Impact of counterclockwise rotation of the occlusal plane on the mandibular advancement, pharynx morphology, and polysomnography results in maxillomandibular advancement surgery for the treatment of obstructive sleep apnea patients.

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.

Effects of transverse maxillomandibular distraction osteogenesis on obstructive sleep apnea syndrome and on the pharynx.

PURPOSE: To assess the effects of transverse maxillomandibular distraction osteogenesis (TMDO) on the treatment of obstructive sleep apnea (OSA) and on the morphology of the pharynx. METHODS: A clinical trial was conducted with seven patients with OSA and with transverse maxillomandibular deficiency, two women and five men aged on average 41.16 ± 10.9 years on the day of surgery. All participants were submitted to computed tomography (CT) and full-night polysomnography (PSG) before and approximately 9 months after surgery. A 95% confidence interval was defined. RESULTS: The AHI and RDI of the participants were reduced by about 62% (from 27.65 ± 36.65 to 10.73 ± 11.78, p = 0.031 and from 41.21 ± 32.73 to 15.30 ± 13.87, p = 0.015, respectively). The airway showed a surprising mean reduction in volume of 10% (from 5.78 ± 2.53 to 4.71 ± 1.42, p = 0.437, for the upper pharynx; from 6.98 ± 2.23 to 6.23 ± 2.05, p = 0.437, for the lower pharynx; and from 12.76 ± 1.56 to 10.94 ± 2.42, p = 0.625, for the total pharynx). However, the site of the smallest area of the pharynx was considerably increased both in the anteroposterior and transverse direction and in its total area (from 0.88 ± 7.11 to 0.99 ± 0.39, p = 0.625; from 1.78 ± 0.81 to 2.05 ± 0.61, p = 0.812; and from 0.99 ± 0.74 to 1.40 ± 0.51, p = 0.180, respectively). CONCLUSION: TMDO proved to be efficient in reducing or curing OSA, producing modifications of upper pharynx morphology with an increase of the smallest area of the pharynx.

Enlargement of the Pharynx Resulting From Surgically Assisted Rapid Maxillary Expansion.

PURPOSE: Given that transverse maxillary deficiency is an etiologic factor of obstructive sleep apnea and is intimately connected to pharyngeal size, the objective of this study was to determine whether surgically assisted rapid maxillary expansion (SARME) would promote pharyngeal enlargement in adults. MATERIALS AND METHODS: This prospective study was conducted in patients with uni- or bilateral posterior crossbite who underwent SARME. Participants were recruited from the Integrated Center for the Study of Face Defects, School of Medicine of Ribeirão Preto, University of São Paulo (São Paulo, Brazil). All patients underwent computed tomography of the pharynx before and after surgery (171.5 days on average), and the sagittal and transverse planes and the total area across 3 levels of the pharynx, including the upper (posterior nasal spine), middle (first cervical vertebra), and lower (second cervical vertebra) levels, were measured on the images. A paired-samples t test was used to evaluate changes in the pharynx before and after surgery. RESULTS: The studied sample consisted of 18 adult patients (10 women and 8 men) with an average age of 37.11 years (standard deviation, 11.73 yr); all patients resided in the region of Ribeirão Preto, São Paulo, Brazil. No statistical changes were observed in the upper level. An enlargement of 17.82% (P = .0107) was observed in the sagittal plane of the middle level. The cross-sectional and area values of this same portion were enlarged (16.96 and 37.38%, respectively), with a trend toward statistical significance (P = .067 and .051, respectively). The airway enlargements in the lower level were 26.41, 24.87, and 53.87% in the sagittal and transverse planes and total area, respectively; these differences were statistically significant (P = .0003, .0033, and .0016, respectively) for all 3 measurements. CONCLUSIONS: SARME promotes pharyngeal enlargement, especially in the lower levels of the pharynx.