young woman found to have an intimal flap in the infrarenal abdominal aorta after a car accident , and the injury progressed to a pseudoaneurysm over 3 months . a 47-year - old woman with a history of hypertension and smoking was involved in a  high - speed motor vehicle accident and presented to the emergency department with back pain . computed tomographic ( ct ) scans were obtained of her abdomen and pelvis . on a single image from the abdominal scan , what appeared to be either an intimal flap or a small amount of contrast extravasation outside of the infrarenal aorta could be seen . her care providers had differing opinions as to what was being seen on the image . since the abnormality was only seen on a single image , the exact etiology could not be delineated ( fig . the patient was observed in the hospital overnight , had minimal complaints the next day , and was discharged on aspirin . figure 1:initial ct scan shows enhancing vascular abnormality on the right side of the aorta , shown by the black arrow . initial ct scan shows enhancing vascular abnormality on the right side of the aorta , shown by the black arrow . a follow - up ct scan was obtained 3 months later . at the location of the previous aortic abnormality , there was a 3    1  cm pseudoaneurysm that had formed and could now be clearly seen ( figs 2 and 3 ) . figure 2:pseudoaneurysm now clearly seen 3 months later . 
 figure 3:black arrow pointing to pseudoaneurysm with enhancing flow outside of the aortic lumen . operative repair was recommended , but the patient s aorta measured only 18  mm at the aortic bifurcation and was too small for even the smallest endovascular stent graft available at our institution . therefore , an open replacement of her infrarenal aorta was performed using a dacron 22  mm graft . in the operating room , after the aorta was clamped and opened , a 4  mm tear in the intima had formed a mature channel into the pseudoaneurysm . the patient recovered very well and was discharged from the hospital without complications . at her 2-year follow - up , she was in good health and had no further problems , but continues to smoke . blunt abdominal aortic trauma occurs in only 0.040.1% of all nonpenetrating traumas [ 3 , 4 ] . and the vast majority of these ( 92% ) are associated with multiple other injuries [ 3 , 5 ] . our patient had no other injuries , and there was no retroperitoneal hematoma or other signs of vascular injury in the area , as is usually seen on ct when the aorta is injured [ 35 ] . the lack of other radiographic traumatic findings added to the initial confusion as to whether there was a true injury to the aorta , or if the single image was showing artifact or an enlarged vertebral vessel . since the majority of intimal flaps heal with anticoagulation alone ( 55% ) or remain stable ( 40% ) , a conservative plan including daily aspirin and re - imaging in 3 months was chosen . when repeat imaging showed a 3  cm pseudoaneurysm , operative repair was necessary . endovascular repair was initially chosen for this case , but after measuring the patient s aorta , femoral vessels and the degree of taper at the bifurcation , there was not an appropriate endovascular prosthesis available in such a small size . only one study has compared conventional open repair with endovascular repair for blunt injuries of the abdominal aorta and found similar results in both groups . endovascular repair is generally favored since the injuries tend to be focal and discrete , making them quite amenable to a short graft . further , the patients usually have other significant injuries that would complicate a long , and potentially morbid , open operation on the aorta . although all blunt infrarenal aortic injuries are unusual , most of them consist of intimal flaps or dissections [ 3 , 58 ] . a post - traumatic pseudoaneurysm , as this patient had , is even more unusual after blunt trauma . one prior publication did document the delayed occurrence of a post - traumatic infrarenal aortic pseudoaneurysm that was diagnosed 3 years after injury . endovascular repair for pseudoaneurysms must include post - procedure angiography to document no evidence of a type i or type ii endoleak , which could allow filling of the aneurysm sac and later rupture . this case report highlights the need for delayed imaging for even minor intimal flaps or small aortic injuries after trauma , since progression does occur . while the vast majority of these injuries improve over time or remain stable , a small percentage will worsen and require intervention .
blunt traumatic infrarenal aortic injuries are unusual , and the formation of a delayed pseudoaneurysm of the aorta is even more rare . in this report 
 , a young woman developed a small intimal flap of the infrarenal aorta after a motor vehicle accident which progressed into a 3  cm pseudoaneurysm after 3 months . 
 operative repair was successful and the patient recovered . 
 this case illustrates the importance of repeat imaging of small blunt aortic injuries since progression can occur .