Orthognathic Considerations of Maxillary and Mandibular Asymmetry at Skeletal Maturity in Patients with Cleft Lip and Palate.

Abstract

Improving occlusion and aesthetics is the primary objective of orthognathic surgery for patients with cleft lip and palate (CLP). However, these patients often suffer from horizontal, vertical, and rotational asymmetry in addition to maxillary retrusion. This study aims to describe maxillary and mandibular asymmetry in patients with CLP undergoing orthognathic surgery and analyze its anatomic basis. Patients with isolated CLP undergoing CT imaging prior to orthognathic surgery were retrospectively reviewed. Maxillary and mandibular positioning and dimensional symmetry were evaluated. Incidence of clinically significant asymmetry, correlations between areas of asymmetry, and associations with clinical history were analyzed. Fifty-eight patients, with mean age 17 years were analyzed, including 32 patients with unilateral CLP and 26 with bilateral CLP. Twenty (34%) patients demonstrated chin deviation ≥4mm and 21 (36%) had a ≥5% discrepancy in mandibular ramus lengths. Horizontal occlusal plane cant of ≥2° was seen in 20 (34%) maxillae and 28 (48%) mandibles, with dental arch yaw ≥2° noted in 32 (55%) of both maxillae and mandibles. Chin deviation correlated with maxillary cant, discrepancy in ramus length, discrepancy in mandibular body length, and discrepancy in condylar volume (p<0.05). Bilateral and unilateral CLP did not show significantly different asymmetry on any measure (p>0.05). Both maxillary and mandibular asymmetry is common in skeletally mature patients with CLP and frequently results in notable chin deviation. Preoperative three-dimensional imaging and virtual surgical planning of orthognathic surgery aid in recognition of facial asymmetries and reveal opportunities to optimize results in this population.