Why most patients do not exhibit obstructive sleep apnea after mandibular setback surgery?

Abstract

Maxillomandibular advancement (MMA) is effective for the treatment of obstructive sleep apnea (OSA). In previous studies, the airway was increased in the anteroposterior and transverse dimensions after MMA. However, the effect of the opposite of mandibular movement (mandibular setback) on the airway is still controversial. Mandibular setback surgery has been suggested to be one of the risk factors in the development of sleep apnea. Previous studies have found that mandibular setback surgery could reduce the total airway volume and posterior airway space significantly in both the one-jaw and two-jaw surgery groups. However, a direct cause-and-effect relationship between the mandibular setback and development of sleep apnea has not been clearly established. Moreover, there are only a few reported cases of postoperative OSA development after mandibular setback surgery. These findings may be attributed to a fundamental difference in demographic variables such as age, sex, and body mass index (BMI) between patients with mandibular prognathism and patients with OSA. Another possibility is that the site of obstruction or pattern of obstruction may be different between the awake and sleep status in patients with OSA and mandibular prognathism. In a case-controlled study, information including the BMI and other presurgical conditions potentially related to OSA should be considered when evaluating the airway. In conclusion, the preoperative evaluation and management of co-morbid conditions would be essential for the prevention of OSA after mandibular setback surgery despite its low incidence.

A severe skeletal Class III malocclusion treated with Le Fort I combined with sagittal split ramus osteotomy, mandibular body ostectomy and tongue reduction surgery. A case report

“…Wolford and Cottrell [11] described 18 clinical features of macroglossia to determine whether a tongue reduction is necessary. Eight of these features were observed in this case: (1) a wide, broad, and flat tongue; (2) open bite; (3) mandibular prognathism; (4) Class III malocclusion; (5) chronic posturing of the tongue between the teeth at the rest; (6) buccal tipping of posterior teeth; (7) increased transverse width of dental arch; (8) instability in orthodontic treatment. All these features were observed at the initial evaluation and were still significant following pre-surgical orthodontic treatment.…”

“…Article in Press the mandibular setback and development of sleep apnea has not been clearly established. [7] Other additional ostectomies in combination, that is, Le Fort I and SSRO two-jaw surgery, have been proposed to reduce a large amount of mandibular setback when correcting an excessive anteroposterior discrepancy. A mandibular setback of 15 mm might be the maximum in patients with narrow rami.…”

A surgery-first approach using single-jaw rotational mandibular setback in low-angle mandibular prognathism

“…[22][23][24] However, patients with prognathic mandible tend to have a larger upper pharyngeal airway, 25,26 and mandibular setback surgery may not degrade the upper airway patency, 24,27,28 resulting in a very low incidence of obstructive sleep apnea (OSA) after mandibular setback surgery. 28 In the present case, pretreatment oropharyngeal volume and minimal crosssectional area were larger than average for non-OSA subjects, 29,30 and the values decreased at 5-day postsurgery (Fig 11). Irani et al 22 showed that this diminished airway could be improved during postsurgical orthodontic treatment even without significant relapse of mandibular setback surgery.…”

Bimaxillary Orthognathic Surgery Does Not Induce Obstructive Sleep Apnea in Skeletal Class III Patients

“…Orthognathic surgery has been the long mainstay of treatment for correcting skeletal deformities. [1][2][3][4][5][6] Despite its versatility and popularity, some studies note a possible association between orthognathic surgery and posterior airway changes, and consequently exhibiting obstructive sleep apnea (OSA). 2,[7][8][9][10][11][12][13] OSA is defined as a long-term condition, characterized by recurrent episodes of upper airway collapse during sleep.…”

“…2,[7][8][9][10][11][12][13] OSA is defined as a long-term condition, characterized by recurrent episodes of upper airway collapse during sleep. 6,[14][15][16][17] The prevalence rate of this disorder varies from 3-7% in different populations. [14][15][16][17][18][19] Constant snoring, witnessed apnea, extensive daytime sleepiness, fatigue, and hypoxia are the most common presenting symptoms for patients suffering from OSA.…”