| Objectives : During the operations for trauma of skull and brain or operations of brain tumor, in order to depress the intracranial pressure and hydrocephalus, the bone flap has to be removed and thus skull damage resulted. Most of these patients need a cranial bone forming operation at the second stage, at present people think the operation should be done in 3to6 months after the decompression procedure. It is rarely done in a super-earlier period(within 2 weeks). Many skull repairing materials are available, but as far as now none can completely substitute skull as the advantages of plastic, anti-impact, resistance, heat prevention and anti-magnetism, etc. So some people preserve the flap in the bone bank to be frozen deeply, and take it out as recover the temperature when it is needed. But this way is not very popular because of the limitations of freezing devices. Repairing by the current titanium alloy is too expensive and it has many disadvantages since it is extraneous material. Repairing by subcutaneously preserved autogenous bone flap is easy, economical and beautiful. So we have designed this animal experiment as the pre-experiment of super-earlier period subcutaneously preserved autogenous skull flap cranial bone forming technique to find out some objective indexes of clinical operation indication. We can also observe the biological and morphological changing regularity of the bone flap both before and after the cranial bone forming operation.Methods :1 Animal modeling: decompression procedure to Experimental animal—32 healthy New Zealand white rabbits. Preserving the bone flap in abdomen to set up animal model of skull defect. The animals were randomly divided into three groups by different time,8 per group. We randomly chose 2 animals after 2,4,4 weeks of the decompression procedure, then observed the subcutaneous bone flap and piece of normal skull in histology and morphology and TEM(electron microscope). At the same time, we did autogenous bone flap forming operation to the rest 6 of every group. After 4, 2, 4weeks of the forming operation, we had the bone flap observed in histology and morphology and by TEM.2 Pathohistology: Observing the pathological changes of autogenous bone flap under optical microscope after performing HE staining.3 Determination of calcium content of bone: The calcium content of normal bone flaps and autogenous bone flaps which were taken out at each time points determinated in oscilloscopic polarography.4 observing with TEM: We had the normal bone and the autogenous bone flaps which were taken out at the different time point observed with HITACHI S-3500N TEM.Results :1 Morphology : Defects of the skull bone window appears with time gradually, the phenomenon of thickened dura mater, hard texture and rich blood supply appear. Abdominal subcutaneous buried bone with time gradually, thickened connective tissue was wrapped and removed after the bone tissue turns into the pale color, no obvious blood supply to establish. After the animal skull shape, with the back bone planting , the edge of a long fibrous connective tissue form, the initial blood supply establish. Bone thickening of the periosteal surface has been covered, and binds tightly, rich bone blood supply, touch of easy bleeding; Dural surface of the connective tissue grew into the flap edge, the edge of bone and bone healing bone window.2 Pathohistology : Structure of the normal skull bone and marrow cavity plate are visible. Buried subcutaneously in the abdominal autologous bone can be seen as the time grew into the fibrous connective tissue, bone plates in the death of pit cells, bone marrow cavity damage, cell death, but the bone plate and trabecular bone exist. After the implantation of bone, with the time pass by, fibrous connective tissue and blood vessels can be seen gradually grow into the surrounding bone edge of the periosteum from the fibrous connective tissue and vascular in growth, the bone island, after the resurrection of the visible part of sequestrum, the formation of new marrow cavity.3 Determination of bone calcium : Autologous bone after subcutaneous longer kept, the calcium content of bone tissue showed the trend of gradually decreasing. The data at each time point obtained by the statistical treatment of Subcutaneous buried 2 weeks the average bone calcium content in the normal group were not statistically significant difference (P>0.05), The buried 4-week average calcium content in the normal group, 2 weeks time the results were statistically significant differences (P<0.05). After replantation the average calcium content in bone with time showed an upward trend gradually. Statistical analysis derived, autologous bone skull shape after 2 weeks, 4 weeks the average bone calcium content bone calcium content in the normal skull there is a statistically significant difference (P<0.05).4 Scanning electron microscope test : normal bones structure: Inside and outside the bone plate and trabecular bone marrow cavity; Abdominal skin flap preservation: Inside and outside the bone plate and trabecular bone remain; After implantation of autologous bone healing of bone.Conclusion :1 An experimental animal decompressive craniectomy in the early time window after 2 weeks, 4 weeks to implement the second autologous skull bone flap angioplasty are feasible.2 Experimental animals after decompressive craniectomy-line autologous bone subcutaneous buried, its biological properties have a certain gap between the normal skull, but buried between 2 weeks and 4 weeks is not.3 Experimental animals after decompressive craniectomy-line autologous skull shape, bone flap back sooner, the better bone healing, that is 2 weeks (very early) back to the bone healing after flap better than 4 weeks.4 Ultra-early bone flap back, the dura thickened to a lesser extent, the degree of adhesion with surrounding tissue lighter, easy-to-flaps full, complete separation, consistent with the physical, brain tissue is conducive to the protection and recovery after injury.
|
PDF Full Text Request