中文摘要：

目的：探讨L5／S1和骶髂关节对腰-髂固定稳定性的影响，为腰-髂稳定性理想重建提供生物力学依据。方法：7具成年新鲜尸体L2-骨盆标本，先行L3～L5椎弓根螺钉固定，并将此结构定义为腰-髂部稳定初始状态。初始状态测试后，在同一标本上实施连续性操作如下：使用髂骨钉的L3一髂骨同定（A组）、L5／S1双侧关节突关节切除（B组）、L5／S1椎间盘切除（C组）、左侧骶髂关节切除（D组）。在MTS材料实验机上，给标本头侧分别施加600N轴向压缩和7Nm轴向扭转载荷，计算并比较各组结构压缩和扭转刚度。结果：初始状态组的压缩刚度值为（332±103）N／mm，A～D组腰-髂固定结构的压缩刚度分别为初始状态组的（122±15．5）％、（118.3±10．5）％、（81．1±7．7）％和（59．2±8．6）％。A和B组问无显著性差异（P〉0．05），两组的压缩刚度均显著高于初始状态组（P〈0．05）；C组和D组的压缩刚度均显著低于A、B组及初始状态组（P〈0．05），C组和D组间的差异也具有显著性（P〈0．05）。初始状态组的扭转刚度值为（2．47±0．88）Nm／deg，A～D组固定结构的扭转刚度分别为初始状态组的（128±14．3）％、（120±12．6）％、（78．4±13．2）％和（62．9±11．3）％，A组和B组获得同等的扭转刚度（Jp〉0．05），而且此两组的扭转刚度均显著高于初始状态、C组和D组（P〈0．05），C、D组和初始状态三组彼此间的差异均具有显著性（P〈0．05）。结论：L5／S1椎间盘切除和单侧骶髂关节切除均显著降低腰-髂固定结构的稳定性，在腰-髂稳宗忡雷律中．薪得脊梓前方专樘和恢第骨龠环完罄件早丰旱高腰-髂罔审结构稳宁件的关锋．

英文摘要：

Objectives： To explore the biomechanical effects of L5/S1 complex and sacroiliac joints on the stability of lumbo-iliae fixation construct, and to provide evidences for the rational reconstruction. Methods： Seven fresh L2-pelvic specimens harvested from donated adult cadavers were used in this study. After testing the initial state simulated by L3-L5 pedicle screw fixation, L3-iliae fixation and sequential joint resections were performed on the same specimen as follows： group A, L3-iliac fixation using bilateral iliac screws; group B, bilateral L5/S1 facetectomy; group C, LS/S1 discectomy; group D, left side sacroiliac joint resection. Biome- ehanieal testing was performed on a material testing machine under 600N compression and 7Nm torsion loading modes for construct stiffness evaluation. Results： The compressive stiffness of initial state was （332＋ 103）N/ram, group A-D obtained（122±15.5）%, （118.3±10.5）%, （81.1±7.7）% and （59.2±8.6）% of the initial com- pressive stiffness, respectively. No significant difference was detected between group A and B（P〉0.05）; further- more, the two groups showed significantly higher compressive stiffness than the initial state（P〈0.05）; group C and D exhibited lower compressive stiffness than group A, B and the initial state（P〈0.05）; there was signifi- cant difference between group C and D（P〈0.05）. The torsional stiffness of initial state was （2.47±0.88）Nm/deg. Group A-D acquired （128±14.3）%, （120±12.6）%, （78.4±13.2）% and （62.9±11.3）% of the initial torsional stiff ness, respectively. Group B obtained sufficient torsional stiffness compared to group A（P〉0.05）; both group A and B exhibited notably higher torsional stiffness than all the other three groups （P〈0.05）. Significant differ- ences were demonstrated among group C, D and initial state （P〈0.05）. Conclusions： LS/S1 discectomy and one-side sacroiliac joint resection significantly decrease the stability of lumbo-iliac fixation con