Surgical failure guided by DISE in patients with obstructive sleep apnea: a systematic review and meta-analysis

OBJECTIVES

The failure rate and risk factors of upper airway surgery with drug induced sleep endoscopy (DISE) remain unknown in the treatment of obstructive sleep apnea (OSA). This review aims to analyze the failure rate of upper airway surgery with DISE and identify obstruction sites for surgical failure.

METHODS

A systematic review was conducted using PubMed, Embase, Web of Science, and Google Scholar until May 20th, 2023. We included studies that used DISE to assess obstructive sites before upper airway surgery and reported surgical failure rates and outcomes in patients with OSA.

RESULTS

25 studies with a total of 1522 patients were included in the systematic review and meta-analysis. Upper airway surgery guided by DISE had a relatively low failure rate of 37% (95% CI 0.31-0.44) in the random effects model (I2 = 85.97%, P < 0.001). According to the velum, oropharynx, tongue base, and epiglottis (VOTE) scoring system, major risk factors for surgical failure included circumferential collapse at the velum, lateral wall collapse and small tonsils at the oropharynx, anterior-posterior lingual collapse and complete collapse at the tongue base. High body mass index and large preoperative apnea hypopnea index were also risk factors for OSA surgical failure.

CONCLUSIONS

Upper airway surgery guided by DISE in patients with OSA had a low failure rate of 37%. DISE can identify obstruction sites associated with surgical failure and guide single-level and multi-level surgeries.

Sleep parameter characteristics of patients with OSA who have retropalatal circumferential narrowing and the clinical significance of lateral pharyngeal wall collapse during sleep

BACKGROUND

The lateral pharyngeal wall (LPW) is a critical anatomic structure in patients with obstructive sleep apnea (OSA). Resolving the retropalatal circumferential (RC) narrowing caused by combination of both LPW collapse and antero-posterior (AP) narrowing holds promise for surgical treatment of OSA. We sought to determine the clinical characteristics and distinctive alterations in sleep parameters of patients with OSA who have RC narrowing and LPW collapse.

METHODS

Drug-induced sleep endoscopy (DISE), polysomnography findings, and sleep questionnaires were reviewed retrospectively in patients with OSA.

RESULTS

Of the 106 OSA patients examined, 48% showed RC narrowing and 44% showed AP narrowing at the oropharynx level during sleep while 8% of the patients showed only LPW collapse. Patients with RC narrowing with LPW collapse exhibited a higher BMI than those with AP narrowing only. In addition, patients with RC narrowing showed more aggravated sleep parameters including apneic events than patients with AP narrowing alone. The degree of RC narrowing correlated significantly with the severity of OSA as shown by a higher apnea index and lower oxygen desaturations.

CONCLUSIONS

Our clinical findings suggest that the presence of RC narrowing with LPW collapse in OSA is closely related to increased apneic and oxygen desaturation events. RC narrowing with LPW collapse may be targets for surgical correction in patients with OSA to improve therapeutic outcomes.

Defining Epiglottic Collapses Patterns in Obstructive Sleep Apnea Patients: Francia-Lugo Classification

Obstructive Sleep Apnea (OSA) is characterized by repetitive collapse of the upper airway during sleep. Drug-Induced Sleep endoscopy (DISE) is used to identify the collapse site. Among the possible sites of collapse, the epiglottis occurs more frequently than previously described. In this study, we reviewed DISE findings and classified different epiglottic collapse patterns. We found 104 patients (16.4%) with epiglottis collapse (primary 12.5% and secondary 3.9%). We described the following patterns of epiglottis collapse: Anterior-Posterior (AP) collapse with rigid component "trapdoor type" (48%); AP collapse with lax component "floppy type" (13.5%); Lateral- Lateral (LL) collapse with omega shape component "book type" (14.5%); and secondary due to lateral pharyngeal wall or tongue base collapse (24%). The identification of the epiglottic collapse pattern is crucial in decision-making when attempting to ameliorate OSA. These findings in OSA phenotyping could influence the type of treatment chosen.

Multilevel Airway Obstruction Phenotypes in Adult OSA

Objective

To describe multilevel phenotypes of airway obstruction identified on drug-induced sleep endoscopy (DISE) in adults.

Study Design

Retrospective chart review.

Setting

Tertiary care center.

Methods

Video recordings of DISE on adult patients were retrospectively scored. A cross-correlation matrix was created to detect significant correlations between DISE findings at anatomical subsites. Three multilevel phenotypes resulted from the matrix: complete collapse at the tongue base with complete collapse at the epiglottis (T2-E2), complete circumferential obstruction at the velum with complete lateral pharyngeal wall collapse at the oropharynx (V2C-O2LPW), and incomplete collapse at the velum with complete collapse due to tonsillar hypertrophy (V0/1-O2T). The mean difference (MD) and 95% confidence interval (CI) were calculated for demographic and polysomnogram metrics of each phenotype compared to all other subjects.

Results

Phenotype 1 (T2-E2) (n = 88) had older ages (MD 5.784 years, CI [1.992, 9.576]), lower body mass index (BMI) (MD -1.666 kg/m², CI [02.570, -0.762]), and smaller neck circumferences (MD -0.448 in., CI [-9.14, -0.009]) than the other phenotypes. Phenotype 2 (V2C-O2LPW) (n = 25) had higher BMIs (MD 2.813 kg/m², CI [1.362, 4.263]), higher neck circumference (MD 0.714 in., CI [0.004, 1.424]), and higher apnea-hypopnea index (MD 8.252, CI [0.463, 16.041]). Phenotype 3 (V0/1-O2T) (n = 20) had younger ages (MD -17.697, CI [-25.215, -11.179]).

Conclusion

Three distinct multilevel phenotypes of obstruction were identified on DISE, suggesting different anatomic subsites collapse in a nonrandom pattern. The phenotypes appear to represent distinct patient groups and their identification may have implications in terms of pathophysiology and treatment modalities.

