Obstruction Patterns During Drug-Induced Sleep Endoscopy vs Natural Sleep Endoscopy in Patients With Obstructive Sleep Apnea

Palate Shape, Drug-Induced Sleep Endoscopy Findings, and Obstructive Sleep Apnea Pharyngeal Surgery Outcomes

OBJECTIVE

Pharyngeal surgery is a treatment option for patients with obstructive sleep apnea (OSA) unable to tolerate positive pressure therapy. This study aims to determine the association between palate shape as described by Woodson and pharyngeal surgical outcomes.

STUDY DESIGN

Exploratory analysis of retrospective cohort.

SETTING

Multicenter.

METHODS

Three blinded reviewers assessed palate shape using drug-induced sleep endoscopy (DISE) videos from a previously-assembled cohort of adults undergoing pharyngeal surgery. Palate shape scores were examined for association with surgical outcomes with univariate and multivariate analyses. Multivariate analyses included adjustment for consensus DISE findings determined previously.

RESULTS

Two hundred nine study subjects were included from 13 centers. Age was 53.7 ± 11.5 years, body mass index (BMI) was 30.3 ± 5.0 kg/m2, and 21% were female. In isolated soft palate surgery, greater GenuAP narrowing was associated with lesser odds of surgical response, whereas greater GenuLW narrowing was associated with greater odds of surgical response. These findings largely persisted after adjustment for key DISE findings, age, gender, OSA severity, BMI, and tonsil size. Other palate-shape findings were not clearly associated with surgical outcomes, although some palate-shape findings demonstrated trends toward an association with outcomes (P < .10).

CONCLUSION

Greater GenuAP narrowing and GenuLW narrowing were associated with lesser and greater, respectively, odds of surgical response after isolated soft palate surgery. Palate shape and other palate shape level scores were not clearly associated with surgical outcomes. Larger studies may determine more precisely the association between palate shape and pharyngeal surgery outcomes.

Pharyngeal Manometry and Upper Airway Collapse During Drug-Induced Sleep Endoscopy

Importance

Drug-induced sleep endoscopy (DISE) is used to guide therapeutic management of obstructive sleep apnea (OSA), depending on the levels and patterns of pharyngeal collapse. However, the collapsibility of specific pharyngeal sites remains unknown.

Objective

To assess collapse sites in patients with OSA undergoing DISE and whether number and location are associated with differences in airway collapsibility; and to quantify differences in collapsibility between primary and secondary sites in multilevel collapse.

Design, Setting, and Participants

This cohort study assessed adult patients (≥18 years) with OSA undergoing DISE with manometry and positive airway pressure (PAP) titration at a tertiary care center from November 2021 to November 2023. Patients with an AHI score greater than 5 were included; those with less than 1 apnea event during DISE or incorrect catheter placement were excluded. Data were analyzed from September 28, 2022, to March 31, 2024.

Exposure

DISE with manometry and PAP titration.

Main Outcomes and Measures

Active pharyngeal critical pressure (Pcrit-A) and pharyngeal opening pressure (PhOP) were used to quantify airway collapsibility, adjusted for covariates (age, sex, race, and body mass index [BMI]).

Results

Of 94 screened, 66 patients (mean [SD] age, 57.4 [14.3] years; BMI, 29.2 [3.9]; 51 [77.3%] males) with a mean (SD) apnea-hypopnea index (AHI) of 31.6 (19.0) were included in the analysis. Forty-seven patients (71.2%) had multilevel collapse, 10 (15.2%) had single-level nasopalatal collapse, and 9 (13.6%) had single-level infrapalatal collapse. Groups did not differ in demographic characteristics or established measures of OSA severity. The single-level nasopalatal group had substantially elevated levels of airway collapsibility (Pcrit-A and PhOP covariate adjusted mean, 2.4; 95% CI, 1.1 to 3.8; and 8.2; 95% CI, 6.4 to 9.9 cmH2O) compared to the single-level infrapalatal group (-0.9; 95% CI, -2.4 to 0.5 cmH2O; and 4.9; 95% CI, 3.0 to 6.8 cmH2O, respectively) and similar to the level among the multilevel group (1.3; 95% CI, 0.7 to 2.0; and 8.5; 95% CI, 7.7 to 9.3 cmH2O). The multilevel group had more negative inspiratory pressure (-24.2; 95% CI, -28.1 to -20.2 cmH2O) compared to the single-level nasopalatal group (-9.8; 95% CI, -18.3 to -1.28 cmH2O). In patients with multilevel collapse, airway collapsibility was significantly higher at the primary nasopalatal compared to secondary infrapalatal site (mean difference, 13.7; 95% CI, 11.3 to 16.1 cmH2O).

