Identification of craniofacial risk factors for obstructive sleep apnoea using three-dimensional MRI

Exploring the Effects of Tirzepatide on Obstructive Sleep Apnea: A Literature Review

Obstructive sleep apnea (OSA) is a sleep disorder commonly secondary to obesity that has detrimental effects on health and quality of life. Thus, weight loss is one of the mainstays of OSA treatment. Tirzepatide, a novel glucagon-like peptide-1 (GLP-1) and glucagon-dependent insulinotropic polypeptide (GIP) dual agonist, demonstrated significant glycemic control and weight loss. This literature review analyzes the current literature on tirzepatide's effects on OSA, mechanism of action, complications, and off-label uses/indications. Also, this review offers potential insights into how tirzepatide and other GLP-1 medications can be repurposed for other metabolic conditions and their associated sequelae.

Influence of natural hyoid bone position and surgical repositioning on upper airway patency: a computational finite element modeling study

The hyoid bone's inferior baseline position in obstructive sleep apnea (OSA) has led to surgical hyoid repositioning (SHR) treatment, yet outcomes vary widely. The influence of baseline hyoid position (BHP; phenotype) and SHR on upper airway (UA) function remains unclear. We aimed to investigate their impact on the UA using computational modeling. A validated finite element model of the rabbit UA was advanced and used to simulate changes in BHP and SHR, alone and in combination. The hyoid was displaced in cranial, caudal, anterior, anterior-cranial, and anterior-caudal directions from 1 to 4 mm. Model outcomes included UA collapsibility, measured using closing pressure (Pclose), cross-sectional area (CSA), and soft tissue mechanics (displacement, stress, and strain). Graded BHP increments increased Pclose for all directions and up to 29%-43% at 4 mm (relative to the original BHP). Anterior-based SHR decreased Pclose (approximately -115% at 4 mm) and increased ΔCSA (approximately +35% at 4 mm). Cranial SHR decreased ΔPclose (-29%), minimally affecting CSA. Caudal SHR increased ΔPclose (+27%) and decreased ΔCSA (-7%). Anterior-cranial and anterior-caudal SHR produced the highest stresses and strains. SHR effects on UA outcomes were dependent on BHP, with more caudal BHPs leading to less effective surgeries. In conclusion, BHP (phenotype) and SHR both alter UA outcomes, with effects dependent on hyoid displacement direction and magnitude. BHP influences the effectiveness of SHR in reducing UA collapsibility. These findings provide further insights into the hyoid's role in UA patency and suggest that considering the hyoid's baseline position and surgical repositioning direction/increment may help improve hyoid surgeries for OSA treatment.NEW & NOTEWORTHY Using computational modeling, this study directly shows that any shift from the healthy natural hyoid bone position increases upper airway collapsibility. Surgical hyoid repositioning alters upper airway outcomes in a direction- and magnitude-dependent manner, with its effects influenced by the natural hyoid position. Accounting for both the natural hyoid position and individually prescribed surgical repositioning may enhance upper airway stability and improve outcomes in obstructive sleep apnea (OSA) treatment.

Predicting OSA Using Radiographs of the Airway Anatomy

Objective

This study aims to analyze the tongue body shape and upper airway anatomical parameters in patients with Obstructive Sleep Apnea (OSA) and to explore the anatomical causes of OSA.

Methods

A total of 345 subjects participated in this study. Lateral pharyngeal images of the upper respiratory tract were captured in both normal and mandibular advancement states using X-ray plain film. Measurements were taken for the following parameters: Tongue Length, Tongue Thickness, Distance from the Mandibular Plane to the Hyoid, Soft Palate Length, Posterior Oropharyngeal Depth, Palatal Airway Space, Tongue Depth Space, and Mental Posterior Space. The correlation between the Apnea-Hypopnea Index (AHI) and these upper airway anatomical factors was analyzed using both univariate and multivariate analyses to develop a predictive model for OSA.

Results

The anatomical structure of the upper airway in patients with OSA is narrower compared to non-OSA individuals, and these patients exhibit a longer and thicker tongue. During mandibular advancement, the pharyngeal airway widens; however, the tongue length decreases while its thickness increases. Univariate correlation analysis revealed that the severity of OSA was significantly associated with tongue length, the ratio of tongue length to tongue thickness, the distance from the mandibular plane to the hyoid, soft palate length, and body mass index (BMI) in both the normal position and during mandibular advancement (p < 0.001). Multivariate linear analysis indicated that the severity of OSA is linked with the mandibular plane to hyoid distance in the normal position (MPH(N)) and BMI. A nomogram was utilized to develop a predictive model for OSA, achieving an area under the receiver operating characteristic curve of 0.838.

Conclusion

The pathogenesis of OSA is related to pharyngeal anatomy and tongue length in the state of mandibular advancement, which can be predicted by the measurement indexes of normal and anterior mandibular displacement lateral pharyngeal radiograph. This may potentially aid in early screening and diagnosis of OSA.

Study of the upper airway anatomy using magnetic resonance imaging in Indian obese patients with obstructive sleep apnea - A pilot study

BACKGROUND

Obstructive sleep apnea (OSA) is very common in obese patients. However, why some obese patients have severe OSA while others do not is unclear. Research is limited regarding which structures contribute to upper airway narrowing, especially in Asian patients where bony restrictions is thought to be important.

METHODS

Nineteen consecutive patients with BMI ≥35 kg/m2, and newly diagnosed with OSA based on overnight polysomnography were studied using non-contrast magnetic resonance imaging (MRI) of the upper airway during wakefulness.

RESULTS

Patients were divided into two groups, one with severe OSA comprising 11 patients and one without severe OSA having 8 patients. The retro-palatal airway was narrowest in both groups. Patients with severe OSA had a significantly narrower retroglossal airway (0.99 ± 0.48 cm2 vs 2.61 ± 2.02 cm2, p = 0.02), primarily due to a narrower anteroposterior diameter at this level (p = 0.03). The tongue volume (p = 0.91), lateral pharyngeal wall volume (p = 0.26), tongue length (p = 0.93), soft palate length (p = 0.13), and dynamic change of upper airway with inspiration (p = 0.31) were not significantly different between the two groups.

CONCLUSIONS

While the retro-palatal airway is equally narrow in both groups of patients, patients with severe OSA also have a significantly narrower retro-glossal airway. This finding could represent either a generalized reduction in airway area in whole of the oropharynx or multiple-level obstruction; probably aggravating upper airway collapse during sleep, predisposing some Asian obese patients to develop severe OSA.

Morphometric measurements of intraoral anatomy in children with Beckwith-Wiedemann syndrome: a novel approach

BACKGROUND

An easy-to-use tool to objectively measure intraoral anatomy with meaningful clinical correlations may improve care for patients with Beckwith-Wiedemann syndrome (BWS), who commonly have symptomatic macroglossia.

METHODS

Children aged 2-17 years with BWS were enrolled between 12/2021 and 01/2024. Digital intraoral photographs with a laser ruler were taken, and morphometric measurements were made using ImageJ software. Relationships between morphometrics and outcomes including BWS clinical score, percentage mosaicism, and incidence of tongue reduction surgery were examined using t-tests and multivariate linear models.

RESULTS

Pharyngeal morphometric measurements were obtained in 49 patients with BWS. Mouth area, width, and height differed significantly across BWS molecular subtypes. Right-to-left tongue width and mouth width were larger in those with loss of methylation at imprinting control region 2 (IC2 LOM) than other BWS variants. Patients with paternal uniparental isodisomy of chromosome 11p15 (pUPD11) had narrower mouths than others. Those with tongue reduction surgery had more tongue ridging than those without surgery. There were correlations between mouth area and BWS clinical score, tongue width and BWS clinical score, and tongue length and percentage mosaicism.

