Results of the ADHERE upper airway stimulation registry and predictors of therapy efficacy

Daytime polysomnography to perform titration for upper airway stimulation in patients with obstructive sleep apnea

PURPOSE

Upper airway stimulation (UAS) is an innovative treatment for patients with obstructive sleep apnea (OSA). UAS titrations are performed 3 months after activation of the device to optimize its effectiveness. In general, these titrations are performed during an in-laboratory overnight polysomnography (PSG). However, overnight titrations are expensive and can be logistically challenging because they are labor-intensive which causes shortage of sleep technicians available for night shifts. In addition, recently, overnight PSGs were postponed and canceled due to the COVID-19 pandemic. We aimed to assess the feasibility of a daytime PSG to perform titration of UAS therapy as an alternative for a conventional overnight PSG.

METHODS

We performed a prospective single-center observational cohort study. Patients were included when planned for UAS titration; this was approximately 6 months after UAS activation. Data on sleep architecture, patient experience, and respiratory outcomes were collected to evaluate the feasibility. An overnight follow-up PSG 12 months after implantation was used to compare sleep architecture and therapy response.

RESULTS

Of 23 patients, four were excluded from analysis because of technical issues during PSG. Even though patients slept significantly shorter during the daytime PSG, this was enough time to complete the titration successfully with 30-min sleep in final therapeutic settings in 84% of the patients. Patients (94%) had a positive experience with the daytime titration. Respiratory outcomes were significantly reduced during titration and were maintained at the 12-month follow-up.

CONCLUSION

Daytime titrations are a valuable alternative for conventional overnight titrations. Our findings suggest the implementation of daytime titrations as standard of care. This will contribute to easier logistics and better work circumstances for sleep technicians without jeopardizing titration quality.

Insomnia affects patient-reported outcome in sleep apnea treated with hypoglossal nerve stimulation

Objective

Comorbid insomnia may impact outcomes of patients with obstructive sleep apnea (OSA) receiving hypoglossal nerve stimulation with respiratory sensing (HNS) therapy. To examine whether the presence of insomnia measured using the Insomnia Severity Index (ISI) is associated with patient-reported outcomes and objective OSA measures in patients receiving HNS therapy.

Methods

In this retrospective chart review, patients with an HNS implant and ISI score at follow-up assessment were categorized as having moderate/severe insomnia or no/subthreshold insomnia. OSA-related data (Apnea Hypopnea Index, AHI; Oxygen Desaturation Index, ODI), Epworth Sleepiness Scale (ESS), Functional Outcomes of Sleep Questionnaire (FOSQ), and overall patient satisfaction was compared between these patient categories. Correlations between ISI scores and each of these variables were examined.

Results

Of the 132 patients, 26% had moderate/severe insomnia at follow-up assessment. ESS and FOSQ scores were worse in the insomnia group at baseline, follow-up, and in the change from baseline, but AHI and ODI scores did not differ between patients with and without insomnia. Frequency of overall satisfaction at follow-up was lower in the insomnia group (58.8% vs. 92.8% with no insomnia, P < .001). Patients with insomnia were more likely to have depression (56% vs. 27% without insomnia, P < .002).

Conclusions

Insomnia is associated with worse patient-reported outcomes of daytime sleepiness and sleep-related quality of life in patients with OSA receiving HNS therapy. Depression is more prevalent in patients with comorbid insomnia. The ISI may help physicians to address comorbid insomnia and achieve high patient satisfaction and adherence to HNS therapy.

Level of Evidence

4.

Association of hypoglossal nerve stimulator response with machine learning identified negative effort dependence patterns

Background

Hypoglossal nerve stimulator (HGNS) is a therapeutic option for moderate to severe obstructive sleep apnea (OSA). Improved patient selection criteria are needed to target those most likely to benefit. We hypothesized that the pattern of negative effort dependence (NED) on inspiratory flow limited waveforms recorded during sleep, which has been correlated with the site of upper airway collapse, would contribute to the prediction of HGNS outcome. We developed a machine learning (ML) algorithm to identify NED patterns in pre-treatment sleep studies. We hypothesized that the predominant NED pattern would differ between HGNS responders and non-responders.

Methods

An ML algorithm to identify NED patterns on the inspiratory portion of the nasal pressure waveform was derived from 5 development set polysomnograms. The algorithm was applied to pre-treatment sleep studies of subjects who underwent HGNS implantation to determine the percentage of each NED pattern. HGNS response was defined by STAR trial criteria for success (apnea–hypopnea index (AHI) reduced by > 50% and < 20/h) as well as by a change in AHI and oxygenation metrics. The predominant NED pattern in HGNS responders and non-responders was determined. Other variables including demographics and oxygenation metrics were also assessed between responders and non-responders.

Results

Of 45 subjects, 4 were excluded due to technically inadequate polysomnograms. In the remaining 41 subjects, ML accurately distinguished three NED patterns (minimal, non-discontinuous, and discontinuous). The percentage of NED minimal breaths was significantly greater in responders compared with non-responders (p = 0.01) when the response was defined based on STAR trial criteria, change in AHI, and oxygenation metrics.

Conclusion

ML can accurately identify NED patterns in pre-treatment sleep studies. There was a statistically significant difference in the predominant NED pattern between HGNS responders and non-responders with a greater NED minimal pattern in responders. Prospective studies incorporating NED patterns into predictive modeling of factors determining HGNS outcomes are needed.

Supplementary Information

The online version contains supplementary material available at 10.1007/s11325-022-02641-y.

Patient Related Outcome and Therapy Effects in Stimulation Treatment of Sleep-Related Breathing Disorders

Several neurostimulation devices exist for the treatment of various sleep-related breathing diseases. The most data for hypoglossal nerve stimulation (HNS) in the therapy of obstructive sleep apnea (OSA) derive the HNS with respiratory sensing. Herewith, daytime sleepiness measured with the Epworth Sleepiness Scale (ESS) was improved in several publications by 5 points with a stability shown for up to several years. Sleep related quality of life, documented with the Functional Outcomes of Sleep Questionnaire, increased by 2 points. In many cohorts showed a mean usage of 5 to 6 hours per night. Under the consideration of shorter follow-ups and smaller group sizes, the ESS improved by 4 under unilateral continuous HNS and by 3 under bilateral HNS. Transvenous stimulation of the phrenic nerve is approved for the treatment in central sleep apnea. In a pivotal trial with 5 year follow-up data, an ESS reduction is documented by 3 points. There is one publication describing a usage of more than 5 hours. The daytime enoral neuromuscular electrical therapy improved ESS (2 points) and sleep-related quality of life of the snoring patients and the bed partner. The daytime training for the effects during the night adherence is given with 83%. For all described devices, there are running or announced studies and/or registry trials that consider patient related outcome.

Clinical Predictors of OSA Treatment Success Following Implantation of a Hypoglossal Nerve Stimulation Device

OBJECTIVE

To identify prognostic indicators associated with successful hypoglossal nerve stimulation (HGNS) therapy to treat obstructive sleep apnea (OSA), focusing on patients' physiologic response to awake tongue protrusion.

STUDY DESIGN

Retrospective chart review.

SETTING

Tertiary care center.

METHODS

We included consecutive patients with moderate-severe OSA who underwent HGNS implantation from December 2017 to December 2019. Data abstracted include standard demographics, body mass index (BMI), pre- and postoperative apnea-hypopnea index (AHI), and Friedman tongue position (FTP). Additionally, change in hypopharyngeal cross-sectional area on awake tongue protrusion was abstracted. Patients protruded their tongues, and the physician visualized change. Positive change in hypopharyngeal cross-sectional area was documented as +1 and a negative change as -1. Chi-square tests for independence and logistic regression analysis were performed to determine indicators of successful surgery.

RESULTS

Thirty-nine patients were included in this study. Mean ± SD AHI decreased significantly from 43.1 ± 17.36 to 9.18 ± 8.18. Surgical success was achieved in 79.5% of patients. Variables analyzed included BMI >32, preoperative AHI, FTP, and change in hypopharyngeal cross-sectional area on awake tongue protrusion (positive, 65.8%; negative, 34.2%). Positive predictors of success were positive change in hypopharyngeal cross-sectional area (P = .0133), severe OSA (P = .0290), and FTP IIb (P < .0001). Negative predictors were BMI >32 (P = .041) and negative change in hypopharyngeal cross-sectional area (P = .02).

