ObjectiveTo evaluate the physical and chemical properties, immunogenicity, and osteogenesis of two antigen-extracted xenogeneic bone scaffolds—decalcified bone matrix (DBM) and calcined bone.MethodsBy removing the inorganic and organic components of adult pig femus, xenogeneic DBM and calcined bone were prepared respectively. The density and pH value of the two materials were measured and calculated, the material morphology and pore diameter were observed by scanning electron microscope, and the surface contact angle was measured by automatic contact angle measuring instrument. The safety, osteogenic activity, and immunogenicity of the two materials were evaluated by cytotoxicity test, osteoblast proliferation test, DNA residue test, and human peripheral blood lymphocyte proliferation test. The two materials were implanted into the 5 mm full-thickness skull defect of 6-week-old male Sprague Dawley rats (the blank control group was not implanted with materials). The materials were taken at 4 and 8 weeks after operation, the repair effect of the materials on the rat skull was observed and evaluated by gross observation, Micro-CT scanning, and HE staining observation.ResultsCompared with calcined bone, DBM has lower density and poor hydrophilicity; the pH value of the two materials was 5.5-6.1, and the pore diameter was 160-800 μm. The two materials were non-cytotoxic and could promote the proliferation of osteoblasts. The absorbance (A) values of osteoblast proliferation at 1, 4, and 7 days in the DBM group were significantly higher than those in the calcined bone group (P<0.05). The DNA residues of the two materials were much lower than 50 ng/mg dry weight, and neither of them could stimulate the proliferation and differentiation of human peripheral blood lymphocytes. The results of animal experiments in vivo showed that the bone volume/total volume (BV/TV) in DBM group and calcined bone group were significantly higher than that in blank control group at 4 weeks after operation (P<0.05), and that in calcined bone group was significantly higher than that in DBM group (P<0.05); at 8 weeks after operation, there was no significant difference in BV/TV between groups (P>0.05). HE staining showed that at 4 and 8 weeks after operation, the defect in the blank control group was filled with fibrous connective tissue, the defect was obvious, and no bone growth was found; the defect in DBM group and calcined bone group had been repaired to varying degrees, and a large number of new bone formation could be seen. The material degradability of DBM group was better than that of calcined bone group.ConclusionThe physical and chemical properties and degradability of the two kinds of xenogeneic bone scaffolds were slightly different, both of them have no immunogenicity and can promote the repair and reconstruction of skull defects in rats.
ObjectiveTo observe and compare the effects of peptides on the repair of rabbit skull defects through two different binding modes of non-covalent and covalent, and the combination of carboxyl (-COOH) and amino (-NH2) groups with materials.MethodsTwenty-one 3-month-old male ordinary New Zealand white rabbits were numbered 1 to 42 on the left and right parietal bones. They were divided into 5 groups using a random number table, the control group (group A, 6 sides) and the material group 1, 2, 3, 4 (respectively group B, C, D, E, 9 sides in each group). All animals were prepared with 12-mm-diameter skull defect models, and bone morphogenetic protein 2 (BMP-2) non-covalently bound multiwalled carbon nanotubes (MWCNT)-COOH+poly (L-lactide) (PLLA), BMP-2 non-covalently bound MWCNT-NH2+PLLA, BMP-2 covalently bound MWCNT-COOH+PLLA, and BMP-2 covalently bound MWCNT-NH2+PLLA were implanted into the defects of groups B, C, D, and E, respectively. At 4, 8, and 12 weeks after operation, the samples were taken for CT scanning and three-dimensional reconstruction, the ratio of bone tissue regeneration volume to total volume and bone mineral density were measured, and the histological observation of HE staining and Masson trichrome staining were performed to quantitatively analyze the volume ratio of new bone tissue.ResultsCT scanning and three-dimensional reconstruction showed that with the extension of time, the defects in groups A-E were filled gradually, and the defect in group E was completely filled at 12 weeks after operation. HE staining and Masson trichrome staining showed that the volume of new bone tissue in each group gradually increased with time, and regenerated mature bone tissue appeared in groups D and E at 12 weeks after operation. Quantitative analysis showed that at 4, 8, and 12 weeks after operation, the ratio of bone tissue regeneration volume to total volume, bone mineral density, and the volume ratio of new bone tissue increased gradually over time; and at each time point, the above indexes increased gradually from group A to group E, and the differences between groups were significant (P<0.05).ConclusionThrough covalent binding and using -NH2 to bound peptides with materials, the best bone repair effect can be achieved.