CONCLUSION

Intraoral morphometric measurements are associated with phenotypic burden in BWS. Tongue morphology varies across the BWS spectrum, with IC2 LOM having wider tongues and mouths, and pUPD11 having narrower mouths. Tongue ridging is more common in those selected for surgery. Intraoral morphometric measurements may be safely obtained at low costs across centers caring for children with BWS or others at risk of upper airway obstruction.

Physiologic and anatomic determinants of hyoid motion during drug-induced sleep endoscopy

PURPOSE

To examine factors accounting for differences in hyoid motion during obstructive breathing events amongst obstructive sleep apnea (OSA) patients.

METHODS

This was a prospective cohort study from June 2022 to October 2022. Patients with OSA undergoing evaluation for PAP alternative therapies with drug-induced sleep endoscopy with positive airway pressure titration (DISE-PAP). All patients underwent DISE-PAP and concurrent hyoid-focused ultrasound. DISE-PAP enabled measurement of airway physiology (flow, respiratory effort) and airway collapsibility (pharyngeal opening pressure, PhOP). Hyoid-ultrasound enabled hyoid bone movement during obstructive breathing. Respiratory effort was measured using a retro-epiglottic pressure-sensitive catheter. Hyoid position was measured using a standardized, awake, CT protocol. Regression analyses adjusted for age, race, sex, and BMI were performed to associate indices of respiratory effort and CT data with hyoid motion.

RESULTS

On average, the 26 patients in this cohort were older (63.9 ± 10.5 years), male (69%), overweight (29.6 ± 3.99 kg/m2), and with moderate-to-severe OSA (26.8 ± 10.4 events/hour). Greater respiratory effort was associated with increased hyoid motion (β [95% CI] = 0.034 [0.016,0.052], standardized β = 0.261,p = 0.0003). Higher hyoid position was associated with greater hyoid displacement (β [95% CI] = -0.20 [-0.38,-0.01], Standardized β = -0.57, p = 0.036).

CONCLUSION

Our data demonstrate that greater respiratory effort, higher hyoid position, and higher airway collapsibility, but not airflow, are associated with greater hyoid motion during obstructive breathing in DISE. These findings suggest that downward hyoid movement represents a compensatory response to upper airway obstruction. Further studies should investigate the vectors of hyoid motion to better understand its role in sleep-related airway collapse.

Relationship between Cephalometric and Ultrasonic Airway Parameters in Adults with High Risk of Obstructive Sleep Apnea

Background/Objectives: Polysomnography and cephalometry have been used for studying obstructive sleep apnea (OSA) etiology. The association between craniofacial skeleton and OSA severity remains controversial. To study OSA's etiology, cephalometry, fiberoptic pharyngoscopy, polysomnography, and sleep endoscopy have been used; however, airway obstructions cannot be located. Recent research suggested ultrasonography for OSA screening and upper airway obstruction localization. Thus, this study aims to investigate the relationship between specific craniofacial cephalometric and ultrasonic airway parameters in adults at high risk of OSA. Methods: To assess craniofacial structure, lateral cephalograms were taken from thirty-three adults over 18 with a STOP-Bang questionnaire score of three or higher and a waist-to-height ratio (WHtR) of 0.5 or higher. Airway parameters were assessed through submental ultrasound. Results: NSBA correlated with tongue base airspace width, while MP-H correlated with oropharynx, tongue base, and epiglottis airspace width. SNA, SNB, and NSBA correlated with tongue width at the oropharynx. At tongue base, ANB and MP-H correlated with tongue width. SNB and NSBA were associated with deep tissue thickness at the oropharynx, while MP-H correlated with superficial tissue thickness at velum and oropharynx. Conclusions: Cephalometric parameters (SNA, SNB, ANB, NSBA, and MP-H) were correlated with ultrasonic parameters in the velum, oropharynx, tongue base, and epiglottis.

The Association of Upper Airway Anatomy with Brain Structure: The Multi-Ethnic Study of Atherosclerosis

Sleep apnea, affecting an estimated 1 in 4 American adults, has been reported to be associated with both brain structural abnormality and impaired cognitive function. Obstructive sleep apnea is known to be affected by upper airway anatomy. To better understand the contribution of upper airway anatomy to pathways linking sleep apnea with impaired cognitive function, we investigated the association of upper airway anatomy with structural brain abnormalities. Based in the Multi-Ethnic Study of Atherosclerosis, a longitudinal cohort study of community-dwelling adults, a comprehensive sleep study and an MRI of the upper airway and brain were performed on 578 participants. Machine learning models were used to select from 74 upper airway measures those measures most associated with selected regional brain volumes and white matter hyperintensity volume. Linear regression assessed associations between the selected upper airway measures, sleep measures, and brain structure. Maxillary divergence was positively associated with hippocampus volume, and mandible length was negatively associated with total white and gray matter volume. Both coefficients were small (coefficients per standard deviation 0.063 mL, p = 0.04, and - 7.0 mL, p < 0.001 respectively), and not affected by adjustment for sleep study measures. Self-reported snoring >2 times per week was associated with larger hippocampus volume (coefficient 0.164 mL, p = 0.007), and higher percentage of time in the N3 sleep stage was associated with larger total white and gray matter volume (4.8 mL, p = 0.004). Despite associations of two upper airway anatomy measures with brain volume, the evidence did not suggest that these upper airway and brain structure associations were acting primarily through the pathway of sleep disturbance.

Exploring long-term changes and influencing factors of the upper airway in patients with a skeletal Class II relationship after mandibular advancement with maxillary setback surgery: A comprehensive 2-year follow-up investigation

INTRODUCTION

The objective of this study was to investigate the 2-year postoperative change and influencing factors of the upper airway after mandibular advancement with maxillary setback surgery for patients with a skeletal Class II relationship.

METHODS

Fifty-seven participants who underwent mandibular advancement with maxillary setback surgery were enrolled consecutively. Cone-beam computed tomography was performed preoperatively, 3 months postoperatively (T1), and 2 years (T2) postoperatively. All parameters were measured using Dolphin Imaging software (Dolphin Imaging and Management Solutions, Chatsworth, Calif).

RESULTS

The total volume (V), minimum cross-sectional area (CSAmin), and glossopharynx increased significantly in both the short-term (V, 13.33%; CSAmin, 33.03%; glossopharynx, 26.73%) and long-term (V, 10.19%; CSAmin, 23.18%; glossopharynx, 18.27%) after the surgery. Mandibular advancement, mandibular width increase, preoperative CSAmin, and body mass index (BMI) significantly affected 2-year postoperative V increases. Mandibular advancement and BMI significantly affected 2-year postoperative glossopharynx increases. Backward movement of point PNS may lead to a reduction of the nasopharynx; however, downward movement of point PNS, upward movement of point A, and increased maxillary width may compensate for this effect by increasing the likelihood of the nasopharynx opening. Furthermore, mandibular body length at T1 is positively associated with relapse rate ([T2 - T1] / T1) of V and CSAmin.

CONCLUSIONS

Mandibular advancement amount, mandibular width increase, preoperative CSAmin, and BMI are the 4 factors for long-term V changes. Patients with a longer mandibular body length might have a lower relapse rate.

Can intraoral and facial photos predict obstructive sleep apnea in the general and clinical population?

STUDY OBJECTIVES

This study aimed to evaluate and compare measurements of standardized craniofacial and intraoral photographs between clinical and general population samples, between groups of individuals with an apnea-hypopnea index (AHI) ≥ 15 and AHI < 15, and their interaction, as well as the relationship with the presence and severity of obstructive sleep apnea (OSA).

METHODS

We used data from 929 participants from Sleep Apnea Global Interdisciplinary Consortium, in which 309 patients from a clinical setting and 620 volunteers from a general population.

