前路TARP系统与后路钉棒系统对枢椎下拉力的生物力学研究

Biomechanical comparison of the pull-down strength between TARP system and posterior atlantoaxial screw fixation system on the axis

目的对比研究前路经口寰枢椎复位钢板(TARP)系统与后路寰枢椎钉棒系统对枢椎的下拉力量。方法取6具新鲜上颈椎尸体标本,分别将TARP钢板和寰枢椎椎弓根钉棒系统固定于寰枢椎上,模拟手术撑开复位过程,在前后路分别加载相同撑开负荷(60、80、100N),测试两套系统在加载撑开负荷过程中对枢椎的下拉分离力及寰枢椎间分离的位移,并进行统计学分析。结果施加60、80、100N撑开负荷时TARP组对枢椎产生的下拉力分别为26.11±2.08、36.08±2.40、45.01±2.26N,而后路钉棒组分别为22.09±1.45、29.77±2.36、40.80±3.41N,TARP组寰枢椎间分离位移分别为0.87±0.07、1.07±0.07、1.14±0.06mm,而后路钉棒组分别为0.82±0.07、1.01±0.08、1.06±0.08mm,两组比较差异有统计学意义(P<0.05)。结论 TARP系统对枢椎产生的下拉力及寰枢椎间分离的位移均大于后路钉棒系统,提示前路TARP系统可作为治疗颅底凹陷症合并寰枢椎脱位的一种较好的选择方案。

Objective To compare the pull-down strength on axis between anterior transoral atlantoaxial reduction plate （TARP） system and posterior atlantoaxial transarticular screw fixation （ATSF） system so as to provide a biomechanical basis for clinical application. Methods Six fresh human cadaveric atlantoaxial specimens （C0-C3） with intact ligaments were instrumented with TARP system and ATSF system respectively to simulate the reduction procedure of operation, the same stretch strength were loaded on anterior and posterior parts of the atlas and axis （60, 80 and 100N）. The pull-down strength on the axis and the degree of displacement of atlantoaxial detachment were measured respectively and then analyzed statistically. Results When loaded with the stretch strength of 60, 80 and 100N, the pull-down strength on the axis generated by TARP system were 26.11 ±2.08, 36.08± 2.40 and 45.01 ± 2.26N, and those generated by ATSF system were 22.09 ± 1.45, 29.77 ±2.36 and 40.80 ± 3.41N, respectively; the atlantoaxial detaching displacement generated by TARP system was 0.87± 0.07, 1.07 ± 0.07 and 1.14 ± 0.06mm respectively, and those generated by ATSF system were 0.82 ±0.07, 1.01 ± 0.08 and 1.06 ±0.08mm respectively. The pull-down strength on both the axis and atlantoaxial detaching displacement showed a significant difference between the two groups （P〈0.05）. Conclusion The pull-down strength on the axis and atlantoaxial detaching displacement generated by TARP system was significantly superior to those generated by ATSF system, suggesting that the TARP system could be a better fixation system for basilar invagination combined with atlantoaxial dislocation.