Automatic scoring of drug-induced sleep endoscopy for obstructive sleep apnea using deep learning

BACKGROUND

Treatment of obstructive sleep apnea is crucial for long term health and reduced economic burden. For those considered for surgery, drug-induced sleep endoscopy (DISE) is a method to characterize location and pattern of sleep-related upper airway collapse. According to the VOTE classification system, four upper airway sites of collapse are characterized: velum (V), oropharynx (O), tongue (T), and epiglottis (E). The degree of obstruction per site is classified as 0 (no obstruction), 1 (partial obstruction), or 2 (complete obstruction). Here we propose a deep learning approach for automatic scoring of VOTE obstruction degrees from DISE videos.

METHODS

We included 281 DISE videos with varying durations (6 s-16 min) from two sleep clinics: Copenhagen University Hospital and Stanford University Hospital. Examinations were split into 5-s clips, each receiving annotations of 0, 1, 2, or X (site not visible) for each site (V, O, T, and E), which was used to train a deep learning model. Predicted VOTE obstruction degrees per examination was obtained by taking the highest predicted degree per site across 5-s clips, which was evaluated against VOTE degrees annotated by surgeons.

RESULTS

Mean F1 score of 70% was obtained across all DISE examinations (V: 85%, O: 72%, T: 57%, E: 65%). For each site, sensitivity was highest for degree 2 and lowest for degree 0. No bias in performance was observed between videos from different clinicians/hospitals.

CONCLUSIONS

This study demonstrates that automating scoring of DISE examinations show high validity and feasibility in degree of upper airway collapse.

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

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

Surgical Treatment Options for Epiglottic Collapse in Adult Obstructive Sleep Apnoea: A Systematic Review

The critical role of epiglottis in airway narrowing contributing to obstructive sleep apnoea (OSA) and continuous positive airway pressure (CPAP) intolerance has recently been revealed. This systematic review was conducted to evaluate available surgical treatment options for epiglottic collapse in adult patients with OSA. The Pubmed and Scopus databases were searched for relevant articles up to and including March 2022 and sixteen studies were selected. Overall, six different surgical techniques were described, including partial epiglottectomy, epiglottis stiffening operation, glossoepiglottopexy, supraglottoplasty, transoral robotic surgery, maxillomandibular advancement and hypoglossal nerve stimulation. All surgical methods were reported to be safe and effective in managing selected OSA patients with airway narrowing at the level of epiglottis. The surgical management of epiglottic collapse can improve OSA severity or even cure OSA, but can also improve CPAP compliance. The selection of the appropriate surgical technique should be part of an individualised, patient-specific therapeutic approach. However, there are not enough data to make definitive conclusions and additional high-quality studies are required.

Evaluation of drug-induced sleep endoscopy as a tool for selecting patients with obstructive sleep apnea for maxillomandibular advancement

STUDY OBJECTIVES

(1) to investigate if DISE findings are predictive of surgical response for patients undergoing MMA for OSA; and (2) to investigate the predictive value of jaw thrust maneuver during DISE in terms of surgical response to MMA.

METHODS

A retrospective cohort study was conducted on patients with OSA who underwent a baseline polysomnography (PSG) and DISE followed by MMA and a 3-6-months follow-up PSG, between September 1, 2011 and September 30, 2020.

RESULTS

Sixty-four OSA patients (50 males [78.1%]; mean ± SD age = 51.7 ± 9.5 years; mean ± SD AHI = 49.0 ± 20.8 events/hour) were included. Thirty-nine patients were responders, and twenty-five were nonresponders. Adjusting for baseline characteristics and surgical characteristics (e.g., age, baseline AHI, degree of maxillary advancement), patients with complete anteroposterior epiglottic collapse had 0.239 times lower odds for response to MMA (95% confidence interval, 0.059-0.979; P = 0.047). No significant relationship was found between complete concentric velum collapse and MMA response. There was no statistically significant association between effect of jaw thrust maneuver during DISE on upper airway patency and treatment outcome of MMA.

CONCLUSIONS

This study indicates that DISE is a promising tool in order to identify patients who will or will not respond to MMA for treating OSA. Patients with complete anteroposterior epiglottic collapse may be less suitable candidates for MMA.

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.

Improving outcomes of hypoglossal nerve stimulation therapy: current practice, future directions and research gaps. Proceedings of the 2019 International Sleep Surgery Society Research Forum

Hypoglossal nerve stimulation (HGNS) has evolved as a novel and effective therapy for patients with moderate-to-severe obstructive sleep apnea (OSA). Despite positive published outcomes of HGNS, there exist uncertainties regarding proper patient selection, surgical technique, and the reporting of outcomes and individual factors that impact therapy effectiveness. According to current guidelines, this therapy is indicated for select patients, and recommendations are based on the Stimulation Therapy for Apnea Reduction (STAR) trial. Ongoing research and physician experiences continuously improve methods to optimize the therapy. An understanding of the way in which airway anatomy, OSA phenotypes, individual health status, psychological conditions and comorbid sleep disorders influence the effectiveness of HGNS is essential to improve outcomes and expand therapy indications. This manuscript presents discussions on current evidence, future directions, and research gaps for HGNS therapy from the 10th International Surgical Sleep Society expert research panel.

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.

