Objective: All unilateral cleft lip (UCL) repair techniques assume and describe a displaced or obliquely rotated Cupid’s bow within the cleft prolabium. This is true, but there is more. A focused anatomic description of the prolabium, and the configuration of Cupid’s bow within the prolabium, in UCL is deficient in the literature. The purpose of this study was to analyze the prolabium in unmanipulated (pre-NAM, pre-surgical) UCL patients, with or without palatal clefts, with emphasis on the size, shape, and symmetry of the Cupid’s bow within the prolabium itself. In addition, a geometric analysis conveys the most efficient location for incisional correction of the “asymmetry within” Cupid’s bow.
Methods: Standardized frontal photographs of 37 infants with UCL were studied by experienced craniofacial team members. Cupid’s bow landmarks were identified and prolabial angles (perpendicular through valley to bow height) were recorded on both the cleft and non-cleft sides. Three groups were analyzed (all n=37, complete n=22, incomplete n=15). Unpaired t-test and two-tailed t-test were utilized for statistical analysis. A geometric linear analysis was preformed to show incisional length and location for correction of the asymmetric Cupid’s bow.
Results: Significant intrinsic Cupid’s bow asymmetry within the prolabium was present in all groups. This asymmetry was exhibited by significance (p<.0001) between angles in all groups. For all UCL the mean difference between angles was 4.992 degrees. (p<.0001) The largest mean difference was 7.608 degrees (95% CI: 4.927-10.289 degrees; p < 0.0001) in the incomplete group.
Conclusions: In UCL not only is the prolabium with its concomitant Cupid’s bow rotated upwards into the cleft, but there exists a significant intrinsic asymmetry of the Cupid’s bow itself within the prolabium. This intrinsically asymmetric Cupid’s bow is then rotated upwards into the cleft itself. This finding has yet to be described in the cleft literature. Furthermore, a linear geometric equation describes incisional locations and lengths within the prolabium for correcting the Cupid’s bow asymmetry. This finding enhances our anatomic understanding of UCL and has significant importance when selecting surgical repair techniques.
Corresponding Author: Ellie Gschwendtner, 2365 Orchard Circle Dr. Unit 13, Traverse City, MI 49686