Bilateral hypoglossal nerve stimulation for treatment of adult obstructive sleep apnoea

Hypoglossal nerve stimulator on extraoral radiography and cone beam computed tomography scan: Case report

BACKGROUND

The hypoglossal nerve stimulator (HNS) device has been employed in some patients with refractory or unsatisfactory outcomes to chronic obstructive sleep apnea management. The objective of this article is to increase recognition of the radiologic appearances of this device within the head and neck region, as seen on extraoral radiographic and cone beam computed tomography (CBCT) images.

CLINICAL PRESENTATION

A 55-year-old man, refractory to a multitude of apneic medical therapies, underwent a series of preorthognathic radiologic studies. Notably, an implanted HNS lead and ribbon electrodes appeared as hyperdense structures on the panoramic radiograph, lateral cephalogram, and CBCT scan.

CONCLUSION

This article provides various radiologic views of the primary components of an HNS. Clinicians should be able to recognize the presence of neurostimulator devices used for management of chronic sleep apnea within the radiologic field of view of examinations of the head and neck.

Selective Adipose Cryolysis for Reduction of Lingual Tissue in a Porcine Model

OBJECTIVES

Oropharyngeal fat volume is associated with obstructive sleep apnea (OSA) severity. Selective adipose cryolysis may produce cold-induced adipose cell death while sparing surrounding tissues. This study explored (1) similarities in tongue fat between porcine and human models and (2) the feasibility and potential reduction of lingual fat using selective adipose cryolysis.

STUDY DESIGN

Porcine model.

SETTING

Preclinical research laboratory under IACUC-approved protocols.

METHODS

Anatomical, histological, and biochemical characterizations of tongue tissue from 6 porcine and 4 human cadaver specimens were conducted to establish comparative frameworks. Comparison of fat distribution and composition was conducted via image analysis of histological sections as well as gas chromatography analysis of fatty acid composition. Safety and efficacy of selective adipose cryolysis were evaluated in an additional 16 porcine animals using a prototype cooling system. Histological analysis examined tissue response at 3, 6, 30, and 45 d posttreatment.

RESULTS

Comparative analysis revealed similar fat distribution and composition between human and porcine tongues. Selective adipose cryolysis induced progressive reduction in treated area tongue fat content at all timepoints, from 42% at baseline to 32% (t = 3 d) and 14% (t = 30 d), accompanied by macrophage infiltration, crown-like structure formation, and tissue remodeling.

CONCLUSION

Selective adipose cryolysis holds promise as a targeted therapeutic approach for reducing lingual fat in humans. The porcine model may provide valuable insight into treatment mechanisms and support initial translational work. Further research is warranted to elucidate long-term treatment outcomes and optimize clinical implementation strategies, with the goal of improving management of OSA in humans.

Effects of Mandibular Advancement Device on Genioglossus of Rabbits in Obstructive Sleep Apnea Through PINK1/Parkin Pathway

BACKGROUND

Early treatment of mandibular advancement device (MAD) reverses the abnormal changes resulting from obstructive sleep apnoea (OSA), but the underlying mechanism is not clear. We analysed the changes of genioglossus function before and after MAD treatment in OSA rabbits and explored the mechanism of mitochondrial autophagy.

METHODS

Eighteen male New Zealand rabbits were randomised into three groups: the control group, Group OSA, and Group MAD. After successful modelling, all animals were induced sleep in supine positions for 4-6 h per day for 8 weeks. Cone beam computed tomography (CBCT) and polysomnography (PSG) were performed to record sleep conditions. The genioglossus contractile force and the levels of LC3-I, LC3-II, Beclin-1, PINK1 and Parkin were detected in three groups. In vitro, C2C12 myoblast cells were cultured under normoxic or hypoxic conditions for 24 h, and then the changes in mitochondrial structure and accumulation of autolysosomes were detected by transmission electron microscopy (TEM).

RESULTS

The contractile tension of the genioglossus in Group OSA was significantly lower than that in the control group. The ratio of LC3II/LC3I and the levels of Beclin-1, PINK1 and Parkin were higher in Group OSA than that in the control group. And the abnormal changes were tended to be normal after MAD treatment. The mitochondrial structure was disrupted, and the number of autolysosomes increased in C2C12 after 24 h of hypoxia.

