Cho Bo Young, Murovic Judith A, Park Jon
National Health Insurance Medical Center, Goyang, South Korea.
J Neurosurg Spine. 2009 Nov;11(5):614-9. doi: 10.3171/2009.6.SPINE08413.
The aim of this study was to correlate the degree of L4-5 spondylolisthesis on plain flexion-extension radiographs with the corresponding amount of L4-5 facet fluid visible on MR images.
Patients underwent evaluation at the Neurosurgical Spine Clinics of Stanford University Medical Center and National Health Insurance Medical Center (Goyang, South Korea) between January 2006 and December 2007. Only patients who were diagnosed with L4-5 degenerative spondylolisthesis (DS) and who had both lumbosacral flexion-extension radiographs and MR images available for review were eligible for this study. Each patient's dynamic motion index (DMI) was measured using the lateral lumbosacral plain radiograph and was the percentage of the degree of anterior slippage seen on flexion versus that seen on extension. Axial T2-weighted MR images of the L4-5 facet joints obtained in each patient was analyzed for the amount of facet fluid, using the image showing the widest portion of the facets. The facet fluid index was calculated from the ratio of the sum of the amounts of facet fluid found in the right plus left facets over the sum of the average widths of the right plus left facet joints.
Fifty-four patients with L4-5 DS were included in this study. Of these 54 patients, facet fluid was noted on MR images in 29 patients (53.7%), and their mean DMI was 6.349 +/- 2.726. Patients who did not have facet fluid on MR imaging had a mean DMI of 1.542 +/- 0.820; this difference was statistically significant (p < 0.001). There was a positive linear association between the facet fluid index and the DMI in the group of patients who exhibited facet fluid on MR images (Pearson correlation coefficient 0.560, p < 0.01). In the subgroup of 29 patients with L4-5 DS who showed facet fluid on MR images, flexion-extension plain radiographs in 10 (34.5%) showed marked anterolisthesis, while the corresponding MR images did not.
There is a linear correlation between the degree of segmental motion seen on flexion-extension plain radiography in patients with DS at L4-5 and the amount of L4-5 facet fluid on MR images. If L4-5 facet fluid in patients with DS is seen on MR images, a corresponding anterolisthesis on weight-bearing flexion-extension lateral radiographs should be anticipated. Obtaining plain radiographs will aid in the diagnosis of anterolisthesis caused by an L4-5 hypermobile segment, which may not always be evident on MR images obtained in supine patients.
本研究旨在将腰椎前屈-后伸位X线片上L4-5椎体滑脱的程度与磁共振成像（MRI）上可见的相应L4-5小关节积液量进行关联。
2006年1月至2007年12月期间，患者在斯坦福大学医学中心神经外科脊柱诊所和韩国高阳市国民健康保险医疗中心接受评估。只有被诊断为L4-5退变性椎体滑脱（DS）且同时有腰骶部前屈-后伸位X线片和MRI图像可供分析的患者才符合本研究条件。使用腰骶部侧位X线片测量每位患者的动态运动指数（DMI），即前屈位时椎体前移程度与后伸位时椎体前移程度的百分比。分析每位患者L4-5小关节的轴向T2加权MRI图像上的关节积液量，选取显示小关节最宽部分的图像。关节积液指数通过右侧和左侧小关节积液量总和与右侧和左侧小关节平均宽度总和的比值计算得出。
本研究纳入了54例L4-5 DS患者。在这54例患者中，29例（53.7%）的MRI图像上可见小关节积液，其平均DMI为6.349±2.726。MRI图像上无小关节积液的患者平均DMI为1.542±0.820；差异具有统计学意义（p<0.001）。在MRI图像上有小关节积液的患者组中，关节积液指数与DMI呈正线性相关（Pearson相关系数为0.560，p<0.01）。在29例MRI图像上显示L4-5小关节积液的L4-5 DS患者亚组中，10例（34.5%）的前屈-后伸位X线片显示明显椎体前移，而相应的MRI图像上未显示。
L4-5 DS患者腰椎前屈-后伸位X线片上的节段运动程度与MRI图像上L4-5小关节积液量之间存在线性相关性。如果DS患者的L4-5小关节积液在MRI图像上可见，则应预期在负重前屈-后伸位侧位X线片上会出现相应的椎体前移。拍摄X线片有助于诊断由L4-5活动度过高节段引起的椎体前移，这在仰卧位患者的MRI图像上可能并不总是明显的。