Conclusions and Relevance

The findings of this cohort study suggest that intervention should target the primary site of pharyngeal collapse, and secondary sites only if they are nearly as collapsible as the primary site. Future work is needed to precisely define the difference in primary and secondary collapsibility that necessitates multilevel treatment.

The Repeatability of Pharyngeal Opening Pressure Under Drug-Induced Sleep Endoscopy

OBJECTIVE

Pharyngeal opening pressure (PhOP) is a measure of upper airway collapsibility that can be obtained during drug-induced sleep endoscopy (DISE) using a continuous positive airway pressure (CPAP) titration. However, the stability of PhOP over the course of sedation during DISE remains unclear. This study aims to compare repeat measures of PhOP over the course of DISE.

STUDY DESIGN

Single arm prospective study.

SETTING

Single tertiary care institution.

METHODS

Patients had 2 CPAP titrations while undergoing DISE. Collected data included patient demographics, PhOP, patient sedation index (PSI), and duration of and between CPAP titrations. t Tests, test-retest coefficient analysis, and repeated measures correlation were performed.

RESULTS

Twenty-five patients completed the study between 2022 and 2023 with 22 patients having sedation depth (PSI) recording. Most were male (76%), obese (average body mass index: 30.24 kg/m2), with severe obstructive sleep apnea (average apnea-hypopnea index: 39.8 events/hr). Test-retest analysis showed good-excellent correlation between PhOP values (intraclass correlation coefficient = 0.892, P < .0001, n = 25). Average time between CPAP titrations was 15 minutes to 6 seconds. Over that time, PhOP increased by an average of 0.72 cmH2O (P = .06, n = 25) and PSI decreased by 9.5 units (P = .01, n = 22). Repeated measures correlation showed a weak negative correlation between PhOP and PSI (r = -.45, P = .03, n = 22).

CONCLUSION

The results showed repeatability of PhOP values over the course of DISE. When adjusted for sedation depth (PSI), deeper sedation was weakly associated with greater PHOP. However, the magnitude of this change was small and we conclude that PhOP remains relatively stable over the course of DISE (Effects of Lung Volume on Upper Airway Patency During DISE [DISE-Pulm], NCT05350332, clinicaltrials.gov).

Polysomnographic airflow shapes and site of collapse during drug-induced sleep endoscopy

BACKGROUND

Differences in the pharyngeal site of collapse influence efficacy of non-continuous positive airway pressure therapies for obstructive sleep apnoea (OSA). Notably, complete concentric collapse at the level of the palate (CCCp) during drug-induced sleep endoscopy (DISE) is associated with reduced efficacy of hypoglossal nerve stimulation, but CCCp is currently not recognisable using polysomnography. Here we develop a means to estimate DISE-based site of collapse using overnight polysomnography.

METHODS

182 OSA patients provided DISE and polysomnography data. Six polysomnographic flow shape characteristics (mean during hypopnoeas) were identified as candidate predictors of CCCp (primary outcome variable, n=44/182), including inspiratory skewness and inspiratory scoopiness. Multivariable logistic regression combined the six characteristics to predict clear presence (n=22) versus absence (n=128) of CCCp (partial collapse and concurrent tongue base collapse excluded). Odds ratios for actual CCCp between predicted subgroups were quantified after cross-validation. Secondary analyses examined complete lateral wall, tongue base or epiglottis collapse. External validation was performed on a separate dataset (ntotal=466).

RESULTS

CCCp was characterised by greater scoopiness (β=1.5±0.6 per 2sd, multivariable estimate±se) and skewness (β=11.4±2.4) compared with non-CCCp. The odds ratio for CCCp in predicted positive versus negative subgroups was 5.0 (95% CI 1.9-13.1). The same characteristics provided significant cross-validated prediction of lateral wall (OR 6.3, 95% CI 2.4-16.5), tongue base (OR 3.2, 95% CI 1.4-7.3) and epiglottis (OR 4.4, 95% CI 1.5-12.4) collapse. CCCp and lateral wall collapse shared similar characteristics (skewed, scoopy), diametrically opposed to tongue base and epiglottis collapse characteristics. External validation confirmed model prediction.

CONCLUSIONS

The current study provides a means to recognise patients with likely CCCp or other DISE-based site of collapse categories using routine polysomnography. Since site of collapse influences therapeutic responses, polysomnographic airflow shape analysis could facilitate precision site-specific OSA interventions.

