The impact of pharyngeal fat tissue on the pathogenesis of obstructive sleep apnea

Causal association between snoring and stroke: a Mendelian randomization study in a Chinese population

Background

Previous observational studies established a positive relationship between snoring and stroke. We aimed to investigate the causal effect of snoring on stroke.

Methods

Based on 82,339 unrelated individuals with qualified genotyping data of Asian descent from the China Kadoorie Biobank (CKB), we conducted a Mendelian randomization (MR) analysis of snoring and stroke. Genetic variants identified in the genome-wide association analysis (GWAS) of snoring in CKB and UK Biobank (UKB) were selected for constructing genetic risk scores (GRS). A two-stage method was applied to estimate the associations of the genetically predicted snoring with stroke and its subtypes. Besides, MR analysis among the non-obese group (body mass index, BMI <24.0 kg/m2), as well as multivariable MR (MVMR), were performed to control for potential pleiotropy from BMI. In addition, the inverse-variance weighted (IVW) method was applied to estimate the causal association with genetic variants identified in CKB GWAS.

Findings

Positive associations were found between snoring and total stroke, hemorrhagic stroke (HS), and ischemic stroke (IS). With GRS of CKB, the corresponding HRs (95% CIs) were 1.56 (1.15, 2.12), 1.50 (0.84, 2.69), 2.02 (1.36, 3.01), and the corresponding HRs (95% CIs) using GRS of UKB were 1.78 (1.30, 2.43), 1.94 (1.07, 3.52), and 1.74 (1.16, 2.61). The associations remained stable in the MR among the non-obese group, MVMR analysis, and MR analysis using the IVW method.

Interpretation

This study suggests that, among Chinese adults, genetically predicted snoring could increase the risk of total stroke, IS, and HS, and the causal effect was independent of BMI.

Funding

National Natural Science Foundation of China, Kadoorie Charitable Foundation Hong Kong, UK Wellcome Trust, National Key R&D Program of China, Chinese Ministry of Science and Technology.

Overall Obesity Not Abdominal Obesity Has a Causal Relationship with Obstructive Sleep Apnea in Individual Level Data

Objective

Both obstructive sleep apnea (OSA) and obesity are highly prevalent worldwide, and are intrinsically linked. Previous studies showed that obesity is one of the major risk factors for OSA, but the causality of the relationship is still unclear. The study was to investigate the causal relationships of overall obesity and abdominal obesity with OSA and its quantitative traits.

Methods

In this case-control study, a total of 7134 participants, including 4335 moderate-to-severe OSA diagnosed by standard polysomnography and 2799 community-based controls were enrolled. Anthropometric and biochemical data were collected. Mendelian randomization (MR) analyses were performed using the genetic risk score, based on 29 body mass index (BMI)- and 11 waist-hip-ratio (WHR)-associated single nucleotide polymorphisms as instrumental variables. The causal associations of these genetic scores with OSA and its quantitative phenotypes were analyzed.

Results

Obesity was strongly correlated with OSA in observational analysis (β= 0.055, P = 3.7 × 10-5). In MR analysis, each increase by one standard deviation in BMI was associated with increased OSA risk [odds ratio (OR): 2.21, 95% confidence interval (CI): 1.62-3.02, P = 5.57 × 10-7] and with 2.72-, 4.68-, and 3.25-fold increases in AHI, ODI, and MAI, respectively (all P < 0.05) in men. However, no causal associations were found between WHR and OSA risk or OSA quantitative traits in men and women.

Conclusion

Compared to abdominal obesity, overall obesity showed a causal relationship with OSA and its quantitative traits, especially in men.

The effect of surgical weight loss on upper airway fat in obstructive sleep apnoea

PURPOSE

Obesity is a reversible risk factor for obstructive sleep apnoea (OSA). Weight loss can potentially improve OSA by reducing fat around and within tissues surrounding the upper airway, but imaging studies are limited. Our aim was to study the effects of large amounts of weight loss on the upper airway and volume and fat content of multiple surrounding soft tissues.

METHODS

Participants undergoing bariatric surgery were recruited. Magnetic resonance imaging (MRI) was performed at baseline and six-months after surgery. Volumetric analysis of the airway space, tongue, pharyngeal lateral walls, and soft palate were performed as well as calculation of intra-tissue fat content from Dixon imaging sequences.

RESULTS

Among 18 participants (89% women), the group experienced 27.4 ± 4.7% reduction in body weight. Velopharyngeal airway volume increased (large effect; Cohen's d [95% CI], 0.8 [0.1, 1.4]) and tongue (large effect; Cohen's d [95% CI], - 1.4 [- 2.1, - 0.7]) and pharyngeal lateral wall (Cohen's d [95% CI], - 0.7 [- 1.2, - 0.1]) volumes decreased. Intra-tissue fat decreased following weight loss in the tongue, tongue base, lateral walls, and soft palate. There was a greater effect of weight loss on intra-tissue fat than parapharyngeal fat pad volume (medium effect; Cohen's d [95% CI], - 0.5 [- 1.2, 0.1], p = 0.083).

CONCLUSION

The study showed an increase in velopharyngeal volume, reduction in tongue volume, and reduced intra-tissue fat in multiple upper airway soft tissues following weight loss in OSA. Further studies are needed to assess the effect of these anatomical changes on upper airway function and its relationship to OSA improvement.

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.

Volume of parapharyngeal fat pad in obstructive sleep apnea syndrome: prognostic role for multilevel sleep surgery

STUDY OBJECTIVES

To evaluate the prognostic role of volume of parapharyngeal fat pad (VPPFP) after multilevel sleep surgery in patients with obstructive sleep apnea syndrome.

METHODS

This retrospective cohort study was conducted in 50 patients with moderate to severe obstructive sleep apnea syndrome who underwent polysomnography (preoperative and postoperative 6 months) and preoperative facial computed tomography with multilevel sleep surgery between May 2010 and February 2019. All patients had failed or refused positive airway pressure treatment.

RESULTS

Of the 50 patients with moderate to severe obstructive sleep apnea syndrome who underwent multilevel sleep surgery, 46 were male (92.0%) with mean ± standard deviation age of 41.2 ± 12.5 years. On the preoperative polysomnography, mean ± standard deviation of apnea-hypopnea index and CT90 (cumulative percentage of time spent at oxygen saturation less than 90%) were 43.4 ± 19.3 events/h and 5.6 ± 9.6%, respectively. The average VPPFP measured by facial computed tomography scan was 4.9 ± 1.9 cm3. Multiple linear regression analysis showed that VPPFP was significantly correlated (R2 = 0.38) with age (β = 0.05; 95% confidence interval [CI], 0.01-0.09) and body mass index (β = 0.31; 95% CI, 0.16-0.45). Surgical success rate was 38%, and VPPFP higher than 5.1 cm3 was significantly associated with surgical failure after covariate adjustment (P = .01; odds ratio = 0.09; 95% CI, 0.02-0.48). Postoperative apnea-hypopnea index was positively correlated (R2 = 0.40) with CT90 (β = 1.33; 95% CI, 0.74-1.92) and VPPFP (β = 3.52; 95% CI, 0.30-6.74).

CONCLUSIONS

VPPFP correlated with age and body mass index, and high VPPFP and CT90 were associated with high postoperative apnea-hypopnea index. VPPFP larger than 5.1 cm3 was a possible risk factor for surgical failure, which may inform a decision on multilevel sleep surgery as salvage therapy for positive airway pressure treatment.