CONCLUSION

Positive change in hypopharyngeal cross-sectional area on awake tongue protrusion and severe baseline AHI were positive predictors of successful HGNS therapy. Negative change in hypopharyngeal cross-sectional area on awake tongue protrusion and BMI >32 were negative predictors.

Representation of Race and Sex in Sleep Surgery Studies

OBJECTIVE

Obstructive sleep apnea (OSA) is a highly prevalent disorder with many treatment modalities, including surgical intervention. While OSA is known to be more prevalent in males and Black Americans, the representation of race and sex in sleep surgery studies is unknown. The aim of this systematic review is to assess the race and sex demographics represented in sleep surgery studies relative to known OSA demographics.

DATA SOURCES

PubMed, MEDLINE, and OVID databases.

REVIEW METHODS

A systematic review was conducted to identify studies published between 2016 and 2020 that investigated sleep outcomes following nonnasal surgical intervention for OSA in adults. Pooled racial, ethnic, and sex data of the enrolled subjects in selected studies were analyzed.

RESULTS

The 148 included studies comprised 13,078 patients. Of the 137 studies that reported sex, 84.0% of participants were male, exceeding the population prevalence of OSA in males, which is estimated at 66%. Only 13 studies reported racial/ethnic demographic data. Of these, 87.8% of patients were White. Out of 30 studies of primarily American patients, only 4 reported race demographic data, with an average of 82.8% White participants.

CONCLUSION

There is a racial/ethnic and sex inclusion bias among sleep surgery studies. Future studies should better document the demographics of enrolled participants as well as recruit participants who better represent the demographics of adults with OSA in the general population.

Early objective adherence to hypoglossal nerve stimulation therapy

STUDY OBJECTIVES

To assess early adherence to therapy with hypoglossal nerve stimulation therapy.

METHODS

This is a prospective study of consecutive patients with moderate to severe obstructive sleep apnea who underwent implantation of hypoglossal nerve stimulation therapy within a single academic practice and attended a follow-up appointment after greater than 30 days of therapy use. Objective adherence data were extracted from an objective monitoring database and compared to patient characteristics.

RESULTS

The study population was 79 participants who were 29.1% female with a mean age of 58.7 ± 12.8 years old, body mass index of 28.9 ± 3.4 kg/m², and baseline apnea-hypopnea index of 33.8 ± 17.6 events/h. In the first 7 days after device activation, average use was 7.8 h/night, with 91.9% of nights with greater than 4 hours of therapy use and an average of 0.2 pauses in therapy per night. These figures remained stable after 30 days of use: 7.7 h/night, 91.0% of nights longer than 4 hours, and 0.3 pauses per night. Objective evidence of difficulty with acclimatization was associated with age less than 60 years (odds ratio 2.8, 95% confidence interval 1.1-7.1, P = .03) and a history of prior upper airway surgery (3.9, 1.2-11.9, P = .015). Insomnia was present in 31 patients and was not associated with objective evidence of difficulty tolerating therapy.

CONCLUSIONS

Early adherence to hypoglossal nerve stimulation is excellent (92.4% >4 hours on >70% of nights), suggesting that the acclimatization period is straightforward in most. Younger age and a history of prior upper airway surgery appear to be associated with an increased risk of difficulty with acclimatization.

CITATION

Huyett P. Early objective adherence to hypoglossal nerve stimulation therapy. J Clin Sleep Med. 2022;18(2):631-636.

Hypoglossal Nerve Stimulation Therapy

Hypoglossal nerve stimulation (HNS) has been shown to be a safe alternative in the treatment of moderate-to-severe obstructive sleep apnea (OSA). A recent meta-analysis of 12 studies by Costantino et al. indicated the surgical success rates at 55-75%, a reduction of the apnea hypopnea index (AHI) of 18 events/h, and a reduction of the Epworth Sleepiness Scale (ESS) of 2.9-5.3. After animal studies in the 1970s, the first trial on humans to decrease upper airway resistance by transcutaneous electrical stimulation of the genioglossus was reported in 1989. A separate stimulation of protruding and retracting muscles was realized in 1995 by fine-wire electrodes that were placed into the tongue transoral. Over the next years, several companies developed implantable devices for hypoglossal stimulation in OSA. Initially, devices were developed that used unilateral stimulation of the hypoglossal nerve. In 2014, a device for unilateral respiratory frequency-controlled hypoglossal stimulation finally received FDA approval after a successful phase III trial. In recent years, a device for bilateral breath rate-independent stimulation of the hypoglossal nerve has been added to these approaches as a new development. Accordingly, hypoglossal nerve stimulation, on the one hand, is now an established tool for patients with OSA when standard treatments are not satisfactory. Beyond that, hypoglossal stimulation is undergoing a continuous and impressive development like hardly any other field of surgical therapy for OSA.

Referral of adults with obstructive sleep apnea for surgical consultation: an American Academy of Sleep Medicine systematic review, meta-analysis, and GRADE assessment

INTRODUCTION

This systematic review provides supporting evidence for the accompanying clinical practice guideline on the referral of adults with obstructive sleep apnea (OSA) for surgical consultation.

METHODS

The American Academy of Sleep Medicine commissioned a task force of experts in sleep medicine. A systematic review was conducted to identify studies that compared the use of upper airway sleep apnea surgery or bariatric surgery to no treatment as well as studies that reported on patient-important and physiologic outcomes pre- and postoperatively. Statistical analyses were performed to determine the clinical significance of using surgery to treat obstructive sleep apnea in adults. Finally, the Grading of Recommendations Assessment, Development and Evaluation (GRADE) process was used to assess the evidence for making recommendations.

RESULTS

The literature search resulted in 274 studies that provided data suitable for statistical analyses. The analyses demonstrated that surgery as a rescue therapy results in a clinically significant reduction in excessive sleepiness, snoring, blood pressure (BP), apnea-hypopnea index (AHI), respiratory disturbance index (RDI), and oxygen desaturation index (ODI); an increase in lowest oxygen saturation (LSAT) and sleep quality; and an improvement in quality of life in adults with OSA who are intolerant or unaccepting of positive airway pressure (PAP) therapy. The analyses demonstrated that surgery as an adjunctive therapy results in a clinically significant reduction in optimal PAP pressure and improvement in PAP adherence in adults with OSA who are intolerant or unaccepting of PAP due to side effects associated with high pressure requirements. The analyses also demonstrated that surgery as an initial treatment results in a clinically significant reduction in AHI/RDI, sleepiness, snoring, BP, and ODI and an increase in LSAT in adults with OSA and major anatomical obstruction. Analysis of bariatric surgery data showed a clinically significant reduction in BP, AHI/RDI, sleepiness, snoring, optimal PAP level, BMI, and ODI and an increase in LSAT in adults with OSA and obesity. Analyses of very limited evidence suggested that upper airway surgery does not result in a clinically significant increase in risk of serious persistent adverse events and suggested that bariatric surgery may result in a clinically significant risk of iron malabsorption that may be managed with iron supplements. The task force provided a detailed summary of the evidence along with the quality of evidence, the balance of benefits and harms, patient values and preferences, and resource use considerations.

CITATION

Kent D, Stanley J, Aurora RN, et al. Referral of adults with obstructive sleep apnea for surgical consultation: an American Academy of Sleep Medicine systematic review, meta-analysis, and GRADE assessment. J Clin Sleep Med. 2021;17(12):2507-2531.

A Noninferiority Analysis of 3- vs 2-Incision Techniques for Hypoglossal Nerve Stimulator Implantation

OBJECTIVE

The only hypoglossal nerve stimulation (HNS) device available for US clinical use is implanted through 3 incisions. A recently proposed 2-incision modification moved the respiratory sensing lead from the fifth to the second intercostal space to eliminate the third lower chest incision. This study compared perioperative data and therapeutic outcomes between the techniques.

STUDY DESIGN

Noninferiority cohort analysis of a retrospective and prospective registry study.

SETTING

Tertiary care and community surgical centers.

METHODS

Patients with obstructive sleep apnea underwent HNS implantation via a modified 2-incision technique (I₂). A cohort previously implanted via the standard 3-incision technique (I₃) were 1:1 propensity score matched for a noninferiority analysis of postoperative outcomes.

RESULTS

There were 404 I₃ patients and 223 I₂ patients across 6 participating centers. Operative time decreased from 128.7 minutes (95% CI, 124.5-132.9) in I₃ patients to 86.6 minutes (95% CI, 83.7-97.6) in I₂ patients (P < .001). Postoperative sleep study data were available for 76 I₂ patients who were matched to I₃ patients. The change in apnea-hypopnea index between the cohorts was statistically noninferior (a priori noninferiority margin: 7.5 events/h; mean difference, 1.51 [97.5% CI upper bound, 5.86]). There were no significant differences between the cohorts for baseline characteristics, perioperative adverse event rates, or change in Epworth Sleepiness Score (P > .05).

