无阻塞性睡眠呼吸暂停低通气综合征的31名老年男性上气道及周围组织形态观察

目的研究无阻塞性睡眠呼吸暂停低通气综合征（obstructive sleep apnea hypopnea syndrome,OSAHS）的70岁以上男性上气道及周围组织的结构特征,为深入认识OSAHS的病因及治疗手段提供依据。方法从182名70岁以上男性中,通过问卷和整夜多道睡眠监测（polysomnography,PSG）检测筛选出无OSAHS者31名,睡眠呼吸暂停低通气指数（apnea and hypopnea index,AHI）〈10次／h,年龄70～84岁,平均（74．5±3．7）岁。对31名研究对象行头颈部MRI扫描。对上气道及周围组织的93项指标进行测量。结果①上气道各段平均横截面积、最小横截面积均以腭咽最小,分别为（190．9±67．1）mm^2,（112．1±47．7）mm^2;②上气道各段横截面的前后径与左右径之比在0．22～0．89之间,各段横截面形状均为左右径长、前后径短的椭圆。其中腭咽段比值最小（0．22～0．71）;③上气道各段最小横截面积与最大横截面积之比在0．38～0．62之间,气道立体形状均为“漏斗形”,其中腭咽的“锥度”最大。结论根据上气道横截面大小和形状,无OSAHS老年男性上气道的腭咽段易塌陷。     

Changes in oropharyngeal airway and respiratory function during sleep after orthognathic surgery in patients with mandibular prognathism

The aim of this study was to examine the effects of mandibular setback surgery on pharyngeal airway space and respiratory function during sleep. The subjects were 22 patients in whom mandibular prognathism was corrected by bilateral sagittal split ramus osteotomy; either one jaw or two jaw surgery. Polysomnography was performed before surgery and 6 months after surgery, and the apnea hypopnea index (AHI) and arterial oxygen saturation during sleep were measured to assess respiratory function during sleep. Morphological changes were studied using cephalograms taken immediately before, a few days after and 6 months after surgery. As a control, 10 subjects without sleep-disordered breathing underwent the same examinations. AHI was not changed significantly after surgery, although two patients were diagnosed with mild obstructive sleep apnea (OSA) syndrome after surgery. They were not obese, but the amounts of mandibular setback at surgery were large. In conclusion, a large amount of mandibular setback might inhibit biological adaption and cause sleep-disordered breathing, and it might be better to consider maxillary advance or another technique that does not reduce the airway for patients with skeletal class III malocclusions who have large anteroposterior discrepancy and/or maxillary hypoplasia.     

可调式口腔矫治器治疗睡眠呼吸暂停综合征后患者的上气道形态变化

目的比较可调式口腔矫治器治疗不同程度阻塞性睡眠呼吸暂停综合征(OSAS)患者前后上气道三维形态的变化。方法采用可调式口腔矫治器对多导睡眠监测仪及白天嗜睡量表诊断为OSAS的36例患者进行治疗,戴用4个月时,比较不同程度OSAS患者治疗前后舌咽、腭咽等不同部位上气道形态在CBCT下的变化。结果相比治疗前,在戴用可调式矫治器4个月时,轻度OSAS患者腭咽和舌咽各部位的变化值均有统计学意义;对于中度OSAS患者,除腭咽段最小横径变化,及舌咽段最小横径和最小截面积变化外,其余变化均有统计意义;重度OSAS患者腭咽和舌咽各部位的变化值均无统计学意义。结论可调式矫治器治疗轻中度OSAS患者,气道变化明显;对于重度OSAS患者来说,气道改善不明显。     

Cephalometric and three-dimensional assessment of the posterior airway space and imaging software reliability analysis before and after orthognathic surgery

