The Association Between Transverse Maxillary Deficiency and Septal Deviation in Adults with Obstructive Sleep Apnea

OBJECTIVES

Recent evidence suggests that environmental factors impact craniofacial development. Specifically, the height and width of the maxilla may impact the degree of septal deviation. We sought to determine the relationship between transverse maxillary deficiency and severity of septal deviation.

METHODS

A prospective cohort of adult sleep surgery patients were evaluated by standardized CT imaging. Primary outcomes evaluated the relationship of a narrow, high-arched palate (the palatal height to width ratio) with the degree of septal deviation at the level of the 1st premolar and 1st molar. Secondary outcome evaluated the relationship of the palatal height-to-width ratio and nasal obstruction. Both adjusted and unadjusted linear regression were performed, including correction for multiple hypothesis testing.

RESULTS

Ninety-three patients were included. On average, the cohort was middle aged (54.7 ± 12.7 years), obese (BMI 30.1 ± 4.5 kg/m2), predominantly male (74.2%), White (73.1%), and with severe obstructive sleep apnea (OSA) (AHI 30.0 ± 18.7 events/h). A moderate correlation was observed between both the relative and absolute inter-premolar palatal height and the degree of septal deviation at the inter-molar region. No significant correlation was observed between palatal dimensions and NOSE score.

CONCLUSION

This study found that transverse maxillary deficiency is moderately associated with greater degree of septal deviation among a sample of OSA patients. This contributes to the concept that craniofacial development impacts the nasal airway, promoting a comprehensive evaluation of both endonasal and extranasal structures.

LEVEL OF EVIDENCE

4 Laryngoscope, 134:2464-2470, 2024.

Airway Collapsibility during Drug-Induced Sleep Endoscopy Relates with Clinical Features of Obstructive Sleep Apnea

INTRODUCTION

Increased pharyngeal collapsibility leads to obstructive sleep apnea (OSA). Positive airway pressure titration during drug-induced sleep endoscopy (DISE-PAP) provides objective collapsibility metrics, the pharyngeal opening pressure (PhOP), and active pharyngeal critical pressure (PcritA ). We examined the interrelationships between risk factors of OSA, airway collapsibility measures, and clinical manifestations of the disease.

METHODS

This is a cross-sectional analysis of consecutive OSA patients undergoing DISE-PAP. Nasal PAP was increased stepwise until inspiratory flow limitation was abolished, signifying PhOP. PcritA was derived from the resulting titration pressure-flow relationships. Clinical data including demographics, anthropometrics, sleep studies, and patient-symptom questionnaires were obtained from the electronic medical record. Multivariate regression was used to evaluate the relationship between risk factors, airway collapsibility, and clinical data.

RESULTS

On average, the 164 patients meeting inclusion criteria were middle-aged (54.2 ± 14.7 years), overweight/obese (BMI 29.9 ± 4.5 kg/m2 ), male (72.6%), White (79.3%) and had severe OSA (AHI 32.0 ± 20.5 events/hour). Mean PhOP was 7.5 ± 3.3 cm H2 O and mean PcritA was 0.80 ± 3.70 cm H2 O. Younger age (Standardized β = -0.191, p = 0.015) and higher BMI (Standardized β = 0.176, p = 0.028) were associated with higher PhOP, but not PcritA . PhOP and PcritA were both associated with AHI, supine AHI, and SpO2 nadir. Higher PhOP was associated with higher snoring scores (Standardized β = 0.246, p = 0.008), but not other patient-reported outcomes.

CONCLUSION

Objective assessment of passive and active airway mechanics during DISE relates with clinical risk factors for OSA. Quantitative measures of collapsibility provide accessible and meaningful data, enhancing the standard sleep surgery evaluation.

