Objective:To compare three techniques of the transarticular screw placement in the lower cervical spine. Methods:The techniques of transarticular screw placements used by Takayasu (group A),Dalcanto (group B) and Klekamp (group C) were applied in twenty-four cervical specimens,among which 14 specimens were male and 10 specimens were female, ranging in age from 55 to 80 years,with an average of 68 years. The entry point of Takayasu technique was between the superior and median third of the vertical medial line of the lateral mass with 60 to 80 degrees caudal tilt and 0 degrees lateral tilt. Dalcanto technique started 2 mm caudal to the midpoint of lateral mass with 40 degrees caudal tilt and 20 degrees lateral tilt. Klekamp technique inserted the screws with the starting point being lmm medial and lmm inferior to the midpoint of the lateral mass with 40 degrees caudal tilt and 20 degrees lateral tilt. The splits of facets, the encroachment of the cervical nerve roots and vertebral arteries,and no-involving facets screws were observed and analyzed. Results:One hundred and ninety-two transarticular screws were implanted on both sides in twenty-four cervical cadavers, sixty-four for each group. There were twenty-five splits of inferior facets in group B, 2 splits in group C and none in group A. No superior facets were found to be broken in all cases. The difference of splits between group B and the other two groups was significant (x 2ab =31.07, P<0.01; X 2bc=24.83 , P<0.01) .while there was no statistical difference between group A and C(X2AC=2.03,P>0.05). Thirty-six screws encroached the vertebral arteries in group A,none in group B and C. There was significant statistical difference between group A and the other two groups (x2ab=50.09 ,P<0.01; X 2ac=50.09 ,P<0.01). Forty anterior branches of lower cervical nerve roots were involved in group A, five in group B and three in group C. There were statistical differences between group A and the other two groups (X2ab= 41.98,P<0.01 ;X 2Ac=47.94,P<0.01) ,and there was no statistical difference between group B and C. Sixteen posterior branchesof lower cervical nerve roots were encroached in group A, 18 in group B a ns 14 in group C. There was statistical difference a-mong the three groups (x2 AR=0.16 ,P>0.05; X2ac=0.17,P>0.05; x2 BC=0.67,P>0.05). Although all screws went thniugh fauels in the study except for 5 in group A,there were no statistical differences between each groups (X2ar=3.33,P>0.05; X-2AC;=3.33,P> 0.05). Conclusion;There are high risk of injury of anterior branch of cervical nerve root and vertebral artery if the screws are loo long and the Takayasu's technique is used. However,the rate of facet split is high if the Dalcanto's technique is applied. Klekamp's technique is value to be applied.%目的:比较3种下颈椎经关节螺钉植入方法的优缺点,为选择下颈椎经关节螺钉的植入方法提供可靠的基础资料.方法:选用新鲜颈椎标本(C1-T1)24具(男14具,女10具),年龄55～80岁,平均68岁.采用抽签随机对照研究方法,在每一颈椎标本两侧用不同的植入方法植入下颈椎经关节螺钉.根据进钉点及进钉方向的不同,采用Takayasu法(A组)、Dalcanto法(B组)、Klekamp法(C组)作为下颈椎经关节螺钉的植入方法.Takayasu法选用侧块中线上中1/3交界处作为进钉点,螺钉向前侧、尾侧倾斜,与侧块冠状面呈60°～80°,平行于矢状面作为进钉方向；Dalcanto法采用进钉点在侧块中点下方2 mm,方向向尾侧倾斜40°,向外侧倾斜20°；Klekamp则将侧块中点内下方1 mm为进钉点,方向向尾侧倾斜40°,向外侧倾斜20°.对A、B、C组分别统计植入时关节突关节劈裂、植入后椎动脉侵犯、神经根前后支损伤和螺钉通过关节突关节的情况.结果:24具颈椎标本共48侧,植入下颈椎经关节突螺钉192枚,其中A、B、C组各64枚.A组未见下关节突劈裂；B组见下关节突下缘劈裂17例,外缘劈裂8例；C组下关节突下缘劈裂1例,外缘劈裂1例.3组均未见上关节突劈裂.3组螺钉植入时关节突关节劈裂情况比较,B组下关节突劈裂最多,与其他2组差异有统计学意义(x2AB=31.07,P＜0.01；x2BC=24.83,P＜0.01).C组2例下关节突劈裂,与A组比较差异无统计学意义(x2AC=2.03,P＞0.05).A组36枚螺钉侵犯椎动脉,B、C组均未见椎动脉侵犯.3组螺钉植入后椎动脉受累情况,A组高于其他2组(x2AB=50.09,P＜0.01;x2AC=50.09,P＜0.01).神经根前支损伤A组40例,B组5例,C组3例；神经根后支损伤A组16例,B组18例；C组14例.3组间颈神经根前支受累比较,A组高于其他2组(x2AB=41.98,P＜0.01;x2AC=47.94,P＜0.01),而B、C组差异无统计学意义.颈神经根后支受累比较,3组间差异无统计学意义(x2AB=0.16,P＞0.05;x2AC=0.17,P＞0.05；x2BC=0.67,P＞0.05).A组5例未经过关节突关节,B、C2组均经过关节突关节,3组间差异无统计学意义(x2AB=3.33,P＞.05；x2AC=3.33,P＞0.05).结论:Takayasu法在螺钉植入过长时易引起神经根和椎动脉损伤,而Dalcanto法在植入螺钉时易引起下关节突的劈裂.相比较而言,Klekamp法临床上更值得推崇.
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