Anthropometric evaluation of bilateral cleft lip nose with cone beam computed tomography in early childhood: Estimation of nasal tip collapse

Background: Nasal tip features of cleft lip nose cannot be defined well using conventional measurement methods. Therefore, we developed a new method in which vertical nasal tip (the pronasale) position is evaluated based on the Frankfurt-Horizontal plane. This measurement was applied to bilateral cleft lip patients in early childhood. Methods: Cone beam computed tomography (CT) records of bilateral cleft lip patients after primary rhinoplasty aged from 5 to 8 years (n = 13) were investigated retrospectively. As age-matched controls, data from a normal group (n = 17) and complete unilateral cleft lip group after primary rhinoplasty (n = 19) were included. In each group, nasolabial angle (β), nasal tip angle (α), nasal width (al-al), columellar length (sn-c′), nasal tip protrusion (sn-prn), and vertical nasal tip position (sn′-prn′/sn′-n′) were investigated. Results: With the exception of vertical nasal tip position and nasal width, the measurement data of the bilateral cleft lip patients were acceptable. In the bilateral cleft lip group, however, vertical nasal tip position was significantly higher and nasal width was significantly larger than those in the normal and unilateral groups (P < 0.0001 and P = 0.0298; P = 0.0001 and P = 0.0002, respectively). Conclusions: In cleft lip nose, the lower lateral cartilage that normally composes the nasal tip domes is splayed out, causing cephalic positioning of the pronasale. Nasal tip collapse was more severe in bilateral cleft lip than in the unilateral group. These results were compatible with the fact that many bilateral cleft lip patients require augmentation rhinoplasty after adolescence even after primary rhinoplasty.