Analysis of the nasal bone and nasal pyramid by three-dimensional computed tomography.

Evaluation of the nasal bone and nasal pyramid is essential for the correct osteotomy. The shape of the nasal bone and nasal pyramid of Korean subjects were analyzed using a three-dimensional computed tomography (CT). This study includes 75 patients who visited Inha University Hospital and got a three-dimensional CT from October 2005 to June 2006 (58 males, 17 females, mean age of 33.1 years). The thickness of the bone at the nasomaxillary suture as well as between the rhinion and nasomaxillary suture, on which a lateral osteotomy was performed, was measured. In addition, the length of the nasal bone and the width of pyriform aperture were measured. The morphology of the nasal bone was classified from A to E type, according to Hwang's method. The subjects included 58 males and 17 females with a mean age of 33.1 years. The mean thickness of the lateral osteotomy point is 2.03+/-0.35 mm and that of the medial osteotomy point is 1.75+/-0.37 mm. The mean length of the nasal bone is 20.95+/-5.99 mm. The number of patients with a long nasal bone (more than 25 mm) is 14.7% (11/75). The most common morphology of the nasal bone is A type and there is no D or E type. Since there is no significant difference in the thickness of the nasal bone at the lateral and intermediate osteotomy point, the same strength should be used to perform the correct lateral and intermediate osteotomy. However, the actual lateral osteotomy is performed at a more lateral position than the nasomaxillary suture, which is our standard of measurement. So, using more power in the lateral osteotomy should be considered. There were nine patients with a long nasal bone in this study. For these patients, better results with percutaneous transverse osteotomy could be expected.