Aneurysm of the meningeal branch of the occipital artery connecting with the distal portion of the posteroinferior cerebellar artery by the dural fistula
We describe a case involving a ruptured intradural aneurysm of the meningeal
branch of the occipital artery arising from the external carotid artery and connecting
with the caudal loop of the posteroinferior cerebellar artery (PICA) by
the dural fistula. Angiography of the left external carotid artery showed a saccular
aneurysm of the occipital artery, but the picture of the left vertebral artery
was normal and no vascular pathology such as an aneurysm or a dural
fistula was noticeable between the meningeal branch of the occipital artery
and the PICA. The diagnosis was confirmed by three-dimensional reconstruction
computed tomography (CT) angiography, magnetic resonance imaging
and magnetic resonance angiography (MRA).
In the knowledge, based on the radiological examinations, that the aneurysm
was located intracranially below the tonsil, compressing the lateral surface of
the medulla oblongata at the level of the foramen magnum, we decided to
operate from the far-lateral suboccipital approach, without removing the arc
of the C1. An aneurysm was visualised at the site of the connection of the
caudal loop of the PICA and an anastomosis of the meningeal branch of the
occipital artery. The aneurysm was successfully clipped and the vascular fistula
was coagulated and dissected in the extradural section.
To our knowledge, the case presented here is the first report of this kind of
vascular pathology. Careful analysis of a cross-sectional CT angiogram, MRA
and arteriography is necessary for the proper diagnosis of such atypical vascular
pathology. In the study presented we focus our attention on the diversity of
the PICA anatomy