CONCLUSIONS

MAD treatment in male rabbits may decrease the contractile tension of the genioglossus and increase the level of mitochondrial autophagy caused by OSA. And the mechanism of mitochondrial autophagy was mediated by the PINK1/Parkin pathway in male rabbits.

Effectiveness of orthognathic surgery by maxillomandibular advancement combined with soft tissue surgery as curative treatment for obstructive sleep apnea syndrome

OBJECTIVE/BACKGROUND

The aim of this study was to compare the efficacy of orthognathic surgery combined with soft tissue surgery with that of soft tissue surgery alone as curative treatments for moderate to severe obstructive sleep apnea (OSA) syndrome.

PATIENTS/METHODS

This retrospective cohort study included 50 patients aged ≥18 years who underwent orthognathic surgery combined with soft tissue surgery or soft tissue surgery alone for OSA syndrome (apnea-hypopnea index [AHI]: >15). The primary outcome was the improvement in AHI measured by overnight in-laboratory polysomnography before and at 6 months after the surgical treatment by. The secondary outcome was the postoperative AHI.

RESULTS

Twenty-eight (56 %) patients underwent orthognathic surgery combined with soft tissue surgery, while 22 (44 %) underwent soft tissue surgery only. There were no significant between-group differences in sex (p = 0.53), age (p = 0.08), body mass index (p = 0.42), and preoperative AHI (p = 0.17). The mean improvement in AHI at 6 months after surgery was significantly greater in the orthognathic surgery group than in the soft tissue surgery group (32.18 vs. 10.41; p < 0.0001). Similarly, the mean postoperative AHI was significantly lower in the orthognathic surgery group than in the soft tissue surgery group (8.46 vs. 29.62; p < 0.0001).

CONCLUSION

Compared with soft tissue surgery alone, orthognathic surgery combined with soft tissue surgery is more effective as curative treatment for OSA syndrome.

Multicentre study conducted across centres in the USA, Europe and Australia to assess the safety and effectiveness of a bilateral hypoglossal nerve stimulation system for the treatment of obstructive sleep apnoea in adults: a protocol for a pivotal, multicentre, open-label, single-arm study

INTRODUCTION

Obstructive sleep apnoea (OSA) is characterised by blood oxygen desaturations and sleep disruptions manifesting undesirable consequences. Existing treatments including oral appliances, positive airway pressure (PAP) therapy and surgically altering the anatomy of the pharynx have drawbacks including poor long-term adherence or often involving irreversible, invasive procedures. Bilateral hypoglossal nerve stimulation (HNSBL) is a new treatment for managing OSA, and this study is intended to determine whether an HNSBL system is a safe and effective treatment option for adults with OSA.

METHODS AND ANALYSIS

This is a pivotal, multicentre, prospective, single-arm study of HNSBL in PAP-intolerant adults with moderate to severe OSA. The device is activated 2 months after implantation with stimulation settings optimised before the final 12-month sleep study. At 12 months, the two coprimary effectiveness endpoints are the percentage of responders based on reduction in the Apnoea-Hypoponea Index, with hypopnoeas associated with 4% oxyhaemoglobin desaturation, and the Oxygen Desaturation Index, using drops in oxygen concentration >4% from baseline (ODI4). Secondary effectiveness endpoints include mean changes in quality-of-life assessments (daytime sleepiness and its effect on activities of daily living, OSA-specific quality of life, daytime sleepiness), levels of intermittent hypoxia, change in hypoxaemic burden and OSA severity.

ETHICS AND DISSEMINATION

The Food and Drug Administration, Advarra Institutional Review Board (IRB), University of Tennessee HSC IRB, University of Pennsylvania IRB, Weill Cornell Medicine IRB, Medical College of Wisconsin/Froedert Hospital, Human Research Protections Programme Vanderbilt University, St. Vincent's Hospital Melbourne Human Research Ethics Committee, Ethisch Comite Universitair Ziekenhuis Antwerpen and Technische Universitat Munchen reviewed and approved this protocol. Study results will be disseminated through journal publications, updates to ClinicalTrials.gov and the Nyxoah website, and presentations at meetings and conferences.

