Distraction osteogenesis in the irradiated rabbit mandible

SummaryPurposeThe potential use of distraction osteogenesis in mandibular reconstruction has been limited by its questionable efficacy in previously radiated bone. The purpose of this study was to evaluate the effects of irradiation on mandibular distraction osteogenesis (DO).Materials and methodsSix rabbits received a unilateral irradiation (group R) in the mandible with a total dose of 27.0 Gy in five 5.4 Gy fractions (equivalent to 50 Gy/25 fractions). The contralateral side served as control (group C). Bilateral osteotomy was made 3 months after completion of irradiation. After a 1-week latency period bone distraction was activated at a rate of 0.5 mm twice daily for 8 days, followed by a consolidation phase of 6 weeks. New bone underwent radiographic, densitometric, histological and histomorphometric analysis.ResultsTwo rabbits were excluded from the study, one due to infection on both sides and death in another animal. After 6 weeks of consolidation, the irradiation group had no significantly lower BMD than control group. No difference was found between the percent area of new bone in both groups. New bone was more mature and organised of group C than in groups R. Larger chondroid islands were found evident in distracted bone of group R than group C.ConclusionsIt seems that DO can be feasible in previously irradiated rabbit mandible.