基于数字三维技术确定腰4/5椎弓根螺钉进钉点的精确性

Determining the accuracy of lumbar 4/5 pedicle screw entry point based on digital three-dimensional technology

目的通过三维成像技术建立腰4、腰5椎体数字化模型,探索腰椎后路内固定手术过程中椎弓根螺钉的精准植入位置。方法采集6例腰椎CT平扫图像数据集,用Mimics软件建模后,采用计算机模拟手术植入椎弓根螺钉的方法,比较人字嵴法、Weinstein法、Magerl法确定椎弓根螺钉钉道的可靠性。结果本研究纳入6例腰椎CT平扫数据集(男性4例,女性2例),年龄平均值42.83岁,腰4椎体右侧Magerl进钉点到真实进钉点的距离显著大于左侧,腰4左侧人字嵴进钉点到真实进钉点距离显著大于Weinstein法及Magerl法(P均<0.001),腰4右侧人字嵴进钉点到真实进钉点距离显著大于Weinstein法(P=0.003);腰4左侧、右侧外展角依次为:真实外展角>Magerl外展角>Weinstein外展角>人字嵴外展角。腰5椎体左侧真-Weinstein、真-人字嵴距离显著大于右侧(P=0.002和P=0.004),腰5椎体右侧Weinstein外展角大于左侧(P=0.003)。腰5椎体左侧、右侧人字嵴进钉点到真实进钉点的距离均显著大于Weinstein法及Magerl法(P均<0.001),腰5椎体左侧、右侧Magerl进钉点到真实进钉点的距离均显著大于Weinstein法。腰5椎体左侧及右侧外展角依次为:真实外展角>Magerl外展角>Weinstein外展角>人字嵴外展角。结论腰4和腰5椎体的Weinstein法及Magerl法进钉点接近真实进钉点,腰4和腰5椎体Weinstein外展角、Magerl外展角均与真实外展角差异较小。因此,建议腰4椎弓根螺钉置钉时首选Weinstein法,腰5椎弓根螺钉置钉时,首选Weinstein法或Magerl法。

Objective To establish a digital model of lumbar 4 and lumbar 5 vertebral bodies through threedimensional imaging technology so as to explore the precise placement of pedicle screws during the lumbar posterior internal fixation operation.Methods CT scan image data set of lumbar spine included six specimens.Then lumbar modeling was produced using Mimics software,implanting pedicle screws was simulated with the computer to determine the reliability of pedicle screw for herringbone crest method,Weinstein method,and Magerl method.Results This study included six specimens(4 males and 2 females),with an average age of 42.83 years.The distance from the right Magerl entry point to the actual entry point of the lumbar 4 vertebrae was significantly greater than that of the left side.The distance from the left herringbone crest entry point of lumbar 4 vertebrae to the actual entry point was significantly greater than Weinstein method and Magerl method(P<0.001 and P<0.001),and the distance from the right herringbone crest entry point of lumbar 4 vertebrae to the actual entry point was significantly greater than Weinstein method(P=0.003).Both left and right abduction angles of lumbar 4 vertebrae were true abduction angle>Magerl abduction angle>Weinstein abduction angle>herringbone abduction angle.The distances of true-Weinstein and true-herringbone ridges on the left side of lumbar 5 vertebrae were significantly greater than those on the right side(P=0.002 and P=0.004),and the Weinstein abduction angle on the right side of lumbar 5 vertebrae was greater than that on the left side(P=0.003).For the left and right sides of lumbar 5 vertebrae,the distance from herringbone crest entry point to the actual entry point was significantly greater than that of Weinstein method and Magerl method(P<0.001 and P<0.001),and the distance from the Magerl entry point to the real entry point was significantly greater than that of the Weinstein method.The abduction angle of left and right sides of lumbar 5 vertebrae was as follows:true abduction angle>Magerl abduction angle>Weinstein abduction angle>herringbone abduction angle.Conclusion Both Weinstein entry point and Magerl entry point for lumbar 4 and lumbar 5 vertebra are close to the real entry point.The Weinstein abduction angle and Magerl abduction angle of lumbar 4 and lumbar 5 vertebrae have minor differences compared with real abduction angle.Therefore,it is recommended that Weinstein method is the preferred choice for lumbar 4 pedicle screw placement,while Weinstein method or Magerl method is the preferred choice for lumbar 5 pedicle screw placement.