Imaging of sleep-disordered breathing in adults

Sleep-disordered breathing (SDB) is a term that includes several chronic conditions in which partial or complete cessation of breathing occurs multiple times throughout the night. Central sleep apnoea (CSA) is uncommon and defined by the episodic cessation of airflow without respiratory effort. Lesions involving the respiratory centre in the brainstem or the origin of the phrenic nerve from the mid-cervical cord are the commonest structural causes of CSA; magnetic resonance imaging (MRI) will demonstrate the lesion and frequently suggest the likely aetiology. In contrast, obstructive sleep apnoea (OSA) is defined as upper airway obstruction despite ongoing respiratory effort. Repetitive episodes of narrowing or closure of the upper airway are the predominant cause leading to snoring and OSA, respectively. OSA affects 33-40% of the adult population and is associated with multiple adverse health consequences, including a significantly increased risk of serious morbidity and mortality. The incidence is increasing proportionally to the worldwide rise in obesity. Imaging, performed primarily without the involvement of radiologists, has been integral to understanding the anatomical basis of SDB and especially OSA. This article will review the pathophysiology, imaging findings, and sequelae of these common conditions. The role of imaging both in suggesting the incidental diagnoses of SDB and in the investigation of these conditions when the diagnosis is suspected or has been established are also discussed.

Patterns of Obstruction on DISE in Adults With Obstructive Sleep Apnea Change With BMI

OBJECTIVES

We describe drug-induced sleep endoscopy (DISE) obstruction patterns in adults with obstructive sleep apnea (OSA) based on body mass index (BMI). We also evaluate subgroups of patients with clinically significant obstruction patterns at the velopharynx and oropharynx.

STUDY DESIGN

Retrospective chart review.

METHODS

Single-institution, retrospective chart review of adults with OSA who underwent DISE with dexmedetomidine sedation from 2016 to 2018. Endoscopic findings were graded using VOTE (Velum, Oropharynx, Tongue base, Epiglottis) classification. Oropharyngeal obstruction was additionally graded with the modifier T when due to palatine tonsil tissue. Findings in patients who had BMI < 25, 25 ≤ BMI < 30, and BMI ≥ 30 were compared.

RESULTS

One hundred and eleven patients (1 underweight, 23 normal weight, 56 overweight, and 31 obese) were reviewed. Patients with lower BMI were more likely to have more severe obstruction at the level of the tongue base (χ2 = 11.52, P = .021) and epiglottis (χ ² = 10.56, P = .032). Conversely, patients with higher BMI were more likely to have complete concentric (grade 2C) velum obstruction (χ ² = 16.04, P < .001) and more severe oropharyngeal obstruction (χ ² = 9.65, P = .046). Patients with grade 2 oropharyngeal obstruction without tonsil obstruction had more severe concurrent velum obstruction compared to subjects with grade 2 T oropharyngeal obstruction (P = .009).

CONCLUSION

In adults with OSA, BMI categories have significantly distinct obstruction patterns at all airway levels on DISE, and there appear to be distinct subgroups associated with certain velum and oropharynx collapse patterns. These findings may have important implications for positive airway pressure-alternative treatment.

LEVEL OF EVIDENCE

3 Laryngoscope, 131:224-229, 2021.

Association Between Breathing Route, Oxygen Desaturation, and Upper Airway Morphology

OBJECTIVES/HYPOTHESIS

This study aimed to assess the role of capnography in objectively evaluating breathing routes during drug-induced sleep endoscopy (DISE) and further elucidate the relationship between breathing route, obstructive sleep apnea (OSA) severity, and DISE findings.

STUDY DESIGN

Prospective observational study.

METHODS

Nighty-five patients with established OSA were recruited for this study from May 2017 to May 2019. DISE was performed in the operating room. Sedation was maintained with propofol using a target-controlled infusion system and the depth of sedation was monitored based on the bispectral index. The breathing routes, which included oral breathing, oronasal breathing, and nasal breathing, were detected using capnography. DISE findings were recorded using the VOTE (velum, oropharynx, base of tongue, and epiglottis) classification.

RESULTS

Patients with mouth breathing were associated with increased OSA severity, worse oximetric variables, and higher body mass index in comparison with those with other breathing routes. Mouth breathing was associated with a higher degree and higher prevalence of lateral pharyngeal wall collapse and tongue base collapse during DISE.

CONCLUSIONS

Mouth breathing was significantly associated with worse oxygen desaturation and increased degree of upper airway collapse. Therefore, patients with mouth breathing during propofol-based intravenous anesthesia should be carefully monitored.

LEVEL OF EVIDENCE

4 Laryngoscope, 131:E659-E664, 2021.

The comparison of multilevel surgery (hyoid myotomy and suspension with uvulopalatopharyngoplasty) with CPAP in moderate to severe OSAS patients

PURPOSE

The study aimed to determine the efficacy of multilevel surgery (hyoid myotomy and suspension with uvulopalatopharyngoplasty) and continuous positive airway pressure (CPAP) for the treatment of moderate to severe obstructive sleep apnea syndrome (OSAS) and to clarify whether our surgical protocol could be as effective as CPAP.

METHODS

We conducted a case series study comparing the effects of multilevel surgery and CPAP in the same subjects to minimize the influence of confounding factors. Fifteen subjects were enrolled with a pretreatment apnea-hypopnea index (AHI) ≥ 15.

RESULTS

Both CPAP and multilevel surgery could improve the AHI and oxygen desaturation index (ODI). The median AHI for baseline, CPAP and surgery were 38.9, 1.2 and 12.6, respectively (p < 0.001). The medina ODI for baseline, CPAP and surgery were 34.8, 0.9 and 7.2, respectively (p < 0.001). However, the results indicated CPAP as the more efficacious treatment modality compared with multilevel surgery. Moreover, CPAP not only decreased N1 sleep but also had beneficial effects on blood pressure control, whereas multilevel surgery did not have any significant difference.

CONCLUSION

CPAP is efficacious in improving OSAS severity, oxygen desaturation, sleep stage, and blood pressure control; while hyoid myotomy and suspension with uvulopalatopharyngoplasty are only efficacious in improving OSAS severity and oxygen desaturation. This study suggested that CPAP is the first choice when considering treatment of OSAS, especially in patients with hypertension or other cardiovascular diseases.

