The Study Of 3D Printed Porous Artificial Bone Scaffold Combined With Autologous Bone And Ectopic Osteogenesis In Vivo

Objective:1. Using the CAD design and 3D printing technology for porous artificial bone scaffold, to provide material foundation for animal experiment.2. Cutting the rabbit iliac bone into pieces and filling the pieces in the pore of the artificial bone scaffold, and implanted in rabbit back muscle bag, to explore the best ectopic bone formation ability of the pore diameter of artificial bone scaffold combined with autologous bone.Method:1. CAD design the parameters of the pore diameter and spacing of the artificial bone scaffolds:According to the Mises Von of bone canal, the Mises Von turning point was located on the 0.8X. When the hole spacing was 0.8 times of the aperture, the collocation of the aperture and the hole spacing was the most suitable. This was also the best safety critical value of the minimum hole spacing. Because when the hole spacing ratio continues to decrease, the maximum Mises Von stress will rise sharply, increased the risk of deformation of the bone tube model. When the hole spacing was 0.8 times of the aperture, the mechanical strength of the bone canal was in the safe range. While the number of drill holes on the bone tube can reach the maximum, which means that the composite bone can reach the maximum amount of bone mass.2.3D printing has between pore structure of artificial bone scaffolds:the CAD software design of the artificial bone scaffold model file import 3D printing system, system of rapid prototyping software to model for slicing, according to slicing two-dimensional interface contour map of transverse and longitudinal alternating, accumulation rules and accurate stratification curing. Finally, layer by layer stacking, step by step sequence superposition into with pore structure of tricalcium phosphate calcium artificial bone scaffolds.3. The autogenous bone particles packing to artificial bone composite scaffold hole and overall implanted into the rabbit back muscle bag:bone chisel from rabbit iliac block size about 13mm*25mm and cut into broken bone grain, respectively packing to the composition of tricalcium phosphate calcium artificial bone scaffold pores, as much as possible packing of close.4. At first, third, fifth months after the operation, the X-ray films were examined by radionuclide bone imaging and Micro-CT, HE staining, Masson staining and COL-1 immunohistochemical staining were observed.Results:1. CAD design of the stent between hole diameter and hole spacing pairing for 4.5mm/3.6mm,3.5mm/2.8mm,2.5mm/2. Omm, and bracket of the main part of the design into the microporous structure of the grid,the microporous aperture diameter of 400μm.This artificial bone bracket between pore structure for packing combined with autologous bone, and the microporous structure of the grid for early capillary network attached ingrowth and post new bone creeping substitution.2.3D printing of the artificial bone scaffold model and design the size of no significant difference, and no morphological change, enough to meet the demand of experimental animals in composite grafting of autogenous bone next. Artificial bone scaffold scanning electron microscope images of the visible artificial bone of the bracket body was grid shaped microporous arranged in neat rows, pore size of uniform size, aperture was about 400 μm, interconnection between the micropores are interlinked and scaffold surface also has from several nanometers to several micron range of natural pore structure. The multi pore structure was beneficial for cell and tissue extending.3. Rabbit autologous bone particles and artificial bone scaffold close combination, and the overall implantation of rabbit back muscle bag, the operation process was smooth.4. THE first, third, fifth months of X-ray, radionuclide bone imaging showed no obvious new bone formation and metabolism, visible artificial bone scaffold material density decreased with time, consider. The Micro-CT, HE staining, Masson staining and COL-1 immunohistochemical staining results showed that in the first after months of no new bone formation was evident, third months after the transplantation of autologous bone artificial bone scaffold implanted in the hole and most lost, small part of re shaping. Until after fifth months of artificial bone scaffold microporous 3.5mm aperture was observed within a small amount of new bone, artificial bone scaffold microporous 4.5mm the aperture also has a small amount of new bone, but no obvious 3.5mm aperture, and autogenous bone artificial bone scaffold 2.5mm diameter hole of almost entirely lost, was a lot of fat and muscle tissue substitutes.Conclusion:1. The CAD design and 3D printing technology can be used to create a personalized porous artificial bone scaffold, and to meet the needs of animal experiments.2.3.5mm pore diameter artificial bone scaffold combined with autologous bone was the most effective in the combination of the pore structure of artificial bone scaffold combined with autogenous bone particles.