枢椎椎弓根-关节突复合体的解剖认识及其临床意义

目的：研究枢椎椎弓根-关节突复合体的解剖结构特征,探讨该解剖概念的临床意义。方法：观察80具枢椎干骨标本椎弓根-关节突部位的解剖结构特征。并随机抽取其中20具标本,在椎弓骨背侧表面做枢椎经椎弓根螺钉固定及经关节（C1-2）螺钉固定钉道投影画线,另2具标本按两种螺钉内固定方式设置直径3．5mm钉道,并螺旋CT扫描多平面重建（MPR）钉道断面影像,了解两种钉道与椎弓根-关节突结构的解剖关系。回顾性分析25例外伤致枢椎椎弓根-关节突部位骨折的CT资料,包括其中12例枢椎螺钉内固定术后CT,研究该部位骨折特点及钉道所在的断面解剖。结果：枢椎解剖学上,无严格定义下完整的椎弓根。而枢椎椎弓根-关节突作为复合体,具有解剖结构上整体性特征,其周围界线清楚。外伤致枢椎椎弓根-关节突复合体骨折可分为椎弓根一上关节突骨折、关节突间部骨折及单纯上关节突骨折。枢椎经椎弓根螺钉固定及经关节（C1-2）螺钉内固定的钉道均通过椎弓峡部中心,但起点不同,走向不同。结论：枢椎椎弓根关节突复合体作为临床解剖概念,具有解剖结构的完整性。明确该解剖概念及各构件对该区域骨折分类与螺钉内固定手术具有指导意义。

The Anatomic Understanding and Clinical Significance of the Axis Pedicle-articular Process Complex

Objective：To study the anatomic structure and evaluate it＇s clinical value of C2 pedicle-articular process complex. Methods： Eighty dry C2 vertebrae were obtained for observation of the external anatomy of the C2 pedicle-articular process from superior,lateral,and inferior views. Among the 80 specimens, 20 C2 vertebrae were selected randomly, and the projection of the trajectories of transpedicular screw and transarticular screw fixation were painted on the lateral mass of the C2 for each trajectory superior views. Two dry C2 specimens were drilled standerd 3.5 mm diameter screw channels,according to two types of screw fixation methods. And the MPR of CT was used to observe the internal structures of pedicle-articular process and the location of two screw channels. The CT imaging data of 25 patients with axis pedicle-articular process trauma were retrospectively analyzed,including 12 patients underwent screw fixation, studying the fracture feature of axis pedicle-articular process and evaluate postoperative screw positions. Results：Based on observation,the pedicle of C2 vertebrae defined as the portion beneath the superior facet and anteromedial to the transverse foramen has not complete anatomic structure. But axis pedicle-articular process as a complex has the integrated features of anatomy,which has clear boundaries around. Fractures can be divided into the pedicle-facet fracture,pars interarticularis fracture and simple superior facet fractures. The screw trajectories of transpedicular screw and transarticular screw fixation all pass through the central focus of isthmus of C2 vertebrae. But the entry point for the screws and the drilling direction and target point are different. Conclusion： The axis pedicle-articular process as a complex concept of clinical anatomy has the anatomic integrity. Understanding the anatomic concept and its components has the guiding significance to study the fracture classification and treatment.