High Tongue Position is a Risk Factor for Upper Airway Concentric Collapse in Obstructive Sleep Apnea: Observation Through Sleep Endoscopy

PURPOSE

Identification of upper airway (UA) obstruction based on pharyngeal factors is important for obstructive sleep apnea (OSA) evaluation. This study is to assess the association between UA collapse characteristics and Friedman tongue position (FTP) in patients with OSA through drug-induced sleep endoscopy (DISE).

PATIENTS AND METHODS

Retrospective study in individuals with OSA who were intolerant to continuous positive airway pressure (CPAP) treatment, submitted to DISE between June 1, 2013, and July 31, 2017. All subjects were classified as having an FTP grade of I to IV, and the velum, oropharynx, tongue base, epiglottis (VOTE) classification was used to analyze the DISE findings. UA collapse characteristics by DISE and FTP grading were compared between groups. The associations between specific DISE findings and FTP were analyzed.

RESULTS

In total, 205 patients were assessed. A positive and significant correlation was identified between the presence of retropalatal complete concentric collapse (CCC) and FTP grade, according to the following distributions: I, 17.4%; II, 22.9%; III, 33.7%; and IV, 48.7% (P = 0.014). A logistic regression model revealed that CCC was associated with FTP grade IV. After adjusting for age, sex, body mass index (BMI), and tonsil size (TS), the grade IV individuals had a 4.4-fold higher risk of having CCC than grade I individuals (P = 0.026). Multiple collapse sites and palatopharyngeal or combined (palatopharyngeal and hypopharyngeal) collapse were more prevalent in grade IV individuals.

CONCLUSION

OSA patients intolerant to CPAP have a strong positive correlation between the FTP grade and presence of retropalatal CCC. FTP grade IV is an independent risk factor for velum-CCC, controlling for sex, age, BMI, and TS grade.

The clinical characteristics of patients with an isolate epiglottic collapse

OBJECTIVE

We analyzed the clinical characteristics of patients with isolated epiglottic collapse (IEC) who had an epiglottic anteroposterior (AP) collapse as the only cause of snoring during drug-induced sleep endoscopy (DISE).

METHODS

A retrospective analysis of 334 consecutive DISE examinations was performed. Patients who had only epiglottic AP collapse were designated as the IEC group. There were four age- and sex-matched controls for each case, and these patients were designated as the control group. Demographic factors, polysomnography findings, cephalometry, and awake nasopharyngoscopic findings were analyzed.

RESULTS

A total of 11 IEC cases and 44 controls were included. The IEC group had a significantly lower apnea-hypopnea index, higher minimum oxygen saturation level, lower body mass index, and shorter mandible plane to hyoid distance than the controls. However, there were no differences in epiglottic shape or curvature between the two groups. In addition, no IEC was noted during awake endoscopy. Nine (81.8%) epiglottic collapses were resolved with the mouth open and jaw thrust maneuver, which simulated the use of an oral appliance. Six (54.4%) were resolved with head turning, mimicking the lateral sleep position.

CONCLUSION

The clinical characteristics of IEC patients differed from the control group, and IEC could not be identified during awake endoscopy. Therefore, patients with severe snoring but AHI < 5 or mild sleep apnea on polysomnographic findings and DISE, should be considered likely to have IEC. In addition, use of an oral appliance is recommended as an effective treatment for IEC.

Dynamic pharyngeal collapse in three cats with different pharyngeal pathology

Dynamic pharyngeal collapse (PC) is a rarely reported condition in cats defined as the partial or complete collapse of the pharyngeal lumen during inspiration. Herein, we report the imaging findings and clinical features of three cats with dynamic PC. Lateral radiograph of the head was insufficient to detect dynamic PC, but fluoroscopy in conscious cats revealed dynamic PC. Magnetic resonance imaging was not helpful to reveal dynamic PC and underlying diseases. We obtained biopsy samples from the irregular nasopharyngeal mucosal membrane through endoscopy in two of the three cases and high-grade B-cell lymphoma was histopathologically diagnosed. In feline cases with abnormal upper respiratory sounds, dynamic PC should be considered, and fluoroscopy is the imaging technique of choice to diagnose the condition.

The Role of the Revised Stanford Protocol in Today's Precision Medicine

Whereas the original Stanford protocol relied on a tiered approach to care to avoid unnecessary surgery, it did not address the issue of surgical relapse, a common concern among sleep medicine specialists. With 3 decades of experience since the original 2-tiered Powell-Riley protocol was introduced and the role of evolving skeletal techniques and upper airway stimulation, we are pleased to present our current protocol. This update includes emphasis on the facial skeletal development with impact on function including nasal breathing, and the incorporation of upper airway stimulation. The increased versatility of palatopharyngoplasty as an adjunctive procedure is also discussed.

Can anatomical assessment of hypopharyngolarynx in awake patients predict obstructive sleep apnea?

OBJECTIVES/HYPOTHESIS

To assess the relationships between laryngeal and hypopharyngeal morphology and obstructive sleep apnea-hypopnea syndrome (OSAHS) in awake patients.

STUDY DESIGN

Prospective study.

METHODS

Awake flexible fiberoptic laryngoscopy and sleep studies were performed in 80 patients for snoring or OSAHS suspicion. Endoscopic videos were reviewed by two examiners to assess morphological characteristics of hypopharynx and larynx using a standardized examination of appearance, shape and position of epiglottis, shape of retropharyngeal-epiglottic aerospace (RPEA), modified Cormack-Lehane score, and length ratios of the hypopharynx and epiglottis. The multivariate logistic regression model was used to assess independent predictors of moderate/severe OSAHS.

