下段颈椎脊椎功能单位活动度与椎管狭窄程度间相关性分析

To investigate the correlation between the segmental activity of the functional units and extent of the vertebral canal stenosis in the lower cervical spine

目的：探讨退变性下段颈椎的脊椎功能单位（FSU）活动度与相应节段椎管狭窄程度间相关性.资料与方法：随机选取拟行手术治疗的脊髓型颈椎病病人62例.全部拍摄MRI及动力位（过伸-过屈位）颈椎侧位CR片.测量参数包括C2～C7过伸/过屈位Cobb角和,反映颈椎整体活动度；选取C3～C4 、C4～C5、C5～C6三个水平的颈椎FSU过伸/过屈位Cobb角和表示FSU的节段性活动度.依据椎管狭窄等级（Ⅰ、Ⅱ、Ⅲ级）,分别对该3个FSU活动度行统计学分析.结果：Ⅰ级椎管狭窄病人的C4～C5、C5～C6椎间活动度大于C3～C4水平,其中C4～C5、与C3～C4水平间显示统计学差异.C4～C5、椎间活动度在Ⅲ级椎管狭窄时显著降低,与Ⅰ级、Ⅱ级有统计学意义.8例未显示Ⅲ级椎管狭窄病人与54例Ⅲ级椎管狭窄病人的椎体整体活动度间差异无统计学意义.结论：颈椎FSU作为维持颈椎稳定性的基本单元,随着椎管狭窄程度的增加稳定性增加,但却以牺牲椎管空间为代价,出现椎管狭窄,联合应用动力位CR侧位片及MR检查在判定颈椎活动度与椎管狭窄程度间关系显示重要价值.

Objective： To investigate relationships between the degree of the cervical spinal canal stenosis and lower cervical segmental stability in patients with cervical spondylotic myelopathy（CSM）. Methods： Sixty-two patients with CSM for prepared surgery were examined with the lateral dynamic radiographs （flexion-extension） and MR scanner. Radiographic evaluation included the C2-C7 Cobb angle and FSU-Cobb angle at C3-C4, C4-C5, and C5-C6. Cervical spinal stenosis was classified by means of the T2-weighted MR images into four grades. Radiological change was analyzed according to the degree of the spinal stenosis during flexion-extension motion. Results： The segmental activity of the C4-Cs, C5-C6 was greater than that at the C3- C4 in Grade I spinal stenosis, and statistical difference was observed between the C4-C5 and the C3-C4. The segmental activity at the C4-C5 decreased significantly in Grade III compared with Grade I and Grade 11 spinal stenosis, and implied the segmental units at the C4-C5 contributed the majority Of the mobility On the cervical spine and motion decreased in the severe spinal stenosis. There was no statistical difference on the range of the motion of the overall cervical spine between grade 0- II and grade III groups. Conclusion： The functional spinal unit（FSU） is the smallest functional unit of the cervical spine and exhibits the generic characteristics of the spine. The mobility of the FSU was significantly reduced in the severe cervical spinal stenosis, from an unstable phase to an ankylosed stage, with the progression of the degenerative change. Hence, combined application of the common lateral dynamic radiographs and MRI in judging the activity of the cervical spine and spinal canal stenosis plays an important role in the clinical practice.