Taylor Davis G, Chatrath Ajay, Mastorakos Panagiotis, Paisan Gabriella, Chen Ching-Jen, Buell Thomas J, Jane John A
1Department of Neurological Surgery, University of Virginia Health System, Charlottesville, Virginia; and.
2Surgical Neurology Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland.
J Neurosurg. 2020 Feb 21;134(3):825-830. doi: 10.3171/2019.11.JNS191439. Print 2021 Mar 1.
Syringogenesis in Chiari malformation type I (CM-I) is thought to occur secondary to impaction of the cerebellar tonsils within the foramen magnum (FM). However, the correlation between the CSF area and syringogenesis has yet to be elucidated. The authors sought to determine whether the diminution in subarachnoid space is associated with syringogenesis. Further, the authors sought to determine if syrinx resolution was associated with the degree of expansion of subarachnoid spaces after surgery.
The authors performed a retrospective review of all patients undergoing posterior fossa decompression for CM-I from 2004 to 2016 at the University of Virginia Health System. The subarachnoid spaces at the FM and at the level of the most severe stenosis were measured before and after surgery by manual delineation of the canal and neural tissue area on MRI and verified through automated CSF intensity measurements. Imaging and clinical outcomes were then compared.
Of 68 patients, 26 had a syrinx at presentation. Syrinx patients had significantly less subarachnoid space at the FM (13% vs 19%, p = 0.0070) compared to those without syrinx. Following matching based on degree of tonsillar herniation and age, the subarachnoid space was significantly smaller in patients with a syrinx (12% vs 19%, p = 0.0015). Syrinx resolution was associated with an increase in patients' subarachnoid space after surgery compared with those patients without resolution (23% vs 10%, p = 0.0323).
Syrinx development in CM-I patients is correlated with the degree to which the subarachnoid CSF spaces are diminished at the cranial outlet. Successful syrinx reduction is associated with the degree to which the subarachnoid spaces are increased following surgery.
I型Chiari畸形（CM-I）中的空洞形成被认为是继发于小脑扁桃体在枕大孔（FM）内的嵌顿。然而，脑脊液区域与空洞形成之间的相关性尚未阐明。作者试图确定蛛网膜下腔的减小是否与空洞形成有关。此外，作者试图确定空洞消退是否与手术后蛛网膜下腔的扩张程度有关。
作者对2004年至2016年在弗吉尼亚大学健康系统接受CM-I后颅窝减压的所有患者进行了回顾性研究。通过在MRI上手动描绘管腔和神经组织区域，在手术前后测量FM处和最严重狭窄水平处的蛛网膜下腔，并通过自动脑脊液强度测量进行验证。然后比较影像学和临床结果。
68例患者中，26例在就诊时有空洞。与没有空洞的患者相比，有空洞的患者在FM处的蛛网膜下腔明显更小（13%对19%，p = 0.0070）。在根据扁桃体疝程度和年龄进行匹配后，有空洞的患者蛛网膜下腔明显更小（12%对19%，p = 0.0015）。与没有消退的患者相比，空洞消退与手术后患者蛛网膜下腔的增加有关（23%对10%，p = 0.0323）。
CM-I患者的空洞形成与颅出口处蛛网膜下腔脑脊液空间减小的程度相关。成功减少空洞与手术后蛛网膜下腔增加的程度相关。
