脳幹部病変，特にcavernous angiomaの外科治療

Surgical Treatment for Brain stem Lesions with Reference to Cavernous Angioma

　MRIの進歩・普及に伴い病変の診断，進展範囲，周辺組織との関係が三次元的に明確に把握できるようになり，脳幹部髄内病変に対する手術の適応が注目される。最近我々が外科的に加療した，脳幹部髄内あるいは髄内から髄外に進展した病変を対象として，術前のMRI所見，手術，臨床経過を検討した。その結果，症候性や出血を繰り返すcavernous angiomaは直達手術の適応であり，摘出にあたっては全摘出すべきと思われた。一方，gliomaでもMRI上境界が明瞭なものではその範囲内での積極的な切除は神経症状の改善が得られ，しかも新たな合併症もみられなかった。

The surgical indications for localized brain stem lesions were evaluated retrospectively through the clinical results of 14 patients : 5 cavernous an-giomas and 9 gliomas. Cavernous angiomas were located in fourth ventricle floor (2 cases), in dorsal midbrain (1 case), in right cerebellar peduncle (1 case), and in medulla oblongata (1 case). Those cases had direct surgery because of relapse of clini-cal symptoms and enlargement of the lesions on follow-up MR imagings. Each lesion was extirpat ed totally. Consequently, the majority of neuro-logical deficits before operation improved. There fore, radical extirpation in brain stem cavernous angioma was strongly recommended. Also, total, subtotal resection was performed for gliomas local-ized in brain stem : 2 low grade astrocytomas, 3 malignant astrocytomas, 3 plexus papillomas, and 1 ependymoma. Most of cases improved without new neurological deficits after surgery. In addition, MR imaging was considered to be essential to accurate diagnosis and surgical strategies for brain stem lesions.