神经根沉降征与重度中央型/混合型腰椎管狭窄受压节段硬膜囊横截面积变化的相关性研究

Correlative study of nerve root sedimentation sign and compression of dural sac in the diagnosis of severe central/complex lumbar spinal stenosis

中文关键词:  腰椎管狭窄症  神经根沉降征  硬膜囊横截面积  椎管正中矢状径  硬膜囊横截面积差  相关性

英文关键词:Lumbar spinal stenosis  Nerve root sedimentation sign  Cross-sectional area of dural sac  Posteroanterior diameter of the spinal canal  Cross-sectional area difference of dural sac  Correlative study

中文摘要:

  【摘要】 目的：评价神经根沉降征与重度中央型/混合型腰椎管狭窄节段硬膜囊横截面积变化之间的关系，并探讨其可能的发生机制。方法：回顾性分析2012年1月~2015年6月齐齐哈尔医学院附属第二医院明确诊断为腰椎管狭窄症（LSS）的87例患者的MRI图像，均被确诊为中央型或混合型LSS，MRI明确显示L3/4或L4/5节段至少一个扫描层面的硬膜囊横截面积（cross-sectional area，CSA）≤80mm2。患者均有间歇性跛行，行走距离≤500m。单节段狭窄61例，其中L3/4狭窄19例，L4/5狭窄42例；双节段（L3/4、L4/5）狭窄26例，共筛选出符合标准的狭窄节段113个，分析其中神经根沉降征阳性的发生率，并将其分为沉降征阳性组与沉降征阴性组。L3/4、L4/5节段各扫描3层，在横截面MRI T2加权相图像上测量最小硬膜囊CSA、最小椎管正中矢状径（PAD）、最大硬膜囊横截面积差（CSAD），组间比较采用t检验；进一步采用受试者工作特征曲线（receiver operating characteristic curve，ROC-curve）即ROC曲线分析神经根沉降征阳性发生率与最小硬膜囊CSA、最小椎管PAD、最大硬膜囊CSAD之间的相关性。结果：在113个重度腰椎管狭窄节段中，28个狭窄节段沉降征阴性，85个狭窄节段沉降征阳性，神经根沉降征阳性发生率为75.22%。神经根沉降征阳性组最小椎管PAD为12.00±2.10mm，阴性组为11.47±2.04mm，两组比较有统计学差异（P<0.05）；阳性组最大硬膜囊CSAD为36.94±13.97mm2，阴性组为18.60±7.70mm2，两组比较有统计学差异（P<0.01）；阳性组最小硬膜囊CSA为47.34±12.55mm2，阴性组为45.16±15.35mm2，两组比较无统计学差异（P>0.05）。最小椎管PAD的ROC曲线下面积值（AUC）为0.64（P<0.05）；最大硬膜囊CSAD的ROC曲线下面积值（AUC）为0.929（P<0.01）；最小硬膜囊CSA的ROC曲线下面积值（AUC）为0.557（P>0.05）。结论：阳性神经根沉降征的发生与狭窄节段硬膜囊受压变窄的变化程度有关，硬膜囊最大CSAD可作为评估腰椎管狭窄节段硬膜囊受压变窄的变化程度的指标。

英文摘要:

  【Abstract】 Objectives: To evaluate the relationship between the presence of nerve root sedimentation sign(SedSign) on MRI and the cross-sectional area changes of dural sac in diseased levels in patients with severe lumbar spinal stenosis(LSS), and to analyze the possible mechanism of sedimentation sign. Methods: From January 2012 to June 2015, MR images of 87 patients with LSS were analyzed in the second affiliated hospital of Qiqihar Medical College, all patients were diagnosed with central/complex LSS. A cross-sectional area(CSA) of dural sac ≤80mm2 at least one level in transverse MRI scans of L3/4 or L4/5 were determined. All patients had typical intermittent claudication with walking distance ≤500m. 61 patients were diagnosed with single segment stenosis(19 patients at L3/4 level and 42 patients at L4/5 level). Two levels stenosis(L3/4, L4/5) were found in 26 patients. 113 narrowing levels were selected and the prevalence of positive sedimentation sign were recorded, and all cases were divided into positive and negative groups. Each level of L3/4 and L4/5 was scanned in three layers, and the smallest CSA of dural sac, the smallest posteroanterior diameter(PAD) of the spinal canal and the largest cross-sectional area difference(CSAD) of dural sac were measured at transverse T2-weighted MRI respectively, the difference of two groups were compared by t-test. The receiver-operator characteristic(ROC) curve analysis was conducted to evaluate the correlations between positive sign and the smallest CSA, the smallest PAD and the largest CSAD. Results: The positive sedimentation sign in 113 narrow levels accounted for 75.22%(85 levels). The smallest PAD of the positive groups was 12.00±2.10mm, and the negative was 11.47±2.04mm, there were significant differences between the two groups(P<0.05). The largest CSAD of the positive groups was 36.94±13.97mm2, and the negative was 18.60±7.70mm2, there were significant differences between the two groups(P<0.01). The smallest CSA of the positive groups was 47.34±12.55mm2, and negative was 45.16±15.35mm2, there were no significant differences between the two groups(P>0.05). The ROC curve showed that the area under ROC curve(AUC) of the smallest PAD of spinal canal was 0.64(P<0.05) and the AUC of the largest CSAD of dural sac was 0.929(P<0.01), the AUC of the smallest CSA was 0.557(P>0.05). Conclusions: In summary, the positive sedimentation sign is closely related to the change of compressed dural sac. The CSAD is proposed to describe the change of dural sac in compressive levels in severe central/complex lumbar stenosis.