Traumatic Aorto-Cisterna Chlyi Fistula with Treatment of Aortic Pseudoaneurysm with CT-Guided Thrombin Injection.

Background: Only 3 cases of aorto-cisterna chyli fistula have been described in the literature but none with a resulting pseudoaneurysm (PSA).

Methods: A 68-year-old man presented following a motor vehicle collision. Imaging revealed a retroperitoneal hematoma with enhancement of the cisterna chyli, representing an aortic to cisterna chyli fistula. Three days later, computed tomography angiography showed resolution of the fistula, but revealed a PSA. The patient underwent arteriography that confirmed the PSA, and then a computed tomography-guided thrombin injection was performed. Follow-up imaging showed resolution of the PSA.

Results: Only 3 cases of aorto-cisterna chyli fistula have been described. We hypothesize that this fistula was caused from his L2 vertebral body fracture, which avulsed the lumbar artery and injured the cisterna chyli. The cisterna chyli provided an outflow tract for the aortic injury. We believe this type of fistula follows a benign clinical course. Aorto-cisterna chyli fistula is rare, and reports point to spontaneous resolution. Our case is unique in that the patient progressed from a fistula to a PSA. Options for treatment of this PSA include covered stent graft, open repair, coil embolization, or thrombin injection.

Conclusions: This case report describes an extremely rare diagnosis and the natural history of this aorto-cisterna chyli fistula. Furthermore, the resulting aortic PSA was successfully treated with computed tomography-guided thrombin injection, which in the appropriate setting, should be considered an acceptable option.