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Immunological evaluation by panel reactive antibody (PRA) and determination of anti-HLA specificity is an important phase in the assessment of patients awaiting kidney transplant. The main causes of immunization are previous solid organ transplants, blood transfusions, and pregnancy; immunogenicity can also be triggered by vascularized tissue grafts. Immune induction by cryopreserved bone allografts is not yet fully understood. We report the case of a 19-year-old patient with osteosarcoma who underwent resection of the left proximal tibia with reconstruction using human bone in 1997 (donor typing: A3, A29 (19) - B44 (12), Bw4 - DR13 (6), DR7, DR52, DR53). The patient was subsequently placed on the waiting list for a cadaver donor kidney transplant because of chronic kidney failure caused by cisplatin toxicity. Pretransplant immunological screening using the CDC (complement dependent cytotoxicity) technique revealed a PRA of 63% and anti-A3 and anti-A68 antibodies. The presence of IgG antibody specificity against class I and class II donor antigens (specifically anti-A3, B44, DR7 antibodies) was highlighted using flow cytometry (Tepnel-Luminex). Further immunological studies using single HLA specificity analysis (LSA Class I - II - Tepnel-Luminex) detected direct antibodies against all donor antigen specificities. This is the first reported case of immune induction after a bone graft in a kidney transplant candidate. It underlines the importance of the availability of HLA typing data of all human allograft donors.

Background: Bone deficits of the midface can be observed following tumor surgery, facial traumas or malformations, and can determine aesthetic deformities requiring surgical corrections. The goal of this study is to illustrate the 23 years experience of the Maxillo-Facial Department of the "La Sapienza" University of Rome, in surgical correction of middle third bone loss for aesthetic improvement, and to compare postsurgical results from the use of biomaterials and homologous bone grafts., Methods: From January 1977 to January 2000, 18 patients were surgically treated with bone grafts for bone deficit of the midface requiring aesthetic improvements, and 23 received biomaterial placement in the same district. A retrospective analysis regarding aesthetic improvements following corrective (reconstructive) surgery was carried out in order to compare long-term results obtained with bone grafts and biomaterials., Results: Of the 19 implants of the zygomatic bone, 1 patient suffered from infection, observ-ed on the 8th day, following iliac bone graft in the maxillary area. Of the 32 prostheses, 7 became infected and in 1 case the material became exposed: Proplast(R) became infected 2 times, Gore-tex(R) 3 times and 1 time became exposed; 2 of the 24 Medpor(R) implants resulted in infection. The employment of bone graft obtained a good short term aesthetic result. Medpor(R) employment, was evaluated as an optimal aesthetic improvement. We cannot evaluate the results obtained with Gore-tex(R) and Proplast(R) because of the few cases treated. Anyway we consider unsatisfactory the corrections obtained with these 2 materials., Conclusions: Homologous bone grafts are still considered as the best choice when a further fixture positioning is planned for prosthetic rehabilitation of the alveolar ridge of the upper jaw or mandible. At the present time, some biomaterials are the definitive solution for restoring facial harmony in the 3 spatial dimensions.

Xenologous bone grafts are frequently used in modern orthopaedic surgery. There is a risk of infection associated with the transmission of diseases among different species for these types of grafts. As for bovine bone grafts in recent times attention has been paid to the diffusion in various countries of the European Economic Community of "bovine spongiform encephalopathy"; this pertains to the same group of encephalopathies as Creutzfeldt-Jakob disease which strikes humans and has a lethal outcome. Thus, in the absence of clinical evidence, there is a potential source of risk of infection associated with specimens of bovine origin in relation to which a document of the European community suggests proceeding by sterilization by autoclaving at 132 degrees C. for at least 1 hour. It is the purpose of this study to verify the effect of this treatment on the mechanical properties of bone graft. The results show how this procedure reduces the graft's resistance to compression by approximately 70%. Thus, it is not acceptable for all bone grafts for which good mechanical resistance is required. In cases such as these, bovine bone grafts may be used only when the immunity of the farm of origin has been certified; then sterilization may be conducted using methods that are less destructive for the mechanical integrity of the bone tissue.

The authors report their experience in the histologic study of massive allografts, explanted as a result of oncological, mechanical or biological complications. The study was conducted according to the method of inclusion in methyl methacrylate that does not involve decalcification. A description is provided of all of the phases of fusion between graft and host bone in the site of the osteotomies, as well as distribution of revascularization and rehabilitation of the graft, attachment of the soft tissues, and finally, modifications in the joint cartilage of the osteoarticular grafts. The allograft must be considered to be osteoconductive, and is only weakly osteoinductive. Incorporation of the graft is a slow and incomplete process that follows sequential phases. The Volkmann's canals in the osteotomies constitute the preferred paths for rehabilitation of the graft that is on the order of millimeters on the surface and centimeters in the site of the osteotomies. The greatest modifications have been observed in the joint cartilage. The cartilaginous cells appear to be vital only from a morphological point of view.

A report is presented on 5 years experience with 33 cases of free vascularized bone transplants for extremity preservation. The indications, results and complications will be demonstrated. The successful results so far were achieved not only by careful indications but by virtue of a strict postoperative treatment scheme extending from direct postoperative blood-flow monitoring through the raising of a skin flap and angiographic control of anastomosis patency to immobilisation/mobilisation and orthotic management.

The authors describe the surgical technique used to obtain (by anterior and posterior access) autoplastic bone from the ilium in 186 oncological cases. Indications, the results obtained and the principal causes of complications are discussed.