CONCLUSION

In a multicenter registry, a 2-incision implant technique for a commercially available HNS device had a statistically noninferior therapeutic efficacy profile when compared with the standard 3-incision approach. The 2-incision technique is safe and effective for HNS implantation.

Novel avenues to approach non-CPAP therapy and implement comprehensive OSA care

Recent advances in obstructive sleep apnoea (OSA) pathophysiology and translational research have opened new lines of investigation for OSA treatment and management. Key goals of such investigations are to provide efficacious, alternative treatment and management pathways that are better tailored to individual risk profiles to move beyond the traditional, continuous positive airway pressure (CPAP)-focused, "one size fits all", trial and error approach which is too frequently inadequate for many patients. Identification of different clinical manifestations of OSA (clinical phenotypes) and underlying pathophysiological phenotypes (endotypes), that contribute to OSA have provided novel insights into underlying mechanisms and have underpinned these efforts. Indeed, this new knowledge has provided the framework for precision medicine for OSA to improve treatment success rates with existing non-CPAP therapies such as mandibular advancement devices and upper airway surgery, and newly developed therapies such as hypoglossal nerve stimulation and emerging therapies such as pharmacotherapies and combination therapy. These concepts have also provided insight into potential physiological barriers to CPAP adherence for certain patients. This review summarises the recent advances in OSA pathogenesis, non-CPAP treatment, clinical management approaches and highlights knowledge gaps for future research. OSA endotyping and clinical phenotyping, risk stratification and personalised treatment allocation approaches are rapidly evolving and will further benefit from the support of recent advances in e-health and artificial intelligence.

Association of Hypoglossal Nerve Stimulation With Improvements in Long-term, Patient-Reported Outcomes and Comparison With Positive Airway Pressure for Patients With Obstructive Sleep Apnea

Importance

Hypoglossal nerve stimulation (HNS) and positive airway pressure (PAP) have been shown to improve patient-reported outcomes (PROs) in obstructive sleep apnea (OSA). However, to our knowledge, there are no data that compare change in PROs between HNS and PAP or that indicate whether HNS improves comorbid insomnia or depression in the long term.

Objectives

To determine whether HNS is associated with improvements in patient-reported sleepiness, insomnia, and depression in the long term and to compare the respective associations of HNS and PAP with improved PROs.

Design, Setting, and Participants

This retrospective cohort study used data from patients treated at the Cleveland Clinic for OSA. Participants received either HNS (referred sample) from November 1, 2015, to September 31, 2018, or PAP (previous cohort) from January 1, 2010, to December 31, 2014, for OSA. Patients were matched 3:1 for PAP:HNS based on age, body mass index (BMI; calculated as weight in kilograms divided by height in meters squared), sex, and apnea hypopnea index (AHI). Data were collected at baseline and at prespecified follow-up points. Data were analyzed from March 26, 2020, to September 9, 2021.

Exposures

Treatment with HNS vs PAP.

Main Outcomes and Measures

Data collected included AHI and Epworth Sleepiness Scale (ESS), Functional Outcomes of Sleep Questionnaire (FOSQ), Insomnia Severity Index (ISI), and Patient Health Questionnaire-9 (PHQ-9; depression) scores.

Results

Among 85 patients receiving HNS (mean [SD] age, 62.8 [9.5] years; 59 men [69.4%]; 77 White patients [90.6%]; mean [SD] BMI, 28.8 [3.1]), compared with 217 matched patients receiving PAP (mean [SD] age, 62.1 [9.9] years; 157 men [72.4%]; 173 White patients [81.2%]; mean [SD] BMI, 29.5 [3.1]) included in the analysis, significant improvements were seen in PHQ-9 scores for HNS vs PAP (least square means, -4.06 [95% CI, -5.34 to -2.79] vs -2.58 [95% CI, -3.35 to -1.82]; mean difference, -1.48 [95% CI, -2.78 to -0.19]) with comparable improvements in ESS, FOSQ, and ISI scores. Clinically meaningful differences were observed in 42 of 65 HNS group patients (64.6%) vs 118 PAP group patients (54.5%) for ESS scores, 29 of 49 HNS group patients (59.2%) vs 67 of 217 PAP group patients (30.9%) for FOSQ scores, 14 of 48 HNS group patients (29.2%) vs 53 of 217 PAP group patients (24.4%) for PHQ-9 scores, and 23 of 49 HNS group patients (46.9%) vs 79 of 217 PAP group patients (36.4%) for ISI scores. At the 1-year post-HNS assessment, meaningful improvements were seen in 17 of 28 patients (60.7%) for ESS scores, 11 of 20 patients (55.0%) for FOSQ scores, 7 of 23 patients (30.4%) for PHQ-9 scores, and 11 of 25 patients (44.0%) for ISI scores.

Conclusions and Relevance

In this cohort study of patients with OSA, sustained improvements in PROs were observed 1 year after HNS and were comparable to those for PAP at 3 months. These findings suggest that HNS is a viable treatment for improving insomnia and depression in patients with OSA.

Influence of apnea vs hypopnea predominance in predicting mean therapeutic positive airway pressures among patients with obstructive sleep apnea

STUDY OBJECTIVES

Lower therapeutic positive airway pressure (PAP) levels are associated with improved response to non-PAP therapies in the treatment of obstructive sleep apnea. The aim of this study was to evaluate the prevailing notion that patients with apnea-predominant obstructive sleep apnea require higher therapeutic PAP levels compared to patients with hypopnea-predominant obstructive sleep apnea.

METHODS

An institutional review board-approved retrospective review was performed using strict inclusion criteria: presence of type I or III sleep study, apnea-hypopnea index > 10 events/h, and adherence to auto-adjusting continuous positive airway pressure. Patients were stratified by apnea (> 50% apneas) or hypopnea (≤ 50% apneas) predominance, and PAP data were compared. Statistical analyses were performed using Student's t test and linear regression modeling.

RESULTS

Between January 1, 2018 and January 1, 2020, 500 patients met inclusion criteria. Two hundred twenty-one (44.1%) patients were apnea-predominant and 279 (55.8%) were hypopnea-predominant. Apnea-predominant patients had a slightly greater mean PAP (9.01 vs 8.36, P = .002) than hypopnea-predominant patients. Univariable and multivariable linear regression of 7 variables (obstructive apnea percentage, age, sex, body mass index, apnea-hypopnea index, O₂ nadir, mask type) showed obstructive apnea percentage was the weakest predictor of therapeutic PAP levels.

CONCLUSIONS

Apnea-predominant individuals demonstrated a clinically insignificant difference in PAP level compared to hypopnea-predominant individuals; moreover, obstructive apnea percentage was not a strong predictor of therapeutic PAP levels. Of the modeled variables, the strongest predictor of PAP level was apnea-hypopnea index. Further studies are needed to explore these relationships as well as additional variables that may contribute to predicting therapeutic PAP levels.

CITATION

Yu JL, Liu Y, Tangutur A, et al. Influence of apnea vs hypopnea predominance in predicting mean therapeutic positive airway pressures among patients with obstructive sleep apnea. J Clin Sleep Med. 2021;17(11):2171-2178.

Post-operative Complication Rate Comparison Between Airway Surgery and Upper Airway Stimulation Using NSQIP and ADHERE

Objective

Postoperative complication rates were compared between obstructive sleep apnea surgery (OSAS) and hypoglossal nerve upper airway stimulation (UAS).

Study Design

Cohort.

Setting

Multi-institutional international databases.

Methods

OSAS data were collected from the NSQIP database (2014; American College of Surgeons National Surgery Quality Improvement Program). UAS data were obtained from the ADHERE registry (Adherence and Outcome of Upper Airway Stimulation for OSA International Registry; 2016-December 2019). ADHERE comorbidities and complications were categorized to match NSQIP definitions. A chi-square test was used for proportion P values.

