- 作者: 洪啟賦
- 作者服務機構: 中國醫藥學院附設醫院外科
- 中文摘要: 水腦症,大腦導水管狹窄,Chiari氏II型畸形,脊椎分裂常合併於人類中樞神經系統畸形,因其手術治癒率相當高,故在臨床上相當重要及有趣。但水腦症在Arnold-Chiari氏畸形中的關係地位仍然是個爭論的問題。 本報告是以每公斤體重240 mg的ethylenethiourea (ETU)給予懷孕第十一天的SD大白鼠經胃灌食,在懷孕第二十天剖腹取出胎兒。54.6%的胎兒有脊椎分裂合併後腦擁擠的先天性畸型,此實驗動物的畸型與人類的Arnold-Chiari氏畸形相似,可供以探討水腦症與Chiari氏II型畸形的相互關係。 由研究結果,水腦症與大腦導水管狹窄極少見於第二十天有Arnold-Chiari畸形的大白鼠胎兒。故作者不贊同Chiari,Cameron,Gardner等學者以流體動力學理論來解釋Chiari氏Il型畸形的形成是因先有水腦症,其顱內壓增高而壓迫後腦導致延腦,小腦蚓部及扁桃體下移到頸脊椎管內。 作者認為Chiari氏II型畸形主要病變是因大腦枕孔的蜘蛛網膜下腔被下移的延腦及小腦下部壓迫而閉塞,使第4腦室外流的脊髓液積存於脊椎蜘蛛網膜下腔內,無法上升至腦蜘蛛網膜下腔以便回流至靜脈而造成交通性水腦症。當交通性水腦症腦壓增高後而壓迫大腦導水管導致大腦導水管狹窄,故水腦症及大腦導水管狹窄於Arnold-Chiari氏畸形並不是原發性的病變,而是續發症。因此,Arnold-Chiari氏畸形併發的水腦症,其外科治療除腦室引流外,後腦窩及上頸椎管減壓術以促進腦脊髓液的上流以便吸收亦是一種可行的治療及預防方法。
- 英文摘要: Spina bifida, Chiari type II malformation, cerebral aqueduct stenosis and hydrocephalus are the mostfrequent association anomalies in the congenital malformation of the central nervous system (Warkany etal., 1958). They are potentially treatable and of clinical importance. But the relationship between hydro-cephalus and Chiari type II malformation is still a controversial subject. A single oral dose of 240 mg/kg of ethylenethiourea (ETU) was given to Sprague Dawley (SD) ratson the 11th day of gestation. Fetuses were removed in the 20th day of gestation by cesarean sections; highincidence of spinal dysraphism associated with hindbrain crowding was found in these fetuses. They aresimilar to Arnold-Chiari malformation in humans. We used these experimental models to analyze the rela-tionship between hydrocephalus and Chiari type II malformation. From the present investigation, no hydrocephalus or cerebral aqueduct stenosis was found in the ex-perimental rat fetuses with the Arnold-Chiari malformation. So we do not consider the hydrodynamictheory that Chiari type II malformation was induced by increasing intracranial pressure in hydrocephalus.Hydrocephalus in the Arnold-Chiari malformation may not be the primary disorder but seems to be causedby plugging the foramen magnum in Chiari type II malformation. So the cerebrospinal fluid in the spinalsubarachnoid space can not move upward to the cranial subarachnoid space for absorption to venous re-turn. Cerebral aqueduct stenosis may be secondarily compressed by hydrocephalus and not be the primarydevelopment anomaly or acquired occlusion due to gliosis. This is in accord with the theory proposed byRussell and Donald (1935). Early posterior fossa decompression and nuchalectomy for Arnold-Chiari malformation may preventthe later appearance of hydrocephalus and the devastating neurological complication of Arnold-Chiarimalformation.
- 中文關鍵字: spinal dysraphism; Arnold-Chiari malformation; Ethylenethiourea; Chiari type II mal-malformation.
- 英文關鍵字: --