進行性頭蓋底骨折の1例―発生メカニズムの考察とともに

Growing Skullbase Fracture : A Case Report with Special Reference to its Pathogenesis

はじめに

　進行性頭蓋骨骨折は乳幼児期に特有のものとされ，頭蓋骨の骨折線が進行性に拡大する病態である。発生は稀であり，そのほとんどは頭蓋冠に起こる。今回われわれは，頭蓋底骨折後に進行性骨折へと移行した症例を経験した。骨折線拡大のメカニズムを考察するとともに，頭蓋骨骨折後の経過観察の重要性を含め報告する。

Abstract

　This report describes a growing skullbase fracture in a six-year-old girl.　She had a history of anterior skullbase fracture three years previously and meningitis two years later.　She was referred to our hospital because of bacterial meningoencephalitis.　Neuroimaging disclosed a bone defect and meningocele at the same site as the previous fracture.　Although a growing skull fracture of the anterior cranial base is extremely rare, the reported cases include not only pediatric patients but also adults.　Furthermore, posttraumatic pseudo-meningocele or encephalocele can be considered to be part of the same entity as growing skullbase fracture.　Therefore, "weakness of surrounding tissue" seems to be another important factor as well as "the expanding force of the growing brain" and "dural tear", which are well-known to be essential in the growth of a fracture.　Since a growing fracture at the anterior skullbase is difficult to identify from the outside, it is very important to follow-up changes in the fracture line from the acute stage of injury.