未破裂脳動脈瘤の開頭術後，くも膜形成に用いた医療材料へのアレルギー反応に起因すると思われる遅発性脳浮腫を認めた2例

Two Cases of Late-onset Brain Edema after Craniotomy for Unruptured Intracranial Aneurysms Suspected to be due to an Allergic Reaction to Arachnoid Plasty Material

Ⅰ．はじめに

　フィブリン糊（fibrin glue：FG）と吸収性ゼラチンスポンジ（gelatin sponge：GS）によるくも膜形成（arachnoid plasty：AP）を用いた未破裂脳動脈瘤の開頭術後，術野周囲に遅発性脳浮腫を認めた2症例を経験した．本病態について，文献的考察を加えて報告する．

　We report two rare cases of late-onset brain edema after craniotomy for clipping or coating of unruptured intracranial aneurysms, possibly due to an allergic reaction to topically applied fibrin glue or gelatin sponge used for arachnoid plasty to cover the opened sylvian cistern. Both patients were women in their 60s with an allergic predisposition and both followed a similar clinical course. A slight fever and headache persisted during the postoperative period. Five to six weeks after surgery without complications, MR images showed an extensive T2 prolongated region in the white matter around the operative field, indicative of vasogenic edema, with mass effect and meningeal enhancement around the sylvian fissure that had been covered with gelatin sponge and sprayed fibrin glue. Swelling of the cerebral cortex around the sylvian fissure subjected to arachnoid plasty was also observed. Blood tests showed the absence of an inflammatory reaction and cerebrospinal fluid examination showed lymphocytosis that was considered to be due to an aseptic meningeal reaction or meningitis. Clinical symptoms and imaging findings steadily improved with the administration of steroids and antiallergic agents.

　Delayed brain edema may occur around the arachnoid plasty area despite an uneventful chronic postoperative period, which could be due to an allergic reaction to locally administered fibrin glue or gelatin sponge. Thus, the application of arachnoid plasty using fibrin glue and gelatin sponge in patients with a predisposition to allergies needs to be carefully considered.