PurposeThis study aimed to compare the reliability of three different imaging software programs for measuring the PAS and concurrently to investigate the morphological changes in oropharyngeal structures in mandibular prognathic patients before and after orthognathic surgery by using 2D and 3D analyzing technique.Material and methodsThe study consists of 11 randomly chosen patients (8 females and 3 males) who underwent maxillomandibular treatment for correction of Class III anteroposterior mandibular prognathism at the University Hospital in Zurich. A set of standardized LCR and CBCT-scans were obtained from each subject preoperatively (T0), 3 months after surgery (T1) and 3 months to 2 years postoperatively (T2). Morphological changes in the posterior airway space (PAS) were evaluated longitudinally by two different observers with three different imaging software programs (OsiriX^® 64-bit, Switzerland; Mimics^®, Belgium; BrainLab^®, Germany) and manually by analyzing cephalometric X-rays.ResultsA significant increase in the upper airway dimensions before and after surgery occurred in all measured cases. All other cephalometric distances showed no statistically significant alterations. Measuring the volume of the PAS showed no significant changes in all cases. All three software programs showed similar outputs in both cephalometric analysis and 3D measuring technique.ConclusionA 3D design of the posterior airway seems to be far more reliable and precise phrasing of a statement of postoperative gradients than conventional radiography and is additionally higher compared to the corresponding manual method. In case of Class III mandibular prognathism treatment with bilateral split osteotomy of the mandible and simultaneous maxillary advancement, the negative effects of PAS volume decrease may be reduced and might prevent a developing OSAS.     

Effects of rapid maxillary expansion on upper airway volume: A three-dimensional cone-beam computed tomography study

Objective:To compare changes in pharyngeal airway volume and minimal cross-sectional area (MCA) between patients undergoing rapid maxillary expansion (RME) and a matched control group and to identify markers for predicting airway changes using cone-beam computed tomography (CBCT).Materials and Methods:Pre- and posttreatment CBCT scans were selected of children who had RME (14 girls and 12 boys; mean age, 12.4 years) along with scans of a control group (matched for chronological age, skeletal age, gender, mandibular inclination) who underwent orthodontic treatment for minor malocclusions without RME. Changes in airway volume and MCA were evaluated using a standardized, previously validated method and analyzed by a mixed-effects linear regression model.Results:Upper airway volume and MCA increased significantly over time for both the RME and matched control groups (P < .01 and P = .05, respectively). Although the RME group showed a greater increase when compared with the matched controls, this difference was not statistically significant. A reduced skeletal age before treatment was a significant marker for a positive effect on the upper airway volume and MCA changes (P < .01).Conclusions:Tooth-borne RME is not associated with a significant change in upper airway volume or MCA in children when compared with controls. The younger the skeletal age before treatment, the more positive the effect on the upper airway changes. The results may prove valuable, especially in RME of young children.     

口呼吸与鼻呼吸儿童上气道矢状径差异的研究

目的 比较口呼吸与鼻呼吸儿童上气道矢状径的差异,探讨呼吸方式与上气道矢状径的关系。方法 通过口鼻气流同步测定系统的随机检测,选择鼻呼吸比例≤70％（口呼吸组）及≥95％（鼻呼吸组）的11－14岁儿童各34人,比较其头颅定位侧位片中上气道矢状径的差异。结果 口呼吸儿童骨性鼻咽（PNS－Ba）、舌咽部的最小距离（P－T）较鼻呼吸儿童明显减小。结论 鼻咽部骨性狭窄和扁桃体肥大是口呼吸的形态学原因,反映呼吸方式受遗传和环境两方面的影响。     

Head posture and pharyngeal airway volume changes after bimaxillary surgery for mandibular prognathism

PurposeThe purpose of this study was to evaluate head posture and the pharyngeal airway volume changes using 3D imaging after bimaxillary surgery in mandibular prognathism patients by null hypothesis.Materials and methodsCone-beam computed tomography (CBCT) scans were obtained for 25 mandibular prognathism patients before bimaxillary surgery (T1) and 6 months after surgery (T2). The head posture of each patient was assessed by measuring cranio-cervical angle on a midsagittal plane passing through the anterior nasal spine at T1 and T2. Additionally, the volume of each subject's pharyngeal airway was measured using InVivoDental 3D imaging software.ResultsThe cranio-cervical angle increased significantly 6 months after bimaxillary surgery (p < 0.01). The total volume of the pharyngeal airway slightly decreased (p > 0.05) at the same timepoints, while naso- and oro-pharyngeal airway volume decreased significantly (p < 0.05, p < 0.05). There was significant relationship between the changes of head posture and those of total airway volume (p < 0.05).ConclusionThe null hypothesis was rejected. Bimaxillary surgery resulted in significant head flexion and a slight decrease in total pharyngeal airway volume.     

Mandibular advancement for pediatric obstructive sleep apnea: A systematic review and meta-analysis

Objectives

Mandibular distraction osteogenesis and mandibular advancement, collectively referred to as mandibular advancement surgeries (MAS), have been used to treat children with mandibular insufficiency and obstructive sleep apnea (OSA). The objective is to perform a systematic review and meta-analysis for MAS as treatment for obstructive sleep apnea.