RESULTS

The interrater agreements were moderate for epiglottis appearance (κ = 0.52), epiglottis form (κ = 0.66), and epiglottis position (κ = 0.49), but fair for the shape of RPEA (κ = 0.26) and modified Cormack-Lehane scoring (κ = 0.38). The presence of a mega-epiglottis was significantly correlated with the severity of OSAHS (P < .05). By multivariate logistic regression analysis, independent predictors of moderate/severe obstructive sleep apnea were mega-epiglottis (adjusted odds ratio [aOR]: = 4.78, 95% confidence interval [CI]: 1.23-18.56, P = .024), modified Cormack-Lehane score of 2 (aOR: 15.3, 95% CI: 1.8-130.3, P = .012), or modified Cormack-Lehane score of 3 (aOR: 10.03, 95% CI: 1.3-78.2, P = .03) and aging (aOR = 1.07, 95% CI: 1.01-1.14, P = .025).

CONCLUSIONS

Routine flexible fiberoptic laryngoscopy performed by otorhinolaryngologists in awake patients may help to detect some predictors of OSAHS such as presence of mega-epiglottis, and modified Cormack-Lehane score of 2 or more. Investigation of sleep disorders should be proposed in these patients.

LEVEL OF EVIDENCE

2 Laryngoscope, 129:2782-2788, 2019.

Controversies in Obstructive Sleep Apnea Surgery

Obstructive sleep apnea (OSA) is a common chronic disease characterized by repetitive pharyngeal collapse during sleep. OSA is associated with cardiovascular disease and increased mortality, among other issues. Continuous positive airway pressure (CPAP) is considered first line therapy for OSA, but is not always tolerated. Both non-surgical and surgical alternative management strategies are available for the CPAP intolerant patient. This article explores controversies surrounding airway evaluation, definition of successful treatment, and surgical management of the CPAP intolerant patient with moderate to severe OSA. Controversies specific to maxillomandibular advancement (MMA) are also discussed.

Lingual tonsillectomy with palatal surgery for the treatment of obstructive sleep apnea in adults: a systematic review and meta-analysis

OBJECTIVE

To conduct a systematic review and meta-analysis to evaluate effects of lingual tonsillectomy with palatal surgery as a combined procedure for the treatment of obstructive sleep apnea (OSA) in adults.

SEARCH METHODS

Data source: a comprehensive search of MEDLINE, Scopus, Ovid, Web of Science, and the Cochrane Library was performed through November 2017. Manual searches and subject matter expert input were also obtained. This review includes studies assessing efficacy of lingual tonsillectomy with palatal surgery as a combined procedure for the treatment of OSA in adults, who had multilevel obstruction including lingual tonsil hypertrophy, in which apnea/hypopnea index (AHI) or respiratory disturbance index (RDI) were reported.

RESULTS

A total of four studies (107 patients) met our inclusion criteria. Pooled random effects analysis demonstrated a statistically significant improvement of polysomnographic respiratory events postoperatively, with average AHI reduction of 18.51 events per hour, [95% confidence interval (CI) (- 31.72, - 5.31); P = 0.006] and increase in minimal arterial oxygen saturation of 5.26 [95% CI (0.10, 10.42); P = 0.05]. The result also showed that the procedures significantly improved sleepiness resulting in an average Epworth Sleepiness Scale (ESS) reduction of 5.44 [95% CI (- 8.69, - 2.18); P = 0.001].

CONCLUSION

A combination of lingual tonsillectomy with palatal surgery may offer benefits in a selected group of OSA adults, in terms of apnea/hypopnea index, minimal arterial oxygen saturation and Epworth Sleepiness Scale. Data were based on meta-analysis of all case series with 2-6 months' follow-up.

Does Sleep Endoscopy Staging Pattern Correlate With Outcome of Advanced Palatopharyngoplasty for Moderate to Severe Obstructive Sleep Apnea?

STUDY OBJECTIVES

Although drug-induced sleep endoscopy (DISE) is an accepted method to localize upper airway obstruction, it is not known whether all sites identified by DISE must be treated to achieve sufficient apnea-hypopnea index (AHI) improvement. The aim of this study was to compare outcomes for unilevel (upper) versus multilevel DISE collapse patterns in a patient cohort that only underwent modern palatopharyngoplasty. Our hypothesis was that not all tongue base-level obstructions on DISE must be treated.

METHODS

Thirty-eight patients with mean AHI of 45 events/h underwent DISE followed by palatopharyngoplasty. Outcome was measured by polysomnography or home sleep apnea testing.

RESULTS

Eleven patients (29%) had multilevel, complete tongue base obstruction and nineteen (50%) had no obstruction. These two groups were similar in age, body mass index, and AHI; the complete group had smaller tonsils and higher tongue position. The postoperative success rate and AHI in the group without tongue base obstruction were not significantly different from those of the complete group (68%; 17.4 ± 11.0 versus 73%; 15.4 ± 20.5, P > .99). Seventeen patients (45%) had circumferential collapse of velum. The postoperative AHI was higher for patients with circumferential collapse (23.6 ± 15.8 from 55.3 ± 22.1 versus 10.5 ± 9.94 from 36.4 ± 16.7, P < .0001), but both groups had clinically and statistically significant AHI reductions.

CONCLUSIONS

Patients with multilevel obstruction on DISE, treated with palatopharyngoplasty alone, had similar AHI outcome as those with unilevel obstruction. Multilevel surgery may not be needed in some patients with a multilevel obstruction pattern. Circumferential collapse of velum, however, was associated with a higher residual AHI.

