Mandibular bi-directional distraction osteogenesis: A technique to manage both transverse and sagittal mandibular diameters via a lingual tooth-borne acrylic plate and double-hinge bone anchorage

Purpose: Mandibular hypoplasia can develop transversely, sagittally, or in both diameters simultaneously. Current techniques achieve either sagittal or transverse expansion with different surgeries. Here, we present a novel method to obtain transverse and sagittal mandibular distraction in one stage.Materials and methods: The technique consists of a double osteotomy: a dento-alveolar osteotomy comprising four or six anterior teeth and a vertical symphysiotomy underneath. The mandibular basal bone is immediately expanded transversely and fixed to the lower symphysis via a miniplate carrying only one screw on each side that functions as a hinge during active distraction. The plate is connected to the anterior dento-alveolar block with a metal wire ligature. A teeth-anchored lingual distraction system can expand transversely at the alveolar bone level and then sagittally with the anterior dento-alveolar segment wired to the lower plate.Results: Satisfying and stable results were achieved, confirmed by measurements on serial plaster casts.Conclusion: To the best of our knowledge, this is the first proposal for ortho-surgical correction of both transversal and sagittal mandibular hypoplasia via a bi-directional distraction procedure. A combination of bone-hardware anchorage and dental-anchored distraction systems is suggested.Transmucosal hardware emergence and need for a second surgery to remove bone-borne appliances are avoided. (C) 2019 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.