BONE LENGTHENING IN THE CRANIOFACIAL SKELETON

The process opf bone lenghthening by cortical fracture and gradual distraction of callus has become well established in the enchondral bones of the extremities. In this study the principles of bone lenghthening were applied to the membranous bone of the craniofacial skeleton using the growing dog mandible as a model. six mongrel dogs five months of age were studied. A unilateral, periosteal-preserving angular corticotomy was performed, and an external minilenghthening device was fixed to the mandible perpendicular to the corticotomy. After 10 days of external fixation, the mandible was lenghthened 1 mm/day for 20 days and then held in external fixation for 56 days (8 weeks) after which all dogs were killed. Anthropometric measurements and histological analysis of the specimens confirmed that bone lenghthening had occured and that new cortical bone was formed in the expanded areas.