先天性寰枕融合和/或C2-3融合与颅底凹陷症发病机制的关系

Relationship between congenital occipital atlas fusion, C2-3 fusion and basilar invagination

中文关键词:  颅底凹陷症  先天性寰枕融合  颈椎2-3融合  发病机制

英文关键词:Pathogenesis basilar invagination  Congenital occipital-atlas fusion  Cervical 2-3 fusion

中文摘要:

  【摘要】 目的：通过对颅底凹陷症患者的影像学观察和测量，探讨寰枕融合和/或C2-3融合在颅底凹陷症发病机制中的意义。方法：选择我院自2009年3月～2011年12月治疗的50例伴有寰枢椎脱位的颅底凹陷症患者（观察组），行颅骨正侧位摄片及包含颅底部的颈椎CT扫描和三维重建，统计其中寰枕融合、C2-3融合、寰椎侧块楔形变、枢椎上关节面斜坡化的例数。并从医院数据库调用相同年龄性别分布的50例正常人的头颅影像数据作为对照。测量两组人群的枕骨斜坡角（α）、齿状突顶点到Chamberlain线的距离（a）、齿状突顶点到枕骨大孔的距离（b）、硬颚后缘投影点距离寰椎侧块下缘的距离（h）、颈脊髓脑干角（β）等参数。比较两组间的差异。结果：50例颅底凹陷症患者中40例（80%）合并寰枕融合（C0-1），28例（56%）合并C2-3融合（其中1例为C2-3-4）融合，20例同时合并C0-1、C2-3融合（40%），49例合并寰椎侧块楔形变。观察组α平均131°±11°，对照组平均135°±8°，两组间比较差异无显著性（P>0.05）。观察组a、b、h及β值分别为-8.6±3.7mm、-5.1±2.3mm、4.8±1.8mm及129°±15°，对照组分别为6.9±2.9mm、9.6±3.7mm、17.7±2.3mm及156°±17°，两组间比较差异均有显著性（P<0.05）。结论：先天性寰枕融合可以导致枢椎齿状突高位，这可能是形成颅底凹陷症的解剖基础；寰椎侧块楔形变及枢椎上关节面斜坡化可造成的寰枢关节结构性不稳；C0-1和/或C2-3融合导致C1/2之间的应力集中和寰枢关节的运动负荷增加，这可能是引发寰枢椎脱位的另一重要解剖因素。

英文摘要:

  【Abstract】 Objectives: To investigate the role of occipital atlas and C2-3 fusion on the formation of basilar invagination associated with atlantoaxial dislocation.　Methods: From March 2009 to December 2011, 50 cases suffering from basilar invagination associated with atlantoaxial dislocation(observation group) were reviewed. All cases underwent X-ray, 3-dimensional reconstruction CT and MRI, and the numbers of occipital atlas fusion(C0-1),cervical 2-3 fusion(C2-3), wedge shape for atlas lateral mass, slope shape for upper facet of axis was counted respectively. Meanwhile, 50 normal persons with the same gender and age distribution were picked up from the image data base of our hospital for control. The following parameters such as basal-clivus angle (parameter α), distance from odontoid to chamberlain line(parameter a) and distance from odontoid to foramen magnum line(parameter b), distance from the projection of bone patella to the low rim of atlas lateral mass (h), and cervicomedullary angle(β) et al were measured respectively in both groups. Results: There were 40 (80%) C0-1 fusions, 28(56%) C2-3 fusions(including C2-3-4 fusion in 1 case), 20 C0-1 and C2-3 fusions together and 49 wedge shape for atlas lateral mass in the 50 basilar invagination patients. The basal-clivus angle(α) was 131°±11°(in observation group) and 135°±8°(in control group) respectively(P>0.05）; the parameter a, b, h and β was -8.6±3.7mm, -5.1±2.3mm, 4.8±1.8mm and 129°±15° respectively for observation group, and 6.9±2.9mm, 9.6±3.7mm, 17.7±2.3mm and 156°±17° for control group respectively. All parameters showed group-related statistical difference(P<0.05). Conclusions: The congenital occipital-atlas fusion brings the dens in a high position, which will lead to the formation of basilar invagination; the wedge shape of atlas mass and slope shape of the C2 upper facet may lead to C1-2 instability; the C0-1 and C2-3 fusion may lead to the stress concentration between the C1 and C2, which will bring C1-2 dislocation anatomically.