The effect of body position on airway patency in obstructive sleep apnea: CT imaging analysis

Does Head and Neck Posture Affect Cone-Beam Computed Tomography Assessment of the Upper Airway?

PURPOSE

Radiographic analysis is often used as a screening tool to assess for risk of sleep-related breathing disorders. This study aimed to address 2 questions: (1) Does head posture significantly affect the minimum cross-sectional area (MCA)? and (2) Is the NBC3 (nasion-basion-C3) angle a reliable measurement to control for alteration of head position in cone-beam computed tomography (CBCT) scans?

METHODS

Study design: prospective cohort study.

SETTING

Private practices affiliated with a research institution.

PARTICIPANTS

convenience sample of adult volunteers.

VARIABLES

CBCT scans were taken in 2 conditions: baseline (natural head position, NHP) and 1 of 5 experimental conditions (head tilted up, head tilted down, sitting vs standing, use of chin-rest, and swallow variation). For the primary aim of our study, the primary predictor variable was head posture and the main outcome variable was percentage change in MCA. For the secondary aim, the primary predictor variable was head posture and the main outcome variable was degree change in NBC3 angle.

RESULTS

Ninety subjects were included (age 40.7 ± 13.7 years, 70% female). Mean NBC3 at baseline was 112.4 ± 8.3°. Head tilted down significantly decreased (-41.4 ± 18.5 mm², P = .03∗) and head tilted up significantly increased MCA (+147.4 ± 43.3 mm², P = .0018∗). Head tilted down significantly reduced the NBC3 angle measurement (-10.5 ± 6.8°, P = .006) and head tilted up significantly increased the NBC3 angle measurement (+14.4 ± 5.8°, P = .0004). A quadratic regression model was fitted with moderately strong correlation (R² = 0.54) showing an exponential effect of small changes in the NBC3 angle on MCA, P < .0001. The model predicts that increasing NBC3 by +5 and + 10° resulted in MCA changes of +25% and +88%, whereas a decrease in NBC3 by -5 and -10° results in MCA changes of -21% and -23%, respectively.

CONCLUSION

Alterations in head posture significantly affect the MCA of the upper airway on CBCT. The NBC3 angle can be used to reliably assess changes in cranio-cervical extension and validate comparisons of MCA between CBCT scans for the same patient. A standardized protocol for CBCT acquisition is proposed.

The role of rapid maxillary expansion in pediatric obstructive sleep apnea: Efficacy, mechanism and multidisciplinary collaboration

This review aims to provide current knowledge about the efficacy, mechanism, and multidisciplinary collaboration of rapid maxillary expansion (RME) treatment in pediatric obstructive sleep apnea (OSA). OSA is a chronic disease characterized by progressively increasing upper airway resistance, with various symptoms and signs. Increasingly the evidence indicates that RME is a non-invasive and effective therapy option for children with OSA. Besides, the therapeutic mechanism of RME includes increasing upper airway volume, reducing nasal resistance, and changing tongue posture. Recent clinical researches and case reports also show that a multidisciplinary approach improves sleep-disordered breathing in children. Applied with adenotonsillectomy, mandibular advancement, continuous positive airway pressure, and comprehensive orthodontic treatment, RME can be more effective in recurrent or residual OSA.

Obstructive sleep apnea: a review for the orthodontist

INTRODUCTION

Obstructive sleep apnea (OSA) affects an important part of the population and is characterized by recurrent total or partial obstruction of the upper airway (UA) during sleep, negatively affecting the quality of life of patients in the short and long terms, and constituting an important public health problem for the society. The field of expertise of orthodontists is closely related to the UA, placing them in a strategic position to diagnose air passage failures and intervene when necessary. Orthodontists, as health professionals, must know how to recognize respiratory problems and manage them appropriately, when indicated.

OBJECTIVE

Thus, this paper aims to review and critically evaluate the related literature, to provide orthodontists with updated knowledge on the diagnosis and therapy related to OSA. Science and technology are constantly evolving; thus, the literature was also reviewed considering new technologies available in consumer-targeted applications and devices for the diagnosis, monitoring, and treatment of sleep-disordered breathing.

Subtypes of obstructive sleep apnea in children and related factors

STUDY OBJECTIVES

To investigate the prevalence of positional obstructive sleep apnea (P-OSA) and rapid eye movement-related OSA (REM-OSA) in children with OSA and identify related factors.