RESULTS

AHI ≥ 15 were observed in 30.3% of the total sample and there were some interactions between facial/intraoral measures with OSA and both samples. Mandibular volume (p < 0.01) and lateral face height (p = 0.04) were higher in the AHI ≥ 15 group in the clinical sample compared to the AHI ≥ 15 group in the general population and AHI < 15 group in the clinical sample. When adjusted for sex and age, greater mandible width (p < 0.01) differed both in the clinical and in the general population samples, reflecting AHI severity and the likelihood of OSA. The measure of smaller tongue curvature (p < 0.01) reflected the severity and probability of OSA in the clinical sample and the higher posterior mandibular height (p = 0.04) showed a relationship with higher AHI and higher risk of OSA in the general population. When adjusted for sex, age, and body mass index, only smaller tongue curvature (p < 0.01) was associated with moderate/severe OSA.

CONCLUSIONS

Measures of greater tongue and mandible were associated with increased OSA risk in the clinical sample and craniofacial measurement was associated in the general population sample.

Novel clinical screening method to identify patients at risk of obstructive sleep apnea

OBJECTIVE

To investigate whether the distance between the two retromolar trigones (RMTs) with the distance between the two posterior plicas (PPs) affects obstructive sleep apnea syndrome (OSAS) and to determine a physical examination method that can be used in the selection of patients to be referred to polysomnography (PSG).

METHODS

The study included 86 OSAS patients and 29 healthy controls. RMTs and PPs were measured using a caliper-like device. The values obtained from these measurements were evaluated in both groups.

RESULTS

The PPs were narrower, and the RMTs-PPs, RMTs-PPs/RMTs, and RMTs/PPs values were greater in the OSAS group (p < .05) compared to the control group. The cut-off values were 0.612 for RMTs-PPs/RMTs and 2.589 for RMTs/PPs. The specificity of these values for OSAS was 97%, and sensitivity was 57% and 58%, respectively.

CONCLUSION

The presented method may play a role in preventing unnecessary PSG among patients with suspected OSAS.

A review of supine position related obstructive sleep apnea: Classification, epidemiology, pathogenesis and treatment

Supine related obstructive sleep apnea (OSA) is the most common clinical and physiological phenotype of OSA. This condition is recognizable by patients, their families and through polysomnographic recordings. Commonly used definitions distinguish the presence of supine related OSA when respiratory events occur at twice the frequency when the patient lies in the supine compared to non-supine sleeping positions. Recent physiology studies have demonstrated that airway obstruction arises more commonly in the supine position particularly at the level of the soft palate and epiglottis. Increased airway collapsibility is reliability observed supine relative to lateral position. To a lesser extent, changes in control of breathing favour less stable ventilation when the supine sleeping posture is adopted. Many treatments have been developed and trialled to help patients avoid sleeping on their back. The last 10 years has seen the emergence of vibrotactile warning devices that are worn on the patients' neck or chest. High quality randomized controlled trial data is accumulating on the efficacy and common pitfalls of the application of these treatments.

Deep learning technique to detect craniofacial anatomical abnormalities concentrated on middle and anterior of face in patients with sleep apnea

OBJECTIVES

The aim of this study is to propose a deep learning-based model using craniofacial photographs for automatic obstructive sleep apnea (OSA) detection and to perform design explainability tests to investigate important craniofacial regions as well as the reliability of the method.

METHODS

Five hundred and thirty participants with suspected OSA are subjected to polysomnography. Front and profile craniofacial photographs are captured and randomly segregated into training, validation, and test sets for model development and evaluation. Photographic occlusion tests and visual observations are performed to determine regions at risk of OSA. The number of positive regions in each participant is identified and their associations with OSA is assessed.

RESULTS

The model using craniofacial photographs alone yields an accuracy of 0.884 and an area under the receiver operating characteristic curve of 0.881 (95% confidence interval, 0.839-0.922). Using the cutoff point with the maximum sum of sensitivity and specificity, the model exhibits a sensitivity of 0.905 and a specificity of 0.941. The bilateral eyes, nose, mouth and chin, pre-auricular area, and ears contribute the most to disease detection. When photographs that increase the weights of these regions are used, the performance of the model improved. Additionally, different severities of OSA become more prevalent as the number of positive craniofacial regions increases.

CONCLUSIONS

The results suggest that the deep learning-based model can extract meaningful features that are primarily concentrated in the middle and anterior regions of the face.

The Prevalence of Obstructive Sleep Apnea and Associated Symptoms among Patients with Sickle Cell Disease: A Systematic Review and Meta-analysis

Previous studies have shown that patients with sickle cell disease (SCD) are at high risk for obstructive sleep apnea (OSA). In the current study, we aimed to systematically review the literature to address the prevalence of OSA and associated symptoms among patients with SCD. Electronic databases, including Web of Science, Scopus, PubMed, Google Scholar, and Embase were systematically searched to identify the relevant original articles on patients with SCD. Newcastle Ottawa scale was used for quality assessment. Data were pooled by using random effects models. Subgroup analyses were performed by age groups. Thirty-nine studies containing details of 299,358 patients with SCD were included. The pooled results showed that more than half of these patients had OSA with different severities. The prevalence rates of OSA among children with apnea hypopnea index (AHI) cutoffs of above 1, 1.5, and 5 were 51% (95% confidence interval (CI) 36-67%), 29% (95% CI 19-40%), and 18% (95% CI 14-23%), respectively. The prevalence of OSA among adults with AHI cutoff of 5 was 43% (95% CI 21-64%). The pooled rates of snoring, nocturnal enuresis, nocturnal desaturation, and daytime sleepiness were 55% (95% CI 42-69%), 37% (95% CI 33-41%), 49% (95% CI 26-72%), and 21% (95% CI 12-30%), respectively. Given the high prevalence of OSA in patients with SCD, probable greater burden of SCD complications, and irreversible consequences of OSA, screening for OSA symptoms and signs seems useful in these patients. By screening and identifying this heterogeneous disorder earlier, available treatment modalities can be individualized for each patient.

The Application of Ultrasound to Quantify Hyoid Motion During Drug-Induced Sleep Endoscopy

INTRODUCTION

The significance of hyoid dynamics in OSA pathophysiology remains unclear. Drug-induced sleep endoscopy (DISE) is often used for evaluating patients intolerant to positive airway pressure (PAP) therapy. We performed DISE with concurrent hyoid-focused ultrasonography to quantify hyoid dynamics during obstructive and non-obstructive breathing.

METHODS

A cross-sectional analysis from a prospective cohort of patients undergoing DISE with PAP titration (DISE-PAP) and hyoid-focused ultrasound was conducted. Hyoid ultrasound was performed during obstructive breathing, and non-obstructive breathing after PAP administration. Motion was quantified by generating displacement curves based on echo-tracking hyoid movement. The image analysis protocol for quantifying hyoid displacement was performed independently by two researchers, and reliability of measures was assessed. Univariate and multivariate regressions were performed for various clinical data and hyoid displacement during obstructive breathing.

RESULTS

Twenty patients met inclusion criteria. On average, the cohort was male (75%), elderly (65.9 ± 10 years), overweight (29.3 ± 3.99 kg/m2 ), and with moderate-to-severe OSA (29.3 ± 12.5 events/h). Mean hyoid displacement during obstructive breathing was 5.81 mm (±3.48). In all patients, hyoid displacement decreased after PAP administration (-3.94 mm [95% CI: -5.10, -2.78]; p < 0.0001). Inter-rater reliability for measures of hyoid displacement was excellent. After multivariate regression, hyoid displacement at baseline was associated with higher AHI (β [95% CI] = 0.18 [0.03, 0.33], p = 0.020).

CONCLUSION

During DISE, hyoid displacement is greater during obstructive breathing with significant variability amongst patients. Further, these ultrasonographic measurements had excellent intra- and inter-rater reliability. Additional, larger studies are needed to understand contributors to hyoid mobility.

LEVEL OF EVIDENCE

4 Laryngoscope, 133:3221-3227, 2023.

Facial Contour Features Measured on CT Reflects Upper Airway Morphology in Patients With OSA

OBJECTIVE

To determine facial contour features, measured on computed tomography (CT), related to upper airway morphology in patients with obstructive sleep apnea (OSA); certain phenotype of facial abnormalities implying restriction of craniofacial skeleton and adipose tissue nimiety has predicted the value of the severity of OSA.

