A comparative analysis of secondary unilateral and bilateral cleft lip nasal deformities: From anatomical characteristics to repair strategies.

Secondary cleft lip nasal deformity presents a persistent challenge in reconstructive surgery, with fundamental differences existing between unilateral and bilateral presentations that dictate distinct management approaches. This systematic review delineates the contrasting anatomical underpinnings of these deformities, where unilateral cases are characterized by marked asymmetry and bilateral cases by a symmetric deficiency marked by severe columellar shortening. It further synthesizes the evolution of assessment methodologies, from traditional anthropometry to advanced three-dimensional (3D) technologies like stereophotogrammetry and CT reconstruction, which enable precise preoperative planning. The review elaborates on differentiated repair strategies, emphasizing symmetry restoration in unilateral deformities versus midline structural reconstruction in bilateral cases, often necessitating substantial costal cartilage grafts. Despite advancements, challenges remain in achieving long-term stability and managing soft tissue limitations. The integration of computational modeling, artificial intelligence (AI), and tissue engineering represents the future direction for progressing toward personalized and predictable reconstruction. This synthesis provides a comprehensive framework to guide clinical decision-making and future research.