摘要
目的 :通过应用解剖学及生物力学测试了解寰椎侧块后路螺钉固定的可行性。方法 :对 3 0例中国成年人的寰椎干骨标本具有临床意义的数据进行解剖学测量 ;对 6例新鲜颈椎尸体标本的后入路C2 神经根与寰椎侧块的关系进行观察 ;同时 ,通过测试寰椎侧块螺钉的拔出力 ,并与枕骨螺钉及枢椎椎弓根螺钉的拔出力进行比较。选 6例新鲜上颈椎标本 ,将标本造成侧块骨折模型后予以后路侧块螺钉固定 ,标本分为 :A组 -正常对照组 ,B组 -侧块及同侧前弓骨折组 ,C组 -侧块后路螺钉固定后组。测量 3组的三维运动范围 (Rangeofmotion ,ROM ) ,并比较其相互间的差异。结果 :寰椎中线至侧块中点、椎动脉内侧壁、椎弓根内缘的距离分别为 :(17.6± 1.2 )mm、(2 3 .0± 1.7)mm及 (14 .2± 1.1)mm ;侧块中部的宽度为 (11.6± 1.4)mm ,侧块中心点的厚度为 (12 .7± 1.0 )mm ;后弓与侧块移行处中点至下关节面间距为 (4 .1± 0 .7)mm ;椎动脉沟处后弓厚度为 (4 .7± 1.0 )mm。解剖学观察见C2 神经根出脊髓后沿C1/ 2 关节间隙的下方向外下行走 ,且C2 神经根有较大的移动度。寰椎侧块螺钉的拔出力平均为 (1718.2± 42 2 .7)N ,明显小于枕骨螺钉的拔出力 ,但与枢椎椎弓根螺钉的拔出力无明显差异。侧块骨折后C0～ 1及C1～ 2
Objective:To study the feasibility of posterior screw fixation on the lateral mass of atlas in the aspects of anatomy and biomechanics.Methods:30 atlas specimens of native adults were used to measure the significant clinical data.6 fresh specimens of upper cervical were used to observe the relationship of C 2 nerve and the lateral mass of atlas.The pull out force of screw on the lateral mass of atlas was measured and compared with that of screw on the occiptal and axial pedicle screw respectively.The ROMs (Range of motion)of upper cervical spine were also measured.Results:The distances from the middle line to the midpoint of lateral mass,to the inner wall of transverse foramen and to the inner edge of pedicle were 17.6±1.2mm?23.0±1.7mm and 14.2±1.1mm respectively.The width and height of lateral mass in the middle of atlas were 11.6±1.4mm and 12.7±1.0mm respectively.The distance between the midpoint in the cross line of posterior arch and the lateral mass to the edge of inferior joint was 4.1±0.7mm.The width of posterior arch in the point of vertebra artery overpass was 4.7±1.0mm.The observation on the fresh specimens showed that the C 2 nerve went down lateral beneath the C 1/2 joint and it could moved easily.The pull out force of screw on the lateral mass of atlas was 1718.2±422.7N.It is significantly smaller than that of screw on the occiptal and there was no different with that of axial pedicle screw.The ROMs of C 0～1 and C 1～2 after screw fixation in the lateral mass were improved significantly in all directions than that of pre fixation,and almost have no difference with that of normal control except the ROM of rotation in C 1～2 motive segment( P <0.05).Conclusions:The width and height of the atlas lateral mass are larger than that of the axial pedicle and there is enough space to insert the screw in the atlas lateral mass over the C 2 nerve.The pull out force of screw on the lateral mass of atlas is the same as that of axial pedicle screw.It is quite possible to insert a screw in the atlas lateral mass.The direction of screw should be about 20° anterosuperior in the vertical plane and 15°inward in the horizontal plane.The suitable length of screw should be about the one with 20～23mm inside the lateral mass.
出处
《中国矫形外科杂志》
CAS
CSCD
2002年第9期888-891,共4页
Orthopedic Journal of China
基金
广东省重点攻关课题基金资助 (99B0 670 3G)
