Lateral sacral artery aneurysm: case report and review of the literature

Abstract

Objective and importance: We report the third case of an aneurysm of the lateral sacral artery (AnLSA). In all cases, because of an incorrect preoperative diagnosis, the surgeons were confronted with severe and unexpected hemorrhaging, and surgery was aborted without effective treatment. Our purpose is to present the preoperative features of AnLSA and its treatment modalities.

Clinical presentation: A 54-year-old man had a medical history of renal transplantation on his left external iliac artery. He complained of acute lumbar pain associated with cauda equina syndrome, which resolved within a few hours. At that time, a magnetic resonance imaging (MRI) scan revealed an intracanal hematoma extending from S1 to T12. Six weeks later, a second MRI scan demonstrated an oval-shaped intracanal mass behind the vertebral body of S1 with intense gadolinium enhancement.

Intervention: An anterior epidural mass was found. An incision into this mass resulted in significant arterial hemorrhaging. Transparietal embolization with a cotton compress and closure of the aneurysm wall were performed. The postoperative clinical status was stable, and a delayed angiographic study suggested a diagnosis of aneurysm of the right LSA, a branch of the internal iliac artery. Its pathophysiology was explained by the development of a high-flow transpelvic shunt from the right iliac artery territory to the left, to maintain the renal graft blood flow that had initially been reduced by stenosis of the left common iliac artery. Six weeks later, a new MRI scan demonstrated that the AnLSA had increased in size. The lesion was then excluded endovascularly by injection of glue.

Conclusion: A medical history of renal transplantation with MRI scans showing an anterior epidural mass behind S1 or a spontaneous spinal epidural hematoma are features that must evoke a diagnosis of AnLSA. Treatment is mandatory and is best achieved by embolization. Surgery based on angiographic findings is indicated if the lesion is responsible for a compressive hematoma.