CITATION

Kim BK, Park SI, Hong SD, Jung YG, Kim HY. Volume of parapharyngeal fat pad in obstructive sleep apnea syndrome: prognostic role for multilevel sleep surgery. J Clin Sleep Med. 2022;18(12):2819-2828.

Upper airway modifications after weight loss: a systematic review

OBJECTIVE

Weight loss is one of the most often prescribed treatments to reduce the level of sleep apnea severity; however, objective assessment of airway alterations after loss of weight has only been studied in the last decades. This study aimed at evaluating alterations after weight loss reported in the literature.

METHODS

A literature review was performed in the medical databases: PubMed, Web of Science, Scopus and Embase. A total of 681 articles were found in the databases and after evaluation only 10 studies were selected for data extraction.

RESULTS

Most studies observed an increase of the area in the retropalatal region; some indicating that this increase occurred mostly in the lateral pharyngeal region. Studies with volumetric reconstruction showed a significant reduction in parapharyngeal fat deposits, lateral wall and tongue fat, and volumetric reduction in all soft tissues of the pharynx, pterygoid and genioglossus muscles. Studies evaluating craniofacial bone structures showed a reduction in the airway height by bringing the hyoid closer to the posterior nasal spine and a reduction in the distance from the hyoid to the chin.

CONCLUSION

There is a limited number of studies with a good level of scientific evidence evaluating changes in the upper airways after weight loss and how these changes impact obstructive sleep apnea. The studies included in this review indicate that weight loss increases the airways space by reducing the volume of the parapharyngeal structures, particularly at the retropalatal site, where there is an apparent gain in the lateral area of the airway and hyoid relocation.

The Predictive Role of the Upper-Airway Adipose Tissue in the Pathogenesis of Obstructive Sleep Apnoea

This study aimed to analyse the thickness of the adipose tissue (AT) around the upper airways with anthropometric parameters in the prediction and pathogenesis of OSA and obstruction of the upper airways using artificial intelligence. One hundred patients were enrolled in this prospective investigation, who were divided into control (non-OSA) and mild, moderately severe, and severe OSA according to polysomnography. All participants underwent drug-induced sleep endoscopy, anthropometric measurements, and neck MRI. The statistical analyses were based on artificial intelligence. The midsagittal SAT, the parapharyngeal fat, and the midsagittal tongue fat were significantly correlated with BMI; however, no correlation with AHI was observed. Upper-airway obstruction was correctly categorised in 80% in the case of the soft palate, including parapharyngeal AT, sex, and neck circumference parameters. Oropharyngeal obstruction was correctly predicted in 77% using BMI, parapharyngeal AT, and abdominal circumferences, while tongue-based obstruction was correctly predicted in 79% using BMI. OSA could be predicted with 99% precision using anthropometric parameters and AT values from the MRI. Age, neck circumference, midsagittal and parapharyngeal tongue fat values, and BMI were the most vital parameters in the prediction. Basic anthropometric parameters and AT values based on MRI are helpful in predicting OSA and obstruction location using artificial intelligence.

Correlation of cephalometric variables with obstructive sleep apnea severity among children: a hierarchical regression analysis

OBJECTIVE

To evaluate the correlation between cephalometric parameters and apnea-hypopnea index (AHI) after controlling gender, body mass index (BMI), and adenoid size in children with obstructive sleep apnea (OSA).

METHODS

Sixty-four children with OSA (40 males, 24 females, 8.72 ± 0.899 years) were chosen by simple random sampling for a cross-sectional study from January 2018 to March 2022. They were diagnosed with OSA, assessed by Obstructive Sleep Apnea-18 questionnaire and home polysomnography and underwent lateral cephalograms.

RESULTS

Hierarchical regression analysis indicated that cephalometric parameters (except adenoid size) were associated with OSA severity, explaining 18.1% of the AHI variance. Among cephalometric measurements, AHI was positively associated with H-RGn and N-Go-Me angle (p < 0.05) and negatively associated with NP (p < 0.05).

CONCLUSION

The sagittal diameter of the oropharynx, lower gonial angle, and hyoid position are significant AHI predictors in children with OSA, independent of demographic characteristics and adenoid size.

Development and Evaluation of a Pillow to Prevent Snoring Using the Cervical Spine Recurve Method

Snoring lowers the quality of sleep, causing many secondary diseases. In response, various types of preventive devices were manufactured, but most of them were far from actual snoring prevention by only sensing snoring and giving feedback. In this study, we proposed a new method to prevent snoring by adjusting the posture during sleep by widening the oropharynx space. An increase in the oropharynx area was confirmed through the expansion of the cervical spine, and a dedicated pillow that can extend through an angle of up to 20° was manufactured. Through this developed method, it was possible to easily extend the cervical spine angle in a supine position to the user, and the frequency of snoring was then tested. As a result, it was confirmed that by using the pillow with an expansion angle of 20° or more, snoring did not occur. Furthermore, looking at the evaluation results of the subjective levels of satisfaction, sleep-related items received an average of 5.9 or higher, and function-related items received high scores with an average of 5.7. We can confirm that the reliability of performance evaluation will be dramatically improved if the scope of the subject group is expanded to include various body types, ages, and genders and conduct performance evaluations for each group.

Development and Validation of a Prognostic Nomogram in Lung Cancer With Obstructive Sleep Apnea Syndrome

To analyze the prognostic factors and survival rate of lung cancer patients with obstructive sleep apnea (OSA) by nomogram. The nomogram was established by a development cohort (n = 90), and the validation cohort included 38 patients. Factors in the nomogram were identified by Cox hazard analysis. We tested the accuracy of the nomograms by discrimination and calibration, and plotted decision curves to assess the benefits of nomogram-assisted decisions. There were significant difference in sex, apnea hypopnea index (AHI), Tumor Node Metastasis (TNM), coronary heart disease, lowest arterial oxygen saturation [LSpO2 (%)], oxygen below 90% of the time [T90% (min)], the percentage of the total recorded time spend below 90% oxygen saturation (TS90%) and oxygen desaturation index (ODI4) between lung cancer subgroup and lung cancer with OSA subgroup (P < 0.05). Lung cancer patients with OSA age, AHI, TNM, cancer types, BMI and ODI4 were independent prognostic factor. Based on these six factors, a nomogram model was established. The c-index of internal verification was 0.802 (95% CI 0.767–0.885). The ROC curve analysis for the nomogram show 1-year survival (AUC = 0.827), 3-year survival (AUC = 0.867), 5-year survival (AUC = 0.801) in the development cohort were good accuracy. The calibration curve shows that this prediction model is in good agreement. Decision curve analysis (DCA) suggests that the net benefit of decision-making with this nomogram is higher, especially in the probability interval of <20% threshold. The nomogram can predict the prognosis of patients and guide individualized treatment.

Evaluation of Central Obesity, Increased Body Mass Index, and its Relation to Oropharyngeal Airway Space Using Lateral Cephalogram in Risk Prediction of Obstructive Sleep Apnea

Introduction

Maxillofacial radiologists play a significant role in detecting airway changes using radiographic tools. Clinical examination parameters and lateral cephalogram parameters play a vital role in diagnosing obstructive sleep apnea (OSA) and dreadful consequences.

Aim and Objectives

This study aims to evaluate central obesity, increased body mass index (BMI), and its relation to oropharyngeal airway space using lateral cephalogram in risk prediction of OSA. Objectives are to measure central obesity and BMI.

