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Multiple aneurysms of the distal posterior inferior cerebellar artery: two case reports.

INTRODUCTION
The distal segment of the PICA (posterior inferior cerebellar artery) is a very rare localization for the occurrence of intracranial aneurysms. They are almost always presented with SAH (subarachnoid hemorrhage). Hydrocephalus often develops following intraventricular hemorrhage (IVH). The distal PICA segment is a quite difficult localization for neurosurgical procedures. The authors could not find any case report presenting multiple aneurysms on a distal segment of PICA in the literature. CASE 1: A 62-year-old male patient was admitted to the emergency room with complaints of sudden headache, vomiting and blackout of consciousness. Early CT scans demonstrated SAH and intraventricular hemorrhage (IVH). In his medical history, SAH had been determined in our clinic 3 month previously. He had carried out conservative treatment ever since the distal located PICA aneurysm had been determined. There was no determined symptom except for moderate neck stiffness in his physical examination. In his neurological examination, he was stuporous and he localized the pain in his left arm. A ventriculo-atrial shunt operation was performed after the external ventricular drainage which was applied at the acute period of hydrocephalus in his previous SAH. Both of the left distal PICA aneurysms were clipped via a left lateral suboccipital craniotomy. The patient was discharged from the hospital without neurological deficit in the seventh day postoperatively. His control examination was normal and there was not any fixed pathological filling in the control cerebral digital subtraction angiography (DSA). CASE 2: A 49-year-old female patient was admitted to the emergency service with the complaint of headache, dizziness and vomiting. She was neurologically intact except for neck stiffness. A cranial CT demonstrated triventricular hydrocephalus and a hemispheric cerebellar hematoma, which was about 1 x 1.5 cm in diameter. The cerebellar DSA was normal. The patient was discharged with no neurological impairment. In the examination of the control cerebral DSA, two aneurysmatic fillings were determined in the distal segments of right posterior inferior cerebellar artery (PICA). Both of the aneurysms were clipped through a microsurgical approach. No neurological deficit was determined in the postoperative early and late stages. In the control cerebral DSA, no aneurysmatic filling was seen.


DISCUSSION
Distal PICA aneurysms constitute only 0.28-1.4% of all intracranial aneurysms. Most of the patients present with SAH and along with this; intraventricular hemorrhage is seen and later on, hydrocephalus develops. As for treatment, surgery and endovascular interference methods can be applied.