Measuring Symmetry in Children With Cleft Lip. Part 3: Quantifying Nasal Symmetry and Nasal Normalcy Before and After Unilateral Cleft Lip Repair.

Abstract

The purpose of this project was to develop objective computer-based methods to measure nasal asymmetry and abnormality in children undergoing treatment of unilateral cleft lip (UCL) and to determine the correlation of these measures to clinical expectations. Thirty infants with UCL undergoing cleft lip repair; 27 children with UCL aged 8 to 10 years who had previously undergone cleft lip repair; 3 control infants; 3 control children aged 8 to 10 years. To measure nasal symmetry, we used a process of depth mapping and calculated the Depth Area Difference. To measure abnormality, we used the reconstruction error from Principle Component Analysis (PCA) that was based upon characteristics of a dataset of over 2000 images of normal control subjects. Depth Area Difference and PCA Reconstruction Error for cleft type, changes with surgery, and individual subjects ranked according to cleft severity were assessed. Significant differences in Depth Area Difference and PCA Reconstruction Error were found between cleft types and found before and after surgery. Nasal symmetry and normalcy scores for infants with UCL approached those of controls after surgery, and there was a strong correlation with ranked cleft severity. For older children, measures of nasal symmetry and abnormality were better than infants prior to repair but worse than infants following UCL repair. Our computer-based 3D analysis of nasal symmetry and normalcy correlated with clinical expectations. Automated processing made measurement convenient. Use of these measures may help to objectively measure cleft severity and treatment outcome.