Morphometric analysis of the Korean mandibular ramus for distraction osteogenesis using micro-computed tomography.

When performing distraction osteogenesis, the osteotomy is normally applied to the cortical bone posterior to the mandibular second molar. We measured the topographic thickness of the cortical and trabecular bone of the mandibular ramus and at the mandibular canal (MC) to provide crucial anatomic data aimed at minimizing complications and elucidating the most appropriate site for placing the distractor. Forty sides of the mandibles were prepared from 20 Korean cadavers (10 men and 10 women with a mean age of 68 years). The specimens were scanned and reconstructed into three-dimensional images using a micro-computed tomography system. Coronal and horizontal sectional images of the mandibular ramus were taken at thickness intervals of 2 mm from the reconstructed three-dimensional images. Image analysis software was used to measure the thicknesses of the cortical and trabecular bone and to identify the locations of the MC within the body and the mandibular ramus on each section. The mean thicknesses of the buccal cortical plate, trabecular bone, and lingual cortical plate were 2.9 mm (men, 3.0 mm; women, 2.8 mm), 9.1 mm (men, 9.8 mm; women, 8.5 mm), and 2.2 mm (men, 2.3 mm; women, 2.1 mm), respectively. The distance from the buccal surface of the mandible to the MC increased from 5.3 to 10.0 mm (men, 5.3-10.0 mm; women, 5.3-9.1 mm) when moving progressively anterosuperior from the mandibular angle region. Morphometric analyses of the mandibular ramus can provide crucial data when performing mandibular osteotomy and locating an appropriate placement site for a distractor device during the distraction-osteogenesis procedure.