Predicting epiglottic collapse in patients with obstructive sleep apnoea

Obstructive sleep apnoea (OSA) is characterised by pharyngeal obstruction occurring at different sites. Endoscopic studies reveal that epiglottic collapse renders patients at higher risk of failed oral appliance therapy or accentuated collapse on continuous positive airway pressure. Diagnosing epiglottic collapse currently requires invasive studies (imaging and endoscopy). As an alternative, we propose that epiglottic collapse can be detected from the distinct airflow patterns it produces during sleep.23 OSA patients underwent natural sleep endoscopy. 1232 breaths were scored as epiglottic/nonepiglottic collapse. Several flow characteristics were determined from the flow signal (recorded simultaneously with endoscopy) and used to build a predictive model to distinguish epiglottic from nonepiglottic collapse. Additionally, 10 OSA patients were studied to validate the pneumotachograph flow features using nasal pressure signals.Epiglottic collapse was characterised by a rapid fall(s) in the inspiratory flow, more variable inspiratory and expiratory flow and reduced tidal volume. The cross-validated accuracy was 84%. Predictive features obtained from pneumotachograph flow and nasal pressure were strongly correlated.This study demonstrates that epiglottic collapse can be identified from the airflow signal measured during a sleep study. This method may enable clinicians to use clinically collected data to characterise underlying physiology and improve treatment decisions.

Tratamiento quirúrgico por otorrinolaringología en el síndrome de apnea-hipopnea obstructiva del sueño (SAHOS)

El síndrome de apnea-hipopnea obstructiva del sueño (SAHOS) se caracteriza por la obstrucción parcial o el colapso total de la vía aérea superior, de manera intermitente y repetitiva, por lo que, en un principio, se vio el manejo quirúrgico como una alternativa curativa para esta patología. Sin embargo, en la actualidad se reconoce que la cirugía, aun sin lograr tasas de efectividad muy altas de manera consistente, sí mejora la tolerancia y adaptación a la terapia de presión positiva, la cual sigue siendo la primera línea de manejo.Así, el primer paso antes de pensar en cualquier procedimiento quirúrgico es un adecuado diagnóstico topográfico, de modo que siempre se debe realizar una nasofibrolaringoscopia para identificar el o los sitios de obstrucción. Además, se sabe que el 75% de los pacientes presentan obstrucciones en múltiples niveles y que, cuando el abordaje se hace multinivel, se logra corregir el SAHOS hasta en un 95%. Entre los procedimientos vigentes se encuentran cirugías de nariz, paladar blando, amígdalas, base de lengua, estimulación del nervio hipogloso y procedimientos del esqueleto facial, así como procedimientos coadyuvantes, entre los que están radiofrecuencia e implantes de paladar.

Fibronasolaringoscopia en el diagnóstico de síndrome de apnea-hipopnea obstructiva del sueño (SAHOS)

En los pacientes con diagnóstico de trastornos respiratorios del sueño (TRS) no se ha podido asociar ningún hallazgo anatómico a la severidad de la patología que el paciente presenta o a su éxito quirúrgico. Los avances actuales en la tecnología de video han permitido evaluar de manera más fidedigna las medidas de la vía aérea (VA) y trazar un mapa más exacto del sitio específico de obstrucción. La fibronasolaringoscopia es una técnica accesible y económica para la evaluación de la VA en múltiples posiciones en períodos de sueño y vigilia; esta requiere un amplio conocimiento por parte del examinador de la anatomía y fisiología de la vía aérea superior para determinar los sitios exactos de obstrucción y los patrones de colapso que podrían determinar la posibilidad del manejo quirúrgico o no, haciendo de este examen diagnóstico parte fundamental en el estudio de los pacientes con TRS.

Effect of Sleeping Position on Upper Airway Patency in Obstructive Sleep Apnea Is Determined by the Pharyngeal Structure Causing Collapse

Objectives

In some patients, obstructive sleep apnea (OSA) can be resolved with improvement in pharyngeal patency by sleeping lateral rather than supine, possibly as gravitational effects on the tongue are relieved. Here we tested the hypothesis that the improvement in pharyngeal patency depends on the anatomical structure causing collapse, with patients with tongue-related obstruction and epiglottic collapse exhibiting preferential improvements.

Methods

Twenty-four OSA patients underwent upper airway endoscopy during natural sleep to determine the pharyngeal structure associated with obstruction, with simultaneous recordings of airflow and pharyngeal pressure. Patients were grouped into three categories based on supine endoscopy: Tongue-related obstruction (posteriorly located tongue, N = 10), non-tongue related obstruction (collapse due to the palate or lateral walls, N = 8), and epiglottic collapse (N = 6). Improvement in pharyngeal obstruction was quantified using the change in peak inspiratory airflow and minute ventilation lateral versus supine.

Results

Contrary to our hypothesis, patients with tongue-related obstruction showed no improvement in airflow, and the tongue remained posteriorly located while lateral. Patients without tongue involvement showed modest improvement in airflow (peak flow increased 0.07 L/s and ventilation increased 1.5 L/min). Epiglottic collapse was virtually abolished with lateral positioning and ventilation increased by 45% compared to supine position.

Conclusions

Improvement in pharyngeal patency with sleeping position is structure specific, with profound improvements seen in patients with epiglottic collapse, modest effects in those without tongue involvement and-unexpectedly-no effect in those with tongue-related obstruction. Our data refute the notion that the tongue falls back into the airway during sleep via gravitational influences.

Impact of continuous positive airway pressure in patients with obstructive sleep apnea during drug-induced sleep endoscopy

OBJECTIVES

The primary objective of the study was to understand the differential impact of continuous positive airway pressure (CPAP) on the location, degree and pattern of airway collapse in obstructive sleep apnea (OSA) patients utilizing drug-induced sleep endoscopy (DISE).

STUDY DESIGN

Non-randomized trial.

SETTING

University Medical Center.

PARTICIPANTS

Fifteen consecutive OSA patients undergoing DISE.

MAIN OUTCOMES AND MEASURES

The patterns of airway collapse were videorecorded at baseline and under differential application of nasal CPAP (nCPAP) at 5, 10 and 15 cm H₂ O. For each modality, the pattern and degree of airway collapse were analyzed by three independent observers using the velum, oropharynx, tongue base, epiglottis (VOTE) classification system.