Advanced Diagnostic Techniques in Obstructive Sleep Apnea

Optimal surgical and medical management of obstructive sleep apnea requires clinically reliable identification of patterns and sites of upper airway obstruction. A wide variety of modalities have been used to evaluate upper airway obstruction. Drug-induced sleep endoscopy (DISE) and cine MRI are increasingly used to identify upper airway obstruction sites, to characterize airway obstruction patterns, to determine optimum medical and surgical treatment, and to plan individualized surgical management. Here, we provide an overview of the applications of DISE and cine MRI in assessing upper airway obstruction in children and adults with obstructive sleep apnea.

Advanced Diagnostic Techniques in Obstructive Sleep Apnea

Optimal surgical and medical management of obstructive sleep apnea (OSA) requires clinically reliable identification of patterns and sites of upper airway obstruction. A wide variety of modalities has been used to evaluate upper airway obstruction. Drug-induced sleep endoscopy (DISE) and cine MRI are increasingly used to identify upper airway obstruction sites, to characterize airway obstruction patterns, to determine optimum medical and surgical treatment, and to plan individualized surgical management. Here, the authors provide an overview of the applications of DISE and cine MRI in assessing upper airway obstruction in children and adults with OSA.

Severity of tongue base collapse in various body positions in patients with obstructive sleep apnea: A trajectory analysis

BACKGROUND

Drug-induced sleep endoscopy (DISE) is used for evaluating upper airway anatomy and determining airway obstruction patterns. It is typically performed with the patient in the supine position. Airway collapse severity is influenced by body position and level of consciousness; the resultant dynamic changes may vary across patients. In this study, we evaluated the severity of upper airway collapse through awake endoscopy and DISE and identified factors affecting the pattern of airway collapse severity.

METHODS

This study included 66 patients with obstructive sleep apnea. The patients underwent type 1 polysomnography, tongue strength assessment, awake endoscopy in the sitting and supine positions, and DISE. Group-based trajectory modeling was performed to identify patients with different collapse severity patterns in different body positions and at different levels of consciousness.

RESULTS

Patient with similar severity trajectory were assigned to the same group. Two different severity trajectories (group 1 and group 2) were identified at the tongue base level. Tongue depression strength varied significantly between groups 1 and 2 (47.00 vs. 35.00 kPa; P = .047). During awake endoscopy, collapse severity was significantly higher in group 2 than in group 1. Group 1 had lower rapid eye movement/nonrapid eye movement apnea-hypopnea index ratios and higher tongue depression strength than did group 2.

CONCLUSION

In patients with obstructive sleep apnea, tongue strength may vary depending on body position. Our results should be interpreted with caution because of the limited sample size. Future studies should investigate the effect of oropharyngeal rehabilitation on tongue strength and collapse severity.

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.

Objective Pharyngeal Phenotyping in Obstructive Sleep Apnea With High-Resolution Manometry

OBJECTIVE

Drug-induced sleep endoscopy (DISE) is a commonly used diagnostic tool for surgical procedural selection in obstructive sleep apnea (OSA), but it is expensive, subjective, and requires sedation. Here we present an initial investigation of high-resolution pharyngeal manometry (HRM) for upper airway phenotyping in OSA, developing a software system that reliably predicts pharyngeal sites of collapse based solely on manometric recordings.

STUDY DESIGN

Prospective cross-sectional study.

SETTING

An academic sleep medicine and surgery practice.

METHODS

Forty participants underwent simultaneous HRM and DISE. A machine learning algorithm was constructed to estimate pharyngeal level-specific severity of collapse, as determined by an expert DISE reviewer. The primary outcome metrics for each level were model accuracy and F1-score, which balances model precision against recall.

RESULTS

During model training, the average F1-score across all categories was 0.86, with an average weighted accuracy of 0.91. Using a holdout test set of 9 participants, a K-nearest neighbor model trained on 31 participants attained an average F1-score of 0.96 and an average accuracy of 0.97. The F1-score for prediction of complete concentric palatal collapse was 0.86.

CONCLUSION

Our findings suggest that HRM may enable objective and dynamic mapping of the pharynx, opening new pathways toward reliable and reproducible assessment of this complex anatomy in sleep.