MATERIALS AND METHOD

Sixty-four male patients with OSA [apnea-hypopnea index (AHI) ≥10/h] who had upper airway CT were randomly selected to quantitatively measure indicators of facial contour and upper airway structures. Pearson correlation analyses were performed. Partial correlation procedure was used to examine correlations while controlling body mass index (BMI).

RESULTS

Upper airway anatomy can nearly all be reflected in the face, except retroglossal airway. Upper face width can be measured to assess the overall skeletal structures of the airway. Lower face width can be used to represent how much adipose tissue deposited. Hard palate, retropalatal, and hypopharyngeal airways have corresponding face indicators respectively. Midface width is a better predictor of AHI severity and minimum blood oxygen even than neck circumference because it contains the most anatomical information about the airway, including RP airway condition, soft palate length, tongue volume, etc. These correlations persisted even after correction for BMI.

CONCLUSIONS

All anatomical features of the upper airway except retroglossal airway can be reflected in the face, and midface width is the best predictor of AHI severity and minimum blood oxygen, even better than neck circumference and BMI.

Obstructive Sleep Apnea Treatment with Oral Appliance in a Myotonic Dystrophy Type I Subject: A Case Report

Objective  to report a myotonic dystrophy type 1 (MD1) subject with obstructive sleep apnea syndrome treated with oral appliance. Methods  A review of individual's history and records, associated with a photographic register of all diagnostic methods and literature research about the topic were done. Final Statements  This case depicts the therapeutical choices disposable to treat subjects with obstructive sleep apnea and DM1. Although considered an uncommon treatment, the oral appliances, if well indicated in adequately selected cases, can satisfactorily improve respiratory parameters, symptoms and quality of life.

Transverse Maxillary Deficiency Predicts Increased Upper Airway Collapsibility during Drug-Induced Sleep Endoscopy

OBJECTIVE

To examine the relationship between craniofacial skeletal anatomy and objective measures of pharyngeal collapse obtained during drug-induced sleep endoscopy. We hypothesized that transverse maxillary deficiency and an increased pharyngeal length will be associated with higher levels of pharyngeal collapsibility.

STUDY DESIGN

Cross-sectional analysis in a prospective cohort.

SETTING

University Hospital.

METHODS

A cross-sectional analysis was conducted in a cohort of consecutive patients from the positive airway pressure (PAP) alternatives clinic who underwent computed tomography (CT) analysis and drug-induced sleep endoscopy for characterization of upper airway collapsibility. PAP titration was used to determine pharyngeal critical pressure (PCRIT ) and pharyngeal opening pressure (PhOP). CT metrics included: Transverse maxillary dimensions (interpremolar and intermolar distances) and pharyngeal length (posterior nasal spine to hyoid distance).

RESULTS

The cohort (n = 103) of severe obstructive sleep apnea (Apnea and Hipopnea Index 32.1 ± 21.3 events/h) was predominantly male (71.8%), Caucasian (81.6%), middle-aged (54.4 ± 14.3 years), and obese (body mass index [BMI] = 30.0 ± 4.9 kg/m2 ). Reduced transverse maxillary dimensions were associated with higher PCRIT (intermolar distance: β [95% confidence interval, CI] = -.25 [-0.14, -0.36] cmH2 O/mm; p = .03) and PhOP (Interpremolar distance: β = -.25 [-0.14, -0.36] cmH2 O/mm; p = .02). Longer pharyngeal length was also associated with higher PCRIT (β = .11 [0.08, 0.14] cmH2 O/mm, p = .04) and PhOP (β [95% CI] = .06 [0.03, 0.09] cmH2 O/mm, p = .04). These associations persisted after adjustments for sex, age, height, and BMI.

CONCLUSION

Our results further the concept that skeletal restriction in the transverse dimension and hyoid descent are associated with elevations in pharyngeal collapsibility during sleep, suggesting a role of transverse deficiency in the pathogenesis of airway obstruction.

Insights into the Use of Point-of-Care Ultrasound for Diagnosing Obstructive Sleep Apnea

Obstructive sleep apnea (OSA) is a sleeping disorder caused by complete or partial disturbance of breathing during the night. Existing screening methods include questionnaire-based evaluations which are time-consuming, vary in specificity, and are not globally adopted. Point-of-care ultrasound (PoCUS), on the other hand, is a painless, inexpensive, portable, and useful tool that has already been introduced for the evaluation of upper airways by anesthetists. PoCUS could also serve as a potential screening tool for the diagnosis of OSA by measuring different airway parameters, including retropalatal pharynx transverse diameter, tongue base thickness, distance between lingual arteries, lateral parapharyngeal wall thickness, palatine tonsil volume, and some non-airway parameters like carotid intima-media thickness, mesenteric fat thickness, and diaphragm characteristics. This study reviewed previously reported studies to highlight the importance of PoCUS as a potential screening tool for OSA.

International Consensus Statement on Obstructive Sleep Apnea

BACKGROUND

Evaluation and interpretation of the literature on obstructive sleep apnea (OSA) allows for consolidation and determination of the key factors important for clinical management of the adult OSA patient. Toward this goal, an international collaborative of multidisciplinary experts in sleep apnea evaluation and treatment have produced the International Consensus statement on Obstructive Sleep Apnea (ICS:OSA).

METHODS

Using previously defined methodology, focal topics in OSA were assigned as literature review (LR), evidence-based review (EBR), or evidence-based review with recommendations (EBR-R) formats. Each topic incorporated the available and relevant evidence which was summarized and graded on study quality. Each topic and section underwent iterative review and the ICS:OSA was created and reviewed by all authors for consensus.

RESULTS

The ICS:OSA addresses OSA syndrome definitions, pathophysiology, epidemiology, risk factors for disease, screening methods, diagnostic testing types, multiple treatment modalities, and effects of OSA treatment on multiple OSA-associated comorbidities. Specific focus on outcomes with positive airway pressure (PAP) and surgical treatments were evaluated.

CONCLUSION

This review of the literature consolidates the available knowledge and identifies the limitations of the current evidence on OSA. This effort aims to create a resource for OSA evidence-based practice and identify future research needs. Knowledge gaps and research opportunities include improving the metrics of OSA disease, determining the optimal OSA screening paradigms, developing strategies for PAP adherence and longitudinal care, enhancing selection of PAP alternatives and surgery, understanding health risk outcomes, and translating evidence into individualized approaches to therapy.

Ultrasonography of the neck in patients with obstructive sleep apnea

INTRODUCTION

In resource-limited settings, obstructive sleep apnea (OSA) often goes undiagnosed as polysomnography (PSG) is expensive, time-consuming, and not readily available. Imaging studies of upper airway have been tried as alternatives to PSG to screen for OSA. However, racial differences in upper airway anatomy preclude generalizability of such studies. We sought to test the hypothesis that ultrasonography (USG), an inexpensive, readily available tool to study soft tissue structures of the upper airway, would have predictive value for OSA in South Asian people.

METHODS

Adult patients with sleep-related complaints suspicious for OSA were taken for overnight PSG. After the PSG, consecutive patients with and without OSA were studied with submental ultrasonography to measure tongue base thickness (TBT) and lateral pharyngeal wall thickness (LPWT).

RESULTS

Among 50 patients with OSA and 25 controls, mean age was 43.9 ± 11.4 years, and 39 were men. Patients with OSA had higher TBT (6.77 ± 0.63 cm vs 6.34 ± 0.54 cm, P value = 0.004) and higher LPWT (2.47 ± 0.60 cm vs 2.12 ± 0.26 cm, P value = 0.006) compared to patients without OSA. On multivariate analysis, TBT, LPWT, and neck circumference were identified as independent factors associated with OSA. These variables could identify patients with severe OSA with a sensitivity of 72% and a specificity of 76%.

