腰椎黄韧带厚度与椎管斜径比值对黄韧带肥厚致椎管狭窄的诊断意义

Diagnostic value of the ratio of ligamentum flavum thickness to oblique diameter of lumbar canal in patients with ligamentum flavum hypertrophy

目的探讨黄韧带厚度与椎管斜径的比值对黄韧带肥厚致椎管狭窄诊断的优越性。方法对71例腰腿痛患者行 CT 与 MR 检查,以 MR 双旁正中矢状面图像上硬膜囊后方是否出现黄韧带压迹为依据分为阳性组和阴性组,同时对50例无腰腿痛志愿者行腰椎 CT 检查;再以 CT 轴面分别选取 L3～4、L4～5、L5～S1椎间盘下缘层面,测量其黄韧带厚度与椎管斜径比值(简称厚度斜径比值),分析其与 MRI 阳性符合率及临床症状体征的关系。结果阴性组(35例)共210条黄韧带,厚度为(3.01±0.72)mm,厚度斜径比值为0.19±0.04;阳性组(36例)共119条黄韧带,厚度为(3.94±0.84)mm,厚度斜径比值为0.28±0.06;对照组黄韧带厚度为(3.16±0.85)mm,厚度斜径比值为0.19±0.04,阳性组黄韧带厚度与阴性组或对照组间差异有统计学意义(P<0.05),阳性组厚度斜径比值与阴性组或对照组间差异有统计学意义(P<0.05);以厚度斜径比值>0.24为标准,其敏感性、特异性、阳性预测值分别为74.8%、89.6%、73.6%;黄韧带厚度、厚度斜径比值与临床症状均呈正相关性(r 值分别为0.72、0.86,P 值均<0.05);黄韧带厚度、厚度斜径比值两种测量方法对临床症状符合率差异有统计学意义(P<0.05)。结论 CT 测量厚度斜径比值较单纯测量黄韧带厚度对判断黄韧带肥厚致椎管狭窄更有诊断意义。

Objective To evaluate the diagnostic advantage of the ratio of ligamentum flavum （LF） thickness to oblique canal diameter （TODR） measured on CT images in patients with lumbar canal stenosis. Methods Seventy-one patients underwent CT and MRI examinations respectively, and they were divided into two groups, the positive group and negative group, according to the presence or absence of dural sac notch caused by the LF on bilateral parasagittal MR images. Meanwhile, 50 volunteers without any symptom in the lumbar region or legs were examined by CT. TODRs were measured at the L3-S1 levels of the inferior margin of the intervertebral disc on transverse CT images, respectively. The results were further analyzed with the positive findings on MR images, clinical symptoms and physical examination, so as to find out the statistical correlation between them. Results LF thickness was （ 3.01 ±0. 72 ）mm and TODR was 0. 19 ± 0. 04 in the negative group, （3.94 ± 0. 84） mm and 0. 28 ± 0. 06 in the positive group, and（3.16 ± 0. 85 ） mm and 0. 19 ± 0. 04 in the control group. There was significant difference between positive group and negative group or control group for LF thickness （ P 〈 0. 05 ）, and TODR （ P 〈 0. 05 ）. With TODR 〉 0. 24, the sensitivity, specificity and positive predictive value were 74. 8%, 89. 6% and 73. 6% respectively. Positive correlation existed between LF thickness or TODR and clinical symptom （ r = 0. 72,0. 86, P 〈 0. 05）. However, TODR is more consistent with the presence of clinical symptoms than LF thickness （ P 〈 0. 05）. Conclusion The measurement of TODR on CT images is more valuable in assessing the canal stenosis and its extent than the measurement of LF thickness.