Phase II study comparing nasal pressure monitoring with capnography during invasive endoscopic procedures: a single-center, single-arm trial

Nasal pressure signal is commonly used to evaluate obstructive sleep apnea. This study aimed to assess its safety for respiratory monitoring during sedation. A total of 45 adult patients undergoing sedation with propofol and fentanyl for invasive endoscopic procedures were enrolled. While both nasal pressure and capnograph signals were continuously recorded, only the nasal pressure signal was displayed. The primary outcome was the incidence of oxygen desaturation below 90%. The secondary outcomes were the ability to predict the desaturation and incidence of harmful events and false alarms, defined as an apnea waveform lasting more than 3 min without desaturation. Of the 45 participants, 43 completed the study. At least one desaturation event occurred in 12 patients (27.9%; 95% confidence interval 15.3-43.7%). In these 12 patients, more than half of the desaturation events were predictable in 9 patients by capnography and 11 patients by nasal pressure monitoring (p = 0.59). In the 43 patients, false alarms were detected in 7 patients with capnography and 11 patients with nasal pressure monitoring (p = 0.427). Harmful events unrelated to nasal pressure monitoring occurred in 2 patients. Nasal pressure monitoring is safe and possibly useful for respiratory monitoring despite false alarms during sedation.

Head rotation improves airway obstruction, especially in patients with less severe obstructive sleep apnea without oropharyngeal collapse

Purpose

Head rotation is thought to have an effect on obstructive sleep apnea (OSA) severity. However, keeping the head rotated fully during sleep is difficult to maintain, and the effect of head rotation is not the same in all OSA patients. Thus, this study aimed to identify whether less head rotation has an effect on airway patency and determine the responder characteristics to the head rotation maneuver (HRM).

Methods

We recruited 221 patients who underwent overnight polysomnography and drug-induced sleep endoscopy (DISE) in a tertiary hospital from June 2019 to July 2020. Airway patency and the site of airway collapse were determined in the supine position with the head at 0, 30, and 60 degrees of rotation (HRM0°, HRM30°, and HRM60°, respectively) during DISE. The site of collapse was determined using the VOTE classification system: the velum (palate), oropharyngeal lateral walls, tongue base, and epiglottis. Each structure was labeled as 0, 1, or 2 (patent, partially obstructed, and completely obstructed, respectively). Airway response to the HRM30° and 60° and the clinical characteristics associated with airway opening were analyzed.

Results

The study population had a median age of 52 (25–61) years, a body mass index of 26.7(24.6–29.4) kg/m², and the apnea-hypopnea index (AHI) of 28.2(13.7–71.9) events/h. HRM influenced airway patency positively not only with HRM60° (p<0.001) but also following limited rotation (HRM30°, p<0.001). Patients with tongue base (40.0% with HRM 60°) and epiglottic (52.6% with HRM 60°) collapse responded particularly well to HRM. Multivariate analysis revealed that lower AHI (p<0.001) and an absence of oropharyngeal lateral walls collapse (p = 0.011) were significant predictors of responders to HRM.

Conclusion

Head rotation improved airway obstruction in OSA patients, even with a small degree of rotation, and should be further explored as a potential form of therapy in appropriately selected patients.

Impact of Upper Airway Characteristics on Disease Severity and CPAP Therapy in Chinese Patients With OSA: An Observational Retrospective Study

Objective

The characteristics of the upper airway (UA) are important for the evaluation and treatment of obstructive sleep apnea (OSA). This study aimed to investigate the association of UA characteristics with OSA severity, titration pressure, and initiation of and 3-month compliance with continuous positive airway pressure (CPAP).

Methods

This retrospective study included consecutive patients examined using a semi-quantitative UA evaluation system (combination with physical examination and awake endoscopy) during 2008–2018 at the Department of Respiratory and Critical Care Medicine, Peking University First Hospital. First, the differences in UA characteristics were compared between patients with simple snorers and mild OSA and those with moderate-to-severe OSA. Then, the effect of UA characteristics on the initiation to CPAP therapy and 3-month adherence to CPAP was conducted.

Results

Overall, 1,002 patients were included, including 276 simple snorers and patients in the mild OSA group [apnea-hypopnea index (AHI) <15] and 726 patients in the moderate-to-severe OSA group (AHI ≥15). Tongue base hypertrophy, tonsillar hypertrophy, mandibular recession, neck circumstance, and body mass index (BMI) were independent risk factors for moderate-to-severe OSA. Among those patients, 119 patients underwent CPAP titration in the sleep lab. The CPAP pressures in patients with thick and long uvulas, tonsillar hypertrophy, lateral pharyngeal wall stenosis, and tongue hypertrophy were higher than those of the control group (P < 0.05, respectively). The logistic regression analysis showed that nasal turbinate hypertrophy, mandibular retrusion, and positive Müller maneuver in the retropalate and retroglottal regions were independent predictors for the initiation of home CPAP treatment.

Conclusion

Multisite narrowing and function collapse of the UA are important factors affecting OSA severity, CPAP titration pressure, and the initiation of home CPAP therapy. Clinical evaluation with awake endoscopy is a safe and effective way for the assessment of patients with OSA in internal medicine.

