Finite element analysis of dynamic changes in spinal mechanics of osteoporotic lumbar fracture.

AIM: This study aims to explore the effects of finite element biomechanical properties of different methods in the treatment of osteoporotic thoracolumbar fractures. METHODS: Based on the ultra-thin computed tomography scan data of a volunteer's thoracolumbar spine, the finite element method was used to simulate the treatment of osteoporotic thoracolumbar fracture. Spiral computed tomography scanning was used to obtain images of the thoracolumbar region, which was then imported into Mimics software to obtain the three-dimensional geometric model. The finite element model of normal T11 - L2 segment was established by finite element software Abaqus and the validity of the model loading was verified. The finite element model of T11 vertebral compression fracture was established based on normal raw data. The clinical overextension reduction manipulation was simulated by different treatment methods and the changes in stress and displacement in different parts of injured vertebrae were analyzed. RESULTS: An effective finite element model of T11-L2 segment was established. The maximum stress, axial compression strength, axial compression stiffness, and transverse shear stiffness were significantly better in the percutaneous kyphoplasty and percutaneous vertebroplasty treatment group than in the conservative treatment group and open treatment group (P < 0.05). Additionally, there was no significant difference between the open treatment group and conservative treatment group, or between the PKP and PVP treatment group. CONCLUSION: Percutaneous vertebroplasty and percutaneous kyphoplasty not only met the requirements of normal functional kinematics of thoracolumbar spine, but also restored the stability of thoracolumbar spine. They had good biomechanical properties and remarkable application effects. The application of finite element analysis can help select a scientific, reasonable, and effective treatment scheme for the clinical diagnosis and treatment of osteoporotic thoracolumbar fractures.

Establishment and clinical application of Kidd, Diego, Duffy blood group system, Shaanxi Province / 中国输血杂志

【Objective】 To screen individuals with rare blood type of Kidd, Diego, Duffy blood group system among the voluntary blood donor in Shaanxi province and to establish on-line and physical database of rare blood type. 【Methods】 Jk(a-b-)phenotype donors were screened by 2 mol/L urea hemolysis test. Blood donors with Di(a+ b-) phenotype were screened by genotyping; Fy(a-) and D-- phenotype donors were screened by modified antiglobulin assay. 【Results】 Three cases of Jk(a-b-) phenotype were detected out of 158 484 voluntary blood donors. The distribution frequency of Jk(a-b-) phenotype was 0.019‰. Di(a+ b-) phenotype was detected in 2(0.436‰) cases out of 4 586 voluntary blood donor. Fy(a-) phenotype was detected in 8(4.034‰) cases out of 1 983 voluntary blood donors. D-- phenotype was not detected in 29 430 voluntary blood donors. 【Conclusion】 The on-line database of Kidd, Diego, Duffy blood group system had been established by large-size screening of blood donor samples, which can conclude the region′s population distribution and genetic characteristics of RBC blood group. And physical database could further be established using the technology of red blood cells cryopreservation when the conditionspermit, so as to provide the most compatible blood for the clinical effectively improve blood transfusion safety, and provide data support for blood early warning.