Assessment of maxillary arch changes and nasolabial esthetics following primary lip repair in patients with complete unilateral cleft lip and palate using nasoalveolar molding therapy

Abstract

Background: Complete unilateral cleft lip and palate (UCLP) is characterized by pronounced facial asymmetry resulting from maxillary arch displacement and nasolabial deformity. Presurgical nasoalveolar molding (NAM), combined with primary lip repair, aims to guide maxillary growth and enhance nasolabial symmetry. However, the combined effects on three-dimensional (3D) maxillary arch development and nasolabial esthetics remain insufficiently explored. This study aimed to evaluate 3D changes in maxillary arch morphology and nasolabial esthetic outcomes following primary lip repair in patients with complete UCLP. Methods: This retrospective-prospective cohort study comprised two parts.In the maxillary arch morphology component, 25 infants with complete UCLP underwent modified NAM therapy prior to primary lip repair. Digital maxillary models were obtained at two time points: T1 (on the day of primary lip repair, aged 3–6 months) and T2 (on the day of palate repair, aged 9–18 months). Three-dimensional linear and angular measurements were conducted to assess transverse, sagittal, and vertical dimensional changes. Paired t-tests or Wilcoxon signed-rank tests were used based ondata distribution, with a significance threshold of p < 0.05. Morphological changes were visualized via digital model superimposition using stable posterior maxillary landmarks.In the nasolabial esthetics component, 22 infants with complete UCLP who had undergone NAM therapy before primary lip repair were included. Nasolabial esthetics were evaluated using nasal and perioral symmetry indices, along with the Asher–McDade rating scale. Standardized two-dimensional facial photographs were taken post-primary lip repair 1-4 weeks (Tn1) and at the 6 month follow-up (Tn2). Symmetry ratios were measured using ImageJ software, based on predefined anatomical landmarks and reference planes. All measurements were performed by calibrated, blinded examiners. Intra- and inter-rater reliability were assessed using intraclass correlation coefficients (ICC). Perceptual esthetics were evaluated by three independent plastic surgeons, with repeated ratings to ensure reliability. Results: In the maxillary arch morphology analysis, significant changes were observed in the transverse and sagittal dimensions. The anterior cleft width significantly decreased (mean difference = -0.95 mm, p = 0.001), while the anterior and posterior arch widths significantly increased (mean differences = 1.81 mm and 0.99 mm, respectively). Both greater and lesser segment lengths increased, and medial rotation of the greater segment was noted. Vertical dimension changes were not significant. Superimposition revealed medial movement of the greater segment and cleft gap narrowing.In the nasolabial esthetics analysis, significant improvements were found between Tn1 and Tn2. Nasal symmetry parameters improved, demonstrating better transverse and vertical nasal symmetry and midline alignment. In the perioral region, philtrum height symmetry significantly increased, while cupid’s bow width, inter-commissure distance, and vermillion height ratios remained stable. These results indicate marked improvement in nasal symmetry and selective enhancement in perioral symmetry, with stable transverse oral dimensions during early growth. Conclusions: Primary lip repair promotes coordinated early skeletal and soft tissue adaptation, evidenced by significant maxillary arch remodeling and nasolabial symmetry improvement. The strong interrelationship between skeletal development and soft tissue esthetics emphasizes the importance of integrated early cleft management.4