CAJ | 학술논문

为设计一种胸椎经椎弓根内固定器，同时与Dick钉进行生物力学对比研究，用游标卡尺对10具成人胸1～11椎体干燥标本、20份MRI和CT片的椎弓根高度、宽度、长度、进钉点及椎弓根轴线的角度、椎弓根之间的宽度、椎弓根的毗邻等进行观测，并将10具新鲜成人尸胸2～胸11椎体标本制成屈曲压缩骨折模型和屈曲牵张型损伤模型，用Dick钉和ARRIF-Ⅱ型分别固定在胸7和胸10及胸4和胸6的椎弓根内，进行三维方向上的生物力学测试。结果确定进钉点在上位椎体下关节突下缘的外缘线上3mm处，与矢状线的夹角在15°～20°。胸4以上椎体可容纳直径4.0mm、长度3.0～3.5cm的椎弓根螺钉，胸4以下椎体可容纳直径5.0mm、长度3.5～4.0cm的椎弓根螺钉。ARRIF-Ⅱ型在三维方向上具有较好的应力遮挡，抗扭转力矩较Dick钉大，ARRIF-Ⅱ型椎弓根螺钉均在椎弓根内。说明胸椎经椎弓根螺钉可较安全地置入椎弓根，内固定器能很好地复位骨折椎体，间接减压椎管。
위설계일충흉추경추궁근내고정기，동시여Dick정진행생물역학대비연구，용유표잡척대10구성인흉1～11추체간조표본、20빈MRI화CT편적추궁근고도、관도、장도、진정점급추궁근축선적각도、추궁근지간적관도、추궁근적비린등진행관측，병장10구신선성인시흉2～흉11추체표본제성굴곡압축골절모형화굴곡견장형손상모형，용Dick정화ARRIF-Ⅱ형분별고정재흉7화흉10급흉4화흉6적추궁근내，진행삼유방향상적생물역학측시。결과학정진정점재상위추체하관절돌하연적외연선상3mm처，여시상선적협각재15°～20°。흉4이상추체가용납직경4.0mm、장도3.0～3.5cm적추궁근라정，흉4이하추체가용납직경5.0mm、장도3.5～4.0cm적추궁근라정。ARRIF-Ⅱ형재삼유방향상구유교호적응력차당，항뉴전력구교Dick정대，ARRIF-Ⅱ형추궁근라정균재추궁근내。설명흉추경추궁근라정가교안전지치입추궁근，내고정기능흔호지복위골절추체，간접감압추관。
To design a kind of thoracic transpedicular internal fixator and make comparative study between it and Dicks′. The three dimensional quantitative anatomy of thoracic spine pedicles was determined in 10 adult dry thoracic spine specimens,and 20 MRI and CT pictures using vernier caliber,including the height,the width,the length,the axis angulation of the pedicle,the point of the screw penetration,the width between two pedicles,the adjacent structure,etc.Flexion compression fracture and flexion expansion fracture were produced in 10 fresh adult spine including T2 to T11 vertebrae.Dicks′ plate was used to fix T7 to T10,and ARRIF-Ⅱ for T4 to T6.Biomechanics was then studied in three dimension.The entrance point of the screw was located in the external edge of inferior articular trabecala of the upper vertebrae and 3 mm below lower edge of inferior articular trabecala,and the angle of the screw was 15～20 degrees in sagittal plane.The vertebrae up to T4 can accept pedicular screws of 4.0 mm in diameter and 3.0～3.5 mm in length,and that below T4 can accept screws of 5.0 mm in diameter and 3.5～4.0 mm in length.The ARRIF-Ⅱ type fixators have better stress-shielding in three dimensions.They also have stronger anti-torsion property than the Dicks′.All the screws of ARRIF-Ⅱ type remained in pedicles. The transpedicular screw of thoracic vertebrae can be placed safely into pedicle,and the internal fixators may reduce vertebral fracture and decompress vertebral canal indirectly.