Experimental Research Of PLA/nano-hydroxyapatite Absorbable Interbody Fusion Cage

Part 1 Preparation and Biomechanical Study of PLA/nano-hydroxyapatite Absorbable Interbody Fusion CageObject:To produce the PLA/nano-hydroxyapatite absorbable interbody fusion cage and analyze the biomechanical capability of the interbody fusion cage.Methods:PLA/nano-hydroxyapatite compound material of different n-HA mass fraction(0,5%,10%,15%,20%,25%,30%,35%,40%,45%,50%) was produced by the thermal induced phase separation method.The absorbable material was characterized by the scanning electron microscope observation.Its mechanics performance(pressure strength,bending strength,curving module) were tested.PLA/nano-hydroxyapatite absorbable interbody fusion cage was produced according to the best n-HA mass fraction.6 fresh lumber spine specimens(L1-L5) from young male cadavers were used,The specimens were classified into 3 groups:the normal group,auto iliac bone group and PLA/n-HA interbody fusion cage group.The specimens were measured by the three dimensional motional stability test,the pullout test,and compression destoryed test. capability of PLA/nano-hydroxyapatite compound material reached the peak value.The absorbable material had the three dimensional porous micro-structure.The PLA/nano-hydroxyapatite absorbable interbody fusion cage was produced according to the 20%mass fraction of HA.The absorbable interbody fusion cage exhibited a significant increase in stability between L3 and L4 in flexion,left/right lateral bending and left/right axial rotation than iliac crest bone.The absorbable interbody fusion cage exhibited a significant increase in stability between L3 and L4 in flexion,left/right lateral bending than the normal group.The material group had the more pullout resistance than iliac crest bone group. The absorbable interbody fusion cage group can protect vertebrae,and it has very good load capacity better than iliac bone group.Conclusion:The produced PLA/nano-hydroxyapatite absorbable interbody fusion cage has the three dimensional porous micro-structure. Its micro-structure is similar to extracellular matrix.It is producted that the material has the better biocompatibility.It has the better capability of mechanics,stability and anti-compression. Object:To detect the cell compatibility of PLA/nano-hydroxyapatite absorbable material.Produce PLA/nano-hydroxyapatite/ Bone marrow derived mesenchymal stem cells(MSCs) Compound Interbody Fusion Cage.Observe the its effect of interbody fusion and absorbability.Methods:Bone marrow derived mesenchymal stem cells were extracted from the bone marrow in goats and cultured.Bone marrow derived mesenchymal stem cells were cultured with PLA/nano-hydroxyapatite absorbable material.Tested the cell multiplication and adhesion under the influence of the material by MTT methods.PLA/nano-hydroxyapatite absorbable interbody fusion cage and Bone marrow derived mesenchymal stem cells were cocultured to produce PLA/nano-hydroxyapatite/ Bone marrow derived mesenchymal stem cells(MSCs) Compound Interbody Fusion Cage.It was imbedded the interbody of goat lumbar to evaluate the effect of interbody fusion.Results:When Bone marrow derived mesenchymal stem cells were seeded into scaffolds,the cell attachment rate in PLA/nano-hydroxyapatite was 72.1%.The cell proliferation assay showed that the cell number in PLA/nano-hydroxyapatite was higher than that in control group.In a short term after operation,the fusion effect of iliac crest bone group was best.But the last all the group can reach the same fusion effect.Conclusion:The PLA/nano-hydroxyapatite absorbable material has the better biocompatibility.It can be used to repair the bone defects in interbody fusion. Objective:Conserve the Biosafety of PLA/nano-hydroxyapatite material by animal experiments,prepare for clinical application.Methods:The leaching liquor of the material was injected into mice to test the acute toxicity.To explore the biocompatibility of PLA/nano-hydroxyapatite absorbable material,implant test were performed in SD rat.Results:All animals were alive in the labor period.No significant difference in general situation,the food utilization rate and the body weight relative growth rate.There was only mild inflammatory reaction and thin fibrosis membrane in the early days after PLA/ PLA/nano-hydroxyapatite absorbable material plate implantation,the fibrosis membrane was nearly disappeared and most of the imflammatory reaction recovered 3 months later.The heart,liver and kidney were all normal.Conclusion:The self-made PLA/nano-hydroxyapatite absorbable material has a good Biosafety,it has a great clinical application prospects.