Results

There were 1623 UAS procedures in ADHERE and 310 in NSQIP. The UAS group was older than the OSAS group (mean ± SD, 60 ± 11 vs 42 ± 13 years) but similarly male (75% vs 77%) and overweight (body mass index, 29 ± 4 vs 29 ± 3 kg/m²). There was a higher proportion of hypertension, diabetes, and heart disease in the UAS cohort. Palatopharyngoplasty was the most common surgical procedure (71%), followed by tonsillectomy (25%). UAS operative time was longer (132 ± 47 vs 54 ± 33 minutes). Postoperative length of stay was not normally distributed, as 71% of UAS stays were <1 day as opposed to 40% of OSA stays (P < .0001). Thirty-day return to the operating room related to the procedure was 0.1% for UAS and 4.8% for OSAS (P < .0001). Surgical site infections were 0.13% for UAS and 0.9% for OSAS (P = .046).

Conclusion

The UAS cohort was older and more likely to have comorbid hypertension, diabetes, and heart disease. Despite baseline differences, the postoperative complication rate was lower with UAS than with OSAS.

Impact of Body Mass Index and Discomfort on Upper Airway Stimulation: ADHERE Registry 2020 Update

OBJECTIVES/HYPOTHESIS

To provide the ADHERE registry Upper Airway Stimulation (UAS) outcomes update, including analyses grouped by body mass index (BMI) and therapy discomfort.

STUDY DESIGN

Prospective observational study.

METHODS

ADHERE captures UAS outcomes including apnea-hypopnea index (AHI), Epworth sleepiness scale (ESS), therapy usage, patient satisfaction, clinician assessment, and safety over a 1-year period. BMI ≤32 kg/m² (BMI₃₂ ) and 32 < BMI ≤35 kg/m² (BMI₃₅ ) group outcomes were examined.

RESULTS

One thousand eight hundred forty-nine patients enrolled in ADHERE, 1,019 reached final visit, 843 completed the visit. Significant changes in AHI (-20.9, P < .0001) and ESS (- 4.4, P < .0001) were demonstrated. Mean therapy usage was 5.6 ± 2.2 hr/day. Significant therapy use difference was present in patients with reported discomfort versus no discomfort (4.9 ± 2.5 vs. 5.7 ± 2.1 hr/day, P = .01). Patients with discomfort had higher final visit mean AHI versus without discomfort (18.9 ± 18.5 vs. 13.5 ± 13.7 events/hr, P = .01). Changes in AHI and ESS were not significantly different. Serious adverse events reported in 2.3% of patients. Device revision rate was 1.9%. Surgical success was less likely in BMI₃₅ versus BMI₃₂ patients (59.8% vs. 72.2%, P = .02). There was a significant therapy use difference: 5.8 ± 2.0 hr/day in BMI₃₂ versus 5.2 ± 2.2 hr/day in BMI₃₅ (P = .028).

CONCLUSIONS

Data from ADHERE demonstrate high efficacy rates for UAS. Although surgical response rate differs between BMI₃₂ and BMI₃₅ patient groups, the AHI and ESS reduction is similar. Discomfort affects therapy adherence and efficacy. Thus, proper therapy settings adjustment to ensure comfort is imperative to improve outcomes.

LEVEL OF EVIDENCE

4 Laryngoscope, 131:2616-2624, 2021.

Upper airway stimulation: Fewer complications, ED presentations, readmissions, and increased surgical success

OBJECTIVES

Evaluate the rate of complications, readmissions, emergency department presentations, and surgical success rates amongst three standard surgical treatment options for obstructive sleep apnea: upper airway stimulation, transoral robotic surgery, and expansion sphincter pharyngoplasty.

STUDY DESIGN

Retrospective cohort.

SETTING

Tertiary care center.

METHODS

Patients were included who were aged ≥18 years old and underwent upper airway stimulation, transoral robotic surgery, or expansion sphincter pharyngoplasty between January 2011 and May 2020.

RESULTS

345 patients were identified: 58% (n = 201) underwent upper airway stimulation, 10% (n = 35) underwent transoral robotic surgery, and 32% (n = 109) patients underwent expansion sphincter pharyngoplasty. There were 22 emergency department presentations and 19 readmissions, most of which were experienced by patients receiving transoral robotic surgery (six emergencies, seven readmissions) and expansion sphincter pharyngoplasty (12 emergencies, 11 readmissions). Patients with upper airway stimulation had four emergencies and one readmission. Only 2% of the upper airway stimulation cohort had a complication, whereas this was 20% and 12% for the transoral robotic surgery and expansion sphincter pharyngoplasty cohorts, respectively. Patients experienced the highest surgical success rate with upper airway stimulation (69%), whereas patients who received transoral robotic surgery and expansion sphincter pharyngoplasty had success rates of 50% and 51%, respectively.

CONCLUSION

Treating obstructive sleep apnea with upper airway stimulation led to lower rates of complications, emergency department presentations, and readmissions in this series. In those for whom upper airway stimulation is appropriate, it may be more effective in successfully treating obstructive sleep apnea than transoral robotic surgery and expansion sphincter pharyngoplasty.

Upper Airway Stimulation versus Untreated Comparators in Positive Airway Pressure Treatment-Refractory Obstructive Sleep Apnea

Rationale: Understand the impact of insurance coverage on sleep apnea outcomes for patients awaiting upper airway stimulation.Objectives: Examine the natural history of impact of upper airway stimulation treatment versus insurance denial (comparators) on sleep apnea outcomes.Methods: A parallel-arm experimental study design was used to compare objective sleep apnea measures and patient-reported outcomes in those who received upper airway stimulation approval versus denial in a multinational prospective study (NCT02907398). Wilcoxon rank-sum test and logistic regression models were used to assess for differences of objective and subjective outcome changes in those who underwent upper airway stimulation versus no treatment comparators.Results: A greater reduction in apnea-hypopnea index was observed in those who underwent upper airway stimulation (n = 230, follow-up: 360 ± 171 d) versus no treatment (n = 100, follow-up: 272 ± 278 d), that is, -19.1 ± 15.8 versus -8.1 ± 20.9, respectively, P < 0.001, with consistent findings observed with nocturnal hypoxia measures. Concordantly, a greater improvement noted with subjective measures of dozing propensity was observed in patients undergoing upper airway stimulation versus comparators (Epworth Score, -5.1 ± 5.5 vs. 1.8 ± 3.7, respectively, P < 0.001) and overall sleep-related patient-reported outcomes. Women and those with previous oral appliance use had a lower odds of insurance approval (odds ratio [OR], 0.40; 95% confidence interval [95% CI], 0.22-0.71 and OR, 0.35; 95% CI, 0.18-0.69, respectively).Conclusions: Objective and subjective sleep apnea burden was more improved in those receiving upper airway stimulation versus not. Results underscore the need to optimize clinical care pathways focused on effective treatment of patients with obstructive sleep apnea who are not upper airway stimulation-insurance eligible and prioritize public health policy initiatives to address insurance-based sex-specific disparities.

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.

Impulse Configuration in Hypoglossal Nerve Stimulation in Obstructive Sleep Apnea: The Effect of Modifying Pulse Width and Frequency

OBJECTIVES

Hypoglossal nerve stimulation is an effective treatment option for obstructive sleep apnea (OSA) in positive airway pressure therapy failure. Nonetheless, data regarding the functional effect of modifying stimulation parameters within each electrode configuration are limited.

MATERIALS AND METHODS

In a retrospective study of 76 patients with 12 months or more follow-up, functional tongue protrusion thresholds were compared for pulse width and frequency configurations of 90 μsec 33 Hz vs 120 μsec 40 Hz. The number of tolerated voltage amplitude steps between sensation, functional, and subdiscomfort thresholds were assessed for both settings as well as impedances.

RESULTS

The overall cohort showed improvement in OSA metrics: median apnea-hypopnea index from 30.0/hour to 18.6/hour and Epworth Sleepiness Scale from 13.5 to 7.6. For both bipolar and unipolar electrode configurations, the stimulation amplitude required for functional tongue protrusion was significantly reduced when the pulse width and frequency were converted from 90 μsec 33 Hz to 120 μsec 40 Hz (p < 0.001). Nevertheless, the number of voltage amplitude steps from sensation, functional, to subdiscomfort thresholds did not differ between the two settings. The ratio of automatically derived impedances between bipolar and unipolar electrode configurations was relevantly correlated with the ratio of functional thresholds at these parameters.

CONCLUSION

Changing the stimulation parameters may lower the voltage requirements while maintaining the same effect on tongue protrusion. Changing these stimulation parameters does not affect the range of tolerated impulse steps between functional and subdiscomfort thresholds. Future technical appliances could help estimate functional thresholds at different electrode configurations for each patient by automatically measuring impedances.

