Zygoma Asymmetry in Non-Syndromic Patients with Unilateral Cleft Lip and Palate

Background: Cleft lip and palate are often accompanied by maxillary asymmetry and midface hypoplasia. However, there has been limited examination of the symmetry of the zygoma in these patients. In this study, computed tomography scans prior to alveolar bone grafting are utilized to examine zygomatic symmetry through width, projection, and volume. Methods: Retrospective review was conducted of patients with nonsyndromic unilateral cleft lip and palate with eligible scans prior to alveolar bone grafting at our institution. Anterior zygomatic width, posterior zygomatic width, and zygomatic projection were measured on axial images oriented to the Frankfort horizontal, and three-dimensional digital models of each zygoma were created from the computed tomography data to estimate zygoma volume. These measurements were then compared on cleft and noncleft sides. Results: Twenty-two patients were included in this study. The mean (95% CI) zygoma volume of the cleft side and non-cleft side was 4219 mm(3) (3858-4574 mm(3)) and 4286 mm(3) (3932-4660 mm(3)), respectively, with a mean difference of -67 mm3 ([-402-266 mm(3)]; P = .704). The zygomatic projection of the cleft side was 43 mm (41-45 mm) in comparison to 47 cm (45-49 mm) for the non-cleft side. Mean difference in zygomatic projection was -4 mm (-5 to -2 mm, P < .001). Mean anterior zygomatic width was greater on the cleft side (42 mm [41-44 mm]) than the non-cleft side (41 mm [40-42 mm]; P = .037). No significant difference was found between posterior zygomatic width of the cleft side (59 mm [58-60 mm]) and non-cleft side (58 mm [57-59 mm]; P = .118). Conclusions: Upon preoperative image analysis in patients with non-syndromic, unilateral lip and palate clefts, zygomatic projection was significantly different between cleft and non-cleft sides. Evaluation of zygoma asymmetry should be included as a component of the physical exam when assessing a patient with unilateral cleft lip and palate, as improved awareness of existing zygomatic asymmetry could aid in setting patient expectations, improving satisfaction/outcomes, and in planning for potential surgical correction.