TRIAL REGISTRATION NUMBER

NCT03868618.

Less is more - Retrospective analysis of the two-incision implantation technique for hypoglossal nerve stimulation and comparison of respiratory sensing lead curves against the three-incision technique

Introduction

Breathing-synchronized hypoglossal-nerve stimulation is a treatment option for suitable patients with severe obstructive-sleep-apnoea. The classical implantation technique requires three incisions: submental to place the stimulating-electrode on terminal branches of the hypoglossal-nerve, sub-clavicular to place the impulse generator, and on the lateral chest-wall to place a breathing-sensor lead. A two-incision-technique has been propagated and widely adopted whereby the respiratory-sensing-lead is placed deeper to the IPG-pocket.

Research question

Our department switched to the 2-incision-technique in May 2021 and we set out to compare the two methods concerning the generated respiratory-sensing-curves.

Material and method

Cases operated between October 2020 and September 2022 were included. Parameters included age, gender, BMI, OR time, positioning of the detection-lead, and preoperative Apnoea-Hypopnoea Index (AHI). The generated respiratory-sensing curves were categorized by an independent expert blinded to the surgical-technique regarding conduciveness to optimal stimulation.

Result

21 patients were included. 5 were operated with the 3-incision-technique. Women were underrepresented. There were no further significant differences in patient characteristics. The expert-opinion on the respiratory-sensing-curves did not vary between groups. Mean OR-time was marginally less in the 2-incision group without being statistically significant.

Conclusion

The 2-incision-technique generates respiratory-sensing curves at par with those generated with 3-incision-implants. The limited patient data collected in this analysis suggests that OR-time can be reduced using the 2-incision-technique. There were no cases of postoperative complications in our cohort. It can be postulated that a 2-incision-implant has a lower risk of infection due to the reduced wound-surface.

Comprehensive Analysis of Adverse Events Associated With Hypoglossal Nerve Stimulators: Insights From the MAUDE Database

OBJECTIVE

This study aims to examine the adverse events associated with hypoglossal nerve stimulator (HNS) implantation for treating obstructive sleep apnea (OSA), drawing data from the Manufacturer and User Facility Device Experience (MAUDE) database. We aim to provide a comprehensive and updated account of these adverse events.

STUDY DESIGN

Retrospective analysis.

SETTING

MAUDE Database review.

METHODS

A retrospective analysis was performed on the MAUDE database to collect all HNS-related reports from May 2014 to December 2023. Variables collected included date of event, event description, nature of event, iatrogenic injuries, required interventions, and, if available, root causes. Each event description was analyzed to classify the adverse event, the postevent intervention, and device model number.

RESULTS

Out of 1178 reports fulfilling the inclusion criteria, 1312 adverse events were identified. Common adverse events included infection (24.0%), pain (19.7%), and hematoma/seroma (10.2%). Approximately 83.1% of these adverse events necessitated medical and/or surgical intervention. The most frequent procedures included explantation (29.4%) and device repositioning (15.8%). Pneumothorax was reported in 50 cases, with 41 (82.0%) requiring a chest tube to be inserted. Three adverse events described overstimulation in the setting of magnetic resonance imaging (MRI) despite the implantation of MRI-compatible second-generation internal pulse generators.

CONCLUSION

While HNS implantation has been established as a reliable intervention for OSA in cases of continuous positive airway pressure failure or intolerance, this study highlights several perioperative and postoperative difficulties and complications. Understanding these challenges is essential for refining surgical practices and enhancing patient consent processes, ultimately aiming to improve therapeutic outcomes.

