CAJ | 학술논문

目的：采用三维有限元方法分析颈前路螺钉矢状角( sagittal screw angle，SSA )对相邻节段生物力学的影响，判断 SSA 是否是引起邻近节段病的危险因素。方法基于健康成年男性 C3～7节段 CT 图像建立颈椎有限元模型。模拟颈前路 C5椎体次全切除、C4～6钢板内固定术，按照 SSA (0°，0°)(5°，5°)(10°，10°)分别建模，计算在不同的 SSA 下，C4上终板、C6下终板以及钢板的应力变化情况。结果 C4上终板在前屈时前方区域所受应力最大，随着 SSA 的增加，C4上终板整体所受的最大应力逐渐减小，SSA 增大10°后，C4上终板前方区域的最大应力减小12.67%。C6下终板在前屈时前方区域所受应力最大，随着 SSA 的增加，C6下终板整体所受的最大应力逐渐减小，SSA 增大10°后，C6下终板前方区域的最大应力减小7.99%。钢板在前屈和后伸时其最大应力均较集中于中部区域，并且显著高于上部及下部区域，随着 SSA 的增加，钢板受到的应力会逐渐增加。结论在颈椎前路融合内固定手术中，增大 SSA，可增加钢板承受的应力，同时降低邻近节段终板的应力，从而减少邻近节段病的发生。
목적：채용삼유유한원방법분석경전로라정시상각( sagittal screw angle，SSA )대상린절단생물역학적영향，판단 SSA 시부시인기린근절단병적위험인소。방법기우건강성년남성 C3～7절단 CT 도상건립경추유한원모형。모의경전로 C5추체차전절제、C4～6강판내고정술，안조 SSA (0°，0°)(5°，5°)(10°，10°)분별건모，계산재불동적 SSA 하，C4상종판、C6하종판이급강판적응력변화정황。결과 C4상종판재전굴시전방구역소수응력최대，수착 SSA 적증가，C4상종판정체소수적최대응력축점감소，SSA 증대10°후，C4상종판전방구역적최대응력감소12.67%。C6하종판재전굴시전방구역소수응력최대，수착 SSA 적증가，C6하종판정체소수적최대응력축점감소，SSA 증대10°후，C6하종판전방구역적최대응력감소7.99%。강판재전굴화후신시기최대응력균교집중우중부구역，병차현저고우상부급하부구역，수착 SSA 적증가，강판수도적응력회축점증가。결론재경추전로융합내고정수술중，증대 SSA，가증가강판승수적응력，동시강저린근절단종판적응력，종이감소린근절단병적발생。
Objective To analyze effects of different screw sagittal angles ( SSA ) on the stress of adjacent levels, and determine whether SSA is a risk factor of adjacent segment disease ( ASD ).Methods A three-dimensional ifnite element ( FE ) model of intact C3-7 segments was developed and validated based on healthy males. C5 anterior corpectomy and allograft interbody fusion with a rigid anterior screw-plate construction was created from C4 to C6. Three additional FE models were developed from the fusion model corresponding to 3 different combinations of SSA: ( 0°, 0° ), ( 5°, 5° ), and ( 10°, 10° ). Von Mises stress on the C4 superior end-plate, C6 inferior end-plate and screw-plate were analyzed.Results The largest stress appeared when the superior end-plate of C4 was in lfexion position in the front area. With the increase of SSA, the peak stress was gradually reduced. When the SSA was increased by 10°, the peak stress was reduced by 12.67%. The largest stress appeared when the lower end-plate of C6 was in lfexion position in the front area. With the increase of SSA, the peak stress was gradually reduced. When the SSA was increased by 10°, the peak stress was reduced by 7.99%. The peak stress was noticed in the middle area when the plate was in lfexion and extension position, which was signiifcantly larger than that in the upper and lower area. With the increase of SSA, the stress would be gradually raised.Conclusions Larger SSA produces greater stress of the screw plate and lower stress of the end-plate in adjacent segments, reducing the incidence of ASD.