Tubbs R S, Elton S, Grabb P, Dockery S E, Bartolucci A A, Oakes W J
Pediatric Neurosurgery, The Children's Hospital of Alabama, University of Alabama at Birmingham, 35233, USA.
Neurosurgery. 2001 May;48(5):1050-4; discussion 1054-5. doi: 10.1097/00006123-200105000-00016.
We previously reported the resolution of syringohydromyelia without cerebellar tonsillar ectopia in five patients after posterior fossa decompression of the so-called Chiari 0 malformation. A sixth patient is described. In this study, the anatomy of the posterior fossa is analyzed using radiological imaging, enabling features of the posterior fossa in this uncommon subgroup of children to be characterized.
Multiple measurements were made on magnetic resonance imaging studies in six children with Chiari 0 malformation to determine the position of the brainstem relative to the foramen magnum. Fifty children with normal magnetic resonance imaging studies of the brain were used as controls.
All children with a Chiari 0 malformation were found to have the following positive results: obices that were located more than 2 standard deviations below normal, an increase in the anteroposterior midsagittal distance of the spinomedullary junction at the level of the foramen magnum, an increase in the angle between the floor of the fourth ventricle and clivus, and an increase in the anteroposterior midsagittal distance of the foramen magnum.
The findings of this study suggest that the contents of the posterior fossa are indeed compromised and/or distorted in patients with syringohydromyelia but no tonsillar ectopia. In this group, the brainstem was caudally displaced more than 3 standard deviations below normal.
我们之前报道过，在对所谓的Chiari 0畸形进行后颅窝减压术后，5例患者的脊髓空洞症得到缓解且无小脑扁桃体下疝。本文描述了第6例患者。在本研究中，利用放射影像学分析后颅窝的解剖结构，以明确这一不常见儿童亚组后颅窝的特征。
对6例Chiari 0畸形患儿的磁共振成像研究进行多项测量，以确定脑干相对于枕骨大孔的位置。将50例脑部磁共振成像研究正常的儿童作为对照。
所有Chiari 0畸形患儿均有以下阳性结果：枕骨大孔低于正常水平超过2个标准差，枕骨大孔水平脊髓延髓连接部矢状位前后径增加，第四脑室底与斜坡之间的角度增大，枕骨大孔矢状位前后径增加。
本研究结果表明，在患有脊髓空洞症但无扁桃体下疝的患者中，后颅窝的内容物确实受到损害和/或扭曲。在该组中，脑干尾端移位超过正常水平3个标准差。