Effect of Upper Airway Stimulation in Patients with Obstructive Sleep Apnea (EFFECT): A Randomized Controlled Crossover Trial

Background: Several single-arm prospective studies have demonstrated the safety and effectiveness of upper airway stimulation (UAS) for obstructive sleep apnea. There is limited evidence from randomized, controlled trials of the therapy benefit in terms of OSA burden and its symptoms. Methods: We conducted a multicenter, double-blinded, randomized, sham-controlled, crossover trial to examine the effect of therapeutic stimulation (Stim) versus sham stimulation (Sham) on the apnea-hypopnea index (AHI) and the Epworth Sleepiness Scale (ESS). We also examined the Functional Outcomes of Sleep Questionnaire (FOSQ) on sleep architecture. We analyzed crossover outcome measures after two weeks using repeated measures models controlling for treatment order. Results: The study randomized 89 participants 1:1 to Stim (45) versus Sham (44). After one week, the AHI response rate was 76.7% with Stim and 29.5% with Sham, a difference of 47.2% (95% CI: 24.4 to 64.9, p < 0.001) between the two groups. Similarly, ESS was 7.5 ± 4.9 with Stim and 12.0 ± 4.3 with Sham, with a significant difference of 4.6 (95% CI: 3.1 to 6.1) between the two groups. The crossover phase showed no carryover effect. Among 86 participants who completed both phases, the treatment difference between Stim vs. Sham for AHI was −15.5 (95% CI −18.3 to −12.8), for ESS it was −3.3 (95% CI −4.4 to −2.2), and for FOSQ it was 2.1 (95% CI 1.4 to 2.8). UAS effectively treated both REM and NREM sleep disordered breathing. Conclusions: In comparison with sham stimulation, therapeutic UAS reduced OSA severity, sleepiness symptoms, and improved quality of life among participants with moderate-to-severe OSA.

Relation between arousability and outcome of upper airway stimulation in the Stimulation for Apnea Reduction (STAR) Trial

STUDY OBJECTIVES

Upper airway stimulation (UAS) is an innovative surgical treatment for obstructive sleep apnea; however, the treatment failure rate is approximately 22%. Easy arousability may limit the tolerability of stimulation and, by extension, its effectiveness. The odds ratio product (ORP) is a continuous electroencephalographic metric of arousal propensity (range: 0 [deep sleep] to 2.5 [full wakefulness]), and its rate of decline after arousal (ORP-9) is a risk factor for susceptibility to arousal in the presence of frequent arousal stimuli. We hypothesized that individuals with deeper sleep (low average ORP and low ORP-9) are more likely to respond to UAS.

METHODS

ORP and ORP-9 were calculated from 126 baseline polysomnograms of participants in the STAR Trial. These values were compared between responders and nonresponders. Adjusted linear modeling was performed to determine the association between ORP-derived variables and treatment response.

RESULTS

No differences were found between responders and nonresponders in unadjusted comparisons of ORP-derived variables. On linear regression modeling, significant correlation was found between non-rapid eye movement ORP and reduction in apnea-hypopnea index (P = .004).

CONCLUSIONS

No significant difference in ORP was noted between responders and nonresponders to UAS therapy; however, contrary to our initial hypothesis, linear regression modeling trended toward a positive relationship between ORP and UAS response, suggesting that those who have lighter sleep are more likely to respond to therapy; however, these results are only exploratory, and future larger prospective studies are needed to confirm this relationship.

CLINICAL TRIAL REGISTRATION

Registry: ClinicalTrials.gov; Name: STAR Trial; Identifier: NCT01161420.

Obstruction level associated with outcome in hypoglossal nerve stimulation

Purpose

Selective hypoglossal nerve stimulation (sHNS) constitutes an effective surgical alternative for patients with obstructive sleep apnea (OSA). sHNS results in tongue protrusion and consecutive alleviation of obstructions at the tongue base level (lower obstructions). Furthermore, obstructions at the soft palate level (upper obstructions) may be prevented through palatoglossal coupling as seen on sleep endoscopy. However, it has not been studied if the distribution of obstruction level during a whole night measurement is a relevant factor for the treatment outcome.

Methods

Obstruction levels were measured with a manometry system during a whole night of sleep in 26 patients with OSA (f = 1, m = 25; age 59.4 ± 11.3; BMI = 29.6 ± 3.6) either before (n = 9) or after sHNS implantation (n = 12). Five patients received a measurement before and after implantation. Obstructions were categorized into velar (soft palate and above), infravelar (below soft palate), and multilevel obstructions. An association between obstruction level and treatment outcome was calculated.

Results

The mean distribution of preoperative obstruction level could be divided into the following: 38% velar, 46% multilevel, and 16% infravelar obstructions. Patients with a good treatment response (defined as AHI < 15/h and AHI reduction of 50%) had fewer preoperative velar obstructions compared to non-responder (17% vs. 54%, p-value = 0.006). In patients measured after sHNS implantation, a significantly higher rate of multilevel obstructions per hour was measured in non-responders (p-value = 0.012).

Conclusions

Selective hypoglossal nerve stimulation was more effective in patients with fewer obstructions at the soft palate level. Manometry may be a complementary diagnostic procedure for the selection of patients for HNS.

Obstructive Sleep Apnea: Non-positive Airway Pressure Treatments

Undiagnosed and untreated obstructive sleep apnea (OSA) is associated with health comorbidities and negatively affects quality of life. Alternative treatments should be considered in patients who are unable to tolerate or benefit from positive airway pressure treatment. When properly indicated, positional devices, oral appliances, airway surgery, and hypoglossal nerve stimulation have been shown to be effective in treating OSA. Hypoglossal nerve stimulation is a successful second-line treatment with low associated morbidity and complication rate.

Evaluation of Therapeutic Positive Airway Pressure as a Hypoglossal Nerve Stimulation Predictor in Patients With Obstructive Sleep Apnea

Importance

Recent retrospective hypoglossal nerve stimulation (HGNS) outcomes data suggest that patients with low therapeutic positive airway pressure (PAP) levels achieve greater success than patients with high therapeutic PAP levels.

Objective

To examine the use of therapeutic nasal PAP levels at the soft palate in predicting the outcomes of HGNS for patients with obstructive sleep apnea.

Design, Setting, and Participants

This prospective cohort study used drug-induced sleep endoscopy (DISE) to evaluate the predictive capacity of therapeutic PAP levels in HGNS outcomes. In an academic sleep surgery center, 27 consecutive patients with obstructive sleep apnea who underwent DISE before implantation of an HGNS device were evaluated. The study was conducted from May 1, 2018, to June 26, 2019.

Exposures

Positive airway pressure delivered through a nasal mask during DISE.

Main Outcomes and Measures

Improvement in apnea-hypopnea index as measured from full-night preoperative and postoperative efficacy studies.

Results

Twenty-seven patients met all inclusion criteria. The mean (SD) age was 62.0 (14.4) years, 14 participants were men (51.9%), and mean body mass index was 28.1 (4.0). Responders to HGNS therapy (n = 18) had significantly lower mean (SD) palatal opening pressure compared with nonresponders (n = 9) (5.0 [2.8] vs 9.2 [3.7] cm H2O, respectively; mean difference, -4.2; 95% CI, -6.8 to -1.6 cm H2O). After adjusting for age, sex, and body mass index, the mean palatal opening pressure value for the responders remained 3.5 cm H2O lower (95% CI, -6.7 to -0.4 cm H2O) than that of nonresponders. A palatal opening pressure cutoff level less than 8 cm H2O demonstrated a positive predictive value of 82.4%; sensitivity, 77.8%; and specificity, 66.7%.

Conclusions and Relevance

In this small prospective cohort study, therapeutic nasal PAP levels during DISE differed significantly between responder and nonresponders to HGNS. Because DISE represents a mandatory, relatively standardized diagnostic tool for HGNS candidacy, the use of therapeutic nasal PAP through DISE can be broadly implemented and studied across multiple centers to possibly improve patient selection for HGNS.