CO2 laser lingual tonsil reduction as a treatment for tongue discomfort during hypoglossal nerve stimulation: a case report

The purpose of this investigation is to demonstrate a multimodality approach to the surgical management of obstructive sleep apnea. Hypoglossal nerve stimulator (HGNS) implantation has been a life-changing procedure for many patients with obstructive sleep apnea. When activated it produces tongue protrusion via electrical stimulation of the hypoglossal nerve. This advances the lingual tonsil, making the pharynx diameter greater. Unfortunately, for some patients the electrical stimulation required is too high and awakens the patient. In such cases the patient's fragmented sleep is not improved with the hypoglossal nerve stimulator. Here we present a case where hypoglossal nerve stimulator and CO2 laser lingual tonsil reduction are used in conjunction to reduce the hypoglossal nerve stimulator setting required for airway patency, thereby allowing the patient to sleep through the night. For those patients who are unable to tolerate hypoglossal nerve stimulator settings, a combined approach with lingual tonsil reduction may be an alternative.

CITATION

Fontenot A, Liu SYC, Dewan K. CO2 laser lingual tonsil reduction as a treatment for tongue discomfort during hypoglossal nerve stimulation: a case report. J Clin Sleep Med. 2024;20(11):1857-1861.

Hypoglossal nerve stimulation for obstructive sleep apnea in adults: An updated systematic review and meta-analysis

OBJECTIVES

This study aims to evaluate the efficacy of Apnex, Inspire, and ImThera hypoglossal nerve stimulation (HGNS) devices in changing the severity of obstructive sleep apnea (OSA).

METHOD

ology: A systematic search was conducted across the databases to collect baseline and postoperative outcome measures. Articles were then filtered and data from post-filtration was extracted. The efficacy of each device was assessed individually, and the reported outcomes were analyzed at short-term (≤1 year) and long-term (>1 year) intervals.

RESULTS

A total of 30 papers were included; 26 were single-arm studies encompassing 549 middle-aged overweight patients. Four RCTs included 273 participants. Results show that HGNS is an effective and safe treatment option. The Inspire device significantly improved, reducing the apnea-hypopnea index (AHI) by -20.14 events/h in the short term and -15.91 events/h in the long term. It also decreased the oxygen desaturation index (ODI) by -14.16 events/h (short term) and -12.95 events/h (long term). Patient-reported outcomes showed decreased Epworth Sleepiness Scale (ESS) scores by -5.02 (short term) and -4.90 (long term) and improved Functional Outcomes of Sleep Questionnaire (FOSQ) scores by 3.58 (short term) and 3.28 (long term). The Apnex and the ImThera devices featured similar improvements but to a lesser extent.

CONCLUSION

Hypoglossal nerve stimulation is a safe and effective treatment for patients with OSA, exhibiting high adherence and satisfaction rates. However, it is important to note the potential for refining selection criteria to include a wider spectrum of patients with OSA.

[Ten years of hypoglossal nerve stimulation in obstructive sleep apnea: a systematic literature review]

OBJECTIVE

To show the importance of hypoglossal nerve stimulation (HGNS) as a treatment method for obstructive sleep apnea (OSA) in the German healthcare context and to better assess the way patients who do not receive adequate care could benefit from HGNS.

METHODS

A systematic literature review in the Medline and Cochrane Library literature database was conducted, including publications using different stimulation technologies for HGNS. The efficacy of HGNS was assessed based on patient-relevant outcomes (daytime sleepiness, quality of life), treatment adherence and the apnea-hypopnea index (AHI) and oxygen desaturation index (ODI). The safety of the treatment method was assessed based on adverse events (AEs).

RESULTS

Inclusion and analysis of 33 publications: 2 randomized controlled trials (RCTs, level Ib), 1 level IIb trial (n = 1) and 30 level IV trials with a study duration of up to 60 months. The RCTs showed better values for daytime sleepiness and quality of life when using HGNS than in the control group. AHI and ODI showed a deterioration under placebo stimulation or therapy withdrawal in the RCTs. Consistently high adherence was also reported in the long-term course. Severe AEs under HGNS were rare and could usually be resolved by repositioning electrodes or replacing device components. Other AEs were mostly transient or could be resolved by non-invasive measures. All investigated parameters showed similar results in the evaluated studies. The results of different stimulation systems are comparable in type and extent.