Comparison of Drug-Induced Sleep Endoscopy and Natural Sleep Endoscopy in the Assessment of Upper Airway Pathophysiology During Sleep: Protocol and Study Design

Study Objectives: Obstructive sleep apnea (OSA) is increasingly recognized as a complex and heterogenous disorder. As a result, a "one-size-fits-all" management approach should be avoided. Therefore, evaluation of pathophysiological endotyping in OSA patients is emphasized, with upper airway collapse during sleep as one of the main features. To assess the site(s) and pattern(s) of upper airway collapse, natural sleep endoscopy (NSE) is defined as the gold standard. As NSE is labor-intensive and time-consuming, it is not feasible in routine practice. Instead, drug-induced sleep endoscopy (DISE) is the most frequently used technique and can be considered as the clinical standard. Flow shape and snoring analysis are non-invasive measurement techniques, yet are still evolving. Although DISE is used as the clinical alternative to assess upper airway collapse, associations between DISE and NSE observations, and associated flow and snoring signals, have not been quantified satisfactorily. In the current project we aim to compare upper airway collapse identified in patients with OSA using endoscopic techniques as well as flow shape analysis and analysis of tracheal snoring sounds between natural and drug-induced sleep. Methods: This study is a blinded prospective comparative multicenter cohort study. The study population will consist of adult patients with a recent diagnosis of OSA. Eligible patients will undergo a polysomnography (PSG) with NSE overnight and a DISE within 3 months. During DISE the upper airway is assessed under sedation by an experienced ear, nose, throat (ENT) surgeon using a flexible fiberoptic endoscope in the operating theater. In contrast to DISE, NSE is performed during natural sleep using a pediatric bronchoscope. During research DISE and NSE, the standard set-up is expanded with additional PSG measurements, including gold standard flow and analysis of tracheal snoring sounds. Conclusions: This project will be one of the first studies to formally compare collapse patterns during natural and drug-induced sleep. Moreover, this will be, to the authors' best knowledge, the first comparative research in airflow shape and tracheal snoring sounds analysis between DISE and NSE. These novel and non-invasive diagnostic methods studying upper airway mechanics during sleep will be simultaneously validated against DISE and NSE. Clinical Trial Registration: www.ClinicalTrials.gov, identifier: NCT04729478.

Natural sleep endoscopy in obstructive sleep apnea: A systematic review

This study's objective is to systematically review the literature on natural sleep endoscopy (NSE), including the set-up, different scoring systems, visualized collapse patterns during natural sleep, additional measurements, and comparison of upper airway collapse between NSE and drug-induced sleep endoscopy (DISE). A computerized search on Medline, Web of Science and the Cochrane library was conducted, obtaining 39 hits. Ten prospective studies were included in which NSE was performed in adults with obstructive sleep apnea (OSA). This study's findings suggest the soft palate to be the most frequent site of obstruction (58.8 %), followed by the tongue base (43.2 %), lateral walls (29.9 %), and epiglottis (22.4 %), which is in line with previous findings during DISE. Based on this literature review, the authors conclude that at this stage high quality, comparative research between DISE and NSE is missing. To adequately compare findings between OSA patients, endoscopic classification of upper airway collapse should be standardized. Non-invasive predictive tools to determine pharyngeal collapse are currently under investigation and may obviate the need for invasive endoscopy. This review highlights the contribution of NSE in validating such novel diagnostic methods and in studying upper airway mechanics in a research setting, yet larger and adequately powered studies are needed.

Upper airway collapse characteristics in adult patients with OSA and previous tonsillectomy

PURPOSE

To analyze upper airway (UA) collapse patterns through drug-induced sleep endoscopy (DISE) in adult patients with obstructive sleep apnea (OSA) who previously underwent tonsillectomy.

METHODS

This was a retrospective study on patients with OSA who underwent DISE between June 1, 2013 and July 30, 2017 at Stanford Hospital. Subjects who had prior tonsillectomy history were classified into the tonsil0 group, whereas others were classified into the tonsil1 and tonsil2/3/4 group based on tonsil grade. UA collapse characteristics were recorded and analyzed among groups according to Velum, Oropharynx, Tongue base and Epiglottis (VOTE) classification.

RESULTS

A total of 205 individuals were included, 38 in tonsil0 group, 104 in tonsil1 and 63 in tonsil2/3/4. The tonsil0 group had a higher percentage of anterior-posterior (AP) velum (58%) and tongue base (45%) collapse compared with the tonsil2/3/4 group (22%, P = 0.0003 and 22%, P = 0.02, respectively) but less oropharyngeal lateral wall collapses (29% vs 53%, P = 0.02). Most of the tonsil0 group (70%) showed multi-sites collapse pattern, the percentage of combined obstruction in both palatopharyngeal and hypopharyngeal region was higher (50% vs 29%, P = 0.03). The difference of velum complete AP collapse remained significant after adjusting for age and BMI (Odds Ratio = 0.33, 95% CI 0.12-0.86, P = 0.02). No significant differences were found between the tonsil0 and tonsil1 groups.

