前路经寰枢关节螺钉内固定术治疗寰枢椎不稳定的生物力学及临床研究

Biomechanical and clinical study of anterior transarticular screw fixation for treatment of traumatic instability of C1-C2 joint

目的探讨前路经寰枢关节螺钉内固定术的生物力学稳定性及疗效。方法8具新鲜颈椎标本，对每一标本先后行正常状态、齿状突Ⅱ型骨折、前路经寰枢关节螺钉内固定术、后路Magerl螺钉内固定术4种状态三维运动范围的测定。并对20例创伤性寰枢椎不稳定患者施行前路经寰枢关节螺钉内固定术，在齿状突与寰椎前结节后方置入颗粒状松质骨。结果前路经寰枢关节螺钉内固定术与后路Magerl螺钉内固定术均明显减少寰枢关节各方向运动范围，经统计学检验差异无统计学意义。20例患者中，1例颈脊髓完全损伤患者，术后1个月死于肺部感染。其余19例病例获得随访，时间7个月～3年，平均18个月，无椎动脉及脊髓损伤，所有病例获得骨性融合。结论前路经寰枢关节螺钉内固定术，操作简便，固定可靠，损伤脊髓或椎动脉的风险较小。

Objective To evaluate the biomechanical stability of C1-C2 after anterior C1-C2 transarticular screw fixation and assess its curative effect clinically. Methods Eight human cadaveric occipitocervical spine specimens which have been harvested freshly were tested in three modes of loading, flexion-extension, lateral bending, and axial rotation, and four configurations including intact, after an odontoid fracture, and after anterior or posterior C1 -C2 transarticular screw fixation. All tests were performed in load and torque control. Clinically, 20 patients who had C1 -C2 traumatic instability were instructed to be operated with anterior C1 -C2 transarticular screw fixation technique, planting cancellated granulate bone into the space between muscular tubercle of atlas and odontoid bone. Results Both the anterior and posterior C1 -C2 transarticular screw fixation techniques limited motion at the C1 -C2 articulation at the tested directions and there were no significant differences between the two techniques. In the 20 patients, one with complete cervical cord injury died of pulmonary infection a month later, and the rest 19 were followed up about 7 months to 3 years （mean 18 months）. They all had no trauma on vertebral artery and cervical cord during their cervical operations, and had atlantoaxial synostoses. Condnsion The anterior C1 -C2 transarticular screw fixation not only is easy to manipulate and provides the same stability as posterior C1 -C2 transarticular screw fixation, but has a less risk of injury on vertebral artery and cervical cord.