Purpose: Evaluate the impact of counterclockwise rotation of the occlusal plane (CCWROP) on pharynx morphology and polysomnography in maxillomandibular advancement (MMA) surgery to treat obstructive sleep apnea (OSA) patients.
Methods: Prospective clinical trial of patients with OSA treated by MMA. Computed tomography and polysomnography were performed pre- and postoperatively and the parameters were compared. The surgery classified the patients into two groups: with (R) and without (NR) CCWROP.
Results: The study sample comprised 38 individuals: R (n = 19) and NR (n = 19). An anterior mandible advancement of 0.71 mm was identified for each degree of CCWROP (p < 0.001). As for polysomnography, the apnea-hypopnea index was reduced by 80% and 62% in R and NR, showing final values of 6.8 and 13.0, respectively. The apnea index changed equally in both groups. Reduction of 68 and 26% in the hypopnea index was observed for R and NR, respectively, with no statistically significant difference. Total volume increased by 45% in R and 30% in NR. Retropalatal and retrolingual volumes increased by 49% and 4% in R and 43% and 15% in NR, respectively. The minimum axial area increased by 92% in the retropalatal region and 97% in the retrolingual region in R, whereas these increases were of 76% and 31% in NR, respectively.
Conclusion: Anterior mandibular advancement of 0.71 mm for each degree of CCWROP is of great importance for surgical planning. As a result of this resource, individuals in R presented better results than those in NR in all parameters assessed, especially regarding the retrolingual region.
Keywords: Counterclockwise rotation occlusal plane; Maxillomandibular advancement surgery; Obstructive sleep apnea syndrome; Orthognathic surgery; Sleep apnea surgery; Upper airway.
© 2020. The Author(s), under exclusive licence to Springer Nature Switzerland AG part of Springer Nature.