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

BACKGROUND

Improving occlusion and aesthetics is the primary objective of orthognathic surgery for patients with cleft lip and palate (CLP). However, these patients often have horizontal, vertical, and rotational asymmetry in addition to maxillary retrusion. This study aimed to describe maxillary and mandibular asymmetry in patients with CLP undergoing orthognathic surgery and to analyze its anatomic basis.

METHODS

Patients with isolated CLP undergoing computed tomographic imaging before 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.

RESULTS

Fifty-eight patients, with a mean age of 17 years, were analyzed, including 32 patients with unilateral and 26 with bilateral CLP. Twenty patients (34%) demonstrated chin deviation of 4 mm or greater, and 21 (36%) had a 5% or greater discrepancy in mandibular ramus lengths. Horizontal occlusal plane cant of 2 degrees or greater was seen in 20 maxillae (34%) and 28 mandibles (48%), with a dental arch yaw of 2 degrees or greater noted in 55% of both maxillae and mandibles ( n = 32). 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).

CONCLUSIONS

Both maxillary and mandibular asymmetry are common in skeletally mature patients with CLP and frequently results in notable chin deviation. Preoperative 3-dimensional imaging and virtual surgical planning of orthognathic surgery aid in the recognition of facial asymmetries and reveal opportunities to optimize results in this population.