Purpose: To describe the posterior airway space and soft tissue changes in patients who received orthodontics and single or dual surgical jaw advancement and to evaluate if there is a correlation between increasing amounts of advancement and long-term reduction in obstructive sleep apnea.
Methods: Records were searched from one oral surgeon and one orthodontist for all patients treated by bilateral sagittal split osteotomy (BSSO) or maxillomandibular advancement (MMA) done in combination with orthodontics. Cephalometric films from pre-treatment, pre-surgery, post-surgery, and final removal of appliances were collected and traced. Pre-surgical and Post-surgical polysomnography results were collected, specifically the apnea-hypopnea indexes (AHI). The patients were recruited to complete a questionnaire and Epworth Sleepiness Scale (ESS) to assess long-term outcomes from treatment. Descriptive statistics were calculated for all cephalometric measurements and the data was analyzed for change from initial to final measurements with significance level set at P < .05. Linear regressions were performed to find estimates for the final OSA outcomes (AHI and ESS) as a function of mandibular advancement.
Results: Forty-three patients, treated from 1995-2010, were identified for the study. Twenty-nine patients had a complete cephalometric film series. The maxilla and mandible were advanced 5.2 mm and 8.3 mm respectively, with a mean 4 mm increase in posterior airway space. The upper and lower lip protrusion increased by 4.8 mm and 7.6 mm but there was no significant change in relation to the nose-chin line. The soft tissue chin increased by 11.3 mm. Thirty-three patients completed the long-term survey at a mean 6.3 years ± 2.6 (range 2-12 years) after removal of appliances. The majority of patients (90%) reported reduction of their OSA symptoms and were pleased with their facial appearance. 79% of patients would recommend the orthodontic and surgical management of OSA to prospective candidates. 22 patients had initial AHI and final ESS values to assess final ESS score as a function of mandibular advancement. The mandibular advancement regression coefficient was -0.03 statistically and clinically insignificant. Twelve patients had initial and final AHI values to assess final AHI value as a function of mandibular advancement. The regression coefficient of mandibular advancement was 0.05, also statistically and clinically insignificant. No correlation could be found due to the lack of variation of mandibular advancement and limited sample size.
Conclusions: Soft tissue profile characteristics, AP airway dimensions, and skeletal maxillomandibular advancement were significantly increased after MMA. Soft tissue parameters were considerably protrusive but still demonstrate facial harmony. There was no evidence of a linear relationship between greater amounts of mandibular advancement and improvement of OSA outcomes. An advancement threshold could not be evaluated due to the limited sample size. Patients well below the recommended 10 mm advancement had successful objective short-term and subjective long-term reduction in OSA symptoms. Overall, patients were satisfied with their OSA management, facial aesthetics, and would recommend the treatment to others.