后路寰椎侧块螺钉结合枢椎椎弓根螺钉固定治疗上颈椎不稳

目的：总结应用寰椎侧块螺钉与枢椎椎弓根螺钉技术固定融合治疗寰枢椎不稳的效果，探讨寰枢椎不稳的治疗方法。方法：采用寰椎侧块螺钉与枢椎椎弓根螺钉技术对15例寰枢椎不稳的患者进行了固定术，同时行自体髂骨融合。分别应用Vertex 7例，Axis 3例，和cervifix 5例，齿状突陈旧性骨折5例，新鲜Ⅱc型齿状突骨折6例，先天性游离齿状突4例。寰椎侧块螺钉进钉点选择在寰椎后结节中点旁开18mm～20mm，与后弓下缘以上2mm的交点，钉道方向在冠状面垂直，矢状面上螺钉头端向头侧倾斜约5°.枢椎进钉点为枢椎下关节突根部中点，钉道与矢状面夹角约15°，横断面夹角约30°。螺钉直径3．5mm，寰椎侧块螺钉长度28mm～32mm，枢椎椎弓根螺钉长度为22mm～26mm。结果：所有患者均未发生脊髓损伤和椎动脉损伤。随访10～25个月，平均14个月。术前JOA评分5．1～10．9分，平均7．6分。术后JOA评分13．2～16．8分，平均14．8分，改善率87．5％。植骨块全部融合，无内固定断裂、松动。结论：后路寰椎侧块螺钉与枢椎椎弓根螺钉技术稳定性良好，具有三维固定的优点，值得推广。

Lateral Mass Screw of Atlas Combined with Vertebra Dentata Pedicle Screw for the Treatment of Upper Cervical Vertebra Instability

Objective： To observe the effects of fixation and fusion with lateral mass screw of atlas and vertebra dentata pedicle screw for the treatment of atlantoaxial instability and discuss the therapy methods. Methods： 15 cases were treated with fixation and fusion with lateral mass screw of atlas and vertebra dentata pedicle screw, and iliac bone graft. Vertex, Axis and Cervifix instruments were used for 7, 3 and 5 cases. There were 5 cases of odontoid process old fracture and 6 cases of odontoid process type Ⅱ c fresh fracture and 4 cases of congenital odontoid process freeing. All patients had atlantoaxial subluxation or instability. The screws were placed in lateral mass of atlas beside the posterior arch of atlas about 18-20mm and the point of intersection above 2mm inferior boarder of posterior arch, vertical with coronal plane, the tip of the screw made 5°to side of head in sagittal plane. Midpoint of the root of inferior articular process of axis was the site of screws placed in vertebra dentate, made 15°with sagittal plane and 30°with cross section. The diameter of screws was 3.5mm, the length of in Lateral mass of atlas was from 28 to 32mm, and from 22 to 26mm in vertebra dentate pedicle screw. Results： Followed-up for 10-25 months （average 14 months）. The preoperative JOA scores were 5.1-10.9 （average 7.6）, and the postoperative JOA scores were 13.2-16.8 （average 14.8）. The improve rate was 87.5% according to Hirabayashi. Symptoms all disappeared and the plant bone all fused. There were no internal fixation rupture and loose. Conclusion： Lateral mass screw of atlas and vertebra dentata pedicle screw with well technic stability and three-dimension fixed virtues are well worth being applied.