Combination of infarctions in the posterior inferior cerebellar artery and anterior spinal artery territories

Microsurgical considerations of the anterior spinal and the anterior-ventral spinal arteries

BACKGROUND

There are few data describing the microanatomy of the anterior-ventral spinal (AVSA) and anterior spinal arteries (ASA) and discussing their clinical and surgical implications. We describe the anatomical features of this arterial complex, and highlight their use when planning and performing surgical approaches to lesions involving the ventral aspect of the medulla and the foramen magnum.

METHOD

The microsurgical anatomy and branching pattern of the AVSA and the ASA from fifty human cadaver brain stems is described using a surgical microscope.

RESULTS

We found one anterior-ventral spinal artery at each side in 30 of the brain stems (60%). The ASA was a direct branch emerging from the left vertebral artery (VA) in 15 (30%), from the right VA in 4 (8%), and from the basilar artery (BA) in one brain stem (2%). The previously described as "typical pattern" of the junction of the AVS arteries from both sides, was observed only in 9 brain stems (18%). The anterior communicating spinal artery (ACoSA) was observed in 15 brain stems (30%). Also multiple ACoS arteries were described in one brain stem. Both, the AVSA and the ASA were observed to send long circumferential branches that supplied irrigation to the olive in 42 (84%) brain stems.

CONCLUSIONS

This anatomical study gives important information for a better understanding of the clinical picture of ischemic lesions of the brain stem, such as the medial medullary syndrome, and highlights the remarkable role of the AVSA and ASA as anatomical landmarks during the surgical approaches to lesions involving the ventral aspect of the medulla and the foramen magnum.

Infarcts presenting with a combination of medial medullary and posterior inferior cerebellar artery syndromes

Cerebellar and medial medullary infarctions are well-known vertebrobasilar stroke syndromes. However, their development in a patient with distal vertebral artery occlusion has not been previously reported. A 49-year-old man with longstanding hypertension suddenly developed vertigo, right-sided Horner syndrome, and left-sided weakness. An MRI of the brain showed acute infarcts in the right inferior cerebellum (posterior inferior cerebellar artery territory) and the right upper medial medulla (direct penetrating branches of vertebral artery). Magnetic resonance angiogram showed occlusion of the distal vertebral artery on the right side. Atherothrombotic occlusion of the distal vertebral artery may cause this unusual combination of vertebrobasilar stroke.