CONCLUSION

Patients with OSA have higher tongue base thickness and lateral pharyngeal wall thickness proportionate to the severity of the disease, independent of BMI and neck circumference. These findings suggest that sub-mental ultrasonography may be useful to identify patients with severe OSA in resource-limited settings.

Physical therapy for sleep apnea: a smartphone application for home-based physical therapy for patients with obstructive sleep apnea

Purpose

In this study, we described "PT for Sleep Apnea", a smartphone application for home-based physical therapy of patients with Obstructive Sleep Apnea (OSA).

Methods

The application was created in a joint program between the University of Medicine and Pharmacy at Ho Chi Minh City (UMP), Vietnam, and National Cheng Kung University (NCKU), Taiwan. Exercises maneuvers were derived from the exercise program previously published by the partner group at National Cheng Kung University. They included exercises for upper airway and respiratory muscle training and general endurance training.

Results

The application provides video and in-text tutorials for users to follow at home and a schedule function to assist the user in organizing the training program, which may improve the efficacy of home-based physical therapy in patients with Obstructive Sleep Apnea.

Conclusion

In the future, our group plans to conduct a user study and randomized-controlled trials to investigate whether our application can benefit patients with OSA.

A cross-sectional study on the relationship between electronic cigarette and combustible cigarette use with obstructive sleep apnea among U.S. adults: result from NHANES 2015-2018

BACKGROUND

To explore whether the use of e-cigarettes and conventional cigarettes affects the prevalence of obstructive sleep apnea (OSA) in adults.

METHODS

Complete records of smoking and sleep about OSA from the 2015-2018 National Health and Nutrition Examination Survey. The adults were divided into four groups: noncurrent smokers, current electronic cigarettes (e-cigarette) users only, current conventional cigarettes (c-cigarette) users only, and dual users. OSA was assessed by three main signs and symptoms from the questionnaire. Multivariable logistic regression after adjusting for covariates was conducted to investigate the association of OSA with different smoking patterns.

RESULTS

Among the 11,248 participants, the prevalence of OSA was higher among smokers compared to non-smokers (P < 0.0001). In a stratified analysis of smoke manners, the results showed that an increased prevalence of OSA with c-cigarette use alone (OR = 1.38, 95% CI = 1.17-1.63) and dual-use (OR = 1.78, 95% CI = 1.37-2.32) compared to non-smoking participants, while there was no significant difference with e-cigarette use (OR = 0.84, 95% CI = 0.52-1.37). Multivariate logistic regression analysis showed the prevalence of OSA is highest in dual users (OR = 1.93, 95% CI = 1.39-2.69) than non-smokers.

CONCLUSION

Our findings indicate the prevalence of OSA was higher in c-cigarette smokers than in non-smokers, while there was no significant difference in the prevalence of OSA between e-cigarette smokers and non-smokers. Dual users had the highest prevalence for OSA compared to c-cigarette smokers, e-cigarette smokers and non-smokers.

Obstructive Sleep Apnea and Its Management: A Narrative Review

Obstructive sleep apnea (OSA) is a disorder in which there is repeated collapse of the upper airway when the person is in sleep, which causes oxygen desaturation and interrupted sleep. While asleep, airway blockages and collapse are accompanied by awakenings with or without oxygen desaturation. OSA is a prevalent disorder, especially in people with known risk factors and other illnesses. Pathogenesis is variable, and the risk factors include low chest volume, erratic respiratory regulation, and muscular dysfunction in the upper airway dilators. The high-risk factors include overweight, male sex, aging, adenotonsillar hypertrophy, interruption of the menstrual cycle, preservation of liquids, and smoking. The signs are snoring, drowsiness, and apneas. A sleep history, assessment of symptoms, and physical examination are all part of the screening process for OSA, and the data can help determine which people need to be tested for the condition. The results of the polysomnogram or at-home sleep apnea test assist in determining the presence and severity of OSA. Still, it is seen many times that the accuracy of home sleep apnea tests is significantly less, so one should take an expert opinion for the same. OSA results in systemic hypertension, drowsiness, and driving accidents. It is additionally related to diabetes mellitus, congestive heart failure (CHF), cerebral infarction, and myocardial infarction, but the exact mechanism is not known. The preferred treatment is continuous positive airway pressure with 60-70% adherence. Other management options include reducing weight, therapy of oral appliances, and correcting any anatomical obstruction (narrow pharyngeal airway, adenoid hypertrophy, and mass in the pharynx). OSA indirectly causes headaches just after awakening and daytime sleepiness. However, there are no age boundaries in OSA as it can occur in any age group. Still, more prevalence is seen in individuals of more than 60 years of age.

Anatomical determinants of upper airway collapsibility in obstructive sleep apnea: A systematic review and meta-analysis

Upper airway (UA) collapsibility is one of the key factors that determine the severity of obstructive sleep apnea (OSA). Interventions for OSA are aimed at reducing UA collapsibility, but selecting the optimal alternative intervention for patients who fail CPAP is challenging because currently no validated method predicts how anatomical changes affect UA collapsibility. The gold standard objective measure of UA collapsibility is the pharyngeal critical pressure (Pcrit). A systematic literature review and meta-analysis were performed to identify the anatomical factors with the strongest correlation with Pcrit. A search using the PRISMA methodology was performed on PubMed for English language scientific papers that correlated Pcrit to anatomic variables and OSA severity as measured by the apnea-hypopnea index (AHI). A total of 29 papers that matched eligibility criteria were included in the quantitative synthesis. The meta-analysis suggested that AHI has only a moderate correlation with Pcrit (estimated Pearson correlation coefficient r = 0.46). The meta-analysis identified four key anatomical variables associated with UA collapsibility, namely hyoid position (r = 0.53), tongue volume (r = 0.51), pharyngeal length (r = 0.50), and waist circumference (r = 0.49). In the future, biomechanical models that quantify the relative importance of these anatomical factors in determining UA collapsibility may help identify the optimal intervention for each patient. Many anatomical and structural factors such as airspace cross-sectional areas, epiglottic collapse, and palatal prolapse have inadequate data and require further research.

Predictors for short-term and long-term automatic PAP compliance

STUDY OBJECTIVES

Positive airway pressure (PAP) is considered a standard treatment for obstructive sleep apnea (OSA), but there are compliance issues. As compliance to PAP tends to decrease with time, it is necessary to consider reasons affecting compliance at each period. Therefore, this study aimed to define factors affecting short-term and long-term compliance to PAP therapy.

METHODS

One hundred eighty-seven patients with OSA who started PAP treatment between July 2018 to March 2020 were included. Acceptance and compliance rates were monitored. Demographics, polysomnography (PSG) profiles, cephalometric data, and physical examination results were analyzed to identify factors predictive of PAP compliance at short-term (3 months) and long-term (12 months) periods.

RESULTS

The acceptance rate of PAP was 92.5%. Compliance at 3 months and 12 months was 79.1% and 51.3%, respectively. Higher apnea-hypopnea index (odds ratio [OR] 1.018, P = .049) and older age (OR 1.032, P = .039) were predictive factors of good automatic PAP (APAP) compliance at 3 months. However, long-term compliance was affected by the percentage of duration with O2 desaturation of < 90% (CT90; OR 1.032, P = .011) and baseline self-reported symptom scores such as nasal obstruction (OR 0.819, P = .038) and awakening (OR 0.796, P = .045).

CONCLUSIONS

In PAP use, indicators of OSA severity such as apnea-hypopnea index affect short-term compliance. On the other hand, the mandibular plane to hyoid distance and self-reported symptoms such as nasal obstruction and awakening can affect long-term compliance.

CITATION

Park SI, Kim BK, Lee KE, Hong SD, Jung YG, Kim HY. Predictors for short-term and long-term automatic PAP compliance. J Clin Sleep Med. 2023;19(1):17-26.

