Biomechanical Comparison of Philtrum and Cupid’s Bow Reconstruction Techniques for Secondary Unilateral Cleft Lip Deformities

Background: Secondary unilateral cleft lip deformities often present with philtral asymmetry and flattening. This study aimed to compare different reconstruction techniques using 3-dimensional finite element analysis (FEA). Methods: This proof-of-concept study used Computed Tomography (CT) imaging data from a representative patient with secondary unilateral cleft lip deformity. Four techniques were compared: Innovative Bilateral Method (with/without lip peak reconstruction), Conventional Unilateral Method, and Overlapping Suture Method. Biomechanical simulations assessed deformation patterns using Y-axis displacement curves and anatomic landmarks. Results: The Innovative Bilateral Method with simultaneous lip peak reconstruction demonstrated superior biomechanical performance across all evaluated parameters. Mean displacement values at the lip peak were 1.23 mm on the unaffected side and 1.13 mm on the affected side, significantly higher than other methods ( P <0.05). This technique achieved optimal bilateral symmetry with displacement differences less than 0.15 mm between sides. The displacement at the nasal columella base was 0.45 mm (unaffected side) and 0.29 mm (affected side). In contrast, the Conventional Unilateral Method showed significant asymmetry with lip peak displacement of only 0.09 mm on the unaffected side versus 0.92 mm on the affected side. Conclusions: These findings highlight the importance of restoring bilateral mechanical balance in surgical planning, which may reduce recurrence and improve aesthetic outcomes. This study provides a biomechanical basis for clinical decision-making in philtrum and Cupid’s bow reconstruction for patients with secondary unilateral cleft lip deformities.