CONCLUSION

The comprehensive review of the literature shows consistent data that highlight the importance of HGNS as an effective and safe treatment for OSA after unsuccessful CPAP treatment. The evaluation also shows that the different stimulation systems make it possible to better tailor the therapy to the patient's individual requirements. A future systematic evaluation of real-world data on the use of HGNS would help gain additional insights into the relevance of the method in routine clinical practice.

Exploring hypoglossal nerve stimulation therapy for obstructive sleep apnea: A comprehensive review of clinical and physiological upper airway outcomes

Obstructive sleep apnea (OSA) is a chronic disorder characterized by recurrent episodes of upper airway collapse during sleep, which can lead to serious health issues like cardiovascular disease and neurocognitive impairments. While positive airway pressure serves as the standard treatment, intolerance in some individuals necessitates exploration of alternative therapies. Hypoglossal nerve stimulation (HGNS) promises to mitigate OSA morbidity by stimulating the tongue muscles to maintain airway patency. However, its effectiveness varies, prompting research for optimization. This review summarizes the effects of HGNS on upper airway obstruction from human and animal studies. It examines physiological responses including critical closing pressure, maximal airflow, nasal and upper airway resistance, compliance, stiffness, and geometry. Interactions among these parameters and discrepant findings in animal and human studies are explored. Additionally, the review summarizes the impact of HGNS on established OSA metrics, such as the apnea-hypopnea index, oxygen desaturation index, and sleep arousals. Various therapeutic modalities, including selective unilateral or bilateral HGNS, targeted unilateral HGNS, and whole unilateral or bilateral HGNS, are discussed. This review consolidates our understanding of HGNS mechanisms, fostering exploration of under-investigated outcomes and approaches to drive advancements in HGNS therapy.

Adverse Events with Hypoglossal Nerve Stimulation in the Treatment of Obstructive Sleep Apnea-A Systematic Review of Clinical Trials and Real-World Data

Background/Objectives: Hypoglossal nerve stimulation (HNS) emerged as an alternative treatment for patients with obstructive sleep apnea (OSA) a decade ago. Long-term clinical trials and real-world data show that HNS treatment provides significant and sustained improvements in both OSA disease control and quality-of-life measures over time. Given the nature of HNS treatment, with the requirement of using an implantable neurostimulation system, patient safety is a critical domain in the assessment of this technology. The objective of this review was to evaluate adverse events (AEs) and complications with HNS therapy in a systematic review of published evidence. Methods: Medline, Cochrane, and Web of Science were systematically searched to identify randomized controlled and real-world observational studies reporting relevant outcomes with HNS therapy for treatment of OSA that included procedure-, device-, and treatment-related AEs. Results: Out of 418 articles screened, 27 were reviewed for eligibility, and 17 studies, the majority found to have low-to-moderate risk of bias, with data on 1962 patients were included for further analysis. Across included studies, reporting of AEs was heterogeneous with regard to the classifications used and the extent of reporting. Over an average follow-up duration of 17.5 ± 16.9 months, the pooled mortality rate was 0.01% (95% CI = 0.0 to 0.2%), with all reported deaths being unrelated to HNS treatment. The HNS system survival probability over the follow-up time of 60 months was 0.9834 (95% CI = 0.9768 to 0.9882), with infections and request for removal by patients being the most common indications. The pooled surgical revision rate was 0.08% (95% CI 0.0 to 0.2%). Most reported treatment-related side effects were transient stimulation-related discomfort (0.08%, 95% CI = 0.0 to 0.2%) and tongue abrasions (0.07%, 95% CI = 0.0 to 0.2%). Based on the systematic review, a standardized set of endpoints was defined, aiming to harmonize safety data relevant to HNS therapy. Conclusions: In this systematic review, HNS therapy for treatment of OSA is associated with a positive patient safety profile. AEs occur mainly at device implantation and during the treatment acclimatization period. Due to a lack of available evidence, partially implantable HNS systems are underrepresented in this review, which limits the generalizability of the results. Significant heterogeneity was found for adverse event reporting. A framework for reporting HNS outcomes that includes AEs and side effects is proposed to facilitate comparability of the reported data.

