| Objective: Many skull repairing materials are available, but as far as now none can completely substitute skull as of the aspects of plastic, anti-impact, resistance, heat prevention and antimagnetism, etc. Therefore somebody used the autogenous skull flap to be buried subcutaneously and then transplant back to the patient after a period. But when burying and taking out the skull flap the patient has to undergo pains of twice operations, and the buried flap is easy to be absorbed to become contracted. Somebody else preserves the flap in the bone bank to be deeply frozen, and when in need take out to recover the temperature. But the need for freezing devices limited its popularization. During the operations for trauma of skull and brain or operations of brain tumor, in order to depress the intracranial pressure, the bone flap has to be removed and thus skull damage results.The bone flaps of these patients are usually intact, and throwing away will be very pitiful. Repairing by the currently popular titanium alloy in the second stage is too expensive and the physiological curve is not perfect. But repairing by autogenous porous flap is very easy, cost-effective and beautiful. Our clinic studies have confirmed that this method is applicable and have achieved remarkable effects. In order to explore the feasibility of the biological repair of skull defect, this study has carried out a pathological study on the bone frame of the receptor zone, to determine whether the isolated autogenous dead bone flap can be used as an ideal repair material for skull defect.Method: New Zealand large white rabbits were taken to make skull defect model. The extracted skull was made into porous flaps by high-speed skull drill. After being seethed for 30 minutes they were transplanted back to the original place. The material was taken out 2, 4, 8 and 12 weeks later respectively for histological, electronic microscope and immunological histochemical tests.Results: l.General shape: After 2 it was still dead bone, no flbrotic or connective tissues grew; after 4 it was covered by some fibrotic and connective tissues, blood supply was already constructed; after 8 weeks in the dural surface some connective tissues grew into the dead bone; after 12 there was new bone to form bony healing. Observation for 12 weeks on the blank control group found no osteogenesis, and the defected area was filledwith fibrotic tissues. 2.Histological tests: The tabular bone and marrow cavity can be seen in the normal skull structures. After being seethed for 30 minutes the lacunar cells in the osseous lamella were dead and the marrow cavity was destroyed. Two weeks after transplantation, some fibrotic and connective tissues as well as blood vessels has grown into the bone foramens; four weeks after transplantation, the fibrotic and connective tissues as well as blood vessels has grown and the bone island was visible; eight weeks after transplantation the dead bone revived and new marrow cavity was formed; 12 weeks after transplantation proliferation of the new bone was active and many bone trabecula were formed and the marrow cavity was connected again. S.Immunological histochemical tests of BMP: the bone matrix of the isolated autogenous porous skull flap that was inactivated by high temperature was slightly positive. The non-differential interstitial cells of the periosteum, dura and fibrotic connective tissues were positive, the osteoblast of the new bone were strongly positive. 4.Electronic microscope test: normal bone structure: internal and outer osseous lamella, bone trabecula in the marrow cavity; after being seethed for 30 minutes: internal and outer osseous lamella, and bone trabecula still existed; 12 weeks after transplantation in the interface the bony healing could be seen. Conclusion: After inactivated by high temperature the flap's bone frame which is formed by organic substances and calcium salts was not destroyed, and they have the natural regeneration conditions of conductive bones. Andin the condition o... |
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