Morphometric Findings in Adolescents with Robin Sequence: A Photographic and Cephalometric Study of the Face and Mandible

Background: The aims of the study were to describe facial morphology and analyze facial growth in adolescents with Robin sequence (RS) or Stickler syndrome. Methods: The facial morphology, mandibular size, and facial growth of 69 adolescents (ages 12–18) with RS were analyzed using existing cephalometric radiographs (n = 37) and photographs (n = 69). All participants were followed in our institution since birth. None underwent growth-modifying treatment for micrognathia during infancy, but all had conservative orthodontic treatment during adolescence. Results: Cross-sectional cephalometric analysis according to Tweed revealed differences in RS adolescents as compared with reference values, such as a proportionate retrusion of both jaws, as indicated by decreased SNA and SNB angles (p < 0.05). This finding was mostly associated with skeletal Class I (62.2%) and a vertical facial pattern as indicated by increased FMA and CoGoMe angles (p < 0.05). In Delaire’s analysis, patients showed decreased maxillary, maxillary alveolar (p < 0.05), and mandibular body territories (p > 0.05) but increased ramus (p > 0.05) and nasopremaxillary territories (p < 0.05). According to Ricketts’ analysis, mandibular width was decreased in half of our patients (p > 0.05). The mandibles were harmoniously downsized before and after the growth spurt (p < 0.05); however, they exhibited greater growth velocities than controls. A long-term study during puberty revealed an increase in SNB angles and a decrease in ANB angles (both p < 0.05), which improved the maxillomandibular relationship. Additionally, the vertical facial pattern attenuated (FMA, SNGoGn, and CoGoMe angles decreased; p > 0.05). On cross-sectional photographic analysis, 33.3% of patients had an orthofrontal (straight), 59.4% a cisfrontal (convex), and 7.3% a transfrontal (concave) profile. Their vertical facial proportions were normal. In the subjective profile analysis, most patients (approximately 84%) had good or acceptable profiles, with no major deficit of chin projection. The initial degree of neonatal retrognathia and type of cleft palate surgery did not affect major skeletal parameters (p > 0.05). However, the degree of neonatal functional impairment affected the vertical parameters (SNGoGn, FMA angle; p < 0.05). Conclusions: Overall, RS patients presented a bi-retrognathic profile, a normal jaw relationship, and a tendency toward a vertical growth pattern. Partial mandibular catch-up growth occurred during the pubertal growth spurt. The degree of neonatal retrognathia does not predict further mandibular growth.