Defining the Shape of the Mylohyoid Muscle: A Morphometric Imaging Study

OBJECTIVES

Implantable hypoglossal nerve stimulation (HNS) therapy is an evolving therapeutic alternative for patients with refractory obstructive sleep apnea (OSA). The muscular anatomy of this region has implications for surgical access through this zone as well as positioning and anchoring of hardware in this area. The purpose of this study was to radiologically describe the topography of the mylohyoid muscle and adjacent structures across a wide age spectrum.

METHODS

We retrospectively evaluated computed tomography scans of the neck in 102 patients who were imaged for reasons unrelated to the floor of mouth or submental space. Patients with prior surgery or pathology in the area of interest were excluded. Fourteen relevant muscle measurements were made on a midline sagittal image and a coronal image positioned at the midpoint between the hyoid bone and the mandible.

RESULTS

We included 49 men and 53 women with an average age of 44 years (range 19-70). The average mylohyoid length was 42 mm; the average distance between the anterior digastric bellies was 17 mm. The average angle of the central mylohyoid was 174° in the sagittal plane and 164° in the coronal plane. Several measurements were significantly correlated with patient age, including the angle measurements and the distance between the digastric muscles. Aberrant digastric anatomy was common.

CONCLUSIONS

The mylohyoid muscle has multiple radiologically distinct segments with predictable curvatures. An understanding of submental muscular anatomy, along with its variability between patients, may be beneficial to the development of bilateral implantable neurostimulation technology for the treatment of refractory OSA.

LEVEL OF EVIDENCE

N/A Laryngoscope, 134:2970-2975, 2024.

Sleep-disordered breathing - clinical spectrum

The clinical spectrum of sleep-disordered breathing comprises a range of diverse conditions including obstructive sleep apnoea, central sleep apnoea and sleep-related hypoventilation syndromes. These distinct conditions have specific diagnostic features and are managed differently from one another. Therefore, it is useful for dental practitioners to have a working knowledge of sleep-disordered breathing beyond that of uncomplicated obstructive sleep apnoea (OSA). This review paper summarizes the diagnosis and management of commonly encountered clinical sleep-disordered breathing syndromes, with a particular focus on management from a dental perspective.

Neurostimulation for Obstructive Sleep Apnea

Neurostimulation of hypoglossal nerve has emerged as an effective treatment option of obstructive sleep apnea (OSA). Since FDA approval in 2014, therapy has been widely used in select patients with moderate-to-severe OSA who do not benefit from positive airway pressure. Ongoing research and technological developments continue to advance the therapy to deliver personalized and efficient treatment to patients with OSA.

Effect of hypoglossal nerve stimulation on snoring: an evaluation using objective acoustic parameters

STUDY OBJECTIVES

Hypoglossal nerve stimulation is an established therapy for sleep apnea syndrome. Whether or not this therapy on snoring and nighttime noise exposure is effective and how strong this effect may be has not been objectively investigated thus far and was the aim of this study.

METHODS

In 15 participants (14 males; age: 30-72 years; mean: 51.7 years), polysomnography and acoustic measurements were performed before and after hypoglossal nerve stimulation.

RESULTS

The therapy led to a significant improvement in sleep apnea (apnea-hypopnea index from 35.8 events/h to 11.2 events/h, P < .001). Acoustic parameters showed a highly significant reduction in the average sound pressure level (42.9 db[A] to 36.4 db[A], P < .001), averaged sound energy, A-weighted (LAeq; 33.1 db[A] to 28.7 db[A], P < .001), snoring index (1,068 to 506, P < .001), percentage snoring time (29.7-14.1%, P < .001), and psychoacoustic snore score, the latter being a measure of annoyance due to snoring (47.9 to 24.5, P < .001).

CONCLUSIONS

This study was able to show for the first time by means of objective acoustic and psychoacoustic parameters that hypoglossal nerve stimulation can not only cause a significant improvement in sleep apnea but also has a positive effect on snoring and thus noise annoyance experienced by the bed partner.

CLINICAL TRIAL REGISTRATION

Registry: German Clinical Trials Register; Name: Effect of Hypoglossal Nerve Stimulation on Snoring: An Evaluation Using Objective Acoustic Parameters; URL: https://drks.de/search/de/trial/DRKS00032354; Identifier: DRKS00032354.