LEVEL OF EVIDENCE

4 Laryngoscope, 134:1978-1985, 2024.

A Critical Analysis of Pharyngeal Patterns of Collapse in Obstructive Sleep Apnea: Beyond the Endoscopic Classification Systems

(1) Background: Drug-Induced Sleep Endoscopy (DISE) enables the three-dimensional and dynamic visualization of the upper airway (UA) during sleep, which is useful in selecting the best treatment option for obstructive sleep apnea (OSA) patients, particularly for surgical procedures. Despite international consensus statements or position papers, a universally accepted DISE methodology and classification system remain a controversial open question. (2) Methods: A review of the English scientific literature on DISE related to endoscopic classification systems and surgical outcome predictors (3) Results: Of the 105 articles, 47 were included in the analysis based on their content's relevance to the searched keywords. (4) Conclusions: A final report and scoring classification system is not universally accepted; the most internationally applied endoscopic classification system during DISE does not cover all patterns of events that occur simultaneously during the endoscopic examination, highlighting that several configurations of collapse and obstruction at different UA levels could be observed during DISE, which should be described in detail if DISE has to be considered in the decision-making process for the UA surgical treatment in OSA patients and if DISE has to have a role as a predictive factor for surgical outcomes analysis.

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.

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.

The Accuracy and Reliability of Visually Assessed Pharyngeal Opening Pressures During Drug-Induced Sleep Endoscopy

OBJECTIVE

To examine the accuracy and interrater reliability of a visually assessed vs airflow-based measure of pharyngeal collapsibility obtained in patients with obstructive sleep apnea undergoing drug-induced sleep endoscopy (DISE).

STUDY DESIGN

Prospective observational study.

SETTING

Academic tertiary care practice.

METHODS

Patients underwent DISE with airflow monitoring and nasal positive airway pressure titration to determine visual and airflow-based levels of pharyngeal opening pressure (PhOP). Visual DISE-PhOP was assessed by 2 blinded independent raters and defined as the pressure at which visual confirmation of airway collapse, including snoring, was abolished. Airflow-based DISE-PhOP was defined as the minimally effective positive airway pressure that abolished inspiratory flow limitation. Equivalence testing between visual and airflow DISE-PhOP of each rater was performed with the two one sided T-test (TOST) with an a priori equivalence bound of ±1 cm H2 O. Interrater reliability was evaluated with the intraclass correlation coefficient.

RESULTS

One hundred patients were enrolled in the study and 77 completed the full evaluation. The population was predominantly male (74%) with an average age of 54.8 years, body mass index of 30.1 kg/m2 , and apnea-hypopnea index of 30.7 events/h. Equivalence testing showed that both raters were within ±1 cm H2 O of airflow-based DISE-PhOP (-0.43 to 0.09 cm H2 O and -0.32 to 0.48 cm H2 O). Interrater reliability of visual DISE-PhOP between the raters was also good to excellent with an intraclass correlation coefficient of 0.895 (95% CI, 0.84-0.932).

CONCLUSION

DISE-PhOP, a measure of upper airway collapsibility, was equivalent between airflow-based and visual assessments with strong interrater reliability, supporting its adoption as a standardized objective parameter in clinical DISE.

0744 A Comparison of Visual and Physiologic Assessments of Upper Airway Collapse during Drug-Induced Sleep Endoscopy (DISE)

Introduction

The VOTE score, critical closing pressure (Pcrit), and therapeutic CPAP levels are assessments that quantify upper airway collapse by either subjective visual scoring or objective pressure-flow analysis. We hypothesized that there would be an association between collapse severity and physiologic metrics (VOTE versus Pcrit and PAP levels, respectively) acquired during drug-induced sleep endoscopy (DISE).

Methods

This prospective cohort study evaluated 100 consecutive patients with obstructive sleep apnea (OSA) who underwent DISE with application of nasal positive airway pressure between June 3rd, 2020 and June 11th, 2021. Patients were assigned a VOTE score of 0, 1, or 2 indicating no collapse, partial collapse, or complete collapse at the velum, oropharynx, tongue base, and epiglottis, respectively. We assessed two metrics of pharyngeal collapsibility with progressive increases in nasal pressure: (1) the pressure at which inspiratory airflow commences (critical pressure, Pcrit), and (2) the pressure at which inspiratory flow limitation is abolished (pharyngeal opening pressure, PhOP). Our analysis examined the association between the composite VOTE score [0-8 units] and collapsibility metrics.