Novel genes linked to Class II Division 1 malocclusion with mandibular micrognathism

INTRODUCTION

Mandibular micrognathism (MM) is an underdeveloped mandible resulting from complex interactions between genetic and environmental factors. Prior research focused mainly on the genetic determinants of mandibular retrognathism, not necessarily reflecting micrognathism, thus supporting the need to study MM. This study aimed to explore the inheritance pattern and identify the candidate genes involved in the development and familial transmission of MM.

METHODS

Diagnosing probands with MM was based on clinical and lateral cephalometric data. The pedigrees were drawn for 11 identified families, 5 of whom accepted to undergo detailed data and biospecimen collection. These families included 15 MM and 13 non-MM subjects over 2-3 generations. The procedure involved the withdrawal of 5 mL of blood. Genomic DNA was isolated from blood cells to investigate protein-coding regions via whole exome sequencing. Standardized filtering steps were employed, and candidate genes were identified.

RESULTS

Most of the pedigrees suggested a Mendelian inheritance pattern and segregated in an autosomal-dominant manner. One of the families, which also underwent biospecimen, displayed an X-linked inheritance pattern of the trait. Genetic screening disclosed 8 potentially novel genes (GLUD2, ADGRG4, ARSH, TGIF1, FGFR3, ZNF181, INTS7, and WNT6). None of the recognized exonic regions were previously reported.

CONCLUSIONS

Eight novel genes were identified in association with MM in the largest number of families reported to date. The genes were X-linked in 1 family, a finding previously not observed in mandibular genetics.

Role of surgical hyoid bone repositioning in modifying upper airway collapsibility

Background: Surgical hyoid bone repositioning procedures are being performed to treat obstructive sleep apnea (OSA), though outcomes are highly variable. This is likely due to lack of knowledge regarding the precise influence of hyoid bone position on upper airway patency. The aim of this study is to determine the effect of surgical hyoid bone repositioning on upper airway collapsibility. Methods: Seven anaesthetized, male, New Zealand White rabbits were positioned supine with head/neck position controlled. The rabbit's upper airway was surgically isolated and hyoid bone exposed to allow manipulation of its position using a custom-made device. A sealed facemask was fitted over the rabbit's snout, and mask/upper airway pressures were monitored. Collapsibility was quantified using upper airway closing pressure (Pclose). The hyoid bone was repositioned within the mid-sagittal plane from 0 to 5 mm (1 mm increments) in anterior, cranial, caudal, anterior-cranial (45°) and anterior-caudal (45°) directions. Results: Anterior displacement of the hyoid bone resulted in the greatest decrease in Pclose amongst all directions (p = 0.002). Pclose decreased progressively with each increment of anterior hyoid bone displacement, and down by -4.0 ± 1.3 cmH₂O at 5 mm. Cranial and caudal hyoid bone displacement did not alter Pclose (p > 0.35). Anterior-cranial and anterior-caudal hyoid bone displacements decreased Pclose significantly (p < 0.004) and at similar magnitudes to the anterior direction (p > 0.68). Conclusion: Changes in upper airway collapsibility following hyoid bone repositioning are both direction and magnitude dependent. Anterior-based repositioning directions have the greatest impact on reducing upper airway collapsibility, with no effect on collapsibility by cranial and caudal directions. Findings may have implications for guiding and improving the outcomes of surgical hyoid interventions for the treatment of OSA.

Hyoid bone position as an indicator of severe obstructive sleep apnea

BACKGROUND

The objective of this study was to evaluate the relationship between hyoid bone position and severity of obstructive sleep apnea (OSA), and to investigate its value as a complementary diagnostic method.

METHODS

A total of 133 patients who were diagnosed as OSA with an apnea-hypopnea index ≥ 5 were included. Clinical examination, level I polysomnography (PSG) and lateral cephalographic analysis were done. Comprehensive PSG characteristics were compared according to hyoid bone position and the predictive power of the distance between the mandible and hyoid was assessed.

RESULTS

The distance between the hyoid bone and mandibular plane was significantly longer in the severe OSA group (p = 0.013). The distance from hyoid bone to third vertebrae (C3) and hyoid bone to mentum were also longer in the severe OSA group but the difference did not reach statistical significance. The distance between hyoid bone and mandibular plane was effective in predicting severe OSA, with a cut-off value of 19.45 mm (AUC = 0.623, p = 0.040). When grouped according to a distance cut-off value of 19.45 mm, those with a longer distance between the hyoid bone and mandibular plane showed more respiratory disturbance, lower oxygen saturation levels, less deep slow wave sleep, and more fragmented sleep with arousals.

CONCLUSIONS

The distance between the hyoid bone and mandibular plane derived from cephalometric analysis can be a valuable diagnostic parameter that can be easily applied in differentiating severe OSA patients.

Obstructive sleep apnea and anatomical structures of the nasomaxillary complex in adolescents

The aim of the present study was to reveal the associations between skeletal and soft tissue features of the nasomaxillary complex and development and severity of obstructive sleep apnea (OSA) in adolescents. A total of 100 adolescents (mean age, 14.9 ± 1.4 years; age range, 13–17 years) were enrolled. All participants underwent full-night polysomnography and had an assessment of size and position of the tongue, tonsillar size, body mass index (BMI), and circumference of the waist, neck, and hip. The skeletal features of the nasomaxillary complex, including the zygomatic arch width, nasal cavity width, nasal base width, intercanine width, intermolar width, maxillary dental arch length, palatal vault angle, palatal depth, and SNA were measured on the three-dimensional images constructed with computed tomography data. Participants with an apnea and hypopnea index (AHI) of lower than 5 (AHI ≤ 5) were classified as control and participants while those with an AHI of greater than 5 were classified as OSA group. Each variable with a significant outcome in the independent T-test and age and sex factors were integrated into the multivariate linear regression and the dependent variable was AHI. There were significant differences in the BMI and hip circumference between two groups. The width of nasal base, palatal vault angle and SNA also showed significant differences between groups. The results from multivariate linear regression demonstrated that the BMI, width of the nasal base, and SNA showed significant contributions to the severity of OSA in adolescents. The features of the nasomaxillary complex seemed to have significant influences on development and severity of OSA.

The Heritability of Upper Airway Dimensions Using MRI Scans in Twins

Introduction: Obstructive sleep apnea (OSA) is a common disorder characterized by the repetitive collapse of the upper airways during sleep, most likely in the oropharyngeal region. Anatomical factors significantly contribute to the disease development; however, the heritability of the upper airway dimensions, which lead to the collapsibility of the upper airways, is less known. In the current study, we aimed to quantify the impact of heritable and environmental factors on the upper airway dimensions in twins using magnetic resonance imaging (MRI). Methods: We completed head and neck MRI imaging on 110 (66 monozygotic and 44 dizygotic, age median and Q1–Q3: 53 (44–63.75) years) adult twins from the Hungarian Twin Registry. We completed cephalometric, soft tissue and fatty tissue space measurements on T1- and T2-weighted images in sagittal, coronal and axial planes. For the analysis of the genetic and environmental, the determination of the measured parameters was performed with an ACE twin statistical model. Results: We found a strong genetic determination in the anteroposterior diameter of the tongue and the thickness of the submental fatty tissue of the neck. Other parameters of the tongue, soft palate and uvula have shown moderate heritability, while we found strong environmental determination in the thickness of the parapharyngeal fatty tissue, the thickness of the pharyngeal wall, and the smallest diameter of the posterior upper airways. Conclusion: Our twin study can help better understand the genetic and environmental background of anatomical structures involved in the development of sleep apnea.

