滑脱腰椎椎体间接触面积变化规律在临床应用中的价值

背景：腰椎滑脱直接导致滑脱椎体与下位椎体间接触面积的减少,滑脱椎体间接触面积是决定椎间应力和腰椎退变的重要因素。腰椎椎体截面是不规则的肾形,没有成熟的数学公式可以直接计算出椎体间接触面积的变化规律。目的：观察腰椎滑脱时椎体间接触面积的变化规律,并分析其临床意义。方法：采集 25 套 L4椎体下表面和 L5椎体上表面的图像,在二维平面上均分为 14 步模拟腰椎滑脱过程,Image-ProPlus 软件计算每一滑脱点（n）椎体间重叠面积 Sn,取平均值后再换算成百分面积,Sn%=Sn/S×100%,观察 0～100%滑移时椎体间接触面积的变化规律。根据此规律提出新的腰椎滑脱临床分期,并应用其指导治疗 56 例腰椎滑脱患者。结果与结论：腰椎滑脱过程中,Sn%的变化是一个双曲线：滑脱率 0～23%阶段,Sn%降低较缓慢;23%～44%阶段,Sn%的变化明显加快;44%～100%阶段,Sn%的变化再次变缓,拐点分别出现在一维滑脱率的（23±2）%和（44±2）%处。48例腰椎滑脱患者获得随访,临床疗效按 Staufee 标准优良率达 90%左右。提示腰椎滑脱时椎体间接触面积的变化是非线性的,有助于腰椎稳定性评估并指导腰椎滑脱的临床治疗。

Change regularity of intervertebral contact areas during lumbar spondylolisthesis and its value in clinical application

BACKGROUND：Lumbar spondylolisthesis directly reduces contact areas between dislocated vertebral body and subjacent vertebral body,which is an important factor that decides intervertebral stress and lumbar degeneration.The cross section of lumbar is irregular reniform shaped and there is no mathematical formula to calculate changing regularity of intervertebral contact areas of lumbar spondylolisthesis directly.OBJECTIVE：To study changing regularity of intervertebral contact areas during lumbar spondylolisthesis and to analyze its clinical significance.METHODS：Super-surface of L5 vertebra and sub-surface of L4 from 25 cases were taken by a digital camera and computer simulation spondylolisthesis process and every intervertebral contact areas （Sn） were measured by Image-Pro Plus software.The mean value was obtained and converted into percentage area according to Sn%=Sn/S×100%.The change rules of vertebral bodies were observed from 0 to 100% spondylolisthesis.Based on this regularity,a new clinical stage of lumbar spondylolisthesis was proposed and guided for treatment of 56 cases with lumbar spondylolisthesis.RESULTS AND CONCLUSION：During lumbar spondylolisthesis process,Sn% changes like a hyperbola.Sn% lost slowly during spondylolisthesis rate at 0-23% and quickly during 23%-44%,and then it become slowly once again after spondylolisthesis rate at 44%-100%,the inflection points appeared at （23±2）% and （44±2）%.Totally 48 patients were followed up,according to Staufee standard rate,the clinical curative effect reached approximately 90%.It suggests that the intervertebral contact areas present with a non-linear change,which is helpful to judge the stability of lumbar spine and guide the treatment of lumbar spondylolisthesis.