Results

Ninety-one patients met inclusion criteria for VOTE scoring; of these, 87 were included for PhOP analysis and 79 for Pcrit analysis. The cohort was 76% male, mean (SD) age was 54.7 (14.1) years, body-mass index was 29.7 (4.9), and AHI was 30.3 (20.9). Composite VOTE score was positively associated with Pcrit (β = 0.88 ± 0.38 cm H2O per unit, standardized estimate = 0.26, p=0.023). We found no significant association between the composite VOTE score and PhOP (β = 0.57 ± 0.40 cm H2O per unit, standardized estimate = 0.15, p=0.162).

Conclusion

Our findings suggest that visual and physiological assessments of upper airway collapsibility provide both overlapping and complementary information in characterizing upper airway mechanics. Measures of pharyngeal collapsibility during DISE can be used to model the ultimate impact of therapeutic maneuvers on OSA. Future studies investigating the utility of each assessment both in isolation and in combination for predicting OSA therapy outcomes are indicated.

Support (If Any)

National Institutes of Health: 1R01HL144859

Obstructive Sleep Apnea: characterization of the obstructive site and type of collapse

Obstructive Sleep Apnea is characterized by recurrent episodes of partial or complete collapse of the pharynx, followed by decreased oxyhemoglobin saturation and frequent arousals. It is regarded as a public health issue with important night and day symptoms that impact life quality. Its effects are associated with the areas of competence of Speech and Language Pathologists. To establish efficient diagnosis and treatment methods, professionals must know the pathogenesis of upper airway obstruction during sleep. This study seeks to enlarge the understanding of obstructive sleep apnea pathophysiology, eligibility of individualized therapeutic procedures and guidance for orofacial myofunctional therapy by describing and illustrating the locations and types of upper airway collapse during sleep. We analyzed original records of Drug Induced Sleep Endoscopy exams of a series of cases with polysomnographic diagnosis of obstructive sleep apnea following the proper ethical processes. The images of the exam recordings were analyzed by five professionals with expertise in the sleep area. Obstructive sites and types of collapse were presented according to the current classification. The videos were divided into screenshots, originating figures from each anatomical site: without collapse and collapsed. The results are visualized in the images of the cases showing a predominance of velopharyngeal collapse: anteroposterior, lateral, or concentric; oropharyngeal lateral collapse; tongue anteroposterior collapse and anteroposterior collapse of the epiglottis. Understanding the obstruction sites and types of collapse illustrated in this study may help to predict therapeutic responses and learn the limitations or direct individual proposals patient.

The role of craniofacial maldevelopment in the modern OSA epidemic: a scoping review

STUDY OBJECTIVES

There is increasing recognition that environmental factors affect human craniofacial development and our risk for disease. A scoping review of the literature was performed looking at environmental influences on craniofacial development to better understand this relationship and investigate what further study is needed to determine how this relationship may impact obstructive sleep apnea.

METHODS

A comprehensive literature search was performed using the Ovid Medline database from inception to May, 2020 with relevance to craniofacial development in 5 clinically-oriented variables: diet, secular change, breastfeeding/non-nutritive sucking habits (NNSH), nasal obstruction/mouth breathing, and masticatory muscle function. The Oxford Centre for Evidence-Based Medicine Levels of Evidence (LoE) was used to assess studies based on study design.

RESULTS

18,196 articles were initially identified, of which 260 studies were fully reviewed and 97 articles excluded. The remaining 163 articles were categorized as follows: Secular change (n = 16), Diet (n = 33), Breastfeeding/NNSH (n = 28), Nasal obstruction/Mouth breathing (n = 57), and Masticatory muscle function (n = 35). 93% of included studies reported a significant association between craniofacial morphology and environmental factors. The majority of studies were characterized as low LoE studies with 90% of studies being LoE 4 or 5.

