终板法与椎弓根法对青少年特发性胸椎脊柱侧凸Cobb角测量的比较

目的:对青少年特发性胸椎脊柱侧凸Cobb角测量的终板法和椎弓根法进行对比研究,比较两种方法的可信度、可重复性及两种方法测量结果的差异。方法:选取我院2010年7月～2011年3月门诊就诊的55例特发性胸椎脊柱侧凸患者,由一名高年资医师预先确定测量主弯的上、下端椎后,3名脊柱外科医师分别使用终板法和椎弓根法对站立位X线片进行手工测量评估,记录冠状面侧凸Cobb角数值,同时根据Nash-Moe法评估测量主弯上、下端椎的旋转度。1周后,打乱患者顺序,再由该3名医师重复测量。对测量结果进行可信度和可重复性分析,检验一致性并对两种方法的测量结果根据端椎旋转度和Cobb角大小分组进行分析比较。结果:终板法和椎弓根法测量主胸弯Cobb角的可信度和可重复性均为好～极佳的水平。终板法测量的总体可信度和可重复性分别为0.969和0.900,椎弓根法测量的总体可信度和可重复性分别为0.972和0.880。根据下端椎旋转度将AIS患者分组后的结果显示:下端椎无旋转组(Nash-Moe 0度)中椎弓根法与终板法测量结果无明显差异(P>0.05),而下端椎旋转明显组(Nash-MoeⅠ度和Ⅱ度)中椎弓根法测量结果较终板法小,差异有统计学意义(P<0.05)。根据Cobb角是否大于25°进行分组后的统计分析表明,在两组中椎弓根法测量结果均显著小于终板法(P<0.05)。结论:对于青少年特发性胸椎脊柱侧凸而言,终板法和椎弓根法测量Cobb角的可信度和可重复性均较好,但对于下端椎旋转明显(Nash-MoeⅠ度以上)的患者,椎弓根法较终板法测量结果小,建议对此类患者采用终板法测量Cobb角。

Comparison of Cobb angle between endplate and pedicle measurement for thoracic adolescent idiopathic scoliosis

Objectives: To determine and compare the interobserver reproducibility and intraobserver reliability between the pedicle method and the conventional endplate method for measuring the Cobb angle in thoracic adolescent idiopathic scoliosis(AIS).Methods: Fifty-five patients with thoracic adolescent idiopathic scoliosis treated in our clinic from July 2010 to March 2011 were reviewed retrospectively.Standing anteroposterior X-ray film was taken in all patients.The end vertebrae of the major thoracic curve were predetermined by a senior doctor,then three spine surgeons independently examined the radiograms using either endplate method or pedicle method respectively.The results of the Cobb angle were recorded and the rotations of the end vertebrae of the major curve were also evaluated according to the Nash-Moe method.The procedure was repeated one week later.Both intraobserver and interobserver agreements were accessed by calculating the intraclass correlation coefficient(ICCC).The results of the two methods were also compared based on the rotations of the end vertebrae and the curve severity.Results: All ICCC values laid in the excellent or good group for the two methods.For the endplate method,the single ICCC value which indicated intraobserver variability was 0.969 and the average ICCC value representing interobserver variability was 0.900;while for the pedicle method,the single and average ICCC value was 0.972 and 0.880 respectively.While considering the rotation for lower end vertebra using Nash-Moe method,no significant difference was noted for those without rotation(Nash-Moe grade 0)(P>0.05),however,the value measured by pedicle method was significantly smaller than that by endplate method for the rotation of lower end vertebra was prominent(Nash-Moe grade Ⅰ and Ⅱ)(P<0.05).The results measured by pedicle method were significantly smaller than those of the endplate method regardless whether the Cobb angle was more than 25°(P<0.05).Conclusions: Both methods can be used in the practical measurement of thoracic AIS.However,the result by pedicle method is sigificantly smaller than that by the endplate method in patients with prominent rotation of the lower end vertebrae(Nash-Moe grade Ⅰ and Ⅱ),so the endplate method is indicated for measuring the Cobb angle in these patients.