Three-dimensional cone beam computed tomography definition of the anatomical subregions of the upper airway: a validation study

The exact boundaries of the upper airway subregions remain undefined. Consequently, anatomical limits vary greatly among different research groups and impede unbiased comparisons. The aim of this study was to provide clinical three-dimensional anatomical limits for the upper airway subregions, translate them into accurate and reliable cephalometric landmarks in cone beam computed tomography (CBCT) data, and validate the proposed measuring protocol. The upper airway of 40 normative individuals aged 23–35 years was evaluated with Dolphin Imaging^® software. An appropriate grey-scale threshold value was pre-calculated. After adapting specific head positioning and virtual orientation protocols, the volume and minimum cross-sectional area of the nasopharynx, oropharynx, and hypopharynx, as previously defined by the authors, were calculated. Intra- and inter-observer reliability was excellent for volumes and moderate for areas. The sexual dimorphism analysis revealed a significantly greater oropharyngeal volume, hypopharyngeal volume, and minimum cross-sectional oropharyngeal area in males than in females. In conclusion, the proposed subregion definition showed technical feasibility and statistical reliability, especially for three-dimensional calculations. The reliability of two-dimensional calculations may be increased with improved head positioning during CBCT scanning and subsequent virtual head orientation. Standardization of the proposed anatomical limits has the potential to homogenize upper airway subregion analysis and permit comparisons among future studies.     

Volumetric changes of the upper airway following maxillary and mandibular advancement using cone beam computed tomography

The objective of this project was to retrospectively evaluate changes in volume of different compartments of the upper airway in response to maxillary, mandibular, and bimaxillary advancement surgeries and to predict the extent of volumetric changes associated with these surgical movements. Pre- and post-surgical cone beam computed tomography scans of 36 patients were evaluated for changes in nasal cavity, nasopharyngeal, oropharyngeal, and hypopharyngeal compartments. The amount of movement for each surgery was measured from skeletal landmarks to reference planes and was correlated with volumetric changes. Maxillary advancement of 4.0 ± 2.2 mm increased the oropharyngeal volume significantly (41.40%), and mandibular advancement of 3.8 ± 1.6 mm also significantly increased the oropharyngeal volume (21.17%). Bimaxillary advancement of 5.1 ± 1.3 mm for the maxilla and 6.4 ± 3.1 mm for the mandible significantly increased nasopharyngeal (27.45%), oropharyngeal (66.39%), and hypopharyngeal (52.48%) volumes. Furthermore, for every millimeter anterior movement, oropharyngeal volume increased by 2319.2 ± 771.8 mm³. Bimaxillary advancement showed a greater increase than isolated maxillary and mandibular advancement in all pharyngeal compartments. Every millimeter of advancement in the bimaxillary group led to a significant increase in oropharyngeal volume, while every millimeter downward movement showed a significant increase in nasopharyngeal volume.     

Difficult-to-treat OSAS: Combined continuous positive airway pressure (CPAP) and mandibular advancement devices (MADs) therapy. A case report

ABSTRACT

Background: Obstructive sleep apnea syndrome and is characterized by recurrent episodes of partial or complete upper airway collapse during sleep with consequent oxygen desaturations and cardiovascular, neurological, and metabolic impairment.

Clinical presentation: The authors report the case of a 66-year-old male presenting “metabolic syndrome” (obesity, impaired glucose tolerance, dyslipidemia, multi-drug treated arterial hypertension), atopy, mouth breathing due to turbinate hypertrophy, and pathological daytime sleepiness. As patient’s compliance to standard continuous positive airway pressure (CPAP) therapy was poor, he was treated using low-pressure CPAP combined with a mandibular advancement device (MAD).

Conclusion: In selected patients, a treatment combining CPAP and MAD might be a more tolerable alternative to CPAP alone. The improved pharyngeal patency, promoted by mandibular advancement and stretching of the pharyngeal muscles, allows operating the CPAP at lower pressures when the MAD alone is not sufficient to induce a safe sleep profile.     