Post-implant care pathway: lessons learned and recommendations after 5 years of clinical implementation of hypoglossal nerve stimulation therapy

Hypoglossal nerve stimulation (HNS) therapy is now an established and widely-available obstructive sleep apnea (OSA) treatment alternative for continuous positive airway pressure (CPAP)-intolerant patients. Additionally, the HNS body of literature is robust with strong data on safety, efficacy, and durability-from the 5-year STAR Trial outcomes, to post-approval studies of independent institutions, to the multicenter ADHERE registry which recently reported outcomes on over 1,000 patients and is poised to enroll 5,000 HNS patients total. Nevertheless, now with thousands of implanted patients across hundreds of certified centers, and that number growing rapidly, the post-implant management of the HNS patient represents the next critical frontier. Post-implant patient management (therapy titration, troubleshooting, adjustments, and adherence monitoring) across a longitudinal care model is key to ensuring long-term therapy success and optimizing patient outcomes and health benefits. As with CPAP, patient education and close clinical monitoring are often essential to successful long-term management. Although many HNS patients are clear responders with excellent comfort and adherence as well as effective improvement in symptomatic and objective outcome measures, and even a smaller subset is clear non-responders, there is a growing body of patients somewhere in the middle: good outcomes but not great; partial but incomplete response. These are the patients in whom a standardized best-practice approach to treatment monitoring and targeted therapy modifications is likely critical to optimizing long-term outcomes.

Hypoglossal nerve stimulation impact on a patient with obstructive sleep apnea and heart failure

A 75-year-old man with body mass index of 30.5 kg/m² and severe obstructive sleep apnea (OSA) with an apnea-hypopnea index (AHI) of 72 events/h was referred for upper airway stimulation (UAS) therapy. Past medical history was significant for cardiovascular disease including congestive heart failure due to ischemic cardiomyopathy with impaired left ventricular function and ejection fraction of 35%. Following evaluation of clinical and polysomnographic data, he was an appropriate candidate for UAS and underwent uncomplicated implantation. Three months postoperatively, polysomnography showed a titrated AHI of 0 events/h. Follow-up cardiac evaluation revealed ejection fraction increase to 47% since implantation. No interval change in medical management or body mass index had occurred. Given the high prevalence of OSA in patients with cardiovascular disease, UAS may become an important adjunct in the comprehensive multidisciplinary treatment of heart failure in patients with OSA. Further clinical studies are required to investigate the impact of UAS on treatment and prognosis of heart disease.

Effect of Electrode Configuration and Impulse Strength on Airway Patency in Neurostimulation for Obstructive Sleep Apnea

OBJECTIVES/HYPOTHESIS

Hypoglossal nerve stimulation (HNS) has gained increasing interest for the treatment of patients with obstructive sleep apnea (OSA). Drug-induced sleep endoscopy (DISE) can both exclude improper airway collapse patterns and visualize airway changes under stimulation. Stimulation outcome effects depend on the impulse voltage and electric field resulting from the electrode configuration of the implanted device. The effects of various combinations of voltage and electric field on DISE airway patterns in contrast to awake endoscopy are unknown.

STUDY DESIGN

Cohort study.

METHODS

During therapy adjustment about 6 months after implantation, patients underwent a DISE and awake endoscopy with 100% and 125% of functional voltage in three typical electrode configurations (+ - +, o - o, - - -). All videos were analyzed by two separate persons for the opening of the airway at velum, tongue base, and epiglottis level.

RESULTS

Thirty patients showed typical demographic data. The opening effects were visible in all patients, but there were changes between different electrode configurations. Several demographic or therapeutic aspects such as obesity, OSA severity, or prior soft palate surgery were associated with changes arising from different electrode configurations, but none resulted in a consistently better airway opening.

CONCLUSIONS

In patients with poor results during the therapy adjustment, electric configuration changes can improve airway patency-an independent variable from increasing voltage. As these effects can only be seen in awake endoscopy or DISE, both endoscopies with live stimulation may be considered in cases with insufficient improvement in apnea-hypopnea index after initiation of HNS therapy.

LEVEL OF EVIDENCE

Prospective case series; level 4. Laryngoscope, 131:2148-2153, 2021.

Advances in Treatment of Sleep-Disordered Breathing

BACKGROUND

Sleep-disordered breathing, composed of obstructive sleep apnea (OSA) and central sleep apnea (CSA), affects millions of people worldwide carrying with it significant morbidity and mortality. Diagnosis is made by polysomnography, and severity of sleep apnea is determined by the apnea-hypopnea index (AHI). Positive airway pressure (PAP) therapy has been the gold standard in treating both OSA and CSA. PAP therapy can greatly reduce AHI burden as well as morbidity and mortality and improve quality of life.

AREAS OF UNCERTAINTY

However, patients report difficulties adhering to PAP therapy because of discomfort with mask interface, sensation of excessive pressure, and claustrophobia. Although other options exist to treat sleep apnea, such as mandibular advancement oral appliance devices, positional therapy, and surgery, these additional therapeutic modalities as current options have limitations. Emerging technology is now available to overcome hindrances to standard therapy.

DATA SOURCES

A literature search was performed from the following databases: PubMed, Cochrane Library (Cochrane Database of Systematic Reviews), and Cochrane Central Register of Controlled Trials, and FDA device database (clinicaltrial.gov).

THERAPEUTIC ADVANCES

Other modalities of treating sleep-disordered breathing now include the hypoglossal nerve stimulator, which stimulates the hypoglossal nerve during sleep to alleviate airflow obstruction by contracting the genioglossus muscle thus treating OSA. Similarly, the phrenic nerve stimulator restores a more stable breathing pattern during sleep by stimulating the phrenic nerve to activate the diaphragm during CSA. Both nerve stimulators have been shown to reduce AHI severity and improve quality of life for patients suffering from sleep-disordered breathing.

CONCLUSIONS

PAP therapy, although the gold standard, has limitations in the treatment of sleep apnea. New modalities such as hypoglossal nerve stimulator and phrenic nerve stimulator may help to overcome difficulties with adherence and offer new options for treatment of both obstructive and central sleep apnea.

Drug-Induced Sleep Endoscopy and Hypoglossal Nerve Stimulation Outcomes: A Multicenter Cohort Study

OBJECTIVES/HYPOTHESIS

To determine the association between findings of blinded reviews of preoperative drug-induced sleep endoscopy (DISE) and outcomes of hypoglossal nerve stimulation (HNS) for obstructive sleep apnea (OSA).

STUDY DESIGN

Cohort study.

METHODS

A retrospective, multicenter cohort study of 343 adults who underwent treatment of OSA with HNS from 10 academic medical centers was performed. Preoperative DISE videos were scored by four blinded reviewers using the VOTE Classification and evaluation of a possible primary structure contributing to airway obstruction. Consensus DISE findings were examined for an association with surgical outcomes based on therapy titration polysomnogram (tPSG). Treatment response was defined by a decrease of ≥50% in the apnea-hypopnea index (AHI) to <15 events/hour.

RESULTS

Study participants (76% male, 60.4 ± 11.0 years old) had a body mass index of 29.2 ± 3.6 kg/m² . AHI decreased (35.6 ± 15.2 to 11.0 ± 14.1 events/hour; P < .001) on the tPSG, with a 72.6% response rate. Complete palate obstruction (vs. none) was associated with the greatest difference in AHI improvement (-26.8 ± 14.9 vs. -19.2 ± 12.8, P = .02). Complete (vs. partial/none) tongue-related obstruction was associated with increased odds of treatment response (78% vs. 68%, P = .043). Complete (vs. partial/none) oropharyngeal lateral wall-related obstruction was associated with lower odds of surgical response (58% vs. 74%, P = .042).

CONCLUSIONS

The DISE finding of primary tongue contribution to airway obstruction was associated with better outcomes, whereas the opposite was true for the oropharyngeal lateral walls. This study suggests that the role for DISE in counseling candidates for HNS extends beyond solely for excluding complete concentric collapse related to the velum.

LEVEL OF EVIDENCE

3 Laryngoscope, 131:1676-1682, 2021.

Hypoglossal Nerve Stimulation Therapy for the Treatment of Obstructive Sleep Apnea

Hypoglossal nerve stimulation (HGNS) therapy was approved in 2014 for the treatment of obstructive sleep apnea in patients who are intolerant to continuous positive airway pressure (CPAP) therapy, which is reported in up to 40-60% of patients. This therapy works via direct neurostimulation of the hypoglossal nerve in synchrony with respiration, to open the airway via tongue stiffening and protrusion. Studies have demonstrated significant reductions in both respiratory parameters such as disordered breathing indices, as well as subjective sleep complaints, such as daytime sleepiness, with the use of this therapy. This has increased the repertoire of treatment options for sleep providers to recommend to those patients that are intolerant to CPAP therapy.

