Biomechanical simulation of correcting primary unilateral cleft lip nasal deformity

For better outcomes of the primary correction of cleft lip nasal deformity, it is important to clarify the specific morphological and biomechanical consequences of major surgical maneuvers during cleft lip nose correction. In this study, a finite element model was established basing on the micro-MRI imaging of an infant specimen with unilateral complete cleft lip deformity. Alar base adduction was simulated as a medially-directed force on the lateral crus (F1); columella straightening was simulated as a laterally-directed force on the medial crus (F2); and nasal tip enhancement was simulated as an anteriorly-directed force on the intermediate crus (F3). The deformation and stress distribution consequent to each force vector or different force combinations were analyzed in details. Our biomechnical analyses suggested that W\when loaded alone, the three forces generated disparate morphological changes. The combination of different force loadings generated obviously different outcomes. F3 generated the most intensive stress when compared to F1 and F2. When F2 was loaded on top of F1-F3 combination, it further relieved nasal deviation without incurring significant increase in stress. Our simulation suggested that alar base adduction, columella straightening, and nasal tip elevation should all be included in a competent cleft lip nose correction.