寰椎后弓形态分类与椎弓螺钉固定的解剖学研究

The classification of arch of posterior atlas and anatomic study of the pedicle screw fixation

目的:探讨寰椎后弓的分类与椎弓根螺钉固定的进钉方法。方法:以电子游标卡尺测量48具干燥寰椎标本的相关解剖学数据。结果:进钉处寰椎侧块高度和宽度分别为(12.40±1.12)mm和(12.69±1.62)mm;进钉处寰椎椎弓根的高度和宽度分别为(4.56±1.82)mm和(7.89±1.10)mm;钉道处椎动脉沟底骨质厚度小于螺钉直径3.5mm的占17%(8例),其中4%(2例)厚度小于螺钉半径1.75mm。结论:对于寰椎后弓高度偏小的患者,可以部分经寰椎后弓或跨越寰椎后弓实现寰椎的椎弓根螺钉固定,进钉位置的确定应以术前三维CT重建和术中探查结合考虑。

Objectivo： To study the classification of the arch of posterior atlas and the methods of the pedicle screw fixation. Methods： 48 dry atlas specimens were measured the relative anatomic data with an electronic caliper. Regults： The mean height and width of the atlas mass at the entry point were 12.40±1.12 mm and 12.40±1.12 mm, and that of atlas pedicle were 4.56±1.82 mm and 7.89±1.10 mm respectively. 17% （8 cases） specimens＇ mean height of the pedicle under the groove for vertebral artery at the entry path were less than 3.5 mm （the screw diameter）, and 4%（2 cases） of it were less than 1.75 mm （the screw semidiameter）. Conclusions： To those patients whose arches of posterior atlas are not high enough to be put in the pedicle screw. We can partly drill through or pass the posterior arch to achieve the pedicle screw fixation. The entry point should be ascertained by preoperative 3D CT restitution and the exploration during the operation.