Methodology

BMI is measured using World Health Organization guidelines to measure oropharyngeal airway space and the tongue and soft palate area using lateral cephalogram to predict OSA's risk using Berlin's questionnaire. Age group between 18 and 60 years with 20 individuals in each group will be present in the study.

Conclusion

Cephalometric upper airway space and soft-tissue variables in different BMI groups were compared, and it was found that there was a decrease in SPAS, MAS with an increase in BMI, and in patients with BMI <24, there was narrower nasopharynx and oropharynx.

The relationship between three-dimensional craniofacial and upper airway anatomical variables and severity of obstructive sleep apnoea in adults

OBJECTIVE

The aim of this study was to evaluate the relationship between three-dimensional craniofacial and upper airway anatomical variables and severity of obstructive sleep apnoea (OSA) using cone beam computed tomography (CBCT).

METHODS

This was a prospective observational study, consisted of 95 adult OSA whose polysomnography and CBCT were available. Three-dimensional craniofacial and upper airway anatomical analysis were performed using 12 CBCT variables, including sagittal and vertical jaw relationships, maxillary width, the volume, length and minimum axial area of upper airway. The severity of OSA was evaluated through the apnea-hypopnea index (AHI). A hierarchical regression was performed to analyze the relationship between OSA severity and craniofacial and upper airway anatomical variables after controlling patients' demographic characteristics (gender, age, and BMI).

RESULTS

After controlling patients' gender, age, and BMI, individual CBCT variables including MAA, V-RPA, L-RPA and Go-Me were related to AHI. The final hierarchical regression model with demographic variables in Step 1 and CBCT variables (MAA, L-RPA and Go-Me) in Step 2 indicated that CBCT variables added additional explanatory power for AHI (ΔF(3,88) = 5.176, P = 0.002). Among these variables, L-RPA and Go-Me were statistically significant (P < 0.05).

LIMITATION

The OSA severity was expressed by AHI alone.

CONCLUSIONS

Three-dimensional craniofacial and upper airway morphology played an essential role in OSA severity. The most relevant anatomical characteristic with OSA severity were the length of retropalatal airway and mandibular body, which could be used to recognize severe OSA patients and as estimators for selecting the most appropriate treatment modality for OSA patients.

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.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00405-021-06942-y.

Use of polysomnography and home sleep apnea tests for the longitudinal management of obstructive sleep apnea in adults: an American Academy of Sleep Medicine clinical guidance statement

INTRODUCTION

Obstructive sleep apnea is an important and common disorder with associated health risks. Assuring successful longitudinal management is vital to patient health and sleep-related quality of life. This paper provides guidance from the American Academy of Sleep Medicine (AASM) regarding the use of polysomnography (PSG) and home sleep apnea tests (HSATs) after a diagnosis of obstructive sleep apnea has been established and, in most cases, treatment implemented.

METHODS

The AASM commissioned a task force of five sleep medicine experts. A literature search was conducted to identify studies that included adult patients with OSA who underwent follow-up PSG or an HSAT. The task force developed clinical guidance statements based on a review of these studies and expert opinion. The AASM Board of Directors approved the final clinical guidance statements.

CLINICAL GUIDANCE STATEMENTS

The AASM supports the following clinical guidance statements on indications for follow-up PSG and HSAT in adult patients with OSA. 1. Follow-up PSG or HSAT is not recommended for routine reassessment of asymptomatic patients with obstructive sleep apnea on PAP therapy, however, follow-up PSG or HSAT can be used to reassess patients with recurrent or persistent symptoms, despite good PAP adherence. 2. Follow-up PSG or HSAT is recommended to assess response to treatment with non-PAP interventions. 3. Follow-up PSG or HSAT may be used if clinically significant weight gain or loss has occurred since diagnosis of OSA or initiation of its treatment. 4. Follow-up PSG may be used for reassessment of sleep-related hypoxemia and/or sleep-related hypoventilation following initiation of treatment for OSA. 5. Follow-up PSG or HSAT may be used in patients being treated for OSA who develop or have a change in cardiovascular disease. 6. Follow-up PSG may be used in patients with unexplained PAP device-generated data. The ultimate judgment regarding propriety of any specific care must be made by the clinician, in light of the individual circumstances presented by the patient, available diagnostic tools, accessible treatment options and resources.

The influences of distraction osteogenesis therapy on airway morphology in patients with craniofacial microsomia

The aim of this study was to explore how mandibular distraction osteogenesis influences morphological changes in the oropharynx and laryngopharynx. This was a retrospective study of airway parameter measurements in CFM patients undergoing mandibular distraction osteogenesis treatment. The indication for surgical treatment was the obvious facial asymmetry. Mimics 17.0 (Materialise Inc., Belgium) was used to build 3D models of the oro- and laryngopharynx. The minimum cross-sectional area (CSA), mean CSA, volume, length, and surface area were measured in the 3D models. All data were entered into SPSS v. 23.0 (SPSS Inc. USA), with statistical differences assessed pre- and postoperatively using the Wilcoxon test. Thirty-two patients diagnosed with CFM were included in this study. Five were classified as type IIa, 21 as type IIb, and six as type III, using the Pruzansky-Kaban classification. The average age of the patients was 8.34 years; 14 were females and 18 were males. The average traction time was 35.59 days and the average length of traction was 35.81 mm. The total volume of the airway was significantly increased after MDO (p = 0.001). In the oropharynx and laryngopharynx segments, the mean CSA, minimum CSA, and surface area were statistically significantly different. According to the results, expansion of oropharynx and laryngopharynx were evident after MDO. Mandibular distraction osteogenensis (MDO) can expand the volume of the oropharynx and laryngopharynx. Therefore, MDO can be considered a clinically useful treatment for changing the structure of the oropharynx and laryngopharynx.

Clinical and Research Solutions to Manage Obstructive Sleep Apnea: A Review

Obstructive sleep apnea (OSA), a common sleep disorder disease, affects millions of people. Without appropriate treatment, this disease can provoke several health-related risks including stroke and sudden death. A variety of treatments have been introduced to relieve OSA. The main present clinical treatments and undertaken research activities to improve the success rate of OSA were covered in this paper. Additionally, guidelines on choosing a suitable treatment based on scientific evidence and objective comparison were provided. This review paper specifically elaborated the clinically offered managements as well as the research activities to better treat OSA. We analyzed the methodology of each diagnostic and treatment method, the success rate, and the economic burden on the world. This review paper provided an evidence-based comparison of each treatment to guide patients and physicians, but there are some limitations that would affect the comparison result. Future research should consider the consistent follow-up period and a sufficient number of samples. With the development of implantable medical devices, hypoglossal nerve stimulation systems will be designed to be smart and miniature and one of the potential upcoming research topics. The transcutaneous electrical stimulation as a non-invasive potential treatment would be further investigated in a clinical setting. Meanwhile, no treatment can cure OSA due to the complicated etiology. To maximize the treatment success of OSA, a multidisciplinary and integrated management would be considered in the future.

Safety, efficacy and airway complications of the flexible laryngeal mask airway in functional endoscopic sinus surgery: A retrospective study of 6661 patients

OBJECTIVES

Although the flexible laryngeal mask airway (FLMA) provides considerable advantages in head and neck procedures, little is known about its safety and efficacy in functional endoscopic sinus surgery (FESS). We conducted a retrospective study to evaluate the success rate of FLMA and relevant airway complications in FESS under general anaesthesia.