METHODS

This was a cross-sectional study among children aged 2-12 years diagnosed with OSA using overnight polysomnography (PSG) between August 1, 2020, and July 31, 2021. Demographics, anthropometrics, PSG, and OSA-18 questionnaire data were recorded.

RESULTS

Data from a total of 474 children were available for analysis. Children had a median age of 4.8 (4.1, 6.4) years, 66.7% were male, and 23.2% were obese. The prevalence of P-OSA was 38.2% and that of REM-OSA was 43.0%. P-OSA was correlated with age and obstructive apnea-hypopnea index (OAHI; odds ratio [OR] = 1.172, 0.947; P = .005, < 0.001, respectively), but not sex, obesity, and adenoid and tonsil size (OR = 1.265, 0.785, 0.826, 0.989; P = .258, 0.327, 0.153, 0.905, respectively). REM-OSA was correlated with age, adenoid size, tonsil size, and OAHI (OR = 0.876, 1.320, 1.387, 1.021; P = .024, 0.040, 0.001, 0.042) but not with sex and obesity (OR = 0.910, 1.281; P = .643, 0.315).

CONCLUSIONS

The prevalence of P-OSA was 38.2% and that of REM-OSA was 43.0% in children with OSA. Age was correlated with both the prevalence of P-OSA and REM-OSA, with an increasing and decreasing prevalence as children grew older, respectively. The severity of OSA was significantly associated with the prevalence of both P-OSA and REM-OSA. Adenoid and tonsil size were correlated with the prevalence of REM-OSA but not P-OSA. Obesity and sex were not associated with the prevalence of P-OSA or REM-OSA.

CITATION

Wu Y, Zheng L, Cui G, Xu Z, Ni X. Subtypes of obstructive sleep apnea in children and related factors. J Clin Sleep Med. 2022;18(10):2397-2404.

Incidence of Sleep Bruxism in Different Phenotypes of Obstructive Sleep Apnea

(1) Background: Sleep bruxism (SB) is a common sleep behavior. Obstructive sleep apnea (OSA) is a prevalent sleep-related breathing disorder with potential long-term major neurocognitive and cardiovascular sequelae. Although the co-occurrence of SB and OSA has been described previously, the exact relationship remains unclear. The present study aimed to evaluate the incidence of SB in different phenotypes of OSA. (2) Methods: The participants of this study were adult patients referred to the Department and Clinic of Internal Medicine, Occupational Diseases, Hypertension and Clinical Oncology at the Wroclaw Medical University. They underwent a single-night video polysomnography in a sleep laboratory. The data related to common OSA phenotypes were analyzed in two separate groups of patients: body position related (n = 94) and rapid eye movement (REM) related (n = 85). (3) Results: The obtained results showed that the incidence of SB and severe SB was higher for body position-related OSA phenotype (p < 0.05 for all comparisons). No statistically significant differences were observed for REM-related OSA phenotype (p > 0.05 for all comparisons). (4) Conclusions: Body position-related OSA phenotype seems to be associated with higher SB and severe SB incidence, but the relationship is not independent. However, in the light of the unclear relationship between SB and sleep-disordered breathing, the topic needs further study.

Diagnostic accuracy of oximetry for obstructive sleep apnea: a study on older adults in a home setting

OBJECTIVES

Owing to the fact that obstructive sleep apnea (OSA) is an underreported disease, the strategy used for the diagnosis of OSA has been extensively dissected to devise a simplified process that can be accessed by the public health services. Polysomnography (PSG) type I, the gold standard for the diagnosis of OSA, is expensive and difficult to access by low-income populations. In this study, we aimed to verify the accuracy of the oxyhemoglobin desaturation index (ODI) in comparison to the apnea-hypopnea index (AHI) using a portable monitor.

METHODS

We evaluated 94 type III PSG home test results of 65 elderly patients (69.21±6.94 years old), along with information, such as the body mass index (BMI) and sex, using data obtained from a clinical trial database.

RESULTS

A significant linear positive correlation (r=0.93, p<0.05) was observed between ODI and AHI, without any interference from sex, BMI, and positional component. The sensitivity of ODI compared to that of AHI increased with an increase in the severity of OSA, while the specificity of ODI in comparison to that of AHI was high for all degrees of severity. The accuracy of ODI was 80.7% for distinguishing between patients with mild and moderate apnea and 84.4% for distinguishing between patients with moderate and severe apnea.