Ultrasound Localization and Percutaneous Electrical Stimulation of the Hypoglossal Nerve and Ansa Cervicalis

OBJECTIVE

Hypoglossal nerve stimulation for obstructive sleep apnea (OSA) can be effective for appropriately selected patients, but current patient selection criteria are complex and still result in a proportion of nonresponders. Ansa cervicalis stimulation of the infrahyoid cervical strap muscles has recently been proposed as a new form of respiratory neurostimulation (RNS) therapy for OSA treatment. We hypothesized that percutaneous stimulation of both nerves in humans with temporary electrodes would make testing of the physiologic response to different RNS strategies possible.

STUDY DESIGN

Nonrandomized acute physiology study.

SETTING

Tertiary care hospital.

METHODS

Fifteen participants with OSA underwent ultrasonography and placement of percutaneous electrodes proximal to the medial division of the hypoglossal nerve and the branch of the ansa cervicalis innervating the sternothyroid muscle (ACST). Procedural success was documented in each participant, as were any failures or procedural complication.

RESULTS

The hypoglossal nerve was successfully localized in 15 of 15 (100%) participants and successfully stimulated in 13 of 15 (86.7%). The ACST was successfully localized in 15 of 15 (100%) participants and successfully stimulated in 14 of 15 (93.3%). Stimulation failure of the hypoglossal nerve was due to suboptimal electrode placement in 1 participant and electrode displacement in the other 2 cases. No complications occurred.

CONCLUSIONS

The hypoglossal nerve and ACST can be safely stimulated via percutaneous electrode placement. Larger trials of percutaneous stimulation may help to identify responders to different RNS therapies for OSA with temporary or permanent percutaneous electrodes. Techniques for electrode design, nerve localization, and electrode placement are described.

Redefining Success by Focusing on Failures After Pediatric Hypoglossal Stimulation in Down Syndrome

OBJECTIVES/HYPOTHESIS

Patients with Down syndrome have a high incidence of obstructive sleep apnea (OSA) and limited treatment options. Hypoglossal stimulation has shown efficacy but has not yet been approved for pediatric populations. Our objective is to characterize the therapy response of adolescent patients with down syndrome and severe OSA who underwent hypoglossal stimulation.

STUDY DESIGN

Prospective longitudinal trial.

METHODS

We are conducting a multicenter single-arm trial of hypoglossal stimulation for adolescent patients with Down syndrome and severe OSA. Interim analysis was performed to compare objective sleep and quality of life outcomes at 12 months postoperatively for the first 20 patients.

RESULTS

The mean age was 15.5 and baseline AHI 24.2. Of the 20 patients, two patients (10.0%) had an AHI under 1.5 at 12 months; nine patients of 20 (45.0%) under five; and 15 patients of 20 (75.0%) under 10. The mean decrease in AHI was 15.1 (P < .001). Patients with postoperative AHI over five had an average baseline OSA-18 survey score of 3.5 with an average improvement of 1.7 (P = .002); in addition, six of these patients had a relative decrease of apneas compared to hypopneas and seven had an improvement in percentage of time with oxygen saturation below 90%.

CONCLUSIONS

Patients with persistently elevated AHI 12 months after hypoglossal implantation experienced improvement in polysomnographic and quality of life outcomes. These results suggest the need for a closer look at physiologic markers for success beyond reporting AHI as the gold standard.

LEVEL OF EVIDENCE

4 Laryngoscope, 131:1663-1669, 2021.

Electrical stimulation of the whole hypoglossal nerve in patients with obstructive sleep apnea

PURPOSE

Electrical stimulation of the whole hypoglossal nerve (HGp-ES) has been demonstrated to enlarge the pharynx and improve pharyngeal stability and patency to airflow in all animals studied, but not in humans. The present study was undertaken to better understand the effect of HGp-ES on the human pharynx.

METHODS

Eight patients with obstructive sleep apnea who had implanted stimulators with electrodes positioned proximally on the main truck of the hypoglossus were studied under propofol sedation. Pharyngoscopy and air flow measurements at multiple levels of continuous positive airway pressure (CPAP) were performed before and during Hgp-ES.

RESULTS

HGp-ES that activates both tongue protrusors and retractors narrowed the pharyngeal lumen at the site of collapse (velopharynx in all subjects) from 1.38 ± 0.79 to 0.75 ± 0.44 cm2, p < 0.05 (measured at mid-range of CPAP levels) and lowered airflow (from 8.88 ± 2.08 to 6.69 ± 3.51 l/min, p < 0.05). Changes in critical pressure (Pcrit) and velopharyngeal compliance were not significant, but oropharyngeal compliance decreased (from 0.43 ± 0.18 to 0.32 ± 0.13 cm2/cmH2O, p < 0.05). No correlation was found between the pattern of change in luminal shape (determined as the ratio of a-p vs. lateral diameter when lowering CPAP) or changes in cross-sectional area and airflow during Hgp-ES.

CONCLUSIONS

Our findings indicate that human retractors dominate when stimulated together with the protrusors during HGp-ES. While co-activation of retractors may be beneficial, it should be limited. We speculate that exercises that augment protrusor force may improve the response to hypoglossal stimulation. The exclusion of patients with concentric pharyngeal obstruction should be re-evaluated.

Home Sleep Testing to Direct Upper Airway Stimulation Therapy Optimization for Sleep Apnea

OBJECTIVES/HYPOTHESIS

Selective upper airway stimulation (sUAS) is a well-established treatment option for obstructive sleep apnea (OSA). This study aimed to determine if there are benefits in performing a home sleep test (HST) to evaluate postoperative sUAS effectiveness after patient acclimatization compared to the generally used polysomnography (PSG) titration, as measured by long-term follow-up outcomes.

STUDY DESIGN

Retrospective comparative cohort analysis.

METHODS

We conducted an analysis of consecutive patients at our center who had completed a 6-month follow-up (month 6 [M6]) and recorded data from M6, month 12 (M12), and month 24 (M24). After device activation, we performed an HST with the patient's stimulation settings, and measured the apnea-hypopnea index (AHI), Epworth Sleepiness Scale (ESS), and device usage. These values were compared to patients who had undergone PSG-based device titration.

RESULTS

Baseline values of the initial 131 patients show high ESS and moderate OSA. At the 2-month time point of the HST, nearly half of the patients (46.2%) reached an AHI ≤15/hr, and approximately a fifth (19.2%) reached <5/hr. The PSG and HST groups differed in median ESS at M24, but no other differences were observed for ESS at M6 and M12. Both groups showed similar AHI, oxygen desaturation, and usage hours per week.

CONCLUSIONS

Adjusting therapy by using the HST technique after device activation and acclimatization has clinical and economic advantages. These advantages are contingent on several conditions being met when deviating from the standard device protocol, including precise communication with the referring sleep medicine physicians, especially their role in helping with long-term follow-up.

LEVEL OF EVIDENCE

4 Laryngoscope, 131:E1375-E1379, 2021.

Safety and effectiveness in explantation and re-implantation of hypoglossal nerve stimulation devices

PURPOSE

Since 2001, hypoglossal nerve stimulators have been implanted in patients with obstructive sleep apnea around the world, initially in trial situations but more recently also in regular care settings. Medium term data indicate effectiveness and tolerability of treatment. However, when assessing the safety of the procedure, the safe feasibility of explantation or reimplantation must also be considered.

PATIENTS AND METHODS

Nine patients with an implanted respiratory-driven hypoglossal nerve stimulator. We have evaluated the feasibility and safety of explantation or re-implantation with another stimulation system.

RESULTS

In 2012, nine patients were implanted with a respiratory-driven hypoglossal nerve stimulator as part of the Apnex Medical Pivotal Study. The study was ended in 2013. For a variety of reasons, the system was explanted from all nine patients by the year 2019. Three of these patients were re-implanted with a different system with respiratory sensing during the same session (mean incision to closure time for explantation 88.2 ± 35.01 min., mean incision to closure time for re-implantation 221.75 ± 52.73 min.). Due to extensive scar tissue formation, all procedures were technically challenging. Complication rate was significantly higher when re-implantation was performed or attempted in the same surgical session (0 of 5 patients with explantation versus 3 of 4 patients with attempted re-implantation; p = 0.018). There was no significant difference between the AHI values before and after implantation in patients with re-implantation.

CONCLUSION

Explantation and re-implantation are technically challenging though possible procedures. The single-staged equilateral reimplantation of another hypoglossal nerve stimulation system can, but need not, be successful.

Prospective Determination of Airway Response to Upper Airway Stimulation: A New Opportunity for Advanced Device Titration

OBJECTIVES/HYPOTHESIS

Response to upper airway stimulation (UAS) is associated with the degree of airway opening during stimulation. UAS programming may affect this opening. The objective of this study was to examine airway changes in response to five different electrode configurations programmable within the Inspire UAS system.