METHODS

A retrospective review of consecutive patients who underwent FESS for chronic rhinosinusitis was performed from 2015 to 2019. All patients scheduled for FLMA ventilation were identified. Patient characteristics, length of the surgery, FLMA size, failed FLMA cases requiring endotracheal intubation, immediate adverse airway events and delayed airway injuries were recorded. The primary outcomes included the FLMA success rate, which was defined as primary success after induction and final success after the whole surgical procedure. The secondary outcomes were specific clinical factors associated with FLMA failure and airway complications related to FLMA usage.

RESULTS

Of the 6661 patients included in our study, primary success was achieved in 6572 (98.7%), and final success was achieved in 6512 (97.8%). Failure occurred in 89 patients (1.3%) during induction, in 14 (0.2%) during surgical preparation and in 46 (0.7%) during the intraoperative procedure. All patients with failed FLMA ventilation were successfully switched to endotracheal intubation. Male sex, advanced age, higher American Society of Anesthesiologists grade (ASA) and higher body mass index (BMI) were independent risk factors associated with failed FLMA. Immediate adverse respiratory events were observed in 0.85% of the patients, and delayed airway injuries associated with use of FLMA were observed in 0.07%.

CONCLUSION

This retrospective study demonstrates a high success rate for FLMA (97.8% in 6661 patients undergoing FESS). Adverse airway events and injuries associated with FLMA are rare, but clinicians should remain vigilant so that early diagnosis and prompt treatment can be provided.

Psychological distress and quality of life in Iranian adolescents with overweight/obesity: mediating roles of weight bias internalization and insomnia

PURPOSE

To examine whether weight-related self-stigma (aka weight bias internalization) and insomnia are potential predictors of psychological distress and quality of life (QoL) among Iranian adolescents with overweight (OW)/obesity (OB). To examine whether weight-related self-stigma and insomnia are potential mediators in the relationship between excess weight and health outcomes of distress and QoL.

METHODS

All participants (n = 934; 444 males; mean age = 15.7 ± 1.2 years; zBMI = 2.8 ± 1.0) completed questionnaires on weight-related self-stigma and insomnia at baseline. Six months later, they completed questionnaires on psychological distress and QoL to assess health outcomes. Relationships among variables were tested using mediation analyses with bootstrapping method.

RESULTS

Weight-related self-stigma significantly mediated the effects of zBMI on psychological distress (effect = 0.22; bootstrapping SE = 0.09; 95% CI = 0.08, 0.45), psychosocial QoL (effect = - 0.64; bootstrapping SE = 0.19; 95% CI = - 1.10, - 0.32), and physical QoL (effect = - 1.35; bootstrapping SE = 0.54; 95% CI = - 2.43, - 0.26). Insomnia also significantly mediated the effects of zBMI on psychological distress (effect = 2.18; bootstrapping SE = 0.31; 95% CI = 1.61, 2.81), psychosocial QoL (effect = - 0.89; bootstrapping SE = 0.33; 95% CI = - 1.60, - 0.28), and physical QoL (effect = - 0.83; bootstrapping SE = 0.42; 95% CI = - 1.69, - 0.02). Full mediations were found in psychosocial QoL; partial mediations were found in psychological distress and physical QoL.

CONCLUSIONS

Weight-related self-stigma and insomnia were significant mediators in the effects of excess weight on health outcomes. Therefore, it is important to identify and treat weight-related self-stigma and insomnia for adolescents with OW/OB.

LEVEL OF EVIDENCE

Level V, cross-sectional descriptive study.

Drug-induced sleep endoscopy findings in surgically-naïve obese vs non-obese children

OBJECTIVE

To determine if drug-induced sleep endoscopy (DISE) findings are different in obese versus non-obese pediatric patients with obstructive sleep apnea (OSA) or sleep-disordered breathing (SDB).

METHODS

Prospective, observational cohort study from June 2017 to June 2018 at a tertiary academic pediatric medical center that included surgically-naïve children ages 2-12 with diagnoses of OSA or sleep-disordered breathing. Subjects with a known diagnosis of craniofacial syndromes, genetic disorders, prior adenoidectomy or tonsillectomy, or chronic tonsillitis as the indication for surgery were excluded. Two groups were assessed for patterns of obstruction based on DISE videos at each anatomic airway level using a previously published DISE scoring system. The groups included obese subjects (BMI ≥ 95th percentile) and non-obese controls (BMI <85th percentile). Each video was graded by two blinded, fellowship-trained Pediatric Otolaryngologists.

RESULTS

Fifty-one patients were included, 26 non-obese and 25 obese. Based on anatomic airway level, there was no statistically significant difference in airway obstruction at the velum (p = 0.134), adenoid (p = 0.592), lateral pharyngeal walls (p = 0.867), tongue base (p = 0.977), or supraglottis (p = 0.428) between obese and non-obese children.

CONCLUSION

Our prospective study did not associate severity of obstruction with obesity status based on anatomic airway levels. Further studies are needed to elucidate the etiology of the high rate of persistent obstructive sleep apnea in obese children.

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.

Factors Affecting Optimal Titration Pressure of Continuous Positive Airway Pressure Device in Patients with Obstructive Sleep Apnea Syndrome

Objective

To assess the effects of anatomical, clinical parameters, and pulmonary respiratory function on the therapeutic titration pressure of continuous positive airway pressure (CPAP) device in obstructive sleep apnea syndrome (OSAS).

Methods

The study comprised 41 OSAS patients whose optimum CPAP titration pressures were measured. Each patient underwent an otorhinolaryngologic and thoracic examination, and data was recorded for height, weight, body mass index, neck-waist circumferences, Mallampati classification, tonsillar hypertrophy, hypopharyngeal collapse, soft palate-tongue base obstruction scores, peak nasal inspiratory flow and acoustic rhinometry measures, and CPAP device therapeutic pressures. Forced vital capacity, forced expiratory volume, FEV1/FVC ratio and peak expiratory flow values were noted.

Results

Median CPAP optimal pressure cut-off value was determined as 9 mmH₂O. Statistical analysis was made in two groups as CPAP titration optimal pressure ≤9 and >9 mmH₂O. In the optimal pressure >9 group, neck and waist circumferences, hypopharyngeal collapse score, retropalatal and retrolingual lateral wall collapse scores were significantly higher (p<0.05). In multivariate and univariate model analysis, neck and waist circumferences, hypopharyngeal collapse score, retropalatal and retrolingual lateral wall collapse scores were observed to be significant in predicting high and low pressures in univariate model.

Conclusion

For the prediction of optimal CPAP titration pressure in OSAS treatment, wide neck and waist circumferences, high hypopharyngeal collapse score and retropalatal and retrolingual lateral wall collapse grades may be determinative.

Injectable slurry for selective destruction of neck adipose tissue in New Zealand obese mouse model

PURPOSE

Increased neck circumference is a major risk factor for obstructive sleep apnea (OSA). New data suggest that increased adipose tissue in the neck may be a contributory cause of OSA. The aim of this study was to investigate safety and efficacy of a recently developed injectable ice slurry in selective reduction of neck adipose tissue in a mouse model.

METHODS

We used the New Zealand obese mice that have increased volume of anterior neck fat, and are commonly used in OSA studies. MRI imaging was used to measure changes in fat tissue volume.

RESULTS

Thirty animals were used in this study. Volumetric measurements in MRI images showed thatchanges in anterior neck adipose tissue volume from baseline in treated mice was significantly different in comparison with the control group (-1.09/kg ± 0.33/kg vs 0.68/kg ± 0.37/kg; p < 0.01 by two-tailed Student's t test). Histological analysis of samples from the treated area of the neck did not show scarring or damage to the surrounding tissues.

