| Objective:To investigate the application of the autogenous outer mandibular cortex in the treatment of cranial defect.To observe the effect of skull defect on the growth of skull and brain,to explore the effectiveness and practicability of the mineralized collagen artificial bone in management of skull defect in immature porcine model.Methods:1.The clinical research of the autogenous mandibular outer cortex to repair the cranial defect.From Jan.2002 to Dec.2016,11 cases with skull defect,who underwent outer mandibular plate implanting operation were retrospectively studied.Preoperative CT data was collected to measure the defect size and outline.Then suitable sampling site was designed and selected.The outer mandibular table wassplitted in oral path.The modified bone was implanted to reconstruct the skull defect.3D CT scan was performed immediately after operation and 3 to 12 months postoperatively.The change of lower face width,the absorption rate and the regeneration rate of autogenous bone were calculated.2.The experimental research of the mineralized collagen artificial bone to repair the skull defect of the immature miniature pig.Animals are divided into three groups.Group A:normal group;Group B:simple defect group;Group C:mineralized collagen artificial bone repairing group.11 immature miniature pigs were randomly divided into 3 groups,skull defect 23 mm in diameter were made in group B and C,group C received material implanting operation at the same time.X-ray and three-dimensional CT were performed immediate postoperatively,3 months and 6 months.After 6 months,animals were killed,histological examination was performed.Each animal 's weight,brain volume and brain weight were weighed and recorded.The biomechanical property of the new bone and normal bone were analyzed,including compressive strength and bending strength measurement.Analyze the effect of skull defect on the growth of skull and brain,discuss the effect of the mineralized collagen artificial bone in repairing the immature miniature pig's skull defect.Results:1.The absorption rates of autogenous bone covered the cranial defect was(21.01±11.42)%postoperatively,the regeneration rate of outer mandibular panel was(41.65±9.85)%.According to Friedman test,there is statistical difference in different period of model A's volume(P<0.05),there is statistical difference in different period of model B's volume(P<0.05).Wilcoxon signed rank test was applied to analyze the change of lower face width.According to the results,significant difference exists between the preoperative postoperative lower surface width and the postoperative.2.7-month old,group A,the volume of brain is(49.00±2.00)ml,the weight of brain is(52.47±1.46)g;group B(46.67±1.53)ml,(50.40±1.47)g;group C(47.20±1.92)ml,(51.12±1.64)g.There is no statistical difference between group A and group B.There is no statistical difference between group A and group C.X-ray and CT imaging,7-month old,bone collapse and a small amount of bone hyperplasia can be observed in group B,group C had visible new bone around the repair material,which covered the entire repair materials,apart from the center spare of materials.10-month old,the surrounding bone collapse of group B is more apparent,a little of bone hyperplasia can be found around the local,disc defect was still obvious,the material area in group C was filled completely with new bone,connected with the surrounding bone,and the defect was repaired basically.Head circumference measurement,when experimental animal was 7-month old and 10-month old,the cranial length and base length of group B are less than group A,there were statistical differences(P<0.05),there is no statistical difference between group A and group C;the orbit and zygomatic wide of three groups have no statistical difference(P>0.05).A small amount of callus can be found around the defect in group B,surrounded by scar connective tissue.The material was covered completely by mature bone,much new bone tissue and osteoblast were distributed in the pore of the material,and partial material was residual.When experimental animal was 10-month old,the compressive strength of new bone is(2.674±0.209)MPa,the normal bone(4.341±0.273)MPa,there is statistical difference with the application of Wilcoxon signed rank test(P<0.05),the compressive strength of new bone is less than the normal's.The new bone's bending strength is(127.3966±4.8959)MPa,normal bone(74.3459±6.2914)MPa,there is statistical difference(P<0.05),the bending strength of new bone is stronger than the normal's.Conclusion:1.The autogenous outer mandibular panel implanting operation can achieve a good clinical effect,with the improvement of the outline of lower contour.The absorption rate of autologous jaw plate is low and the lower jaw plate can regenerate very well.2.Skull defect can affect the development of the skull of immature porcine,and have no effect on brain development.3.Nano-hydroxyapatite-collagen composite is a kind of applicable skull defect repair materials. |
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