| Partâ… The preparation and physicochemical properties of injectable boneObjective:To study on the preparation of an injectable bone combined withα-Calcium sulphate hemihydrate (a-CSH), test their physicochemical properties of different components.Methods:1. The mineralized collagen of which the content was 0%,5%,10% and 20%were mixed into calcium sulphate dihydrate(CSD) of which the content was 0%,5%,10%,15%,20% andα-CSH,then 189 samples of which the mass was 2g were added by distilled water at different liquid/solid ratio (0.5,0.6,0.7,0.8,0.9,1.0,1.1,1.2, unit ml/g) then mixed into paste,and the pastes were put into 5ml syringe without needle and then pushed out of the syringe easily and recorded the ratio of liquid to solid.2. Study on the relation of curing properties bwteen different liquid to solid ratio,different mineralized collagen content and different accelerator content.3.After the injectable bone of different components solidification the bones were produced a cylindrical body with 6 mm in diameter and 10 mm in height, then placed at universal testing machine and the compression performance of the material was tested.Results:(1) There was relations between the content of mineralized collagen and liquid to solid ratio that with the content of mineralized collagen increasing the liquid to solid ratio had to be increased in order to maintain good injectable properties.(2) With the mineralized collagen content increasing and the liquid to solid ratio increasing the curing time increased,but the curing time could be shortened substantially because of the calcium sulfate dihydrate being put into them.The curing time could be controlled at 4.3±0.6 minutes-169±22.3 minutes according to different composition. (3) With the liquid to solid ratio and the content of mineralized collagen increasing,the compressive strength of the material from the highest 18.3±2.3 Mpa to 1.5±0.5 Mpa.Conclusion:A self-curing and in situ injectable bone was produced by a-CSH combined with mineralized collagen Partâ…¡The preparation thoracolumbar burst fracture modelObjective:study on the method of rapid Preparation of thoracolumbar burst fractureMethods:1. To produce 20 thoracolumbar 3-conjoined porcine specimens, the upper and lower vertebrae was resin-embeded by epoxy and the middle vertebrae was drilled a hole through the vertebrae with 3.2mm in diameter by dill respectively on one side of the middle 1/3,2/3 resulting in limited damage and the height of the front of the middle vertebrae was measured by vernier caliper (HInt).2. The 9Kg stainless steel hammer was placed at 0.5m,then impacted the specimen along the vertical guide rod, if the middle vertebrae had no signs of fracture the stainless steel hammer was promoted by 0.1m at the basis of 0.5m, if the middle vertebrae had signs of fracture the stainless steel hammer was ascended by 0.1m at the basis of 0.5m, until the formation of the middle vertebral body burst fracture, recorded the total impact energy.3. After the formation of burst fracture of the middle vertebrae the height of the front of the middle vertebrae was once again measured (HFr).then all the models were examined by radiological.Results:(1) Before fracture the height of anterior vertebral was 27.405mm±1.453mm, and after fracture the height of the front of vertebrae was 17.784mm±1.362mm, there was significantly different differences bwteen before and after fracture (p=0.0015); (2) When the impact height was 0.5m,4 burst fracture model formed,and when the cumulative impact height was 0.9m,13 burst fracture model formed, when the cumulative impact height is 1.3m 3 burst fracture model formed. The Cumulative average impact height was 0.865m±0.216m and the cumulative average impact energy was 76.313J±19.044J. (3)The models of burst fracture was made by radiological observationConclusion:A typical thoracolumbar burst fracture model can be made by Several times impact Part III Injectable bone initial application in bust fractures of the spineObjective:Study on the injectable bone initial application in the fracture of spineMethods:1.20 burst fractures were randomly divided into A,B groups,after manual traction,the height of the front of the middle vertebrae was recorded (HRe) after reset,and then the difference between A and B was counted after reset.2. The group A was enhanced with injectable bone then the amount of the injectable bone was read out. The distribution of injectable bone was observed by radiation and then the specimens were placed in incubator at 37℃for 2 hours,the height of the front of the middle vertebraes was recorded (Hpv).3. The the groups A, B were palaced at biomechanical testing machine,50N was preloaded to eliminate the effects of intervertebral discs of the time Relaxation, creep and other effects, and destructive mechanical tests was done at the speed of 5mm/min,thc displacement-load curves of the specimens were then recorded, when the inflection point appeared the rresponding ultimate compression strength was recorded and the stiffness was calculated. The difference of compression strength and the stiffiness between A and B were counted.Results:(1) The height of the front of the verteraces were fully restored after resetting and the height of enhanced group was effectively maintained.There was statistically significant difference in A or B group between before fracture and reset (P<0.01); (2) There was no significant difference between the vertebrace enhanced and reset.(3) The average amount of vertebral body enhanced was 3.140ml±0.591ml,the gap of vertebral fractures could be filled by radiology. (4) The biomechanical tests of A group showed that the ultimate compression strength was 1200±423N,The stiffness was 235±134N/mm. the B group was 505±300N and 36±25N/mm,there was significantly significant differences in both A and B (P<0.01 and P=0.03).Conclusion:The compressive strength and stiffness of vertebral bodies can be effectively restored after vertebral burst fractur enhanced injectable bone... |
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