直视枢椎峡部对寰枢椎经关节螺钉固定术中寰椎侧块置钉的可靠性观察

目的 探讨寰枢椎经关节螺钉固定术（Magerl术）中不做正位透视，而向寰椎侧块置钉的可靠性。方法 对75例患者进行Magerl术，男48例、女27例，平均年龄35．1岁，术中通过直视枢椎峡部间接判断寰椎位置的方法获取螺钉在寰椎侧块正位的位置。术后通过观察X线开口位，侧位和CT重建影像，分析150枚螺钉在寰椎内的位置。将寰椎侧块划分出A、B、C3个区域。A区：位于侧块关节面内，螺钉在此区域内固定强度可靠；B区：位于关节面周缘的骨质内（B。内侧，B：外侧），螺钉在此区域内固定强度不可靠，螺钉周围有一侧的骨质太少；C区：位于侧块以外（C1椎管内，C2横突孔内），无固定作用，损伤脊髓或椎动脉。结果 150枚螺钉，139枚螺钉位于A区．占92．7％，8枚位于B1区，3枚位于B2区，占7．3％。无螺钉位于C区。所有患者在术后3个月随访时寰枢椎植骨都已融合。结论 不做正位透视，而向寰椎侧块置钉的方法可以在寰椎内获得满意的螺钉位置。

Reliability of direct probing isthmus of axial vertebrae to defining the screw path in atlas during Magerl technique

OBJECTIVE: To evaluate the accuracy and reliability of atlantoaxial transarticular screw insertion (Magerl's technique) in atlas under lateral fluoroscopic monitoring without anteroposterior view. METHOD: Seventy-five consecutive patients with atlantoaxial instability, 48 males and 27 females, aged 35.1, were treated by Magerl's technique. The screw path in atlas was achieved by direct probing the isthmus of axial vertebrae then identifying its position through the atlantoaxial joint correlation. Postoperative transoral X ray and CT film were used for analysis of the position of the 150 screws in the mass of atlas. Three areas were delimitated in and around the lateral mass of atlas: area A (inside the joint face), area: B (outside the joint face but still in lateral mass), and area C area (outside the lateral mass) so as to analyze the location of screws. RESULTS: Among the 150 screws 139 (92.7%) were located in area A, 8 in area B(1) and 3 in area B(2) (7.3%), and none in area C. All cases got atlantoaxial union 3 months after operation. CONCLUSION: The method of "direct probing" is reliable for identifying the path of screw in atlas.