[Vertebral dissecting aneurysm treated with trapping and bilateral posterior inferior cerebellar artery side-to side anastomosis; case report].

A case is reported of ruptured dissecting aneurysm of the intracranial vertebral artery (VA) operated on with VA trapping and bilateral posterior inferior cerebellar artery (PICA) side-to-side anastomosis. A 42-year-old male suddenly developed severe headache and vomiting. On admission, 3 hours later, he was in a state of moderate confusion (Japan Coma Scale 3) and had neck stiffness. Computed tomography (CT) revealed diffuse subarachnoid hemorrhage, especially thick in the posterior fossa with right side dominance. Right vertebral angiography disclosed a fusiform dilatation with proximal narrowing of the right VA which originated just proximal to the VA-PICA junction. Lateral suboccipital craniectomy was undertaken with the patient in a left park bench position. Right VA was dilated and discolored black, and right PICA arose from the proximal portion of this aneurysmal dilatation. Since it was impossible to clip the VA distal to the PICA for the proximal clip-occlusion, the VA including the VA-PICA junction was trapped. Considering the risk of developing infarction at the PICA territory, bilateral PICA was anastomosed at their posterior medullary segment in a side-to-side fashion because the occipital artery (OA) had been cut at the skin incision and could not be used for the OA-PICA anastomosis. The postoperative course was benign, but a mild lateral medullary syndrome developed. CT revealed no abnormal low density area and left vertebral angiography demonstrated the patency of the bypass. Thereafter, the deficit subsided gradually and the patient was discharged. He is presently working without neurological deficit.(ABSTRACT TRUNCATED AT 250 WORDS)