Occipital transtentorial approachを用いて全摘し得た小脳上正中部アストロサイトーマの1例

A Case of Superomedial Cerebellar Astrocytoma Completely Removed, Using the Occipital Transtentorial Approach

I．はじめに

　Occipital transtentorial approach（以下OTTと略す）は松果体腫瘍に対しての標準的到達法であるが，小脳上正中部腫瘍に対しても最良の到達法とされる^2,3,7,8）．われわれは小脳上正中部の近傍に発生したアストロサイトーマに対してOTTを用いて摘出術を行い良好な結果を得た1小児例を経験した．小脳上正中部腫瘍に対するOTTの適応と手術の工夫について文献的に考察したい．

The occipital transtentorial approach (OTT) is showed to be effective not only for pineal body tumors, but also for superomedial cerebellar tumors. We satisfactorily removed a superomedial cerebellar astrocyto-ma in a 3-year-old infant using OTT. The magnetic resonance images showed a tumor located in the left superomedial cerebellum, and the distance between the midline and the outer margin of the tumor was 2.5cm. OTT was performed on the left side, and the tumor was removed completely. Herein, relying on own experiments and some reports, we discussed some helpful techniques and the indications for OTT for superomedial cerebellar tumors. In brief, an arch shift of the superior sagittal sinus to the contralateral side by tracting the dura, a long incision of tentorium, and aspiration of CSF were very useful measures for avoiding occipital lobe injury. We emphasized that a preoperative estimation of possibilities for these tech-niques is very important.