Dove tail osteotomy in distraction osteogenesis of costochondral bone grafts in the mandible: a new concept.

To correct the malocclusion and facial asymmetry in patients with Pruzansky type III hemifacial microsomia after autogenous costochondral grafting during early childhood (two male and three female patients with an average age of 17.8 years), the technique of distraction osteogenesis with a three-dimensional device was used. Because of the missing periosteum of the transplanted rib and its relatively small height compared with the horizontal mandible, a dovetail geometrical pattern osteotomy was introduced to increase the osteotomy surface area, which by itself could enhance the amount of fibrin filaments between 30% and 40% in the hematoma occurring during the initial distraction process. These fibrin filaments are biofunctional guiding structures for the development of the microcallus, followed by enhancement of the bone-healing capacity, which allows optimal bone regeneration. Between 20 and 27 days (mean = 21.5 days) after distraction, complete ossification was noted radiographically in all treated patients. Based on our histological animal studies and clinical investigations, dove tail osteotomy enhances the osteotomized surface area and offers protection to the tension-sensitive structures in the center of the distraction zone. It increases early bone formation and mineralization adjacent to the center zone in the distraction gap. Therefore, the dove tail geometrical pattern in combination with distraction osteogenesis of autologous costochondral grafts in the treatment of congenital Pruzansky type III mandibular hypoplasia is strongly recommended.