Silent Changes in Sleep Quality Following Mandibular Setback Surgery in Patients with Skeletal Class III Malocclusion: A Prospective Study

Abstract

Mandibular setback surgery (MSS) for skeletal class III patients can result in a relative reduction of pharyngeal airway space (PAS). Consequently, there is a possibility of the decline of sleep quality after surgery. We investigated changes in sleep quality measured by overnight polysomnography (PSG) and the three-dimensional (3D) volumes of PAS following MSS with or without Le Fort I osteotomy (LF I) in class III patients (N = 53). Overnight PSG and cone beam computed tomography were conducted at preoperative stage (T0) and postoperative 3 months (T1). Measurements of PAS volumes were performed, and the subjective symptoms of sleep were evaluated by self-questionnaires. There were significant increases in respiratory disturbance index (RDI) and total respiratory effort-related arousal (RERA) index during T0-T1. The 3D volumes of PAS showed significant decreases in the oropharyngeal airway, hypopharyngeal airway, and total airway spaces. No significant changes were observed in subjective symptoms of sleep. MSS with or without LF I for class III patients could worsen sleep quality by increasing sleep parameters such as the RDI and RERA in PSG, and reduce volumes of PAS at postoperative 3 months. Although subjective symptoms may not show significant changes, objective sleep quality in PSG might decrease after MSS.

Changes in the pharyngeal airway after different orthognathic procedures for correction of class III dysplasia

“…Other studies reported worsening of sleep quality or the occurrence of sleep apnea after mandibular setback surgery in subjects with no signs or symptoms of airway obstruction before the operation [24,25]. The present findings also corroborate the results of some studies [26][27][28] that indicated narrowing of the pharyngeal airway was less in subjects treated with 2-jaw orthognathic surgery than mandibular sagittal compression alone. The widening of the pharyngeal airway after maxillary advancement has also been reported in previous investigations [28][29][30], implying reduced airway resistance and improved breathing.…”

Comparing Outcomes of Airway Changes and Risk of Sleep Apnea after Bimaxillary Orthognathic Surgery and Mandibular Setback Surgery in Patients with Skeletal Class III Malocclusion: A Systematic Review and Meta-Analysis

“…According to this meta-analysis, there has been no statistically significant increase in sleep apnea risk before and after surgery. A three-dimensional (3D) PAS volume showed a significant decrease in the oropharyngeal airway, and no significant change has been observed in the sleep symptoms [8]. Reports indicated that bimaxillary orthognathic surgery to reduce PAS played a role, but it does not increase AHI, one of the important determinants of sleep apnea [18,19,21,23].…”

“…Dynamic changes in airway anatomy may also contribute to obstructive sleep apnea [8]. The mandibular setback surgery (MdS) effect on the association of the soft tissue and skeletal tissue has been also demonstrated that could result in a relative reduction of the pharyngeal airway space [9,10].…”

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

“…For patients with severe mandibular prognathism or patients with potential for OSA development, two-jaw surgery should be strongly considered [34]. In addition, a study reported that although there are no subjective symptoms after mandibular setback with or without maxillary surgery, objective sleep quality determined by polysomnography may be decreased [5]. However, a short-term observation period (3 months) needs to be considered in this previous study.…”

“…In addition, a recent study reported that among 12 patients with a mandibular setback exceeding 10 mm, 4 patients developed postoperative OSA, and the apnea-hypopnea index (AHI) was slightly increased significantly after the surgery [4]. Another study found that although subjective symptoms were not exacerbated, objective sleep quality was decreased after mandibular setback surgery [5]. When mandibular setback was performed with maxillary advancement or posterior impaction, the pharyngeal airway volume significantly decreased.…”