CONCLUSIONS

Injection of ice slurry safely, effectively, and selectively reduces upper airway fat in New Zealand obese mice without scarring or damage to surrounding tissue. Our results suggest that slurry injection may be a novel and minimally invasive method of removing neck adipose tissue. This intervention should be further investigated to determine its suitability for treatment of OSA.

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

Maxillomandibular advancement (MMA) is effective for the treatment of obstructive sleep apnea (OSA). In previous studies, the airway was increased in the anteroposterior and transverse dimensions after MMA. However, the effect of the opposite of mandibular movement (mandibular setback) on the airway is still controversial. Mandibular setback surgery has been suggested to be one of the risk factors in the development of sleep apnea. Previous studies have found that mandibular setback surgery could reduce the total airway volume and posterior airway space significantly in both the one-jaw and two-jaw surgery groups. However, a direct cause-and-effect relationship between the mandibular setback and development of sleep apnea has not been clearly established. Moreover, there are only a few reported cases of postoperative OSA development after mandibular setback surgery.

These findings may be attributed to a fundamental difference in demographic variables such as age, sex, and body mass index (BMI) between patients with mandibular prognathism and patients with OSA. Another possibility is that the site of obstruction or pattern of obstruction may be different between the awake and sleep status in patients with OSA and mandibular prognathism. In a case-controlled study, information including the BMI and other presurgical conditions potentially related to OSA should be considered when evaluating the airway. In conclusion, the preoperative evaluation and management of co-morbid conditions would be essential for the prevention of OSA after mandibular setback surgery despite its low incidence.

Parapharyngeal fat pad area at the subglosso-supraglottic level is associated with corresponding lateral wall collapse and apnea-hypopnea index in patients with obstructive sleep apnea: a pilot study

The aim of this study was to assess associations between fat pad areas at various anatomic levels and the sites of lateral wall collapse and disease severity in adult patients with obstructive sleep apnea (OSA). Forty-one patients with OSA who prospectively underwent drug-induced sleep computed tomography were included. Areas of parapharyngeal fat pads and degrees of lateral wall collapse at three representative anatomic levels (nasopharynx, oropharynx, and subglosso-supraglottis), and apnea-hypopnea index (AHI) were measured. In the subglosso-supraglottic region, the parapharyngeal fat pad area in 17 (41%) patients with complete lateral wall collapse was significantly larger than that in 24 (59%) patients without complete collapse (median, 236.0 mm² vs 153.0 mm²; P = 0.02). In multivariate regression analysis, the parapharyngeal fat pad area at the subglosso-supraglottic level (β = 0.02; P = 0.01) and body mass index (β = 3.24; P = 0.01) were independently associated with AHI. Our preliminary results supported that parapharyngeal fat pads at the subglosso-supraglottic level may be involved in the development of lateral wall collapse and then determine the severity of OSA. Further studies are warranted to investigate the effect of reducing parapharyngeal fat pads in the treatment of OSA.

The Role of Animal Models in Developing Pharmacotherapy for Obstructive Sleep Apnea

Obstructive sleep apnea (OSA) is a highly prevalent disease characterized by recurrent closure of the upper airway during sleep. It has a complex pathophysiology involving four main phenotypes. An abnormal upper airway anatomy is the key factor that predisposes to sleep-related collapse of the pharynx, but it may not be sufficient for OSA development. Non-anatomical traits, including (1) a compromised neuromuscular response of the upper airway to obstruction, (2) an unstable respiratory control (high loop gain), and (3) a low arousal threshold, predict the development of OSA in association with anatomical abnormalities. Current therapies for OSA, such as continuous positive airway pressure (CPAP) and oral appliances, have poor adherence or variable efficacy among patients. The search for novel therapeutic approaches for OSA, including pharmacological agents, has been pursued over the past years. New insights into OSA pharmacotherapy have been provided by preclinical studies, which highlight the importance of appropriate use of animal models of OSA, their applicability, and limitations. In the present review, we discuss potential pharmacological targets for OSA discovered using animal models.

Is neck circumference an appropriate tool to predict cardiovascular risk in clinical practice? A cross-sectional study in Chilean population

OBJECTIVES

Neck circumference has emerged as a predictor of obesity and metabolic syndrome, but its clinical usefulness for different groups of population is not clearly defined. The aim is to evaluate the predictive capacity of neck circumference in order to detect cardiovascular risks (CVRs) on the Chilean population and to compare it with waist circumference performance.

DESIGN

Cross-sectional study.

SETTING

General Chilean population.

PARTICIPANTS

Data of 4607 adults aged 18 and over from the Chilean National Health Survey 2009-2010 were analysed.

PRIMARY AND SECONDARY OUTCOME MEASURES

Anthropometrics measures included neck and waist circumference, height and weight. CVR was identified according to the Framingham tables adapted for the Chilean population. Receiver operating characteristics curves and logistic regression models were made to evaluate the performance of neck circumference to predict a moderate/high CVR, comparing it to waist circumference.

RESULTS

Almost 10% of the sample had a moderate or high CVR. The probability of having a moderate/high cardiovascular risk increase with cervical obesity (OR 1.95, 95% CI 1.04 to 3.68) and central obesity (OR 4.5, 95% CI 2.47 to 8.22). The area under the curves were high for cervical obesity (AUC 81.4%, 95% CI 78.8% to 84.0%) and central obesity (AUC 82.2%, 95% CI 79.7% to 84.7%) and not statistically different (p=0.152).

CONCLUSIONS

Neck obesity has a high capacity to predict moderate/high CVR in the Chilean population. Its good performance appears as an opportunity to use it in clinical practice when waist circumference measurement is difficult to measure and eventually replace the waist circumference measurement as the technique is easier.

Association between the ADAMTS proteinases and obstructive sleep apnea

BACKGROUND

A disintegrin and metalloproteinase with thrombospondin type-1 motifs (ADAMTS) proteinases have important roles in degradation/repairing of extracellular matrix (ECM). They are thought to play a key role in pathogenesis of many diseases. We aimed to investigate the association between ADAMTS 2, 3, and 14 (procollagen) and obstructive sleep apnea (OSA).

METHODS

Eighty-six individuals who were suspected of OSA were included. All cases underwent polysomnography. Participants were divided into 3 groups according to apnea-hypopnea index (AHI): control (n = 22), mild-to-moderate OSA (n = 36), and severe OSA (n = 28). ADAMTS proteinases 2, 3, and 14 were analyzed in serum samples.

RESULTS

When compared with other groups, patients with severe OSA showed significantly higher body mass index (BMI) (p = 0.001), whereas they showed significantly lower ADAMTS 3 levels (p = 0.016). No difference was found between groups with respect to the levels ADAMTS 2 and 14. There was a negative relation between the levels of ADAMTS 3 and the severity of OSA (Kendall's tau = - 0.19, p = 0.021). The levels of ADAMTS 3 were also found to be positively correlated with minimum SpO₂ (r = 0.31, p = 0.004) and negatively correlated with BMI, AHI, oxygen desaturation index (ODI), time duration with oxygen saturation < 90% (T90), and CRP (r = - 0.31 to - 0.49, p < 0.05). Multivariable regression analysis revealed that BMI (p = 0.013) and CRP levels (p = 0.005) were significantly associated with the levels of ADAMTS 3.

