Lateral sacral artery aneurysm of the lumbar spine: hemorrhage resulting in cauda equina syndrome

OBJECTIVE: To describe the effective treatment of a ruptured lateral sacral artery aneurysm presenting as a spinal epidural hematoma. DESIGN: Case report and literature review. SETTING: University teaching hospital, neurovascular center. PARTICIPANT: A man with a history of renal allograft who presented with sudden onset low back pain. INTERVENTION: The patient underwent emergent decompressive surgery, diagnostic angiogram and endovascular embolization. MAIN OUTCOME MEASURE: Obliteration of aneurysm and restoration of neurological function. RESULTS: Surgery resulted in decompression of the cauda equina. The patient's aneurysm was endovascularly obliterated. There was complete restoration of neurological function. CONCLUSION: Lateral sacral artery aneurysm formation and rupture is a rare cause of epidural hemorrhage and one described only in patients who have undergone renal transplantation. It may be caused by high flow from transpelvic collaterals between both internal iliac arteries. Treatment includes endovascular obliteration and may necessitate operative decompression in the setting of neurological compromise.