脊髓型颈椎病伴发育性椎管狭窄患者的脊髓储备空间

Magnetic resonance imaging study on the available space of the spinal cord in patients with developmental cervical stenosis and cervical spondylotic myelopathy

目的：观察脊髓型颈椎病伴发育性椎管狭窄患者颈椎MRI上脊髓在硬膜囊内的储备空间。方法：2006年2月-2010年7月,以脊髓型颈椎病就诊于北京大学第三医院骨科的患者123例,其中66例不伴后纵韧带或黄韧带骨化、椎体后缘骨赘或椎间盘突出的椎管侵占不超过50%的患者被纳入研究,其中男性41例,女性25例;年龄34-84岁,平均57岁。依据颈椎中立位X线平片上中矢径比值将所有患者分为伴发育性椎管狭窄组（狭窄组,中矢径比值≤0.75,n=38）和不伴发育性椎管狭窄组（非狭窄组,中矢径比值〉0.75,n=28）,在MRI T2矢状位像上测量C3-C7硬膜囊中矢径和椎体中矢径,在MRI T2横断位像上测量脊髓横截面积和硬膜囊横截面积,计算并比较两组患者MRI中矢径比值（硬膜囊中矢径/椎体中矢径）和硬膜囊占有率（脊髓横截面积/硬膜囊横截面积）。结果：狭窄组C3-C7各节段MRI中矢径比值均显著小于非狭窄组（P〈0.001）;C3-C6节段硬膜囊占有率与非狭窄组无显著性差异（P〉0.05）,而C7节段有显著性差异（P〈0.05）。结论：脊髓型颈椎病患者中,伴有发育性颈椎管狭窄的患者硬膜囊矢状径明显减小,但C3-C6节段脊髓在硬膜囊内的储备空间并未显著减小,呈现＂小椎管小脊髓＂的特点。

Objectives： To observe the intra-dural available space of the spinal cord in patients with developmental cervical stenosis and cervical spondylotic myelopathy by using magnetic resonance imaging. Methods： Among the 123 patients encountered for cervical spondylotic myelopathy in Peking University Third Hospital from February 2006 to July 2010, 66 patients without ossification of the posterior longitudinal ligament or the ligamentum flavum or vertebral osteophytes and with the occupation ratio of the herniated disc less than 50% were included in the study. There were 41 males and 25 females with age ranging from 34 to 84years（average, 57 years）. Based on their lateral radiographs, all patients were divided into two groups： developmental cervical stenosis group（stenosis group, n =38） and non-developmental cervical stenosis group（non-stenosis group, n=28）. On the magnetic resonance images, the sagittal diameter of the dural sac and the vertebral body on T2-weighted sagittal images as well as the cross-sectional area of the spinal cord and the dural sac on T2-weighted transverse images from C3 to C7 were measured. Then the MRI Pavlov ratio（the sagittal diameter of the dural sac/the sagittal diameter of the vertebral body） and the occupation ratio（the cross-sectional area of the spinal cord/the cross-sectional area the dural sac） were calculated and compared.Results： The MRI Pavlov ratio of the stenosis group was lower than that of the non-stenosis group in C3-C7（P〈0.001）. While the occupation ratio in the stenosis group was higher than that of the non-stenosis group in C7（P〈0.05）, while no significant difference was noted in C3-C6（P〉0.05）. Conclusions： The sagittal diameter of the dural sac decreases significantly in developmental cervical stenosis, however this does not lead to a sig1 b 1c1anificant decrease of the intra-dural space available for the spinal cord.