CAJ | 학술논문

背景:椎体后凸成形后相邻椎体新发骨折的发生率为2.4%-23%,并且6个月内2/3骨折发生于邻近椎体,其原因是骨质疏松的发展,还是骨水泥强化的结果,目前存有争论.目的:应用脊柱有限元分析方法分析生理载荷作用下,椎体后凸成形后相邻椎体终板的应力变化与相邻椎体新发骨折的相关性.方法:收集老年骨质疏松女性胸腰椎CT扫描资料,利用一系列计算机辅助设计软件构造相对应的T_(12)-L_1-L_2骨质疏松性椎体的三维有限元模型.模拟L_1椎体为楔形压缩骨折椎体(前缘高度较正常降低60%),模拟经皮椎体后凸成形模型,复位骨折椎体(L_1椎体高度较正常降低10%,代表骨折椎体复位),在L_1椎体内置入2个对称的圆柱体PMMA骨水泥块共约4 mL.分析轴向压缩、前屈和后伸3种加载状态下正常椎体、手术前后相邻椎体的应力变化情况.结果与结论:与正常椎体比较,L_1压缩性骨折模型和椎体后凸成形后模型相邻椎体终板最大应力值分别增高76%和27%;椎体后凸成形模型后部结构的应力水平较正常椎体平均增加13.2%,其中椎弓根增加4.5%,峡部增加6.15%和关节点增加25.6%.与L_1椎体压缩性骨折模型相比,L_1椎体后凸成形后椎弓根、峡部和关节突应力均有所降低.结果说明椎体后凸成形后,T_(12)椎体下位终板和L_2椎体上位终板的应力值在各种状态下均较正常椎体增加,应力增加可能导致终板骨折可能性增加,进而导致相邻椎体骨折的风险性增加,这一观点尚需进一步研究的支持.
배경:추체후철성형후상린추체신발골절적발생솔위2.4%-23%,병차6개월내2/3골절발생우린근추체,기원인시골질소송적발전,환시골수니강화적결과,목전존유쟁론.목적:응용척주유한원분석방법분석생리재하작용하,추체후철성형후상린추체종판적응력변화여상린추체신발골절적상관성.방법:수집노년골질소송녀성흉요추CT소묘자료,이용일계렬계산궤보조설계연건구조상대응적T_(12)-L_1-L_2골질소송성추체적삼유유한원모형.모의L_1추체위설형압축골절추체(전연고도교정상강저60%),모의경피추체후철성형모형,복위골절추체(L_1추체고도교정상강저10%,대표골절추체복위),재L_1추체내치입2개대칭적원주체PMMA골수니괴공약4 mL.분석축향압축、전굴화후신3충가재상태하정상추체、수술전후상린추체적응력변화정황.결과여결론:여정상추체비교,L_1압축성골절모형화추체후철성형후모형상린추체종판최대응력치분별증고76%화27%;추체후철성형모형후부결구적응력수평교정상추체평균증가13.2%,기중추궁근증가4.5%,협부증가6.15%화관절점증가25.6%.여L_1추체압축성골절모형상비,L_1추체후철성형후추궁근、협부화관절돌응력균유소강저.결과설명추체후철성형후,T_(12)추체하위종판화L_2추체상위종판적응력치재각충상태하균교정상추체증가,응력증가가능도치종판골절가능성증가,진이도치상린추체골절적풍험성증가,저일관점상수진일보연구적지지.
BACKGROUND: The incidence of the adjacent vertebral fracture after kyphoplasty is about 2.4%-23.0%, and 2/3 of new fractures occurred in adjacent vertebrae in 6 months. There is controversy addressing the reason which is the development of osteoporosis or the result of bone cement augment at present.OBJECTIVE: To determine the correlations between percutaneous kyphoplasty on adjacent vertebral endoplates stresses pressure under physiologianl load and a new fracture of adjacent vertebral body in physiological load.METHODS: Computed tomography (CT) data of an old female osteoporotic patient was selected, and a three-dimensional finite element model of the osteoporetic thoracolumbar spine T_(12)-L_1-L_2 was created by using kinds of computer aided design software.The height of vertebral L_1 was compressed by 60% to simulated the compressed fracture, and the height of L_1 became the 90% of normal to simulate the replacement, two columns-like PAMA mass (4 mL) was placed in vertebral L_1 to simulate pemutaneous kyphoplasty. The stress on inferior endplate of L_(12) and superior endplate of L_2 was compared with three models. RESULTS AND CONCLUSION: Compared to the normal vertebral body, the maximum stress in the adiacent vertebral bodies endplates increased by 76% for L_1 compress fracture model and increased by 27% for kyphoplasty model, respectively. The stress on the posterior part of vertebral body after percutaneous kyphoplasty have an average increase of 13.2%, of which 4.5% increase in the pedicle, isthmus, and 6.15% increased in the key points 25.6%, but with the wedge-shaped fracture of L_1 vertebral body compared to the model, percutaneous kyphoplasty after pedicle, isthmus and the articular process had reduced stress. The results indicate that the stress on inferior endplate of L-(12) and superior endplate of L_1 increased after percutaneous kyphoplasty under all loading conditions. Increased stress may lead endplate fracture, and increase the risk of adjacent vertebral body fracture. Further researches are needed to support the conclusion.