RESULTS

The modest nCPAP pressures (10 cm H₂ O) had the greatest impact on the lateral walls of the pharynx, followed by the palatal region. The collapsibility of the tongue base and epiglottis demonstrated significant resistance to nCPAP application, which was overcome by increasing nCPAP to 15 cm H₂ O. Compared to 5 cm H₂ O, nCPAP pressures of 10 and 15 cm H₂ O improved complete collapse at least at one level of the upper airway (P=.016 and .001, respectively). Increased nCPAP pressures also led to changes in the configuration of airway collapse at the level of the velum.

CONCLUSIONS

The differential nCPAP effects observed in this study may help to understand some of the mechanisms responsible for inadequate patient response and poor nCPAP compliance. The use of DISE in combination with CPAP may serve as a first step in optimizing patients that failed to adapt to treatment with CPAP. This approach can help the physician identify patterns of airway collapse that may require varying pressures different from the one the patient is using, as well as anatomical factors that may be corrected to help with compliance.

[Drug-induced sedation endoscopy-quo vadis? : Review and outlook]

BACKGROUND

Drug-induced sedation endoscopy (DISE) is a diagnostic procedure which allows evaluation of the collapsibility of the upper airway. According to expert opinion, it is possible to imitate nocturnal collapsibility and perform a realistic investigation of the site of obstruction and vibration. This should enable sufficient and precise therapeutic advice to be given solely on the basis of clinical assessment.

OBJECTIVE

The current publication critically evaluates the present state of development of DISE and its potential indications.

MATERIALS AND METHODS

A PubMed literature research was performed using "sleep" and "endoscopy" or "DISE" as keywords. Relevant publications were evaluated.

RESULTS

The present publication provides a historical summary of the available publications and relates these to other methods for examining obstructive sleep apnea. The present state of DISE in terms of drugs applied, grading systems, and validity is evaluated. Indications for DISE are described and critically discussed on the basis of literature data.

CONCLUSION

DISE provides deep insights into the genesis of obstructions of the upper airway and snoring. Although its value for diagnosis and treatment of sleep-disordered breathing could not yet be demonstrated for all non-CPAP (continuous positive airway pressure) therapies, DISE could identify predictive parameters some methods. Further potential indications for DISE might be predictive examinations for mandibular advancement devices and respiration-synchronous neurostimulation of the hypoglossal nerve. DISE will thus remain a valuable diagnostic tool for obstructive sleep apnea and rhonchopathy.

Dynamic Drug-Induced Sleep Computed Tomography in Adults With Obstructive Sleep Apnea

Surgical success for obstructive sleep apnea (OSA) depends on identifying sites of obstruction in the upper airway. In this study, we investigated sites of obstruction by evaluating dynamic changes in the upper airway using drug-induced sleep computed tomography (DI-SCT) in patients with OSA. Thirty-five adult patients with OSA were prospectively enrolled. Sleep was induced with propofol under light sedation (bispectral index 70–75), and low-dose 320-detector row CT was performed for 10 seconds over a span of 2–3 respiratory cycles with supporting a continuous positive airway pressure model. Most (89%) of the patients had multi-level obstructions. Total obstruction most commonly occurred in the velum (86%), followed by the tongue (57%), oropharyngeal lateral wall (49%), and epiglottis (26%). There were two types of anterior-posterior obstruction of the soft palate, uvular (94%) and velar (6%), and three types of tongue obstruction, upper (30%), lower (37%), and upper plus lower obstruction (33%). DI-SCT is a fast and safe tool to identify simulated sleep airway obstruction in patients with OSA. It provides data on dynamic airway movement in the sagittal view which can be used to differentiate palate and tongue obstructions, and this can be helpful when planning surgery for patients with OSA.

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.

Efficacy of Maxillomandibular Advancement Examined with Drug-Induced Sleep Endoscopy and Computational Fluid Dynamics Airflow Modeling

OBJECTIVES

To use drug-induced sedation endoscopy (DISE) and computational fluid dynamics (CFD) modeling to study dynamic airway and airflow changes after maxillomandibular advancement (MMA), and how the changes correlate with surgical success based on polysomnography parameters.

STUDY DESIGN

Retrospective cohort study.

SETTING

University medical center.

METHODS

DISE was rated with the VOTE (velum, oropharynx, tongue, epiglottis) classification, and CFD was used to model airflow velocity and negative pressure exerted on pharyngeal wall. Changes in VOTE score by site and CFD measurements were correlated with perioperative polysomnography outcomes of apnea-hypopnea index (AHI), apnea index (AI), oxygenation desaturation index (ODI), and lowest oxygen saturation.

RESULTS

After MMA, 20 subjects (17 males, 3 females) with a mean age of 44 ± 12 years and body mass index of 27.4 ± 4.6 kg/m(2) showed mean decreases in AHI (53.6 ± 26.6 to 9.5 ± 7.4 events/h) and ODI (38.7 ± 30.3 to 8.1 ± 9.2 events/h; P < .001). Improvement in lateral pharyngeal wall collapse during DISE based on VOTE score correlated with the most decrease in AHI (60.0 ± 25.6 to 7.5 ± 3.4 events/h) and ODI (46.7 ± 29.8 to 5.3 ± 2 events/h; P = .002). CFD modeling showed significant positive Pearson correlations between reduction of retropalatal airflow velocity and AHI (r = 0.617, P = .04) and ODI (r = 0.773, P = .005).

CONCLUSION

AHI and ODI improvement after MMA is best correlated with (1) decreased retropalatal airflow velocity modeled by CFD and (2) increased lateral pharyngeal wall stability based on VOTE scoring from DISE.