Sleep bruxism and related risk factors in adults: A systematic literature review

ObjectiveThe aim of this article was to systematically review the literature to assess the relationship between risk factors and sleep bruxism (SB) in adults (age ≥18 years).DesignA systematic search of the following databases was carried out: PubMed, Embase, Scopus, Cochrane Oral Health Group’s Trial Register and Cochrane Register of Controlled Trials, Web of Science, LILACs and SciELO. Nine out of the 4583 initially identified articles were selected. This review was conducted according to the guidelines from the Cochrane Handbook for Systematic Reviews of Interventions, with reporting in agreement to the Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines.ResultsAmong the nine analyzed articles, associations between SB and gastro-esophageal reflux disease (GERD) (OR = 6.6, CI = 1.4–30.9) was found in one randomized clinical trial (RCT). Four cross-sectional studies suggested history of SB during childhood (OR = 8.1 CI = 5.4–12–2), age (OR = 3.1, CI = 2.3–4.1) and chronic migraine (OR = 3.8, C.I = 1.8–7.8) as determinant factors for the development of SB. In one case-control study, patients with genetic polymorphisms were more likely to present SB (OR = 4.3, CI = 1.6–11.3). Smoking (OR = 2.8, CI = 2.2–3.5) and alcohol intake (OR = 1.9, CI = 1.2–2.8) showed moderate association in two case-control studies.ConclusionsHistory of SB during childhood, gastro-esophageal reflux disease and genetic polymorphisms seem to be important risk factors associated to SB in adults. Dry mouth on awakening seems to be a protective factor. Association does not infer with causality. Even if the evidence emerged from the considered studies was clinically relevant, further studies are requested to better understand the biological mechanisms behind the described associations.     

Newly defined landmarks for a three-dimensionally based cephalometric analysis: A retrospective cone-beam computed tomography scan review

Objectives:To identify two novel three-dimensional (3D) cephalometric landmarks and create a novel three-dimensionally based anteroposterior skeletal measurement that can be compared with traditional two-dimensional (2D) cephalometric measurements in patients with Class I and Class II skeletal patterns.Materials and Methods:Full head cone-beam computed tomography (CBCT) scans of 100 patients with all first molars in occlusion were obtained from a private practice. InvivoDental 3D (version 5.1.6, Anatomage, San Jose, Calif) was used to analyze the CBCT scans in the sagittal and axial planes to create new landmarks and a linear 3D analysis (M measurement) based on maxillary and mandibular centroids. Independent samples t-test was used to compare the mean M measurement to traditional 2D cephalometric measurements, ANB and APDI. Interexaminer and intraexaminer reliability were evaluated using 2D and 3D scatterplots.Results:The M measurement, ANB, and APDI could statistically differentiate between patients with Class I and Class II skeletal patterns (P < .001). The M measurement exhibited a correlation coefficient (r) of −0.79 and 0.88 with APDI and ANB, respectively.Conclusions:The overall centroid landmarks and the M measurement combine 2D and 3D methods of imaging; the measurement itself can distinguish between patients with Class I and Class II skeletal patterns and can serve as a potential substitute for ANB and APDI. The new three-dimensionally based landmarks and measurements are reliable, and there is great potential for future use of 3D analyses for diagnosis and research.     

Computational fluid dynamics for the assessment of upper airway changes in skeletal Class III patients treated with mandibular setback surgery

Objective:To analyze and compare pharyngeal airflow characteristics pre- and post–mandibular setback surgery in patients with Class III skeletal dysplasia using cone beam computed tomography (CBCT) and computational fluid dynamics (CFD).Materials and Methods:Records of 29 patients who had received orthodontic treatment along with mandibular setback surgery were obtained. CBCT scans were obtained at three time points: T1 (before surgery), T2 (average of 6 months after surgery), and T3 (average of 1 year after surgery). Digitized pharyngeal airway models were generated from these scans. CFD was used to simulate and characterize pharyngeal airflow.Results:Mean airway volume was significantly reduced from 35,490.324 mm³ at T1 to 24,387.369 mm³ at T2 and 25,069.459 mm³ at T3. Significant increase in mean negative pressure was noted from 3.110 Pa at T1 to 6.116 Pa at T2 and 6.295 Pa at T3. There was a statistically significant negative correlation between the change in airway volume and the change in pressure drop at both the T2 and T3 time points. There was a statistically significant negative correlation between the amount of mandibular setback and change in pressure drop at the T2 time point.Conclusions:Following mandibular setback surgery, pharyngeal airway volume was decreased and relative mean negative pressure was increased, implying an increased effort required from a patient for maintaining constant pharyngeal airflow. Thus, high-risk patients undergoing a large amount of mandibular setback surgery should be evaluated for obstructive sleep apnea and the proposed treatment plan be revised based on the risk for potential airway compromise.