摘要
目的研究新型腰椎动态内固定系统（dynamic internal fixation system，DIFS）对腰椎节段稳定性和椎间盘内压力的影响。方法收集8具新鲜小牛腰椎标本，制作测试模型，在屈伸、侧屈和旋转方向上加载8N·m的纯力矩进行测试。测试的状态包括完整状态、失稳状态、动态固定状态、半硬性固定状态和坚强固定状态。从第3个循环进行数据的采集，测量相应节段的活动范围、中性区和椎间盘内压力。结果失稳模型明显地增加了节段在三个运动平面的活动范围和中性区，对椎间盘内压力没有明显影响。三种内固定系统均对失稳节段有稳定作用和承载作用，其中DIFS在前屈、后伸、侧屈和旋转方向上分别将活动范围恢复至完整状态水平的77％、60％、61％和70％，在侧屈、旋转和前屈方向上分别承载椎间盘负荷的45％、29％和40％，但在后伸方向上承载了全部的椎间盘负荷。测试状态对邻近节段的稳定性和椎间盘内压力没有明显影响。结论DIFS能较好地恢复失稳节段的活动性，并且在多个方向上承载适当的椎间盘负荷。
Objective To investigate effect of a new lumbar dynamic internal fixation system （DIFS） on the stability and intradiscal pressure of lumbar segment. Methods Eight fresh calf lumbar specimens were collected to build test models, which were loaded with pure moments of 8 N · m in flexion/extension, lateral bending, and rotation planes. The test states included intactness, destabilization, dynamic fixation, semi-rigid fixation, and solid fixation. The data were collected from the third loading cycle to determine range of motion and neutral zone of corresponding segments, and the intradiscal pressure. Results Destabilization significantly increased segmental range of motion and neutral zone in three motion planes without obvious influence on intradiscal pressure. The three fixation systems were all able to stabilize and load destabilizing segments. DIFS restored the range of motion of unstable segment to 77%, 60%, 61% and 70% of the intact level in anterior flexion, posterior extension, lateral bending and rotation planes. Meanwhile, DIFS bore 45%, 29% and 40% of the intradiseal load in lateral bending, rotation and flexion directions, but 100% of the intradiscal load in back extension. The stability and intradiscal pressure of adjacent segments were not affected by the test states. Conclusion DIFS can effectively restore range of motion of unstable segments and share appropriate intradiscal load in most directions.
出处
《中华创伤杂志》
CAS
CSCD
北大核心
2012年第11期1026-1031,共6页
Chinese Journal of Trauma
基金
辽宁省医学高峰建设工程资助项目（2010012）
关键词
腰椎
生物力学
动态稳定
钛合金
Lumbar vertebrae
Biomecbanics
Dynamic stabilization
Titanium alloy