Efficacy of Upper Airway Stimulation on Collapse Patterns Observed during Drug-Induced Sedation Endoscopy

OBJECTIVE

To describe upper airway collapse patterns observed on drug-induced sedation endoscopy (DISE) during screening for a clinical trial and to evaluate the impact of collapse patterns found on preoperative DISE on response rates to upper airway stimulation (UAS) therapy.

STUDY DESIGN

Retrospective review of an ongoing prospective multi-institutional cohort study.

SETTING

Twenty-two participating institutions of the STAR trial.

SUBJECTS AND METHOD

In total, 222 subjects were screened with DISE to determine eligibility for an implantable UAS device. Supine laryngoscopy was performed during moderate sedation (propofol and/or midazolam). Airway collapse pattern and severity were graded at 4 levels, including velum, oropharynx, tongue base, and epiglottis (VOTE classification). Patients with complete concentric collapse (CCC) at the velum were excluded from implantation.

RESULTS

The CCC at the velum was observed in 52 (23%) of screened subjects, and these subjects were subsequently excluded from implantation. Of the 170 subjects without CCC at the velum, 126 (77%) underwent implantation: 121 (96%) had multilevel collapse and 5 (4%) had single-level collapse. When comparing preimplantation DISE findings, UAS responders at 12 months had lower baseline VOTE scores compared with therapy nonresponders.

CONCLUSION

Drug-induced sedation endoscopy is an efficient and safe method for determining UAS eligibility and has the potential to identify UAS nonresponders. Most patients had multilevel airway collapse, illustrating the limitations of single-level upper airway surgery in treating obstructive sleep apnea. Upper airway stimulation is effective therapy for most patients with multilevel airway collapse; however, patients with complete anterior-posterior or lateral soft palate and/or epiglottic collapse may be at increased risk of therapy failure.

Static craniofacial measurements and dynamic airway collapse patterns associated with severe obstructive sleep apnoea: a sleep MRI study

OBJECTIVES

Using sleep MRI, we aimed to identify static craniofacial measurements and dynamic upper airway collapse patterns associated with severe obstructive sleep apnoea (OSA) during natural sleep in age and BMI-matched patients.

DESIGN

Nested case-control study.

SETTING

Sleep MRI images (3.0 Tesla scanner) and synchronised acoustic recording were used to observe patterns of dynamic airway collapse in subjects with mild and severe OSA. Midsagittal images were also used for static craniofacial measurements.

PARTICIPANTS

Fifteen male subjects with severe OSA (mean AHI 70.3 ± 23 events/h) were matched by age and BMI to 15 subjects with mild OSA (mean AHI 7.8 ± 1.4 events/h). Subjects were selected from a consecutive sleep MRI study cohort.

MAIN OUTCOME MEASURES

Static craniofacial measurements selected a priori included measurements that represent maxillomandibular relationships and airway morphology. Axial, sagittal and coronal views of the airway were rated for dynamic collapse at retropalatal, retroglossal and lateral pharyngeal wall regions by blinded reviewers. Bivariate analysis was used to correlate measures associated with severity of OSA using AHI. Statistical significance was set at P < 0.01.

RESULTS

Lateral pharyngeal wall collapse from dynamic sleep MRI (β = 51.8, P < 0.001) and upper airway length from static MRI images (β = 27.2, P < 0.001) positively correlated with severity of OSA.

CONCLUSIONS

Lateral pharyngeal wall collapse and upper airway length are significantly associated with severe OSA based on sleep MRI. Assessment of these markers can be readily translated to routine clinical practice, and their identification may direct targeted surgical treatment.

Lateral Pharyngeal Wall Tension After Maxillomandibular Advancement for Obstructive Sleep Apnea Is a Marker for Surgical Success: Observations From Drug-Induced Sleep Endoscopy

PURPOSE

The efficacy of maxillomandibular advancement (MMA) for obstructive sleep apnea (OSA) with anatomic airway changes has previously been studied using static imaging and endoscopy in awake subjects. The aim of the present study was to use drug-induced sleep endoscopy (DISE) to evaluate the dynamic upper airway changes in sleeping subjects before and after MMA and their association with the surgical outcome.

PATIENTS AND METHODS

This was a retrospective cohort study of subjects with OSA who had undergone MMA at the Stanford University Sleep Surgery Division from July 2013 to July 2014. The subjects were included if perioperative polysomnography and DISE had been performed. The predictor variable was the perioperative DISE velum-oropharynx-tongue-epiglottis score. The outcome variables were the apnea-hypopnea index (AHI), oxygen-desaturation index (ODI), and Epworth Sleepiness Scale (ESS). A subgroup analysis was performed for the subjects who had undergone primary and secondary MMA. The statistical analyses included Cronbach's α coefficient, the McNemar test, and the independent Student t test. The P value was set at <.01.

RESULTS

A total of 16 subjects (15 males, 1 female) were included in the present study, with an average age of 47 ± 10.9 years and body mass index of 29.4 ± 5.1 kg/m(2). Significant post-MMA decreases were found in the AHI (from 59.8 ± 25.6 to 9.3 ± 7.1 events/hr) and ODI (from 45 ± 29.7 to 5.7 ± 4.1 events/hr; P < .001). Greater improvement in the AHI occurred in the primary MMA group (P = .022). The post-MMA change in airway collapse was most significant at the lateral pharyngeal wall (P = .001). The subjects with the most improvement in lateral pharyngeal wall collapsibility demonstrated the largest changes in the AHI (from 60.0 ± 25.6 events/hr to 7.5 ± 3.4 events/hr) and ODI (from 46.7 ± 29.8 to 5.3 ± 2 events/hr; P = .002).

CONCLUSIONS

Using DISE, we observed that after MMA, the greatest reduction in upper airway collapsibility is seen at the lateral pharyngeal wall of the oropharynx, followed by the velum, and then the tongue base. The stability of the lateral pharyngeal wall is a marker of surgical success after MMA using the AHI, ODI, and ESS.