CONCLUSIONS

ADAMTS 3, one of the procollagen proteinases, was decreased in severe OSA. Lack of ADAMTS 3 proteinase may contribute to process of sleep apnea due to insufficient collagen syntheses.

Genetic influences on the onset of obstructive sleep apnoea and daytime sleepiness: a twin study

Background

Obstructive sleep apnoea (OSA) is one of the major sources of the excessive daily sleepiness, cognitive dysfunction, and it increases cardiovascular morbidity and mortality. Previous studies suggested a possible genetic influence, based on questionnaires but no objective genetic study was conducted to understand the exact variance underpinned by genetic factors.

Methods

Seventy-one Hungarian twin pairs involved from the Hungarian Twin Registry (48 monozygotic, MZ and 23 dizygotic, DZ pairs, mean age 51 ± 15 years) underwent overnight polysomnography (Somnoscreen Plus Tele PSG, Somnomedics GMBH, Germany). Apnoea hypopnea index (AHI), respiratory disturbance index (RDI) and oxygen desaturation index (ODI) were registered. Daytime sleepiness was measured with the Epworth Sleepiness Scale (ESS). Bivariate heritability analysis was applied.

Results

The prevalence of OSA was 41% in our study population. The heritability of the AHI, ODI and RDI ranged between 69% and 83%, while the OSA, defined by an AHI ≥5/h, was itself 73% heritable. The unshared environmental component explained the rest of the variance between 17% and 31%. Daytime sleepiness was mostly determined by the environment, and the variance was influenced in 34% by the additive genetic factors. These associations were present after additional adjustment for body mass index.

Conclusion

OSA and the indices of OSA severity are heritable, while daytime sleepiness is mostly influenced by environmental factors. Further studies should elucidate whether close relatives of patients with OSA may benefit from early family risk based screening.

Obstructive sleep apnea in patients with laryngeal cancer after supracricoid or vertical partial laryngectomy

Objective

To investigate whether partial laryngectomy is a risk factor for obstructive sleep apnea (OSA) and the effect of different partial laryngectomy methods on OSA.

Method

A prospective study was carried out involving 40 patients who underwent supracricoid partial laryngectomy (SCPL) (24) or vertical partial laryngectomy (VPL) (16) for carcinoma of the larynx. Apnea-hypopnea index (AHI) and oxygen saturation determined by polysomnography (PSG), Epworth sleepiness scale (ESS) score, and body mass index (BMI) were evaluated in patients before surgery, on the day of tracheal tube removal and three months later. In patients who developed apnea, laryngoscopy, Muller’s test, computer tomography (CT) and dynamic sleep magnetic resonance imaging (MRI) were performed to assess the location of airway stenosis and collapse.

Results

The AHI (P<0.001) increased and the lowest oxygen saturation (P<0.001), ESS score (P<0.001) and BMI (P=0.017) decreased after extubation compared with before surgery. Three months after extubation, the same changes were found in AHI (P<0.001) and the lowest oxygen saturation (P<0.001), but the ESS score (P<0.001) increased compared with that preoperatively. The AHI in the SCPL group was significantly higher than that in the VPL group post-operatively (P=0.010), while the miniSpO2 in the SCPL group was lower than that of the VPL group (P=0.022). Laryngoscopy showed that the patients with partial excision of the larynx had a narrowed retropalatal and retrolingual space post-operatively. Muller's test showed the collapse of the retropalatal and retrolingual space, and the CT scan showed that the tongue root was positioned lower in the SCPL group. Compared with the retropalatal and retrolingual space in the expiratory phase according to dynamic sleep MRI, the space in the inspiratory phase was clearly decreased.

Conclusion

Laryngeal function preservation surgery for laryngeal cancer results in the occurrence of OSA by altering the anatomical structure of the larynx and pharynx. OSA was more severe in patients undergoing SCPL than in patients undergoing VPL. The effect of partial laryngectomy on OSA may be related to the surgical method used.

The parapharyngeal adipose corpus: anatomic and radiologic study

PURPOSE

Although the morphology of the parapharyngeal adipose corpus (PAC) has been already described, the clinical interest of its volume and weight in the genesis of obstructive sleep apnea syndrome (OSAS) is still controversial. The volume of the PAC has been determined in OSAS patients but not in a normal population. The aim of our study was to investigate the morphology of the PAC by dissection and MRI in a normal population and to determine if there is a relation between the dimensions and volume of the PAC and the Body Mass Index (BMI).

METHODS

Thirty hemifaces of 15 fresh cadavers have been dissected after silicone injection with dissection of the external carotid artery and its main branches, with harvesting of the PAC. The PAC has been measured and weighed. Twenty-nine MRI of healthy subjects have been examined to determine the volume of the PAC, the palate-pharynx distance, and epiglottis-pharynx distance.

RESULTS

In dissection study the weight of the PAC was 18.57 g ± 2.24, the vertical dimension (height) was 4.61 cm ± 0.51, the frontal dimension (width) was 1.62 cm ± 0.24. The blood supply of the PAC constituted of branches coming from the ascending palatal and ascending pharyngeal arteries. The volume of the PAC on the right side was 1.56 cm³ ± 0.38, on the left side 1.54 cm³ ± 0.37. Its horizontal greater dimension was 1.70 cm ± 0.07.

CONCLUSIONS

There is a correlation between the volume of the PAC and the BMI in a normal population. A surgical resection of the PAC in OSAS patients by transoral robotic-assisted surgery can be proposed with preservation of the ascending palatal and ascending pharyngeal arteries.

Influence of mandibular setback surgery on three-dimensional pharyngeal airway changes

The aim of this study was to investigate the factors influencing three-dimensional changes in pharyngeal airway space after mandibular setback surgery. Airway changes in 48 skeletal class III patients who had undergone mandibular setback surgery alone (n=25, group 1) or with maxillary surgery (n=23, group 2) were analyzed. Linear parameters, cross-sectional area, and volumes of the pharyngeal airway were evaluated before (T0), immediately after (T1), and 1year after surgery (T2) by cone beam computed tomography. Although the reduced airway volume and cross-sectional area recovered slightly in the long term after surgery, the total pharyngeal airway volume (TPV) was significantly reduced compared to baseline, by 15% in group 1 and 12% in group 2. Regression analysis showed that maxillary posterior impaction in two-jaw surgery had a protective effect on preserving TPV. A change in body mass index from T0 to T2 was an important predictor of decreased TPV in one-jaw surgery patients. Maxillary posterior impaction can be a reliable option for compensating the pharyngeal airway reduction after mandibular setback surgery. Postoperative weight gain can increase the risk of postoperative pharyngeal airway reduction. Therefore, these factors need to be considered before and after mandibular setback surgery.

Effects of Increased Pharyngeal Tissue Mass Due to Fluid Accumulation in the Neck on the Acoustic Features of Snoring Sounds in Men

STUDY OBJECTIVES

Snoring sounds are generated by the vibration of pharyngeal tissue due to the upper airway narrowing. While recorded by a microphone placed over the neck, snoring can pass through the pharyngeal tissue surrounding the upper airway. Thus, changes in the pharyngeal tissue content may change the acoustic properties of the snoring sounds. Rostral fluid shift and the consequent increases in neck fluid volume (NFV) and neck circumference (NC) can increase pharyngeal tissue mass. Therefore, the goal of this study was to investigate the relationship between increases in pharyngeal tissue mass, as assessed by increased NFV and NC, and snoring sounds features.

