骶髂融合治疗下腰痛的生物力学效应

Biomechanical effects on sacroiliac fusion for treating low back pain

目的基于有限元方法,建立骶髂关节融合和接触的模型,比较两模型的生物力学差异,探究骶髂融合治疗下腰痛的生物力学机理。方法构建包含骨盆环、骶骨、部分股骨、关节软骨和关节连接的骨盆有限元模型两例,分别设定骶髂关节连接为接触和融合,探究在500 N载荷下,两例模型中骨盆环特别是骶髂关节处力学传导的差异。结果在融合条件下骶髂软骨承受的应力及位移明显低于接触条件,在双侧骶髂软骨处尤为明显,其中左骶骨关节处,位移由0.83 mm减低为0.23 mm,减低幅度达约261%,等效应力由6.6 MPa减低至5.0 MPa,减低约32%。但融合条件下,骨盆环应力的传递相对更集中。结论骶髂融合可能提供较好的疼痛治疗效果,但同时必须谨慎评估伴发骨盆损伤和股骨头损伤的危险性。

Objective Based on the finite element method, both sacroiliac fusion and sacroiliac contact models were built to compare the biomechanical differences between the two models and to explore the biomechanical mechanism in the treatment of low back pain by sacroiliac fusion. Methods Two pelvic finite element models were constructed, including the pelvic ring, sacrum, part of the femur, ligaments, cartilage and joint contact. The sacroiliac joints were set to be contact in one model and fusion in the other, respectively. Differences in me- chanical conduction on the pelvic ring and the stress on the sacroiliac cartilage under 500 N load between the two models were explored. Results For the fusion model, stresses and displacement on the sacroiliac joint were sig- nificantly lower than that of the contact model, especially on the sacroiliac cartilage, where the displacement was reduced by 261% from 0.83 mm to 0.23 ram, and the stresses reduced by 32% from 6.6 MPa to 5.0 MPa. How- ever, the transfer of stress on the pelvic ring was relatively more concentrated in the fusion model. Conclusions Sacroiliac fusion may provide better therapeutic effects on the treatment of low back pain, but the risk of disc herniation and femoral head necrosis must be assessed seriously in advance.