Aortic Nonanastomotic Pseudoaneurysm Eroding Lumbar Vertebra: A Case Report

Nonanastomotic pseudoaneurysms are uncommon complications of prosthetic grafts, which are mostly associated with axillofemoral grafts. The case presented describes a pseudoaneurysm secondary to a previously placed end-to-side aortobifemoral bypass. Back pain developed 3 years after the original bypass and was not relieved with narcotics and muscle relaxants. The patient also complained of a 20-pound weight loss, night sweats, and frequent emesis. Approximately 1 year after the onset of back pain, left leg claudication developed. He eventually underwent magnetic resonance imaging of the lumbosacral spine, which depicted a tumorlike mass eroding the vertebral bodies of L2 and L3. Full oncologic workup was pursued preoperatively. The patient also underwent aortography, computed tomography of the abdomen and pelvis, and an inferior venacavogram to elucidate the relationships between the mass and the major vascular structures. On exploration, no malignancy was present. A hole in the native aorta approximately 2 cm above the level of the end-to-side aortic anastomosis was discovered. This was contiguous with the vertebral bodies and the left psoas muscle. The pseudoaneurysm was repaired by conversion of the proximal anastomosis to an end-to-end aorto right iliac and left femoral bypass. All of the preoperative symptoms resolved after repair of the pseudoaneurysm. Chronic aortic rupture or pseudoaneurysms are difficult to diagnose due to the unusual clinical presentations. Despite complete radiologic evaluation, preoperative diagnosis may be difficult or impossible without a high degree of suspicion. Surgical repair will depend on the cause of the pseudoaneurysm-all but infected aneurysms may be repaired in line by creating a proximal anastomosis above the level of the pseudoaneurysm. Atypical back pain in patients with previous aortic reconstructions should alert the clinician to the possibility of vascular involvement. Patients with aortic pseudoaneurysms should undergo prompt repair to avert the potential risk for rupture when the surrounding structures are no longer able to contain the pulsatile flow.