METHODS

We obtained data from a previous study where 20 males who were not obese participated in a daytime polysomnography and their NC and NFV were measured before and after sleep. During sleep, snoring sounds were recorded with a microphone placed over the neck. Spectral centroid of the snoring sounds was estimated. Then, the first five snoring segments were selected from the first and last 30 minutes of stage N2 sleep.

RESULTS

We found a significant decrease in the snoring spectral centroid from the beginning to end of sleep. We also found that spectral centroid from the end of sleep in frequency ranges below 200 Hz was inversely correlated with the increases in NFV and NC from before to after sleep.

CONCLUSIONS

These results suggest that snoring spectral centroid can be used as a noninvasive and convenient method to assess variations in the pharyngeal tissue mass.

The relationship between the neck circumference and the carotid intima-media thickness in Amerindians. Potential links to health risks?

The carotid intima media thickness (cIMT) is a predictor of cardiovascular events. The neck circumference (NC) has been investigated as a risk factor for increased cIMT with contradictory results. This study assessed the relationship between NC and cIMT in Atahualpa residents aged ≥40 years who had sonographic examination of carotid arteries (n = 590). We also discussed on potential pathogenetic mechanisms underlying this association. Participants belonged to the Native Ecuadorian (Amerindians) ethnic group. Non-parametric regression models were used to assess the aforementioned relationship, after adjusting for relevant confounders. The mean age of participants was 60.9 ± 12.7 years (58% women). The mean value of the cIMT was 0.85 ± 0.19 mm. The mean NC was 35.8 ± 34 cm. The NC was normally distributed, but the cIMT was not. Mean values of NC and cIMT were significantly greater in men than in women. Non-parametric models showed significant differences in median cIMT values according to quartiles of NC. Predictive cIMT margins increased by quartiles of NC, significantly among individuals in the 1st quartile as compared to the 3rd quartile. In this population of Amerindians, smaller NC is associated with lower values of cIMT. The pattern of this association is different in men than in women. Sex-related differences in cervical fat tissue distribution probably accounted for such differences.

Imaging of adult obstructive sleep apnoea

Obstructive sleep apnoea (OSA) is characterised by recurrent upper airway collapse during sleep resulting in chronic and repetitive hypoxia, hypercapnia, subsequent arousal and fragmented sleep. Symptoms are insidious and diagnosis is usually delayed. Moderate to severe OSA has serious health implications with significant increase in all causes of mortality in patients with the condition as compared with unaffected individuals. The prevalence of OSA in the 30-70 year age group is estimated at 27% of males and 11% of females and it increases with age. 80% of affected individuals are obese and as obesity rates rise, so has the prevalence of OSA. An overnight polysomnogram (PSG) is required for a definitive diagnosis of OSA. Imaging has played a fundamental role in the evaluation of the anatomical factors associated with recurrent upper airway collapse and the pathogenesis of OSA. The upper airway is frequently imaged by radiologists, providing an opportunity to detect features that are strongly associated with unsuspected OSA and to raise the possibility of this diagnosis. The gold standard of treatment is continuous positive airway pressure (CPAP) which acts as a pneumatic splint for the upper airway. However, efficacy is frequently limited by poor tolerance; clinicians and patients are increasingly opting for one of a range of surgical procedures. Dedicated imaging protocols can be performed for evaluation of the upper airway to aid surgical planning.

Obstructive sleep apnea: the effect of bariatric surgery after 12 months. A prospective multicenter trial

BACKGROUND

Obstructive sleep apnea (OSA) is a highly prevalent sleep disorder, particularly in bariatric patients. It is known to be tightly linked with metabolic abnormalities and cardiovascular morbidity. Obesity is the most noteworthy individual risk factor for OSA. The aim of this study was to investigate the effect of a laparoscopic Roux-en-Y gastric bypass (LRYGB) on OSA one year after surgery.

METHODS

In this prospective multicenter study standard overnight cardiorespiratory recording was conducted 12 months after bariatric surgery in 132 patients who had OSA in the baseline recording prior to the operation. The main outcome measures were changes in the prevalence of OSA and apnea-hypopnea index (AHI). In addition, the changes in anthropometric and demographic measurements including weight, body mass index (BMI), and waist and neck circumference were evaluated. A sleep symptom questionnaire was administered at baseline and at 12 months.

RESULTS

The prevalence of OSA decreased from 71% at baseline to 44% at 12 months after surgery (p < 0.001). OSA was cured in 45% and cured or improved in 78% of the patients, but moderate or severe OSA still persisted in 20% of the patients after the operation. De novo OSA occurred in eight percent of the patients, and total AHI decreased from 27.8 events/h to 9.9 events/h (p < 0.001).

CONCLUSIONS

LRYGB is effective in treating OSA. However, the findings demonstrate that a postoperative cardiorespiratory recording is needed in order to identify the patients with persistent moderate to severe OSA after the operation.

CLINICAL TRIAL REGISTRATION

ClinalTrials.gov; No.: NCT01080404; URL: www.clinicaltrials.gov.

Impact of gender and sleep position on relationships between anthropometric parameters and obstructive sleep apnea syndrome

OBJECTIVE

Considering the mechanisms by which obesity affects obstructive sleep apnea syndrome (OSAS) and the differences of fat distribution depending on gender, associations between anthropometric parameters, and OSAS may differ depending on gender or sleep position. We analyzed the impact of gender and sleep position on the relationship between fat distribution and development of OSAS.

METHODS

One thousand thirty-two consecutive subjects were analyzed. Recorded anthropometric measurements and overnight polysomnographic data of the subjects were reviewed retrospectively. The presence of OSAS was defined by the respiratory disturbance index (RDI) ≥5 with documented symptoms of excessive daytime sleepiness.

RESULTS

Eight hundred fifty-eight males and 174 females were included. Male subjects had significantly higher body mass index (BMI), larger waist circumference (WC), and lower percent of overall body fat (P < 0.0001, P < 0.0001, and P < 0.0001, respectively). The severity of OSAS was significantly higher in male subjects (RDI 26.9 ± 22.4 in males vs. 10.2 ± 13.8 in females, P < 0.0001). In male subjects, BMI, WC, and overall body fat were significantly associated with severity of OSAS and had larger impacts on supine RDI than lateral RDI. Overall body fat was not associated with severity of OSAS in female subjects, and there were no significant differences of the associations between all anthropometric parameters and RDIs depending on sleep position.

CONCLUSIONS

Evaluation of the correlation of anthropometric data with severity of OSAS should consider sleep position as well as gender.

Dynamic upper airway collapse observed from sleep MRI: BMI-matched severe and mild OSA patients

Dynamic magnetic resonance imaging (MRI) allows real-time characterization of upper airway collapse in sleeping subjects with obstructive sleep apnea (OSA). The aim of our study was to use sleep MRI to compare differences in upper airway collapse sites between BMI-matched subjects with mild OSA and severe OSA. This is a prospective, nested case-control study using dynamic sleep MRI to compare 15 severe OSA subjects (AHI >40) and 15 mild OSA (AHI <10) subjects, who were matched for BMI. Upper airway imaging was performed on sleeping subjects in a 3.0 T MRI scanner. Sleep MRI movies were used by blinded reviewers to identify retropalatal (RP), retroglossal (RG), and lateral pharyngeal wall (LPW) airway collapse. Mean AHI in the severe OSA group was 70.3 ± 23 events/h, and in the mild group was 7.8 ± 1 events/h (p < 0.001). All mild and severe OSA subjects demonstrated retropalatal airway collapse. Eighty percent in the mild group showed single-level RP collapse (p < 0.001). All subjects in the severe group showed multi-level collapse: RP + LPW (n = 9), RP + RG + LPW (n = 6). All severe OSA subjects showed LPW collapse, as compared with three subjects in the mild group (p < 0.001). LPW collapse was positively associated with AHI in simple regression analysis (β = 51.8, p < 0.001). In conclusion, severe OSA patients present with more lateral pharyngeal wall collapse as compared to BMI-matched mild OSA patients.