CITATION

Fischer R, Vielsmeier V, Kuehnel TS, et al. Effect of hypoglossal nerve stimulation on snoring: an evaluation using objective acoustic parameters. J Clin Sleep Med. 2024;20(3):363-370.

Hypoglossal Nerve Stimulation Effects on Obstructive Sleep Apnea Over Time: A Systematic Review and Meta-analysis

OBJECTIVES

This study aimed to determine the efficacy of hypoglossal nerve stimulation (HGS) in the treatment of obstructive sleep apnea.

DATA SOURCES

PubMed, Cochrane database, Embase, Web of Science, SCOPUS, and Google Scholar.

REVIEW METHODS

Five databases were reviewed to identify relevant studies that measured polysomnography parameters such as the apnea-hypopnea index (AHI) and oxygen desaturation index, as well as quality of life and functional outcomes of sleep questionnaire scores, before and after HGS.

RESULTS

In total, 44 studies involving 8670 patients met the inclusion criteria. At 12 months after treatment, approximately 47%, 72%, and 82% of patients achieved AHI values of <5, < 10, and <15, respectively. The reported clinical success rates according to Sher criteria were 80% within 12 months and 73% between 12 and 36 months. While the favorable effects exhibited a gradual reduction up to 12 months postimplantation, they generally maintained a consistent level between the 12th and 36th months, as assessed by AHI < 5, <15, and success rate according to Sher criteria.

CONCLUSION

HGS can enhance quality of life scores and polysomnography outcomes in obstructive sleep apnea patients. Although the positive effects gradually decreased until 12 months after implantation, they generally remained consistent between 12 and 36 months.

Obstructive sleep apnoea-hypopnoea syndrome

Obstructive sleep apnoea-hypopnoea syndrome (OSAHS) is a common disorder characterised by repetitive episodes of the complete or partial collapse of the pharyngeal airway during sleep. This results in cessation (apnoea) or reduction (hypopnoea) of airflow, leading to oxygen desaturation and sleep fragmentation. An individual's disposition to develop OSAHS depends on the collapsibility of a segment of the upper airway. The degree of collapsibility can be quantified by the balance between occluding or extraluminal pressures of the surrounding tissues. Patients can experience snoring, unrefreshing sleep, witnessed apnoeas, waking with a choking sensation and excessive daytime sleepiness. OSAHS has a broad range of consequences, including cardiovascular, metabolic, and neurocognitive sequelae. Treatment options include lifestyle measures, in particular weight loss, and strategies to maintain upper airway patency overnight, including continuous positive airway pressure, mandibular advancement devices and positional modifiers.

Direct optogenetic activation of upper airway muscles in an acute model of upper airway hypotonia mimicking sleep onset

STUDY OBJECTIVES

Obstructive sleep apnea (OSA), where the upper airway collapses repeatedly during sleep due to inadequate dilator muscle tone, is challenging to treat as current therapies are poorly tolerated or have variable and unpredictable efficacy. We propose a novel, optogenetics-based therapy, that stimulates upper airway dilator muscle contractions in response to light. To determine the feasibility of a novel optogenetics-based OSA therapy, we developed a rodent model of human sleep-related upper airway muscle atonia. Using this model, we evaluated intralingual delivery of candidate optogenetic constructs, notably a muscle-targeted approach that will likely have a favorable safety profile.

METHODS

rAAV serotype 9 viral vectors expressing a channelrhodopsin-2 variant, driven by a muscle-specific or nonspecific promoter were injected into rat tongues to compare strength and specificity of opsin expression. Light-evoked electromyographic responses were recorded in an acute, rodent model of OSA. Airway dilation was captured with ultrasound.

RESULTS

The muscle-specific promoter produced sufficient opsin expression for light stimulation to restore and/or enhance electromyographic signals (linear mixed model, F = 140.0, p < 0.001) and induce visible tongue contraction and airway dilation. The muscle-specific promoter induced stronger (RM-ANOVA, F(1,8) = 10.0, p = 0.013) and more specific opsin expression than the nonspecific promoter in an otherwise equivalent construct. Viral DNA and RNA were robust in the tongue, but low or absent in all other tissues.

