A longitudinal three-dimensional analysis of nasolabial morphology following primary cheiloplasty of unilateral cleft lip deformity

Background Primary cheiloplasty is the first definitive surgical intervention for infants with cleft lip and plays a central role in establishing the foundation of postoperative nasolabial morphology. Because the early configuration of the lip and nose can influence long-term facial harmony, achieving an anatomically favorable morphology at the time of initial surgery is an important clinical objective. At our institution, primary cheiloplasty is performed using the Cronin method in combination with nasal vestibular expansion (NVE), a technique designed to improve symmetry by simultaneously repositioning the soft tissues of both the lip and the nose. However, the extent and pattern of nasolabial morphological change during the early postoperative period and throughout the first year of growth remain insufficiently understood. This study therefore aims to longitudinally investigate postoperative changes in nasolabial morphology following primary cheiloplasty performed using the Cronin method with NVE. Methods Twenty children with unilateral complete cleft lip were included in this study. Three-dimensional (3D) soft-tissue images were obtained using the Vectra H1® system at 1, 3, and 6 months and 1 year after surgery. An image analysis was performed using HBM-Rugle®, and symmetry was assessed by comparing the affected and non-affected sides. A reference plane was defined using the bilateral endocanthion points and the alar base point on the non-cleft side to ensure consistent spatial measurement of 3D coordinates. Results The cleft-to-non-cleft side ratios of the alar base were 0.85–0.93 for the X -coordinate, 1.01–1.07 for the Y -coordinate, and 1.06–1.22 for the Z -coordinate across the four time points. Ratios for white-lip length were 0.86, 0.86, 0.84, and 1.02, whereas nasal-floor length ratios were 1.31, 1.38, 1.50, and 1.41. These trends indicated a slight deterioration in anteroposterior symmetry of the alar base and nasal floor over the first postoperative year, while white-lip length progressively improved and approached near-symmetry by 1 year. Conclusions This longitudinal 3D analysis demonstrates region-specific postoperative changes within the nasolabial complex, suggesting that individual anatomical components exhibit distinct growth or relapse patterns. These findings may help refine surgical planning and early postoperative management aimed at optimizing nasolabial morphology following primary cheiloplasty with NVE.