"The Septum and Nasomaxillary Vault Associated with Unrepaired Unilateral Cleft Lip and Palate: A Data-Driven 3D Model".

Background: Defining the nature of the unilateral cleft lip and palate nasal deformity (uCLND) and its optimal surgical correction continues to be a challenge. The purpose of this study was to develop a data-driven model of the primary unrepaired osseocartilaginous skeleton of the nasomaxillary complex.

Methods: CT scans of nineteen 3-month-old infants with unrepaired unilateral cleft lip and palate and nineteen age- and race-matched controls were analyzed. Osseous landmark deviation in subjects with clefts was compared to controls. Segmentation of the osseocartilaginous septum was performed, and deformational differences were calculated between cleft and non-cleft cohorts.

Results: Compared to controls, the rhinion, non-cleft nasomaxillary junction, and cleft nasomaxillary junction deviated towards the non-cleft side. The piriform margins each diverge away from midline with the non-cleft side deviating lateral and superior, and the cleft side deviating lateral and posterior. These alterations result in a bony torsion with sigmoidal configuration of the cleft side aperture, vertical shortening of the central midface, and de-projection of the nasal pyramid. Segmentation of the septum revealed anterior deviation toward the non-cleft side with a single convexity toward the cleft.

Conclusions: This three-dimensional data-driven model contradicts prior models and confirms a collapsing twist of the cleft side aperture and medialization of the bony margin of the nasal airway with deviation of the nasal bone complex toward the non-cleft side. This analysis defines the critical anatomic characteristics of the cleft nasal deformity and informs the goals of nasal correction at the time of primary repair.