O'Shaughnessy Brian A, Bendok Bernard R, Parkinson Richard J, Shaibani Ali, Walker Matthew T, Shakir Ebrahim, Batjer H Hunt
Department of Neurological Surgery, Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611, USA.
J Neurosurg. 2006 Jan;104(1 Suppl):28-32. doi: 10.3171/ped.2006.104.1.28.
Chiari malformation Type I (CM-I), a condition defined by caudal descent of the cerebellar tonsils through the foramen magnum, is generally considered a congenital lesion. Several authors, however, have described an acquired form that appears identical to the congenital lesion on neuroimages. The most commonly reported cause of an acquired CM-I is cerebrospinal fluid diversion through a lumboperitoneal shunt. In this paper, the authors report the case of a patient in whom an acquired CM-I developed in association with a supratentorial arteriovenous malformation (AVM) of the brain. Development of the acquired CM was documented on serial magnetic resonance images. Moreover, the CM was seen to originate and worsen in concert with the clinicoradiological progression of the AVM. The underlying mechanism responsible for the acquired CM in this case is thought to be a high-flow venopathy of the transverse and sigmoid sinuses causing occlusion on the right and redirection of venous outflow into posterior fossa veins, with consequent venous congestion and swelling of the posterior fossa structures.
I型Chiari畸形（CM-I）是一种由小脑扁桃体经枕骨大孔向下移位所定义的疾病，通常被认为是一种先天性病变。然而，有几位作者描述了一种在神经影像学上与先天性病变表现相同的后天性形式。后天性CM-I最常见的报道病因是通过腰大池-腹腔分流进行脑脊液引流。在本文中，作者报告了一例患者，其后天性CM-I与大脑幕上动静脉畸形（AVM）相关。通过系列磁共振成像记录了后天性CM的发展过程。此外，观察到CM与AVM的临床放射学进展同步发生并加重。该病例中后天性CM的潜在机制被认为是横窦和乙状窦的高流量静脉病变导致右侧闭塞，静脉血流出重新导向至后颅窝静脉，从而导致后颅窝结构的静脉充血和肿胀。