Craniofacial Sleep Medicine: The Important Role of Dental Providers in Detecting and Treating Sleep Disordered Breathing in Children

Obstructive sleep apnea (OSA) is a clinical disorder within the spectrum of sleep-related breathing disorders (SRDB) which is used to describe abnormal breathing during sleep resulting in gas exchange abnormalities and/or sleep disruption. OSA is a highly prevalent disorder with associated sequelae across multiple physical domains, overlapping with other chronic diseases, affecting development in children as well as increased health care utilization. More precise and personalized approaches are required to treat the complex constellation of symptoms with its associated comorbidities since not all children are cured by surgery (removal of the adenoids and tonsils). Given that dentists manage the teeth throughout the lifespan and have an important understanding of the anatomy and physiology involved with the airway from a dental perspective, it seems reasonable that better understanding and management from their field will give the opportunity to provide better integrated and optimized outcomes for children affected by OSA. With the emergence of therapies such as mandibular advancement devices and maxillary expansion, etc., dentists can be involved in providing care for OSA along with sleep medicine doctors. Furthermore, the evolving role of myofunctional therapy may also be indicated as adjunctive therapy in the management of children with OSA. The objective of this article is to discuss the important role of dentists and the collaborative approach between dentists, allied dental professionals such as myofunctional therapists, and sleep medicine specialists for identifying and managing children with OSA. Prevention and anticipatory guidance will also be addressed.

Effects of Combined Training With Linear Periodization and Non-Periodization on Sleep Quality of Adults With Obesity

Background: Combined exercise training has proven effective in preventing and treating sleep disorders among obese adults. However, structured progression of intensity in sleep parameters remains poorly investigated within this population. Purpose: To verify the effects of non-periodized and linear periodization combined training on the sleep quality of obese adults. Methods: This was a randomized controlled trial involving adults with body mass index ≥ 30 kg/m2, allocated to 3 groups: control (CG; n = 13), non-periodized training (NG; n = 9), and with linear periodization (PG; n = 13). Groups PG and NG trained for 16 weeks in 3 weekly sessions lasting of 60 minutes. The NG trained in 50-59% heart rate reserve (HRR) e 2 × 10-12 repetition maximum (RM) and the PG with progression in 3 mesocycles: 40-49%;50-59%; 60-69% HRR e 2x12-14; 2x10-12; 2 × 8-10 RM, with the total volume equated. Sleep quality was evaluated by the Pittsburgh Sleep Quality Index. For statistics, we used Generalized Estimation Equations considering p ≤ 0.05. Results: Sleep latency was reduced in both training groups after intervention (NG-Δ = -25.56 minutes p = .028; PG-Δ = -22.23 minutes p = .035), while significant improvements in sleep efficiency were found only in the NG (Δ = 20.67%; p = .042). Conclusion: Despite the NG's apparent superiority, which model has the best sleep effects on obese adults cannot be stated. Hence, caution is needed while extrapolating the results.

Dynamic sleep MRI in obstructive sleep apnea: a systematic review and meta-analysis

PURPOSE

The objective of this study is to systematically review the international literature for dynamic sleep magnetic resonance imaging (MRI) as a diagnostic tool in obstructive sleep apnea (OSA), to perform meta-analysis on the quantitative data from the review, and to discuss its implications in future research and potential clinical applications.

STUDY DESIGN

A comprehensive review of the literature was performed, followed by a detailed analysis of the relevant data that has been published on the topic.

METHODS

Clinical key, Uptodate, Ovid, Ebscohost, Pubmed/MEDLINE, Scopus, Dynamed, Web of Science and The Cochrane Library were systematically searched. Once the search was completed, dynamic sleep MRI data were analyzed.

RESULTS

Nineteen articles reported on 410 OSA patients and 79 controls that underwent dynamic sleep MRI and were included in this review. For meta-analysis of dynamic sleep MRI data, eight articles presented relevant data on 160 OSA patients. Obstruction was reported as follows: retropalatal (RP) 98%, retroglossal (RG) 41% and hypopharyngeal (HP) in 5%. Lateral pharyngeal wall (LPW) collapse was found in 35/73 (48%) patients. The combinations of RP + RG were observed in 24% and RP + RG + LPW in 16%. If sedation was used, 98% of study participants fell asleep compared to 66% of unsedated participants.

CONCLUSIONS

Dynamic sleep MRI has demonstrated that nearly all patients have retropalatal obstruction, retroglossal obstruction is common and hypopharyngeal obstruction is rare. Nearly all patients (98%) who are sedated are able to fall asleep during the MRI. There is significant heterogeneity in the literature and standardization is needed.

Usefulness of Hard Palate Measurements in Predicting Airway Dimensions in Patients Referred for Cone Beam CT

Purpose:

The aim of the study was to evaluate the usefulness of hard palate measurements in predicting airway dimensions in patients referred for cone-beam CT (CBCT).

Materials and Methods:

Six hundred forty-three patients (239 males and 404 females) were examined by CBCT. Using dedicated CBCT software (Kodak CS 3D imaging version 3.8.6, Carestream, Rochester, NY, USA); different hard palate (palatal interalveolar length, palatal arch depth, maxillo-palatal arch angle, and alveolar width) and airway measurements (airway volume, minimum cross-sectional area, minimum anteroposterior distance, minimum right to left distance and airway length) were obtained and correlated using Pearson’s correlation coefficients and regression analysis.

Results:

Although the correlation between hard palate and airway measurements was weak (Pearson coefficient (r) < 0.40), there were significant (P < 0.05) additive effects for hard palate measurements in predicting airway dimensions. Maxillo-palatal arch angle was the only hard palate measurement that had no effect in predicting airway dimensions.

Conclusion:

Hard palate measurements are considered useful in predicting airway dimensions in patients referred for CBCT.

Application of personalized medicine to obstructive sleep apnea in China

Obstructive sleep apnea (OSA) is a common sleep disorder whose prevalence is increasing in China consistent with rising obesity trends. OSA is a heterogeneous disorder depends on anatomical and nonanatomical risk factors. Ethnicity differentially influences the attribution of these OSA risk factors. Chinese patients had more craniofacial bony restriction and Caucasians were more obese. This suggests ethnic differences in potential applications for diagnostics and therapeutics. However, current strategies for the management of OSA reflect a one-size-fits-all approach based on the apnea-hypopnea index (AHI). Although continuous positive airway pressure (CPAP) remains the first-line and most efficacious treatment for OSA, the acceptance is unacceptably low in China. Therefore, targeted therapies to treat OSA need to be developed. This review summarizes the differences in OSA pathogenesis of Chinese patients and analyzes the current condition of personalized medicine to patients with OSA in China. The application of personalized medicine to OSA in the Chinese population is still a long way off.

Diagnosis of obstructive sleep apnea with prediction of flow characteristics according to airway morphology automatically extracted from medical images: Computational fluid dynamics and artificial intelligence approach

BACKGROUND

Obstructive sleep apnea syndrome (OSAS) is being observed in an increasing number of cases. It can be diagnosed using several methods such as polysomnography.

OBJECTIVES

To overcome the challenges of time and cost faced by conventional diagnostic methods, this paper proposes computational fluid dynamics (CFD) and machine-learning approaches that are derived from the upper-airway morphology with automatic segmentation using deep learning.

METHOD

We adopted a 3D UNet deep-learning model to perform medical image segmentation. 3D UNet prevents the feature-extraction loss that may occur by concatenating layers and extracts the anteroposterior coordination and width of the airway morphology. To create flow characteristics of the upper airway training data, we analyzed the changes in flow characteristics according to the upper-airway morphology using CFD. A multivariate Gaussian process regression (MVGPR) model was used to train the flow characteristic values. The trained MVGPR enables the prompt prediction of the aerodynamic features of the upper airway without simulation. Unlike conventional regression methods, MVGPR can be trained by considering the correlation between the flow characteristics. As a diagnostic step, a support vector machine (SVM) with predicted aerodynamic and biometric features was used in this study to classify patients as healthy or suffering from moderate OSAS. SVM is beneficial as it is easy to learn even with a small dataset, and it can diagnose various flow characteristics as factors while enhancing the feature via the kernel function. As the patient dataset is small, the Monte Carlo cross-validation was used to validate the trained model. Furthermore, to overcome the imbalanced data problem, the oversampling method was applied.

