頭蓋内圧亢進により描出されなかった上位頸椎部硬膜動静脈奇形の1例＊

Angiographically Occult High Cervical Dural Arteriovenous Malformation Secondary to Intracranial Hypertension : a case report

I．はじめに

　上位頸椎部の硬膜動静脈奇形は比較的まれな疾患である．しかし近年，画像診断の進歩により，その報告が散見される^{2-4,7-9,12,13,15-17）}．

　今回，発症時の脳血管造影では描出されず，再検査にて診断されたくも膜下出血で発症した上位頸椎部硬膜動静脈奇形の1例を経験したので，その特徴につき若干の文献的考察を加えて報告する．

We have recently encountered a case of high cervical arteriovenous malformation which caused sub-arachnoid hemorrhage. A 54-year-old male was admitted to our hospital due to sudden onset of severeheadache. Neurological examination revealed right sixth nerve palsy which suggested elevated intracranialpressure. A CT scan showed subarachnoid hemorrhage predominantly in the posterior fossa, massivelyventral to the brain stem, with reflux into the fourth ventricle. No abnormal vascular lesions were found inthe first cerebral angiography which included four vessels and bilateral thyrocervical trunks.

Ten days later, the second cerebral angiography demonstrated an arteriovenous shunt via the rightvertebral artery draining into the epidural space of the upper cervical region. A suboccipital craniotomyand laminectomy of the atlas were performed. An abnormally dilated vein along the right C1 nerve ventralroot which drained into the tortuous dilated coronary venous plexus on the ventral side of the spinal cordwas found. We made a diagnosis of dural arteriovenous malformation fed by the C 1/C2 raclicular arteryvia the right vertebral artery and draining into the radiculomedullary vein and the epidural venous plexus.The interruption of both intra- and extradural draining veins was carried out. The postoperative coursewas uneventful.