From the Division of Neuroradiology (K.A.G., D.M.Y.), The Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins Medical Institutions, Baltimore, Maryland.
Radiology Department (K.A.G.), Faculty of Medicine, Suez Canal University, Ismailia, Egypt.
AJNR Am J Neuroradiol. 2017 Sep;38(9):1833-1838. doi: 10.3174/ajnr.A5290. Epub 2017 Jul 6.
The association of syringohydromyelia with Chiari I malformation has a wide range, between 23% and 80% of cases in the current literature. In our experience, this range might be overestimated compared with our observations in clinical practice. Because there is an impact of Chiari I malformation-associated syringohydromyelia on morbidity and surgical intervention, its diagnosis is critical in this patient population. Identifying related variables on the basis of imaging would also help identify those patients at risk of syrinx formation during their course of disease.
We performed a retrospective analysis of the MR imaging studies of 108 consecutive cases of Chiari I malformation. A multitude of factors associated with syrinx formation were investigated, including demographic, morphometric, osseous, and dynamic CSF flow evaluation.
Thirty-nine of 108 (36.1%) patients with Chiari I malformation had syringohydromyelia. On the basis of receiver operating characteristic curve analysis, a skull base angle (nasion-sella-basion) of 135° was found to be a statistically significant classifier of patients with Chiari I malformation with or without syringohydromyelia. Craniocervical junction osseous anomalies (OR = 4.3, = .001) and a skull base angle of >135° (OR = 4.8, = .0006) were most predictive of syrinx formation. Pediatric patients (younger than 18 years of age) who developed syringohydromyelia were more likely to have associated skull base osseous anomalies than older individuals ( = .01).
Our findings support evidence of the role of foramen magnum blockage from osseous factors in the development of syringohydromyelia in patients with Chiari I malformation.
在当前文献中，脊髓空洞伴 Chiari I 畸形的关联范围很广，在 23%到 80%的病例中都有发现。根据我们的临床观察，与文献报道相比，这个范围可能被高估了。由于 Chiari I 畸形伴发的脊髓空洞症会对发病率和手术干预产生影响，因此在这类患者群体中，准确诊断是至关重要的。基于影像学识别相关变量，也有助于确定那些在疾病过程中存在形成脊髓空洞风险的患者。
我们对 108 例连续 Chiari I 畸形患者的磁共振成像研究进行了回顾性分析。我们研究了多种与脊髓空洞形成相关的因素，包括人口统计学、形态学、骨骼和动态 CSF 流评估。
在 108 例 Chiari I 畸形患者中，有 39 例（36.1%）伴有脊髓空洞症。基于受试者工作特征曲线分析，我们发现颅底角度（鼻根-蝶鞍-基底）为 135°是 Chiari I 畸形伴或不伴脊髓空洞症患者的一个具有统计学意义的分类器。颅颈交界区骨骼异常（OR=4.3，P=.001）和颅底角度>135°（OR=4.8，P=.0006）是脊髓空洞形成的最具预测性因素。发生脊髓空洞症的儿童（年龄小于 18 岁）比年龄较大的患者更有可能伴有颅底骨骼异常（P=.01）。
我们的研究结果支持了颅底骨性结构异常导致的枕骨大孔阻塞在 Chiari I 畸形患者脊髓空洞形成中的作用。