CONCLUSION

Compared with individuals with larger tonsils (grade 2 to 4), those with previous tonsillectomy and OSA were susceptible to the velum AP configuration collapse. Diversity of multi-sites obstruction and combined collapse in both palatopharyngeal and hypopharyngeal level was the main characteristic.

Efficacy, predictors of success and failure of an updated lateral pharyngoplasty approach as an independent procedure in treating obstructive sleep apnea with CPAP failures

PURPOSE

To assess predictors of success and failure of an updated lateral pharyngoplasty as an independent procedure in treating obstructive sleep apnea with CPAP failures.

METHODS

Forty-six patients with known OSAS who were resistant to CPAP or failures were included. BMI, Stop-Bang score, and sleep study data were recorded before and after the updated Cahali pharyngoplasty procedure. Pre-operative DISE was done for all cases; however, postoperative DISE was done only for non-responders.

RESULTS

Successful operation outcomes achieved in 69.6% (32 cases) and 30.4% (14 cases) were failure rates. Postoperative snoring index, Stop Bang score, and AHI were significantly decreased compared to pre-operative data (p value < 0.001). There is statistically a significant increase in minimal and baseline SpO₂ postoperatively (p value < 0.001). Patients with no laryngeal collapse (L0) predict operation success. However, patients with high pre-operative snoring index, collapse at lateral wall hypopharynx, high tongue collapse, laryngeal collapse, tongue palate interaction, and low grades tonsils (1, 2) predict the failure of the surgery (p value = 0.006*,0.024*,0.047*, respectively).

CONCLUSION

Updated Cahali lateral pharyngoplasty could not be used as an independent procedure in all OSA patients. The lack of laryngeal collapse (L0) is a considerable success predictor for the procedure. However, the pre-operative low-grade tonsils (1, 2) and high snoring index predict operation failure.

Diagnosis of Retrolingual Obstruction during Drug-Induced Sleep Endoscopy versus Polysomnography with Nasopharyngeal Tube in Patients with Obstructive Sleep Apnea

OBJECTIVE

To compare the retrolingual obstruction during drug-induced sleep endoscopy (DISE) with the retrolingual obstruction during polysomnography with nasopharyngeal tube (NPT-PSG).

METHODS

A cross-sectional study of 77 consecutive patients with moderate and severe obstructive sleep apnea (OSA) was conducted. After 15 patients were excluded from the study for not completing DISE or NPT-PSG successfully, 62 patients were included in this study. Retrolingual sites of obstruction grade 2 determined by DISE according to the VOTE (velum, oropharynx lateral wall, tongue base, and epiglottis) classification were considered as retrolingual obstruction, while apnea-hypopnea index (AHI) ≥ 15 events/hour determined by NPT-PSG was considered as retrolingual obstruction. The extent of agreement between DISE and NPT-PSG findings was evaluated using unweighted Cohen's kappa test.

RESULTS

The 62 study participants (11 moderate OSA, 51 severe OSA) had a mean (SD) age of 39.8 (9.9) years, and 58 (94%) were men. No statistically significant differences between included and excluded patients were observed in patient characteristics. The extent of agreement in retrolingual obstruction between DISE and NPT-PSG was 80.6% (Cohen k = 0.612; 95% CI, 0.415-0.807).

CONCLUSION

Retrolingual obstruction requiring treatment showed good agreement between DISE and NPT-PSG, suggesting that NPT-PSG may also be a reliable method to assess the retrolingual obstruction.

The Use of Middle Latency Auditory Evoked Potentials (MLAEP) as Methodology for Evaluating Sedation Level in Propofol-Drug Induced Sleep Endoscopy (DISE) Procedure

To analyze the middle latency auditory evoked potential index (MLAEPi), compared to the standard bispectral index (BIS), as a method for evaluating the sedation level in drug-induced sleep endoscopy (DISE). In this controlled clinical study on a sample of 99 obstructive sleep apnea (OSA) or snoring patients, we compared the MLAEPi with the BIS after propofol infusion during the standard DISE technique in order to define the MLAEPi values within the observational window of the procedure. The DISE procedure was divided into eight steps, and we collected both MLAEPi and BIS data values from the same patient in every step. The MLAEPi showed a faster response than the BIS after propofol infusion during DISE. Therefore, the clinical use of the MLAEPi in evaluating the sedation level seems to be a good alternative to the current technological standards.

