The Lurking Catastrophic Complication of an Equally Catastrophic Disease

BACKGROUND Medullary-bridging vein dural arteriovenous fistula (DAVF) is an uncommon type of DAVF with an aggressive clinical course due to direct fistulous shunting into medullary and brainstem veins. Important considerations need to be given to retrograde embolic migration or perforator involvement while treating these fistulas endovascularly with a liquid embolic agent. We report a lateral spinal artery feeding the DAVF, the recognition of which is important to avoid potential catastrophic complications during definitive therapy, and which has not been described before. OBJECTIVE To discuss the anatomy of the lateral spinal artery (LSA) and its communications with pial arteries such as the posterior inferior cerebellar artery (PICA) that may have important implications in the management of neurovascular diseases in and around the foramen magnum. METHODS A retrospective analysis of cerebral angiograms and 3-dimensional rotational angiograms of a patient with medullary-bridging vein DAVF treated by transarterial embolization under balloon protection was performed after the patient developed lateral medullary syndrome in the postoperative period. RESULTS Detailed analysis revealed a dural branch from the LSA feeding the DAVF which anastomosed with rudimentary PICA. CONCLUSION LSA has important anastomoses with perforating arteries of the medulla and cervical cord and, hence, it is important to recognize and identify LSA prospectively in the vascular pathologies of the foramen magnum to avoid fatal neurological complications during endovascular therapy. This is especially important while treating neurovascular pathologies using liquid embolic agents such as Onyx or SQUID, because they can percolate retrogradely through the anastomoses into PICA or other vertebrobasilar perforators.

Vascular Microanatomy of the Pontomedullary Junction, Posterior Inferior Cerebellar Arteries, and the Lateral Spinal Arteries

This study of 25 brains at the pontomedullary junction defined the different possible origins of the perforating arteries and lateral spinal arteries in relation to the posterior inferior cerebellar arteries (PICAs). - If the PICA emerges from the common trunk of the AICA-PICA coming from the basilar artery, it never gives perforating arteries or a lateral spinal artery on the lateral surface of the brain stem but supplies blood to a part of the ipsilateral cerebellar hemisphere. - If the PICA arises extradurally at C1, it never gives perforating arteries for the lateral surface of the brain stem, but it gives pial branches for the posterior surface of the medulla oblongata and is always the origin of the lateral spinal artery. - If the PICA emerges in the intradural vertebral artery, it is the source of the perforating arteries for the lateral surface of the brain stem and of the blood supply of the ipsilateral cerebellum.

Aneurysms of the Lateral Spinal Artery: Report of Two Cases

OBJECTIVE AND IMPORTANCE The goal of this report was to describe aneurysms arising from the lateral spinal artery. The locations of aneurysms contributing to subarachnoid hemorrhage (SAH) have been well characterized and are primarily in the circle of Willis or at the bifurcation points of the internal carotid artery or the vertebrobasilar system. Although the spinal arteries are also in direct communication with the subarachnoid space, aneurysms of these arteries that lead to SAH are rare. To date, only aneurysms of the anterior and posterior spinal arteries have been described. In this communication, we report two patients with aneurysms of the lateral spinal artery who presented with SAH. CLINICAL PRESENTATION Review of our neurointerventional database from 1997 to the present revealed two patients with lateral spinal artery aneurysms. The medical records, as well as the operative and radiological findings, were reviewed for both patients. In both cases, the lateral spinal arteries were involved as collateral pathways for occlusive vertebral lesions, suggesting hemodynamic stress as a cause. INTERVENTION Endovascular treatment was attempted in both cases and was successful in one; open surgery, with aneurysm resection, was performed in the other case. We review the vascular anatomic features of the spinal cord as they relate to the lateral spinal artery, as well as treatment options for lateral spinal artery aneurysms. CONCLUSION Lateral spinal artery aneurysms are a rare cause of SAH. Both endovascular and surgical treatment options are available.