A microradiographic investigation of cancellous bone healing after irradiation and hyperbaric oxygenation: A rabbit study

Purpose: To analyze the effect of irradiation on cancellous bone healing at different times after irradiation and to study if hyperbaric oxygen therap y (HBO) would affect the bone healing capacity, when delivered directly aft er irradiation. Methods and Materials: Rabbits were given a single dose of 15 Gy Co-60 radi ation to one hind leg, the other hind leg serving as control. A standardize d defect through the femoral metaphysis of the rabbits was created by a tre phine drill biopsy at different times after irradiation. New bone formation in the defect was evaluated by a new biopsy through the previous defect af ter a healing time of 8 weeks. The mineral contents of the biopsies were an alyzed by microradiography and microdensitometry. Results: There was a large variation in the bone-forming capacity expressed as bone mineral content between the animals, No statistically significant differences could be detected regarding the effect of irradiation, HBO, or delayed surgery. Qualitative histology revealed more pronounced inflammatio n, fibrosis, and bone resorption in the irradiated bone. Conclusions: No definite conclusions can be drawn from the results: of this study, however it might be hypothesized that cancellous bone recovers fast er than cortical bone from radiation trauma. (C) 2000 Elsevier Science Inc.