Computed Tomography Evaluation of Nasal Dimensions among Different Singaporean Ethnicities

Osteotomies in rhinoplasty are performed to correct deformities in nasal contour. The size of osteotome used is dictated by the thickness of the bony nasal pyramid along the osteotomy route. The aim of this study is to determine whether nasal bony dimensions differ between different ethnic groups in Singapore. Randomly selected patients' computed tomography (CT) scans of the face performed between the years 2010 to 2013 in our institution (Khoo Teck Puat Hospital) were evaluated. The setting was a tertiary government hospital. CT images of 309 patients (233 Chinese [147 males, 86 females], 32 Malays [16 males, 16 females], and 44 Indians [33 males, 11 females]) were evaluated. Anthropomorphic measurements of the nasal bone along the track of the lateral, medial, and intermediate osteotomies, as well as the nasal bone length and pyriform aperture width were measured on the CT images by two independent observers. Statistical analysis was performed using Student's t-test and two-way analysis of variance (ANOVA) test. There was no significant difference between the nasal pyramid bone thickness between different ethnicities along the osteotomy tracks (p > 0.05; degrees of freedom [df] = 2). However, there was a significant difference between males and females of the same ethnicity at the low level of the lateral osteotomy (p = 0.003) and the midlevel (p = 0.002) and high-level (p = 0.004) of the intermediate osteotomy. There was a statistically significant difference in nasal pyramid length (p < 0.05, df = 2) and pyriform aperture width (p < 0.05, df = 2) among the races and between the genders (p < 0.05). The mean difference in nasal pyramid length of 2.54 mm and pyriform aperture width of 1.89 mm was particularly significant between the Chinese and the Indians. Gender and ethnic differences in nasal bony dimensions should be considered in surgical planning for rhinoplasty.