Abstract
Both intended and unintended surgical modifications of nasal width and shape of the
nasal tip continue to be of interest to the rhinoplasty surgeon. As validated instruments
for quantifying width and boxiness are lacking, the objective of this study was to
introduce a width index and a boxiness index for the nasal dorsum and the nasal tip.
A width index and a boxiness index were defined within the methodological limits of
noncontact sonography. The reliability of both indices was studied by comparing the
measurements of two examiners on the noses of five volunteers. The validity of the
indices was studied by correlating the sonographic width and boxiness with the 5-point
Likert scale ratings of photographs of 5 noses by 21 lay persons. Nasal width was
defined as the diameter at a distance of 5 mm from the skin surface on a sonographic
cross-section perpendicular to the skin surface. Boxiness was defined as the quotient
of width at a depth of 1 and 5 mm. Bland–Altmann analysis revealed negligible bias
between both examiners and 95% of limits of agreement of 13, 7, and 13% for width
at 1 mm, width at 5 mm, and boxiness, respectively. Corresponding Pearson's correlation
coefficients were r = 0.93, r = 0.93, and r = 0.71. The correlation between the cumulative lay persons' scores and sonographic
width and boxiness were r = 0.97, r = 0.66, and r = 0.81 for nasal tip width, dorsal width, and boxiness, respectively. Both the width
at a depth of 5 mm as measured with sonography and the boxiness index that is defined
as width at a depth of 1 mm divided by the width at a depth of 5 mm may prove to be
acceptable surrogate parameters for width and boxiness of the nose in comparative
morphometric studies.
Keywords
rhinoplasty - morphometry - sonography - nasal width
