Correlation Between Speech Outcomes and the Amount of Maxillary Advancement After Orthognathic Surgery (Le Fort I Conventional Osteotomy and Distraction Osteogenesis) in Patients With Cleft Lip and Palate.

BACKGROUND: The purpose of this study is to evaluate the factors affecting the speech outcome following Le fort I conventional osteotomy(CO) or Le Fort I distraction osteogenesis(DO) in patients with cleft lip and palate at a single institution. METHOD: Records of cleft lip and palate patients who underwent orthognathic surgery between 2010 and 2015 were reviewed. Data included age at orthognathic surgery, sex, cleft lip and palate type, type of orthognathic surgery, the amount of maxillary advancement, and speech assessment. Speech outcomes were classified into 2 categories. Compared with the pre and post-operative Pittsburgh Weighted speech scale scores, in case that the post-operative total score is increased the authors define it as "Speech deterioration" and if not, the authors define it as "Speech preservation." RESULT: The 44 patients were identified, 33 patients underwent CO and 11 patients underwent DO. The mean age was 19.4 +/- 1.4. The mean period time of speech evaluation after orthognathic surgery was 1.0 +/- 0.46 year. The mean amount of maxillary advancement was 7.2 +/- 3.2 mm and show significant correlation with speech outcomes. (P = 0.012) . In CO group, the patients who had the maxilla 1 approximately 5 mm advancement maintained their speech completely and 44% of patients with 6 approximately 8 mm deteriorated their speech. In DO group, patients with 9 approximately 10 mm maintained their speech completely, 50% of patients with 11 approximately 12 mm deteriorated their speech and 100% of patients with 13 approximately 16 mm deteriorated their speech. According to the relationship between the amount of maxillary advancement and speech outcomes, there was a statistically significant correlation in both CO and DO groups. (P = 0.04, 0.029). CONCLUSION: It was found that speech of the patients with more amount of maxillary advancement tended to get worse. Also, it was observed that there exist some stable ranges of maxillary advancement for speech safety which does not effect on speech. (1 approximately 5 mm in CO group and 9 approximately 10 mm in DO group).