CONCLUSIONS

The studies in this review suggest that environmental factors are associated with changes in craniofacial development. However, most studies were heterogeneous and low-level studies, making strong conclusions about these relationships difficult. Future rigorous studies are needed to further our understanding of environmental influences on craniofacial development and OSA risk.

Correlation between the transverse dimension of the maxilla, upper airway obstructive site, and OSA severity

STUDY OBJECTIVES

Acquiring a better comprehension of obstructive sleep apnea physiopathology can contribute to improving patient selection for surgical treatments. We hypothesize that maxillary transverse deficiency restricts the space available for the tongue, leading to upper airway obstruction during sleep. Our primary hypothesis was that maxillary transverse deficiency increases the prevalence of tongue collapse during drug-induced sleep endoscopy (DISE). The secondary hypothesis was that maxillary transverse deficiency will also increase the prevalence of circumferential collapse at the velopharynx. The exploratory hypothesis was that maxillary transverse deficiency is associated with increased obstructive sleep apnea severity. The objectives of this study were to correlate maxillary morphometric measurements with (1) the anatomic level of obstruction during DISE and (2) the apnea-hypopnea index on polysomnography.

METHODS

We made a cross-sectional analysis of patients with obstructive sleep apnea undergoing DISE in search of positive airway pressure alternative treatment. Maxillary measurements were collected from a computed tomography scan (interpremolar distance, intermolar distance [IMD] and sella-nasion A point angle), findings from DISE, and sleep study variables from polysomnography. Correlation between computed tomography, DISE, and polysomnography data was assessed using Pearson's correlation, and receiver operating characteristic curves were determined for each facial measurement.

RESULTS

Sixty-nine patients were included in the study. The group with velopharyngeal circumferential collapse had mean IMD = 26.30 mm (25.5-31.45), and the group with anteroposterior collapse had mean IMD = 29.20 mm (26.8-33.10; P = .040). The group with complete tongue-base obstruction had mean interpremolar distance = 26.40 mm (25.1-28) and IMD = 26.30 mm (25.6-28.4), and the group without obstruction had mean interpremolar distance = 28.7 mm (27.2-30; P = .003) and IMD = 34.06 mm (32.1-37; P < .001). The receiver operating characteristic curve determined an IMD cutoff of 29.8 mm for predicting tongue-base obstruction.

CONCLUSIONS

The maxillary transverse deficiency, identified by reduction in interpremolar distance and IMD, predicted the occurrence of complete tongue-base obstruction, complete concentric collapse at the velopharynx, and multilevel obstruction during DISE. We did not find an association between the maxillary measurements and obstructive sleep apnea severity. These associations hold some promise in ultimately supplanting insights previously available only through DISE.

A comparison of the Fujita classification of awake and drug-induced sleep endoscopy patients

Only a few studies have compared the outcomes of patients kept awake during endoscopic examination and subjects submitted to drug-induced sleep endoscopy.

OBJECTIVE

This study aimed to compare the endoscopic findings of patients submitted to outpatient endoscopy and endoscopic examination with sedation by propofol based on the Fujita Classification.

METHOD

This cross-sectional cohort study enrolled 34 patients. The subjects underwent ENT examination, nasal endoscopy with Müller's maneuver, and drug-induced sleep endoscopy with propofol. The Fujita Classification was used to compare the two modes of endoscopic examination. The examinations were correlated to patient clinical data such as BMI, age, and OSAS severity.

RESULTS

There was no agreement between the two modes of endoscopic examination, whether for the group in general or for the analyzed subgroups.

CONCLUSION

There was no agreement between the endoscopic findings of endoscopic examinations done with the patient awake or in drug-induced sleep.