寰椎椎弓根螺钉骨性通道的形态学研究

A morphologic study of the bone channel of the atlas pedicle for screw placement

[目的]本研究利用三维影像学技术对寰椎椎弓根螺钉骨性通道进行解剖学测量,根据测量结果,归纳骨性通道的形态学特点并总结出一些置钉方面的建议。[方法]从本院PACS系统中选取60例同时行头部CTA及颈椎MRI检查的患者影像学资料,测量脊髓和椎弓根内壁的距离,椎动脉和椎弓根外壁的距离,椎弓根内侧皮质骨厚度,椎弓根外侧皮质骨厚度及椎弓根宽度,应用SPSS 12.0软件对上述测量结果进行统计学分析。[结果]测量的解剖学数据双侧差异均无统计学意义,脊髓和椎弓根内壁的距离男性(10.45±2.35)mm,女性(9.98±2.30)mm;椎动脉和椎弓根外壁的距离男性(1.03±0.41)mm,女性(1.34±0.52)mm,椎弓根内侧皮质骨厚度男性(3.03±0.41)mm,女性(3.18±0.72)mm;椎弓根外侧皮质骨厚度男性(1.43+0.31)mm,女性(1.63±0.48)mm,椎弓根宽度男性(8.25±1.58)mm,女性(7.94±1.42)mm。脊髓和椎弓根内壁的距离大于椎动脉和椎弓根外壁的距离,椎弓根内侧皮质骨厚度大于椎弓根外侧皮质骨厚度。[结论]椎弓根内侧皮质骨厚度较大导致寰椎椎弓根钉置钉过程中实际骨性通道较理想骨性通道偏外是徒手置入寰椎椎弓螺钉有较高误置率的主要原因,所以术中尽量磨掉内侧皮质骨是保证置钉过程中保持理想骨性通道的有效途径。同时脊髓和椎弓根内壁之间有较大的缓冲空间,即使内侧皮质骨不慎磨漏仍有较大的安全性。

[Objective]To investigate the morphological characteristics of the bone channel of the atlas pedicle with three-dimensional imaging,and to provide recommendations for screw placement. [Method]Sixty patients with a lesion- free atlas,who had undergone computed tomography angiography（ CTA） and magnetic resonance imaging（ MRI） screening,were randomly selected from the Shengjing Hospital PACS system. We measured the relative anatomical information including the distance between the spinal cord and inner wall of the atlas pedicle,distance between the vertebral artery and outer wall of the atlas pedicle,thickness of the medial cortical bone of the atlas pedicle,thickness of the lateral cortical bone of the atlas pedicle,and thickness of the atlas pedicle. The above measurements were statistically analyzed with SPSS 12. 0 software. [Result]The differences in the anatomical measurements between the two sides were not statistically significant. The distance between the spinal cord and inner wall of the atlas pedicle was 10. 45 ± 2. 35 mm and 9. 98 ± 2. 30 mm,the distance between the vertebral artery and outer wall of the atlas pedicle was 1. 03 ± 0. 41 mm and 1. 34 ± 0. 52 mm,and the thickness of the medial cortical bone of the atlas pedicle was 3. 03 ± 0. 41 mm and 3. 18 ± 0. 72 mm,in men and women,respectively. The thickness of the lateral cortical bone of the atlas pedicle was 1. 43 ± 0. 31 mm and 1. 63 ± 0. 48 mm and the thickness of the atlas pedicle was 8. 25 ± 1. 58 mm and 7.94 ± 1. 42 mm,in men and women,respectively. The distance between the spinal cord and inner wall of the atlas pedicle was larger than that between the vertebral artery and outer wall of the atlas pedicle,and the thickness of the medial cortical bone of the atlas pedicle was greater than that of the lateral cortical bone of the atlas pedicle. [Conclusion]The thickness of the medial cortical bone of the atlas pedicle is greater than the optimal thickness. This is the morphological basis for more damage to the vertebral artery during pedicle screw placement. Therefore,attempting to grind the medial cortical bone interoperatively is an effectiveway of preventing damage to the vertebral artery. Meanwhile,there is a larger buffer space between the spinal cord and inner wall of the atlas pedicle,the more media screw channel is still security enough.