Role of drug-induced sleep endoscopy in evaluation of positional vs non-positional OSA

Background

The study aimed to evaluate the anatomical differences between positional and non-positional OSA, and to identify the potential predictors for distinguishing between these two types of OSA.

Methods

A cross-sectional study of 230 consecutive patients with OSA undergoing DISE (Drug-induced Sleep Endoscopy) was carried out at a tertiary academic medical center. The factors correlating with positional and non-positional OSA were analyzed, including clinical characteristics, polysomnography data, and DISE findings.

Results

Univariate analysis revealed that non-positional dependency was correlated with a higher BMI (p < 0.001), neck circumference (p < 0.001), modified Mallampati score (p = 0.003), AHI (p < 0.001), degree of velum concentric collapse (p = 0.004), degree of oropharyngeal lateral wall collapse (p < 0.001), and degree of tongue base anteroposterior collapse (p = 0.004). Multivariate analysis revealed that oropharyngeal lateral wall collapse (OR = 1.90, p = 0.027) was the only anatomical factor significantly predicted non-positional dependency in OSA patients. AHI (OR = 1.04, p < 0.001), although significant, made only a marginal contribution to the prediction of non-positional dependency.

Conclusions

Oropharyngeal lateral wall collapse was identified as the only anatomical predictor for non-positional dependency in OSA patients. Therefore, further treatment modalities should address the distinct anatomical trait between positional and non-positional OSA.

Graphical abstract

The correlation between drug-induced sleep endoscopy findings and severity of obstructive sleep apnea

OBJECTIVE

This study aimed to assess the relationship between anthropometric data, drug-induced sleep endoscopy (DISE) findings, and severity of obstructive sleep apnea (OSA).

METHODS

From August 2016 to August 2017, a total of 147 surgically naïve adult patients with OSA underwent DISE. Factors that were analyzed included anthropometric data and DISE findings.

RESULTS

When anthropometric data and DISE findings were analyzed with AHI by univariate analysis, the results showed that Epworth Sleepiness Scale (ESS), body mass index (BMI), neck circumference, concentric collapse of the velum, lateral oropharyngeal collapse, and anterior-posterior collapse of the tongue base were considered potentially independent predictors (p = 0.024, p < 0 .001, p < 0 .001, p < 0.001, p < 0.001, p < 0 .001, respectively, by Spearman correlation). When all important factors were evaluated in a stepwise multiple linear regression analysis, BMI, lateral oropharyngeal collapse, and anterior-posterior collapse of the tongue base were identified as significant predictors for the severity of OSA. The final model was listed as below: AHI score = 2.19 BMI + 7.56 Oropharynx/Lateral degree + 8.23 Tongue base/ Anterior-Posterior degree - 40.59.

CONCLUSION

By analyzing anthropometric data and DISE findings with AHI score, the results indicated that BMI, lateral oropharyngeal collapse, and anterior-posterior collapse of the tongue base were important factors associated with the severity of OSA.

Drug-induced sleep endoscopy: techniques, interpretation and implications

PURPOSE OF REVIEW

The purpose of this article is to highlight recent advances in the burgeoning field of drug-induced sleep endoscopy (DISE).

RECENT FINDINGS

One of the first studies to investigate the correlation of DISE findings and natural sleep endoscopy found good agreement in clinically significant obstruction. Previous studies have shown good agreement of DISE findings with the use of different sedative agents implying that the choice of sedative may not be crucial. However, recent studies show variable patterns of collapse, especially at the tongue base, with the use of different sedative agents. A universally accepted classification scheme for drug-induced sleep endoscopy is lacking. A new DISE classification system, termed Palate, Tonsils, Lateral pharyngeal wall, Tongue base, Epiglottis, was introduced this year with the noted advantage of being able to better differentiate between clinically relevant tonsillar and lateral pharyngeal wall collapse. Despite recent advances in the field, there remains no general consensus that DISE findings predict surgical success but may aid in the identification of patients who will respond well to oral appliance therapy.

SUMMARY

Drug-induced sleep endoscopy is a structure-based evaluation of the upper airway that more closely resembles the natural sleep state compared with awake evaluation.

