Abstract：
OBJECTIVE: The objective of this study was to investigate the optimal entry point and pedicle camber angle for L5 pedicle screws of different canal types.
METHODS: CT imaging data were processed by Mimics for simulated pedicle screw placement, and PD (Pedicle diameter), PCA (Pedicle camber angle), LD (Longitudinal distance), TD (Transverse distance), and PBG (Pedicle screw breach grade) were measured. Then they were divided into the Round group and Trefoil group according to the type of spinal canal. When comparing PD, PCA, LD, TD, and PBG, the two sides of the pedicle were compared separately, so they were first divided into the round-type pedicle group and the trefoil-type pedicle group.
RESULTS: In the round-type pedicle group (n = 134) and the trefoil-type pedicle group (n = 264), there was no significant difference in PD and LD, but there was a significant difference in PCA between the two groups (t = - 4.072, P < 0.05). A statistically significant difference in the distance of the Magerl point relative to the optimal entry point (t = - 3.792, P < 0.05), and the distance of the Magerl point relative to the optimal entry point was greater in the trefoil-type pedicle group than in the round-type pedicle group.
CONCLUSIONS: The optimal entry point for L5 is more outward than the Magerl point, and the Trefoil spinal canal L5 is more outwardly oriented than the Round spinal canal L5, with a greater angle of abduction during pedicle screw placement.
METHODS: CT imaging data were processed by Mimics for simulated pedicle screw placement, and PD (Pedicle diameter), PCA (Pedicle camber angle), LD (Longitudinal distance), TD (Transverse distance), and PBG (Pedicle screw breach grade) were measured. Then they were divided into the Round group and Trefoil group according to the type of spinal canal. When comparing PD, PCA, LD, TD, and PBG, the two sides of the pedicle were compared separately, so they were first divided into the round-type pedicle group and the trefoil-type pedicle group.
RESULTS: In the round-type pedicle group (n = 134) and the trefoil-type pedicle group (n = 264), there was no significant difference in PD and LD, but there was a significant difference in PCA between the two groups (t = - 4.072, P < 0.05). A statistically significant difference in the distance of the Magerl point relative to the optimal entry point (t = - 3.792, P < 0.05), and the distance of the Magerl point relative to the optimal entry point was greater in the trefoil-type pedicle group than in the round-type pedicle group.
CONCLUSIONS: The optimal entry point for L5 is more outward than the Magerl point, and the Trefoil spinal canal L5 is more outwardly oriented than the Round spinal canal L5, with a greater angle of abduction during pedicle screw placement.
摘要：
目的：本研究的目的是研究不同类型的L5椎弓根螺钉的最佳进入点和椎弓根外倾角。
方法：通过模拟椎弓根螺钉放置对CT成像数据进行处理，和PD（椎弓根直径），PCA（椎弓根外倾角），LD（纵向距离），TD（横向距离），并测量椎弓根螺钉破口等级(PBG)。然后根据椎管类型将其分为Round组和三叶组。比较PD时,PCA,LD,TD,PBG,分别比较椎弓根两侧，因此，它们首先被分为圆型椎弓根组和三叶型椎弓根组。
结果：在圆型椎弓根组（n=134）和三叶型椎弓根组（n=264）中，PD和LD没有显着差异，但两组间PCA差异有统计学意义(t=-4.072,P<0.05)。Magerl点相对于最佳切入点的距离有统计学意义的差异（t=-3.792，P<0.05），三叶型椎弓根组的Magerl点相对于最佳进入点的距离大于圆形椎弓根组。
结论：L5的最佳切入点比Magerl点更向外，并且三叶椎管L5比圆形椎管L5更向外定向,在椎弓根螺钉放置期间具有更大的外展角度。
方法：通过模拟椎弓根螺钉放置对CT成像数据进行处理，和PD（椎弓根直径），PCA（椎弓根外倾角），LD（纵向距离），TD（横向距离），并测量椎弓根螺钉破口等级(PBG)。然后根据椎管类型将其分为Round组和三叶组。比较PD时,PCA,LD,TD,PBG,分别比较椎弓根两侧，因此，它们首先被分为圆型椎弓根组和三叶型椎弓根组。
结果：在圆型椎弓根组（n=134）和三叶型椎弓根组（n=264）中，PD和LD没有显着差异，但两组间PCA差异有统计学意义(t=-4.072,P<0.05)。Magerl点相对于最佳切入点的距离有统计学意义的差异（t=-3.792，P<0.05），三叶型椎弓根组的Magerl点相对于最佳进入点的距离大于圆形椎弓根组。
结论：L5的最佳切入点比Magerl点更向外，并且三叶椎管L5比圆形椎管L5更向外定向,在椎弓根螺钉放置期间具有更大的外展角度。