STUDY DESIGN

Prospective single-arm cohort study.

METHODS

Subjects who underwent UAS implantation were recruited for a prospective single-arm cohort study during UAS device activation. Functional thresholds were recorded for all settings. Awake nasopharyngoscopy was performed to examine the retropalatal (RP) and retroglossal (RG) regions at rest and during activation with all settings at their functional thresholds. Cross-sectional measurements were made by two blinded reviewers and reported as percent change in airway size.

RESULTS

Sixteen patients were included. The standard setting (+-+) resulted in the greatest change in RP area in 43.8% of patients. An alternative setting resulted in greatest change in 56.2% of patients (--- and o-o in 18.8% each, -o- in 12.5%, and -+- in 6.3% of patients). Average response to all five settings was utilized to classify degree of palatoglossal coupling. Most patients had some enlargement (20%-70% change in RP area, 43.8%) or no enlargement (<20% change, 43.8%), whereas a minority of patients (12.5%) had marked enlargement (>70% change). RP and RG expansion were not correlated.

CONCLUSION

Degree of RP expansion varied among patients and settings. Although the standard setting resulted in greatest RP change in a plurality of patients, over half had a greater response to an alternative setting. Future studies should address whether choice of setting based on RP expansion results in improved outcomes.

LEVEL OF EVIDENCE

4 Laryngoscope, 131:218-223, 2021.

Transoral Versus Endoscopic Examination in Predicting Outcomes of Hypoglossal Nerve Stimulation for Obstructive Sleep Apnea

OBJECTIVES/HYPOTHESIS

To examine the correlation between transoral and awake endoscopic examination and investigate their respective ability to predict outcomes of hypoglossal nerve stimulation (HGNS).

STUDY DESIGN

Retrospective cohort study at a US medical center.

METHODS

Subjects were adults with apnea-hypopnea index (AHI) >15 events/hr who underwent HGNS according to standard indications. Eligible subjects had diagnostic preoperative sleep studies, full-night efficacy postoperative studies, as well as postoperative video recordings of transoral examination and awake endoscopy. Recordings were independently scored by two blinded reviewers. Cohen's κ coefficient, Student t test, and χ² analyses were performed.

RESULTS

Fifty-seven patients met all inclusion criteria. On average, patients were Caucasian, middle aged, and overweight. The mean preoperative AHI was 36.7 events/hr, which improved significantly to 18.3 events/hr following HGNS (P < .01). Overall, the response rate (defined as AHI reduction >50% and AHI < 20 events/hr) was 49%. There was slight correlation between transoral tongue protrusion and endoscopic tongue base movement (κ = 0.10). On transoral examination, patients with minimal/moderate tongue motion achieved a greater mean AHI reduction than patients with full motion (26.0 ± 18.0 vs. 12.8 ± 24.1, P = .02). In contrast, on awake endoscopy, patients with minimal/moderate tongue motion achieved a lesser mean AHI reduction than patients with full motion (8.7 ± 19.9 vs. 22.1 ± 22.7, P = .04).

CONCLUSIONS

Transoral tongue protrusion bears an inverse relationship to HGNS success and correlates poorly with endoscopic tongue base movement. Endoscopic tongue base motion appears reflective of response to HGNS, with greater motion corresponding to greater AHI reduction.

LEVEL OF EVIDENCE

4 Laryngoscope, 131:675-679, 2021.

Changes in breath cycle sensing affect outcomes in upper airway stimulation in sleep apnea

BACKGROUND

Upper Airway Stimulation (UAS) is a well-established therapy option for obstructive sleep apnea (OSA).

AIMS

There are no data on whether respiratory sensing contributes to successful UAS therapy.

MATERIALS & METHODS

After initial measurements of 3 implanted patients (M1), the sensing signal was inverted (M2) without changing other parameters. Two weeks later, the signal was converted back again, and the sensitivity of breathing cycle detection was turned to a very low state (M3).

RESULTS

At M2 and M3, the apnea-hypopnea index and oxygen desaturation index increased.

DISCUSSION

Correct respiratory sensing is important for controlling OSA using UAS.

CONCLUSIONS

Therefore, implant centers should should optimize respiratory sensing placement and adjustment.

Effect of Gender, Age, and Profound Disease on Upper Airway Stimulation Outcomes

OBJECTIVE

To evaluate treatment outcomes of upper airway stimulation (UAS) in obstructive sleep apnea (OSA) patients based on patient age, gender, and preoperative disease severity.

METHODS

Retrospective chart review of patients undergoing UAS from 2014 to 2018 at a tertiary care center. Data collected included demographic information, implantation records, and pre- and postoperative polysomnography (PSG) results. Profound OSA was defined as AHI >65 and age ≥65 was considered advanced age. The primary outcome measured was initial treatment response, defined as a post-operative AHI <20 with a >50% reduction from baseline.

RESULTS

145 patients underwent UAS at our institution including 98 males and 47 females with a mean age of 61.7 ± 11.5 years, mean BMI of 29.1 ± 3.9 kg/m², and mean preoperative AHI of 34.1 ± 18.2 events/hour. After surgery, patients had a significantly lower mean AHI of 8.6 ± 15.0 events/hour (<0.001). Older patients had a lower initial treatment response rate (78%) when compared to their younger counterparts (94%) (P = 0.005). Male gender and profound disease status did not significantly impact treatment response rates; young age was the only variable found to predict early treatment response on multivariate analysis (P = 0.003).

CONCLUSION

Although the overall OSA population showed significant postoperative AHI reduction with UAS, patients age ≥65 years were less likely to have an initial response to treatment, when compared to their younger counterparts. A larger proportion of elderly patients and patients with profound OSA had residual moderate disease (AHI > 15) after UAS.

LEVEL OF EVIDENCE

4.

Hypoglossal Nerve Stimulation in the Treatment of Obstructive Sleep Apnea: Patient Selection and New Perspectives

Hypoglossal nerve stimulation (HNS) is an increasingly widespread OSA treatment. It is a non-anatomical modifying surgery able to achieve an adequate objective and subjective result with a reasonable complication rate. HNS exploits the neurostimulation to reduce upper airway collapsibility providing a multilevel upper airway improvement within a single procedure. Proper patient selection has a fundamental role in determining an adequate long-term clinical outcome. All patient candidates for HNS undergo a standard comprehensive sleep medicine assessment and upper airway surgical examination. Several features should be assessed preoperatively in order to predict patients' response to HNS treatment. In particular, the assessment of OSA severity, BMI > 32 Kg/m², collapse pattern during drug-induced sleep endoscopy (DISE), and many other parameters, is central for a good patient selection and customization of OSA treatment. HNS is indeed one of the most promising tools in the widespread context of personalized sleep medicine. HNS is an adjustable medical device that could be titrated in order to improve HNS effectiveness, maintaining patient comfort. Moreover, HNS provides the opportunity for patients to play an active role in their own care, with a potential improvement in therapy adherence and efficacy. This review summarizes the current evidence in patient selection for HNS, highlighting the reasons behind the optimistic future of this OSA treatment in the context of personalized medicine.

Nerve Stimulation for the Treatment of Obstructive Sleep Apnea

Purpose

This review will trace the elements of neurostimulation for obstructive sleep apnea and details on its implementation, efficacy and safety, immediate clinical outcomes, and future prospects.

Methods

The literature on upper airway neurostimulation was surveyed from July, 2013, to July 2019, with a focus on the components of devices, evidence for clinical utility, and adverse events.

Results

Current technology is focused on the hypoglossal nerve stimulation (HNS). The most long-term experience is with the Inspire Medical System (Maple Grove, MN USA) which has both FDA and European regulatory approval. Given the inclusion criteria (BMI <35, ideally <32), AHI 15-65/h, and a favorable anterior-posterior velopharyngeal collapse pattern on DISE), across many centers ~65% of patients who are intolerant to primary therapy achieve clinical success (AHI <20/h with a reduction of <50% in AHI), and more have symptomatic relief. Adverse events are generally mild, often self-limited, with occasional need for uncomplicated surgical adjustments or replacement of the implantable generator. Three other devices are in various phases of development, each with a differences in nerve electrodes, implantable components, power sources, proprietary programming, and activation patterns.

Conclusions

HNS is not considered a first-line treatment option. HNS therapy, however, should be considered as one alternative therapeutic option for patients meeting the inclusion criteria when more traditional therapeutic options have been considered.