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The authors describe in detail the preparation of six batches of human AAA/autolyzed antigen-free allogenic bone/ prepared in 1985 to 1988. This bone was administered to a total of 48 children and adolescents aged 6 to 19 years. It was used to fill cavities after metaphyseal connective tissue bone defects /31 x/, solitary bone cysts /10 x/, enchondromas /5 x/ and fibrous dysplasia /2 x/. The observation period was 2 years and 2 months to 5 years and 9 months. The mean volume of the cavities was 21 ml. In all patients the X-ray pictures were evaluated in a chronological sequence and changes on the host s bones in the cavity and the inserted AAA bones were described, and finally also changes of the entire bone complex with incorporated AAA implants. The results were arranged in tables. On the host's bones a periosteal reaction was observed in the area surrounding the focus, the entire cavity was covered with a soft shadow, there was sclerosis of the margins and bottom of the bone bed and gradual diminution of the bone defect from the sides and bottom of the bed. On the AAA bones the following observations were of interest: the connection of AAA bone with the surrounding newly formed bone, less clearly defined outlines of the AAA bone, loss of identity of the AAA bone. Sclerosis or elimination of the AAA bone were not observed. In three patients with batch 5 a "halo" effect was observed. On the entire complex with incorporated AAA bones the following were investigated: sclerosis of the entire portion of the bone, then regression and diminution of sclerosis, differentiation of the corticalis and medullary cavity and formation of a normal bone structure without signs of previous treatment. Preparation of six different batches of AA bone revealed that: 1.The spongious parts are more readily and more rapidly incorporated than the cortical part which is only partly demineralized. 2.Gelatinization with LiCI had a favourable effect on the incorporation of thus prepared implants. X-ray investigation revealed that the course of incorporation and reconstruction of these bones has the following specific features: 1.Reconstruction begins as a rule by the periosteal reaction of the host and its shift above the gap has a favourable effect on healing of the defect. 2.Two months after operation the cavity is covered by a soft shadow when the newly formed vessels and mesenchymal cells of the host infiltrate into the focus. 3.Activation of the bed is manifested by its greater density, sclerotization and by gradual diminution of the volume of the cavity. The greater density is not necessarily associated with diminution of the size of the cavity. 4.Bone implants are connected to the newly formed bone without passing through the stage of densi fication and sclerotization. The newly formed bone infiltrates them, absorbs and replaces the bone proper without signs of the previous stage of scle rosis, as observed in patients with frozen allogenic bones. 5.After incorporation of AAA implants further bone reconstruction takes place, as known from the healing of fractures or bone gaps. Key words: demineralized bone, AAA bone, benign bone tumors, reconstruction of bone transplant. |