RESULT

The segmented upper-airway results of the high-resolution and low-resolution models present overall average dice coefficients of 0.76±0.041 and 0.74±0.052, respectively. Furthermore, the classification accuracy, sensitivity, specificity, and F1-score of the diagnosis algorithm were 81.5%, 89.3%, 86.2%, and 87.6%, respectively.

CONCLUSION

The convenience and accuracy of sleep apnea diagnosis are improved using deep learning and machine learning. Further, the proposed method can aid clinicians in making appropriate decisions to evaluate the possible applications of OSAS.

Novel non-invasive assessment of upper airway inflammation in obstructive sleep apnea using positron emission tomography/magnetic resonance imaging

PURPOSE

To develop a novel non-invasive technique to quantify upper airway inflammation using positron emission tomography/magnetic resonance imaging (PET/MRI) in patients with obstructive sleep apnea (OSA).

METHODS

Patients with treatment naïve moderate-to-severe OSA underwent [18F]-fluoro-2-deoxy-D-glucose (FDG) PET/MRI. Three readers independently performed tracings of the pharyngeal soft tissue on MRI. Standardized uptake values (SUV) were generated from region of interest (ROI) tracings on corresponding PET images. Background SUV was measured from the sternocleidomastoid muscle. SUV and target-to-background (TBR) were compared across readers using intraclass correlation coefficient (ICC) analyses. SUV from individual image slices were compared between each reader using Bland-Altman plots and Pearson correlation coefficients. All tracings were repeated by one reader for assessment of intra-reader reliability.

RESULTS

Five participants completed our imaging protocol and analysis. Median age, body mass index, and apnea-hypopnea index were 41 years (IQR 40.5-68.5), 32.7 kg/m² (IQR 28.1-38.1), and 30.7 event per hour (IQR 19.5-48.1), respectively. The highest metabolic activity regions were consistently localized to palatine or lingual tonsil adjacent mucosa. Twenty-five ICC met criteria for excellent agreement. The remaining three were TBR measurements which met criteria for good agreement. Head-to-head comparisons revealed strong correlation between each reader.

CONCLUSIONS

Our novel imaging technique demonstrated reliable quantification of upper airway FDG avidity. This technology has implications for future work exploring local airway inflammation in individuals with OSA and exposure to pollutants. It may also serve as an assessment tool for response to OSA therapies.

Two-dimensional upper airway normative values in children aged 7 to 17 years

Objective: To develop two-dimensional (2D) upper airway normative values in pediatric patients and correlate upper airway measurements with age.Methods: Cone beam computed tomography scans of 3738 patients were examined, and a sample of 61 patients, divided into two age groups (7-11 and 12-17 years), w used to reconstruct lateral cephalograms.Results: The mean adenoid-nasopharynx (A/N) ratio was 0.45 and 0.44 for age groups 1 and 2, respectively. The mean PNS-ad1 and PNS-ad2 were 24 and 18.7 mm, respectively, for age group 1, and 26.7 and 21.2 mm, respectively, for age group 2. Additional normative values for the hyoid bone, airway space, uvula, and tongue are presented. The highest correlation with age was the upper airway length (r = 0.557, p < 0.001).Conclusion: Although cephalometric radiographs remain 2D reconstructions of three-dimensional structures, they have significant value and can aid clinicians in the screening process for pediatric sleep apnea.

Orofacial Myofunctional Therapy in Obstructive Sleep Apnea Syndrome: A Pathophysiological Perspective

Obstructive sleep apnea (OSA) syndrome is a multi-factorial disorder. Recently identified pathophysiological contributing factors include airway collapsibility, poor pharyngeal muscle responsiveness, a low arousal threshold, and a high loop gain. Understanding the pathophysiology is of pivotal importance to select the most effective treatment option. It is well documented that conventional treatments (continuous positive airway pressure (CPAP), upper airway surgery, and dental appliance) may not always be successful in the presence of non-anatomical traits, especially in mild to moderate OSA. Orofacial myofunctional therapy (OMT) consists of isotonic and isometric exercises targeted to oral and oropharyngeal structures, with the aim of increasing muscle tone, endurance, and coordinated movements of pharyngeal and peripharyngeal muscles. Recent studies have demonstrated the efficacy of OMT in reducing snoring, apnea-hypopnea index, and daytime sleepiness, and improving oxygen saturations and sleep quality. Myofunctional therapy helps to reposition the tongue, improve nasal breathing, and increase muscle tone in pediatric and adult OSA patients. Studies have shown that OMT prevents residual OSA in children after adenotonsillectomy and helps adherence in CPAP-treated OSA patients. Randomized multi-institutional studies will be necessary in the future to determine the effectiveness of OMT in a single or combined modality targeted approach in the treatment of OSA. In this narrative review, we present up-to-date literature data, focusing on the role of OSA pathophysiology concepts concerning pharyngeal anatomical collapsibility and muscle responsiveness, underlying the response to OMT in OSA patients.

The predictive value of photogrammetry for obstructive sleep apnea

STUDY OBJECTIVES

The aim of this study was to develop a prediction model for obstructive sleep apnea (OSA) based on photographic measurements of upper airway structures and to compare this to the model based on general physical examination.

METHODS

Participants with suspected OSA were recruited consecutively. General physical examination and photography of the oropharyngeal structures were performed prior to polysomnography. Logistic regression analysis was used to establish the prediction models.

RESULTS

A total of 197 eligible participants were included, and 74% were confirmed with OSA. The logistic regression model consisted of 4 photographic measurements (tongue area, uvula area, frenulum length, and retroposition distance) that classified 82.7% of the participants correctly and had 85.6% (95% confidence interval, 78.9-90.9%) sensitivity and 84.3% (95% confidence interval, 71.4-93.0%) specificity at the best cutoff point (0.71). The area under the receiver operating characteristics curve of the model was 0.90, which was higher than that of the model based on general physical measurements alone (area under the curve 0.80). The prediction performance further improved when photographic and general physical measurements were combined (area under the curve 0.93).

CONCLUSIONS

Detailed abnormality data of upper airway structures in OSA could be provided by photogrammetry. Prediction models comprising photographic measurements could be useful in the prediction of OSA.

CLINICAL TRIAL REGISTRATION

Registry: Chinese Clinical Trial Registry; Name: Mechanisms of cessation of respiratory events in patients with different phenotypes of obstructive sleep apnea; URL: http://www.chictr.org.cn/historyversionpuben.aspx?regno=ChiCTR2000031748; Identifier: ChiCTR2000031748.

Upper airway lengthening caused by weight increase in obstructive sleep apnea patients

BACKGROUND

The longer upper airway is more collapsible during sleep. This study aims to reveal relationships among upper airway length, weight, and obstructive sleep apnea (OSA), particularly to answer why the upper airway of OSA patients is longer than that of healthy people and why some obese people suffer from OSA while others do not.

METHODS

We perform head and neck MRI on male patients and controls, and measure > 20 morphological parameters, including several never before investigated, to quantify the effect of weight change on upper airway length.

RESULTS

The upper airway length is longer in patients and correlates strongly to body weight. Weight increase leads to significant fat infiltration in the tongue, causing the hyoid to move downward and lengthen the airway in patients. The apnea-hypopnea index (AHI) strongly correlates to airway length and tongue size. Surprisingly, a distance parameter h and angle β near the occipital bone both show significant differences between healthy males and patients due to their different head backward tilt angle, and strongly correlates with AHI. The contributions of downward hyoid movement and head tilt on airway lengthening are 67.4-80.5% and19.5-32.6%, respectively, in patients. The parapharyngeal fat pad also correlates strongly with AHI.

CONCLUSIONS

The findings in this study reveal that the amount of body weight and distribution of deposited fat both affect airway length, and therefore OSA. Fat distribution plays a larger impact than the amount of weight, and is a better predictor of who among obese people are more prone to OSA.