Three-dimensional morphometric analysis of alar asymmetry in unilateral secondary cleft nasal deformity: implications for non-cleft alar reduction in surgical planning.

Preoperative surgical planning for alar reduction remains challenging due to the lack of objective references in traditional measurements. Therefore, this study aimed to objectively quantify preoperative bilateral alar symmetry using 3D best-fit alignment analysis, and to establish an evidence-based threshold for alar morphological deviation for alar reduction in secondary cleft rhinoplasty. 26 patients with unilateral secondary cleft nasal deformity were retrospectively assessed: 13 underwent secondary cleft rhinoplasty alone and 13 received concurrent alar reduction. Preoperative 3D facial images were processed with best-fit alignment analysis to quantify alar morphological deviation between the cleft and non-cleft alar surfaces. Symmetry scores were also assessed by plastic surgeons using a four-point Likert scale (1 = poor, 2 = fair, 3 = good, 4 = excellent), based on pre- and postoperative standard photographs. In both groups, the cleft-side alar exhibited a distinctly smaller size compared with the non-cleft side. The combined alar reduction group showed significantly larger preoperative alar morphological deviation (2.49 ± 0.52 mm versus 1.19 ± 0.35 mm; p < 0.05). Morphological deviation analysis revealed a surgical threshold of 1.5-2 mm. Postoperative symmetry scores were significantly improved in both groups. 3D best-fit alignment analysis is a reliable method for objectively quantifying alar asymmetry. Non-cleft alar reduction is recommended during secondary rhinoplasty when preoperative alar morphological deviation reaches 2 mm.