Three-dimensional imaging of the upper airway anatomy in obstructive sleep apnea: a systematic review

INTRODUCTION

The pathogenesis of upper airway collapse in people with obstructive sleep apnea (OSA) is not fully understood. The aim of this study was to systematically review the literature in order to assess the most relevant anatomical characteristics of the upper airway related to the pathogenesis of OSA by analyzing the three-dimensional upper airway anatomy.

METHOD

A PICO (population/patient, intervention, comparison, outcome) search strategy, focusing on the upper airway anatomy of people with OSA, was conducted using the following databases: MEDLINE (PubMed), Excerpta Medica database (EMBASE), Web of Science, and Cochrane Library. The studies in which three-dimensional images were made from the participants who were awake and in the supine position during quiet breathing were selected in this systematic review.

RESULTS

Of the 758 unique retrieved studies, eight fulfilled the criteria for this systematic review. The minimum cross-sectional area of the upper airways of people with OSA, which is influenced by many factors such as hard and soft tissues surrounding the upper airway, was significantly smaller than that of those without OSA.

CONCLUSION

Within the limitation of the selected studies, this systematic review suggested that a small minimum cross-sectional area is the most relevant anatomical characteristic of the upper airway related to the pathogenesis of OSA.

The influence of a mandibular advancement plate on polysomnography in different grades of obstructive sleep apnea

Objectives

The purpose of this study was to investigate the effect of a mandibular advancement device on different grades of obstructive sleep apnea using a relatively simple test for the apnea-hypopnea index to determine if a mandibular device will be effective.

Material and Methods

A total of 68 patients with obstructive sleep apnea syndrome (OSAS) including, 31 with mild, 23 with moderate and 14 with severe OSAS were treated with a mandibular advancement device (MAD) and monitored with polysomnography.

Results

25 of the 31 mild, 15 of the 23 moderate and 2 of the 14 severe OSAS patients were cured of their OSAS if a post treatment apnea-hypopnea index of less than 5 is regarded as cured. The odds ratios for success with MAD therapy are 3 for women over men, 14.9 for mild obstructive sleep apnea, 5.42 for moderate obstructive sleep apnea if severe obstructive sleep apnea is assigned an odds ratio of 1.

Conclusions

The use of the apnea-hypopnea index alone is useful in mild and moderate disease to predict the effectiveness of mandibular advancement device. Treatment with a mandibular advancement device is very effective in treating mild and moderate obstructive sleep apnea. Conservative treatment with a mandibular advancement device can be successful in less severe grades of sleep apnea and may be an alternative for non-surgical patients with severe obstructive sleep apnea intolerant of Continuous Positive Airway Pressure management.

Maxillomandibular Advancement and Tracheostomy for Morbidly Obese Obstructive Sleep Apnea

Objective

The objective of this study is to systematically review polysomnography data and sleepiness in morbidly obese (body mass index [BMI] ≥40 kg/m2) patients with obstructive sleep apnea (OSA) treated with either a maxillomandibular advancement (MMA) or a tracheostomy and to evaluate the outcomes.

Data Sources

MEDLINE, Scopus, Web of Science, and the Cochrane Library.

Review Methods

A search was performed from inception through April 8, 2014, in each database.

Results

Six maxillomandibular advancement studies (34 patients, age 42.42 ± 9.13 years, mean BMI 44.88 ± 4.28 kg/m2) and 6 tracheostomy studies (14 patients, age 52.21 ± 10.40 years, mean BMI 47.93 ± 7.55 kg/m2) reported individual patient data. The pre- and post-MMA means ± SDs for apnea-hypopnea indices were 86.18 ± 33.25/h and 9.16 ± 7.89/h ( P < .00001), and lowest oxygen saturations were 66.58% ± 16.41% and 87.03% ± 5.90% ( P < .00001), respectively. Sleepiness following MMA decreased in all 5 patients for whom it was reported. The pre- and posttracheostomy mean ± SD values for apnea indices were 64.43 ± 41.35/h and 1.73 ± 2.68/h ( P = .0086), oxygen desaturation indices were 69.20 ± 26.10/h and 41.38 ± 36.28/h ( P = .22), and lowest oxygen saturations were 55.17% ± 16.46% and 79.83% ± 4.36% ( P = .011), respectively. Two studies reported outcomes for Epworth Sleepiness Scale for 5 patients, with mean ± SD values of 18.80 ± 4.02 before tracheostomy and 2.80 ± 2.77 after tracheostomy ( P = .0034).

Conclusion

Data for MMA and tracheostomy as treatment for morbidly obese, adult OSA patients are significantly limited. We caution surgeons about drawing definitive conclusions from these limited studies; higher level studies are needed.

Enhanced upper-airway muscle responsiveness is a distinct feature of overweight/obese individuals without sleep apnea

RATIONALE

Body habitus is a major determinant of obstructive sleep apnea (OSA). However, many individuals do not have OSA despite being overweight/obese (body mass index > 25 kg/m(2)) for reasons that are not fully elucidated.

OBJECTIVES

To determine the key physiologic traits (upper-airway anatomy/collapsibility, upper-airway muscle responsiveness, chemoreflex control of ventilation, arousability from sleep) responsible for the absence of OSA in overweight/obese individuals.

METHODS

We compared key physiologic traits in 18 overweight/obese subjects without apnea (apnea-hypopnea index < 15 events per hour) with 25 overweight/obese matched patients with OSA (apnea-hypopnea index ≥ 15 events per hour) and 11 normal-weight nonapneic control subjects. Traits were measured by repeatedly lowering continuous positive airway pressure to subtherapeutic levels for 3 minutes during non-REM sleep.

MEASUREMENTS AND MAIN RESULTS

Overweight/obese subjects without apnea exhibited a less collapsible airway than overweight/obese patients with apnea (critical closing pressure: -3.7 ± 1.9 vs. 0.6 ± 1.2 cm H2O; P = 0.003; mean ± 95% confidence interval), but a more collapsible airway relative to normal-weight control subjects (-8.8 ± 3.1 cm H2O; P < 0.001). Notably, overweight/obese subjects without apnea exhibited a threefold greater upper-airway muscle responsiveness than both overweight/obese patients with apnea (Δgenioglossus EMG/Δepiglottic pressure: -0.49 [-0.22 to -0.79] vs. -0.15 [-0.09 to -0.22] %max/cm H2O; P = 0.008; mean [95% confidence interval]) and normal-weight control subjects (-0.16 [-0.04 to -0.30] %max/cm H2O; P = 0.02). Loop gain was elevated (more negative) in both overweight/obese groups and normal-weight control subjects (P = 0.02). Model-based analysis demonstrated that overweight/obese individuals without apnea rely on both more favorable anatomy and collapsibility and enhanced upper-airway dilator muscle responses to avoid OSA.

CONCLUSIONS

Overweight/obese individuals without apnea have a moderately compromised upper-airway structure that is mitigated by highly responsive upper-airway dilator muscles to avoid OSA. Elucidating the mechanisms underlying enhanced muscle responses in this population may provide clues for novel OSA interventions.