CONCLUSION

The ODI values obtained in uncontrolled conditions exhibited high sensitivity for identifying severe apnea compared to the AHI values, and correctly identified the severity of OSA in more than 80% of the cases. Thus, oximetry is promising strategy for diagnosing OSA.

Correlation between short-time and whole-night obstruction level tests for patients with obstructive sleep apnea

Identification of obstructive level is crucial for successful surgical outcomes in patients with obstructive sleep apnea (OSA). Unfortunately, most of the dynamic airway evaluations are performed for a short duration under drug-induced sleep; therefore, it is uncertain whether they represent airway events that occur during a whole night of sleep. This study was aimed to evaluate the correlation between obstructive levels that were identified by a short-time and a whole-night test in patients with OSA. Total 101 patients with OSA underwent drug-induced sleep fluoroscopy (DISF) and pressure manometry (PM). For DISF, the obstructive pattern was classified into one of three groups: soft palate, tongue-based, and a combined obstruction. PM was used to measure the proportion of retroglossal events out of total whole-night obstructive events in each patient. The mean age of the patients was 43.8 years. The obstructive pattern was identified as soft palate in 56 patients, combined in 38 patients, and tongue-based in 7 patients following DISF. Results from PM showed that the mean percentage of retroglossal obstructive events was 31.2 ± 30.7%. The average proportion of retroglossal obstructive events that were identified by PM in patients with soft palate, combined, and tongue-based obstruction was 27.2%, 32.1%, and 59.0%, respectively (p = 0.033). There are limitations of evaluating obstructive events that occur during a whole night with short-time tests. Surgeons should be aware the possibility of disagreement in the obstructive level between short-time and whole-night tests.

Surgical Algorithm for Obstructive Sleep Apnea: An Update

Sleep surgery is part of a continuum of care for obstructive sleep apnea (OSA) that involves medical, pharmacologic, and behavioral therapy. Upper airway surgery for OSA can significantly improve stability by way of modulating the critical negative closing pressure. This is the same mechanism of action as positive airway pressure or oral appliance therapy. The updated surgical algorithm in this review adds precision in three areas: patient selection, identification of previously unaddressed anatomic phenotypes with associated treatment modality, and improved techniques of previously established procedures. While the original Riley and Powell phase 1 and 2 approach to sleep surgery has focused on individual surgical success rate, this algorithm strives for an overall treatment success with multi-modal and patient-centric treatments.

Quantitative Morphometric Measurements of the Oropharynx in Obstructive Sleep Apnea Syndrome Using a Laser Depth Measurement Module

INTRODUCTION

Current diagnostic routines in obstructive sleep apnea syndrome (OSAS), including drug-induced sleep endoscopy (DISE), provide qualitative data. Quantitative morphometric measurements of oropharyngeal structures remain challenging. This study aims to introduce a special linear laser projection device that can facilitate computer-assisted digitalized analysis and provide important quantitative information for OSAS prediction.

MATERIALS AND METHODS

We used a single-wavelength green three-linear laser to provide the scaling reference, with one at an angle of 8.5 degrees with the other two which were parallel. The oropharyngeal images were divided into two groups: the non-OSAS and OSAS group, after polysomnography. A minimum of three evaluations were carried out to determine the maximum cross-sectional area of the oropharyngeal inlet (CSAOI) and the retropalatal depth.

RESULTS

A total of 132 subjects were enrolled in this study, with 76 subjects in the non-OSAS group and 56 cases in the OSAS group. In the non-OSAS group, the CSAOI was significantly larger in males than in females. There was a trend toward deeper retropalatal region in men than in women (14.25 vs 11.76 mm). Correlation analysis revealed that retropalatal depth is significantly related to body height and the CSAOI. The body weight and BMI of patients with OSAS were significantly higher than those of participants without OSAS. The retropalatal depth and CSAOI were significantly decreased in OSAS patients as compared to those without OSAS. Our new parameter, the oropharyngeal index, showed the most outstanding discrimination by ROC analysis to predict OSAS.

CONCLUSION

Our innovative module can provide reference parameters, which make it possible to directly estimate the objective absolute values of relevant oropharyngeal structures. Our non-invasive approach can be used for outpatient screening, since it allows the identification of potential OSAS patients who should be referred for polysomnography, as many patients do not require DISE early in their evaluation.