Prevalence and patterns of tongue deformation in obstructive sleep apnea: A whole-night simultaneous ultrasonographic and polysomnographic study

Tongue deformation during whole-night natural sleep in adult patients with obstructive sleep apnea has not been well evaluated. Through simultaneous ultrasonography and polysomnography during whole-night sleep, we examined the prevalence and patterns of tongue depth changes and their relationship with the severity of obstructive sleep apnea. Sixty consecutive eligible adults presenting with symptoms suggesting obstructive sleep apnea were enrolled. We observed that 88.4% (38/43) of patients with obstructive sleep apnea exhibited a significant increase in the maximum ultrasonographic tongue depth when hypopnea or apnea occurred during sleep. A mixed-model analysis of variance demonstrated that compared with patients with primary snoring or mild obstructive sleep apnea, those with moderate to severe obstructive sleep apnea have significantly greater maximum ultrasonographic tongue depth during respiratory events (p = .0047). We identified three different ultrasonographic patterns of tongue deformation, namely en bloc, tongue body and tongue base. Approximately 82% (27/33) of patients with moderate to severe obstructive sleep apnea demonstrated an en bloc tongue deformation. By contrast, 70% (19/27) of primary snorers or patients with mild obstructive sleep apnea showed a tongue body obstruction. Recognizing the prevalence and patterns of tongue deformation during sleep may provide insights into pathogenesis and treatment decisions in patients with obstructive sleep apnea. Future studies are warranted to verify the treatment results of various tongue procedures by using this approach.

Sleep Studies Interpretation and Application

Obstructive sleep apnea is a common, but under-recognized, condition. Polysomnography remains the gold standard for diagnosing obstructive sleep apnea and determining whether treatment is appropriate. The development of home sleep apnea testing has allowed for a faster and more convenient method of diagnosis. Continuous positive airway pressure is the therapy of choice for most patients with obstructive sleep apnea, but otorhinolaryngologists can expect to see more and more patients looking for alternative treatments. This review highlights salient points relevant to sleep study application and interpretation for otorhinolaryngologists.

Lateral pharyngoplasty techniques for obstructive sleep apnea syndrome: a comparative experimental stress test of two different techniques

PURPOSE

To show the different effects of expansion sphincter pharyngoplasty (ESP) and barbed reposition pharyngoplasty (BRP) on muscle tension and muscle fiber tearing using a comparative experimental stress test with a frog thigh muscle model.

METHODS

Frog thigh muscle was used for this experimental study. A Barbed suture was used to simulate the BRP pharyngoplasty whereas a Vicryl 3-0 suture was used to simulate the ESP technique. The other extremity of the suture was attached to traction scales. The traction scales were used to measure the weight relative to the amount of force required to obtain muscle breaking. Both surgical techniques were simulated on the frog muscle. Traction was performed until muscle breaking was observed, measuring the value of force needed to obtain muscle rupture.

RESULTS

Specimen muscle breakdown in the ESP simulation occurred with an average value of 0.7 kg of traction force. Contrarily, specimen muscle breakdown in the BRP simulation with Barbed suture occurred with an average value of 1.5 kg of traction force CONCLUSION: During simulation of the ESP technique, specimen muscle breakdown occurred with an average value of traction force lower than in the BRP technique. During traction the multiple lateral sustaining suture loops of BRP could ensure greater stability then the single pulling tip suture of ESP with minor risk of muscle fiber damage.

The Impact of Drug-induced Sleep Endoscopy on Therapeutic Decisions in Obstructive Sleep Apnea: A Systematic Review and Meta-analysis

Objective The aim of this study was to assess the ability of drug-induced sleep endoscopy (DISE) to change therapeutic decisions through the identification of obstruction sites in patients with obstructive sleep apnea (OSA). Materials and methods A systematic review and meta-analysis were conducted concerning studies that reported the impact of DISE on therapeutic recommendations. The percentage of change was collected for each study and per site of the collapse. The pooled rate of change and the respective 95% confidence interval (CI) were computed. Subgroup analysis was performed based on patients' age, sample size, the applied DISE protocol, and the originally used diagnostic modality before DISE. Results In a total of nine studies, 1247 patients were included (69.2% males, 59.7% children, 78.04% with a multilevel collapse). Therapeutic decisions changed in 43.69% of patients (CI, 33.84 to 53.54). The change rates were significantly higher in adults (54.0% versus 25.9% in children, P = 0.001), midazolam-based DISE protocols (78.4% versus 48.45% for midazolam plus propofol and 33.9% for propofol, P < 0.001), and after awake endoscopy (62.2% as compared to 44.6% after clinical basic examination [CBE], 40.1% after CBE, lateral cephalometry, and Müller maneuver, P = 0.02). Changes at uvular and palatal sites were more frequent in adults and at the tonsils in children. Conclusion The DISE approach can be promoted via implementing unified classification systems of obstruction sites; the widescale application of target-controlled infusion and its therapeutic benefits can be explored in well-designed randomized studies that compare its efficacy with other diagnostic modalities.