Intraventricular Hemorrhage caused by a Ruptured Aneurysm of the Distal Posterior Inferior Cerebellar Artery : Report of Two Cases

Abstract

We report 2 cases of ruptured aneurysms of the distal posterior inferior cerebellar artery (PICA)and review 85cases reported in the literature ． Case 1 ：A72 ． − year − old man had headaches ． Cornputed tornography (CT)revealed intraventricular hemorrhage (IVH)and hydrocephalus without subarachnoid hemorrhage (SAH) ． Cerebral angiography showed an a1 ユeurysm located on the telovelo − tonsmar seglnent of the left PICA ． The aneurysm ruptured again during angiography ， causing the patient ' s death． Case 2 ：A72 −． year − old man experienced disturbance of consciousness ， CT revealed SAII and IVH with hydrocephalus ， Cerebral angiography showed an aneurysm Iocated on the tonsillo − medullary segment of the left PICA ． The aneurysrn was clipped successfully and the patient underwent ventriculo − per｛ toneal shunting ． The postoperative course was uneventful ， Whereas angiography in Case 工showed that the aneurysm had bled through the roof of the fourth ventricle and into the ventricle but showed nQ apparent SAH ， the surgicaI findings in Case 2 suggested that intracisternal blood had entered the ventricle ． These contrasting findings indicate that the pathology of IVH varies among different segments of the PICA ． Review of the literat しlre revealed that the incidence of IVH after the rupture of aneuryslns of the distal PICA is 55 ％ ， In the case of the telovelo − tonsillar segment ， the incidence is 7／％ ， which is clearly higher than that for other segments of the PICA． The outcome of distal PICA aneurysms in rep 〔 ， rted series is good in 72， 4 ％ of patients． 1▽H alone is not necesSarily a factor affecting the prognosis of distal PICA aneurysms ， but when compliCated by hN ・ droCephalus tends to worsen the prognosis．

Subarachnoid Hemorrhage Caused by Ruptured Posterior Inferior Cerebellar Artery Aneurysm Arising From the Extracranial Portion of an Anomalous Vertebral Artery

“…2) Cadaveric and angiographic studies have shown that the PICA arises from the extracranial portion of the vertebral artery (VA) in only 17-18% of the cases. 3,4) Some PICA aneurysms have an intradural cervical origin and are usually located in the intracranial portion.…”