CALLOTASIS IN NONVASCULARIZED PERIOSTEAL BONE-GRAFTS AND THE ROLE OF PERIOSTEUM - A NEW CONTRIBUTION TO THE CONCEPT OF DISTRACTION OSTEOGENESIS

Bone lengthening by slow, progressive distraction has gained widesprea d acceptance. In this study we investigated the possibility of distrac tion osteogenesis in nonvascularized periosteal bone grafts, and asses sed callus formation and callotasis by means of radiological and histo logical examination with the aim of determining the role of the perios teum. The process of distraction osteogenesis in nonvascularized bone grafts was studied histologically and radiologically in 22 growing rab bits. The metatarsal bone grafts taken from the rabbits were divided i nto two groups. Group 1 contained 15 bone grafts covered with perioste um and group 2 (the control group) contained 7 bone grafts without per iosteum. These grafts were subjected to osteotomy and then placed in t he lumbar pocket. After 10 days, distraction was started and continued at 0.5 mm per day for 10 days. Thus an elongation of 4 to 6 mm was ac hieved in both groups. Radiological examination was performed postoper atively and after 10, 15, 20, and 30 days of starting the distraction. Histological examination was performed after 15, 20, and 30 days. Rad iologically, progressive calcification and, histologically, both intra membranous and endochondral ossification were detected in group 1 Howe ver, in the control group (group 2), bone lengthening failed. Our stud y demonstrated the possibility of distraction osteogenesis in perioste al bone grafts, and provides information regarding the importance of p eriosteum as well as its osteogenic capacity.