胸椎后路经关节螺钉固定的可行性研究

目的:明确胸椎后路经关节螺钉固定的解剖学可行性和技术参数,为临床应用提供参考。方法:2009年9月至2009年12月,取20具胸椎标本,男12具,女8具,仔细解剖颈部的后侧和前侧方,以清楚地暴露胸椎椎板和椎弓根。以椎板下缘向上,外缘向内各7mm为进钉点,在T1,2,T5,6,T9,10直视下置入经关节螺钉,通过CT重建,测量经关节螺钉内固定进钉角度和钉道长度。结果:胸椎后路经关节螺钉均成功置入,螺钉固定方向在矢状面呈尾倾,冠状面呈外倾。经关节螺钉固定的平均角度在矢状面尾倾(52.6±5.9)°,在冠状面外倾(12.4±2.9)°。螺钉钉道长度(22.5±1.9)mm,各固定节段间角度略有不同,差异无统计学意义(P>0.5),但上、中、下不同胸椎节段之间的钉道长度差异有统计学意义(P<0.01)。结论:胸椎后路经关节螺钉具有解剖学可行性,可以作为胸椎椎弓根螺钉固定的一种补充内固定方法,但置钉时要求较高的准确性。

Study on the feasibility of posterior thoracic transarticular screw fixation

Objective: To study the feasibility and technical parameters of posterior transarticular screw fixation in the thoracic spine. Methods: Since September 2009 to December 2009,20 thoracic cadaveric spines(12 males and 8 females) were dissected. The lateral masses and pedicles were exposed carefully. After the entrance point of transarticular screws was determined,posterior transarticular screws implantation was performed under direct visualization into T_1,2,T_5,6 and T_9,10. Then CT scan was performed. On the CT scan,the angle and length of the transarticular screw trajectory were measured. Results: The thoracic transarticular screw trajectory were caudal tilting in the sagittal plane and lateral tilting in the coronal plane with successful placement. There was little differences between different segmental of thoracic vertebrae of the angle,but without significance(P>0.5). The average angles of the screws were (52.6±5.9)° caudal tilting in the sagittal plane and (12.4±2.9)°lateral tilting in the coronal plane. The average trajectory lengths were (22.5±1.9) mm. There was significant differences statistically among T_1,2,T_5,6 and T_9,10(P<0.01). Conclusion: Posterior transarticular screw fixation is feasible. Transarticular screw fixation in the thoracic spine affords an alternative to standard pedicle screw placement for thoracic stabilization.