脊髄腹側の冠状静脈叢の拡張蛇行を認めた脊髄硬膜動静脈瘻の1例

A Case of Spinal Dural Arteriovenous Fistula Draining to the Ventral Coronal Venous Plexus

要旨　脊髄背側のみならず，脊髄腹側の冠状静脈叢の拡張蛇行を認めた脊髄硬膜動静脈瘻の1例を経験したので報告する。症例は80歳女性。両下肢痛，両下肢筋力低下，膀胱直腸障害を主訴に前医を受診後に紹介来院した。MRIで脊髄硬膜動静脈瘻が疑われ，脊髄血管造影では硬膜に動静脈瘻を認め，radiculomedullary vein（RMV）が脊髄腹側の冠状静脈叢に流入する所見を得た。その際，斜位像が有用であった。治療は直達術を選択し，上行するRMVが脊髄腹側の冠状静脈叢に流入することを確認し結紮，切断した。術後，血管撮影で動静脈瘻は描出されなくなった。両下肢はMMTで3/5まで改善を認めたが，膀胱直腸障害，感覚障害，両下肢痛は残存した。脊髄硬膜動静脈瘻は稀な疾患であるが，なかでも腹側に導出静脈を認める例は極めて稀である。血管造影の正面像のみでは判別が困難な場合があるので，治療時の検討では斜位像が有用である。

Here we report a case of spinal dural areteriovenous fistula （AVF） draining to the anterior spinal vein. An 80-year-old female presented with progressive weakness of lower extremities. MRI showed spinal enlargement at the Th10 to L1 with high intensity signals on T2-weighted image and multiple flow voids on the dorsal and ventral surface of the spinal cord. Angiogram of the left L2 lumbar artery demonstrated a hairpin-shaped vessel with ascending and descending limbs, mimicking radiculomedullary artery. Oblique view angiogram of the left L2 lumbar artery showed that radiculomedullary vein drained to the dilated anterior spinal vein, which then drained cranially and caudally on the anterior and posterior surface of the spinal cord. The patient underwent T9～L2 laminectomy. Several large tortuous dilated veins in the subarachnoid space were found. Examination of the inner surface of the dura revealed a arterialized vein that began at the level of L2 and coursed superioly. The arterialized vein was coagulated and interrupted. The postoperative angiogram demonstrated the obliteration of the fistula. Postoperative MRI returned to normal with complete disappearance of T2 high signal, cord enlargement.

　In most spinal dural AVF, the venous drainage is predominantly upward on the posterior surface of the spinal cord. The spinal dural AVF draining to the anterior spinal vein is atypical, and cause difficulty in differentiating the anterior spinal artery from the anterior spinal vein. Oblique view angiogram may be helpful to differentiate the anterior spinal vein from anterior spinal artery.

（Received : April 20, 2005）