Objective To investigate the clinical application of self-cranial bone powder in one stage cranioplasty．Methods From October 1999 to December 2002,self-cranial bone powder and medical adhesive were used to repair the skull defect, for one stage cranioplasty, caused by operations on cranium in 128 casesof severe dangerous craniocerebral injury, acute intracranial hematome, sick skull and intracranial tumor．The bone growth was observed by CT or X-ray examination 3-24 months after replantation of cranioplasty．Results The decompression and cranioplasty were performed simultaneously, the time prolonged 5-10 minutes than that of routine, the appearance of repaired cranial bone was normal, without concavity and convexity. After 12 months of operation, the replanted bone merged with the normal bone completely, with normal appearance. The operation successful rate was 96.1%(123/125) without any complication. Only fivecases were not better in growing because of less bone powder, but withoutcerebral pulse and defective syndrome. All the cases did not need secondary cranioplasty．Conclusion The effect of cranioplasty with self-cranial bone powder effect is good in taking shape. This new method can avoid the traditional secondary cranioplasty for skull defect and complications．
Based on the dye injection investigation, the territory of blood supply through the superficial temperal artery system was defined. Vascularized grafts, composed of temperal-parietal fascia, periosteum and outer-table of calvarial bone, can be transferred by microvascular anastomosis or transposed to repair full-thickness defects of skull bone was demonstrated. Six of such cases following electrical burn were successfully treated. The average size of skull bone defects was 50cm2. The largest one among them was 80cm2.
In order to investigate the possibility of porous hydroxyapatite ceramics (HAC) in the repair of skull bone defect, twenty-four rabbits were used. The bone defect model was created by operation to obtain a defect in parietal bone in a size of 1 cm x 1 cm. Filled the defect with HAC and methyl-methacrylate-syrene copolymer (MMAS) to fill the defect as control. At 1st, 2nd and 3rd months after operation, behavior of the rabbits was observed and then these animals were sacrificed and specimens were examined under microscope. Results showed as follows: after operation, behavior of all animals were normal. By histological examination, it was found that in HAC group, there were granulation tissue, fibrous tissue and newly formed vessels grew into the pores and the osteoblasts formed osseous trabeculae. There was no inflammatory cell infiltration. In the MMAS grafted asea, there was formation of fibrous membrane. It suggested that HAC might be a good material for bone substitute in repair of skull bone defect.
Craniofacial malformation caused by premature fusion of cranial suture of infants has a serious impact on their growth. The purpose of skull remodeling surgery for infants with craniosynostosis is to expand the skull and allow the brain to grow properly. There are no standardized treatments for skull remodeling surgery at the present, and the postoperative effect can be hardly assessed reasonably. Children with sagittal craniosynostosis were selected as the research objects. By analyzing the morphological characteristics of the patients, the point cloud registration of the skull distortion region with the ideal skull model was performed, and a plan of skull cutting and remodeling surgery was generated. A finite element model of the infant skull was used to predict the growth trend after remodeling surgery. Finally, an experimental study of surgery simulation was carried out with a child with a typical sagittal craniosynostosis. The evaluation results showed that the repositioning and stitching of bone plates effectively improved the morphology of the abnormal parts of the skull and had a normal growth trend. The child’s preoperative cephalic index was 65.31%, and became 71.50% after 9 months’ growth simulation. The simulation of the skull remodeling provides a reference for surgical plan design. The skull remodeling approach significantly improves postoperative effect, and it could be extended to the generation of cutting and remodeling plans and postoperative evaluations for treatment on other types of craniosynostosis.