Application of a novel method to analyse lip motion of cleft lip patients before and after lip repair

The aim of this study was to apply a novel method to the analysis of lip motion in patients with bilateral cleft lip and palate before and after lip repair with cross-lip flaps, and to compare lip motion between the patients and healthy volunteers. Two 17-year-old bilateral cleft lip patients (one male and one female) who underwent lip repair with an Abbé flap and six healthy volunteers were enrolled in the study. Motion images from three infrared and one colour digital video camera were captured on a personal computer. By applying a multiple-baseline stereo, range images were produced across the whole images. Lip motion during phonation was then analysed as follows. The lips were divided into eight areas as designated by landmarks and Bézier curved lines, and virtual grid intersections set on the range images were calculated. The lip motion was divided into four periods along a time axis and the velocities were then calculated. The mobility of the prolabium increased following surgery in both patients. Changes in the ratio of movement of the upper vermilion to the lower vermilion, before vs after surgery, differed in both patients. The timing of the maximal speed during lip motion varied in both patients before and after surgery, and in the healthy volunteers.