椎弓根钉道参数CT三维测量方法的准确性分析

目的：评价椎弓根钉道参数CT三维测量方法在不同旋转程度椎体中应用的准确性。方法：1个椎体标本,在10个不同三维旋转角度下（10°-90°）分别进行CT扫描,由3人采用双盲法分别对上述10组数据进行CT三维重组及重复测量4次。依次找出椎体的冠、轴、矢状面,椎弓根钉道的矢状面、轴状面并进行校正。在椎体的冠、轴、矢状面上分别测得椎体在冠状面、轴状面、矢状面上的旋转角度（c、a、s）,在椎弓根钉道的矢状面、轴状面上分别测得椎弓根钉道在椎体自身矢状面（ss）、轴状面上的倾斜角度（aa）及椎弓根钉道的长度（Len）、宽度（Wid）等。对测量参数结果用SPSS 12.0进行统计学分析。结果：本研究10组中,测量者组内或组间的参数c、a、s来自于同一总体（P〉0.05）,测量者组内或组间的参数aa、Len、Wid来自于同一总体（P〉0.05）,10组间的参数aa、Len、Wid来自于同一总体（P〉0.05）（对于参数Len、Wid,需除外其协变量因素的影响）。结论：椎弓根钉道参数CT三维测量方法可准确测得椎弓根钉道的参数值。

Evaluation of accuracy of CT measuring method of vertebral pedicle screw parameters

Objective：To evaluate the accuracy of CT 3D measurements of the vertebral pedicle screw parameters under different vertebral rotational angles.Methods：A thoracic vertebral specimen was scanned 10 times with spiral CT under different rotational angles from 10° to 90°,and the data were reformatted and measured four times by three observers separately with double blind method.The following parameters of each scan with multi-planar reformation（MPR） technique were obtained：the angles（c,s,a）of vertebral rotation on the coronal,sagittal and axial planes of the vertebra body,the angles（ss、aa） of pedicle screw＇s rotation and the pedicle screw＇s length（Len） and width（Wid）on the sagittal and axial planes of the vertebra itself.The measuring results of the parameters were analyzed with SPSS 12.0（One-Way ANOVA,General linear model-repeated measures）.Results：The measuring data of c,s,a from intraobservers or interobservers of each of the 10 groups were not significantly different（P〉0.05）.The measuring data of aa,Len and Wid from intraobservers or interobservers of the 10 groups were not significantly different（P〉0.05）.The measuring data of aa、Len、Wid from intergroups of the 10 groups were not significantly different（P〉0.05）（the covariate variables had been considered into the statistical analysis of the data of Len and Wid）.Conclusion：The parameters of the vertebral pedicle screw can be measured accurately with CT 3D method.