EXTRACORPOREAL IRRADIATION AND INCORPORATION OF BONE-GRAFTS - AUTOGENEIC CORTICAL GRAFTS STUDIED IN RATS

The incorporation of resected, extracorporeally irradiated (1, 5, 25 a nd 50 kGy) and orthotopically reimplanted autogeneic cortical bone was investigated in 116 adult Wistar rats. 7 mm-long diaphyseal segments of the tibia were resected, irradiated and reimplanted using K-wire os teosynthesis. Autogeneic fresh grafts served as controls. Graft healin g was evaluated by radiography and histomorphometric study at 3, 6, 9, and 12 weeks. At 3 weeks, two thirds of the 50 key irradiated grafts were fractured and therefore the series with this dose was interrupted because of mechanical graft insufficiency. After 3 and 6 weeks there were no statistically significant differences among the control group and 1 or 5 kGy irradiated grafts. The healing of 25 kGy irradiated gra fts was delayed from the sixth week onwards and continued until the en d of the experiment at 12 weeks (50% reduction of incorporation). The incorporation of 1 and 5 key irradiated grafts showed a 16% (1 kGy) to 24% (5 kGy) delay at 12 weeks, compared to autogeneic fresh grafts. 1 and 5 kGy irradiated autogeneic bone grafts retain most of their biol ogical potential. Resection, extracorporeal irradiation and reimplanta tion of bone tumors may therefore be a possible alternative to allogra fting.