XENOGENIC DEPROTEINIZED BONE SUBSTITUTE P YROST - EXPERIMENTAL BASICSAND 13 YEARS OF CLINICAL-EXPERIENCE IN MORE THAN 1000 CASES

In different animal investigations Pyrost demonstrated osteoconductive and osteostimulative effects. In ectopic tissues and especially in co nditions of low osteogenetic potency, the combination of Pyrost and au togenic bone marrow effects bone formation. In a clinical prospective study, Pyrost was implanted in 1117 cases in the following indications : Donor site defects after bone transplantation, bone defects after tu mor resection, revision of THA, acetabuloplasty, fracture treatment, p seudarthrosis and lengthening osteotomy, spondylodesis. In 87.3 % the regeneration of the bone defects was complete, in 8 % a partial regene ration was found. Excessive bone formation took place in 2.7 %, insuff icient regeneration in 2.0 % in cases of instability or infection. Acc ording to the clinical results Pyrost is a suitable bone substitute in small bone defects and it is a valuable completion to the autogenic b one graft in large defects. In disadvantageous bone bed Pyrost has to be augmented with bone marrow and in large segmental defects the combi nation with autogenic bone grafts is recommendable. Pre-supposition fo r the application of bone substitutes like Pyrost in large defects is a sufficiant primary stability of the bone bed. The application in inf ected tissue is not favorable.