CONCLUSIONS

Significant functional responses to direct optogenetic muscle activation were achieved following muscle-specific promoter-driven rAAV-mediated transduction, providing proof-of-concept for an optogenetic therapy for patients with inadequate dilator muscle activity during sleep.

Hypoglossal nerve stimulation for adults with obstructive sleep apnea

ABSTRACT

Obstructive sleep apnea (OSA) is a common chronic condition in which upper airway collapse interferes with breathing during sleep, reducing sleep quality. Untreated OSA can impair a patient's health and quality of life. The recommended first-line treatment for OSA in adults is positive airway pressure, but difficulty tolerating this device limits adherence to treatment for many patients. Treatment with an implanted hypoglossal nerve stimulation (HNS) device is a relatively new second-line option for these patients, and is gaining more widespread use. Clinicians who treat OSA or provide other healthcare services to patients with HNS implants should be familiar with these devices. This article reviews HNS technology and relevant OSA pathophysiology, along with device candidacy criteria, efficacy, risks, and considerations related to use of other medical technologies for patients with HNS implants.

[Hypoglossal Stimulation: Indication, Surgical Technique and Clinical Results]

Hypoglossal stimulation is a safe and effective treatment option for patients with obstructive sleep apnea and unsuccessful PAP therapy. A number of criteria must be met for the indication: proof of failed PAP therapy and ineffectiveness of the other therapy alternatives, AHI of 15-65/h (a relevant number of central and/or mixed apneas should be excluded) and BMI up to max. 35kg/m2. In the case of the respiratory-synchronous and bilateral stimulation system, a complete concentric collapse at the velum level should currently be ruled out in DISE. In the future, stimulation of the branch of the ansa cervicalis innervating the sternothyroid muscle and the ramus internus of the superior laryngeal nerve could open up additional treatment options.

Patient-reported outcomes with hypoglossal nerve stimulation for treatment of obstructive sleep apnea: a systematic review and meta-analysis

INTRODUCTION

Hypoglossal nerve stimulation (HNS) has recently been introduced as an alternative treatment for patients with OSA. A large number of studies have demonstrated substantial changes in OSA with this therapy by reducing respiratory events and improving symptoms such as daytime sleepiness and quality of life. The objective of this review was to conduct a systematic review and meta-analysis to evaluate patient-reported outcomes and experience with HNS therapy.

METHODS

A systematic literature search of MEDLINE, Cochrane, and Web of Science was performed to identify randomized controlled and observational studies reporting subjective outcomes with different HNS systems in patients with OSA. Abstracts of 406 articles were screened and a subset of 55 articles were reviewed for eligibility. Risk of bias was assessed using the ROBINS-I tool. Meta-analysis using RevMan was performed when > 2 studies were identified that reported data on a specific outcome.

RESULTS

Thirty-four publications reporting data on 3785 patients with a mean follow-up of 11.8 ± 12.2 months were identified and included in the meta-analysis. The analysis revealed a pooled effect of 4.59 points improvement in daytime sleepiness as measured by the ESS questionnaire (Z = 42.82, p < .001), 2.84 points improvement in daytime functioning as measured by the FOSQ score (Z = 28.38, p < .001), and 1.77 points improvement in sleep quality as measured by the PSQI questionnaire (Z = 2.53, p = .010). Patient-reported experience was consistently positive and revealed additional relevant aspects from this perspective.

CONCLUSION

HNS therapy significantly improves quality of life in patients with OSA and reliably produces clinically meaningful effects on daytime sleepiness, daytime functioning, and sleep quality. Treatment regularly meets or exceeds the minimum clinically important differences defined for the respective instruments. Additional research is needed to further investigate effects on quality of life beyond improvements in daytime sleepiness and daytime functioning.

Obstructive sleep apnea improves with non-invasive hypoglossal nerve stimulation using temporal interference

BACKGROUND

Peripheral nerve stimulation is used in both clinical and fundamental research for therapy and exploration. At present, non-invasive peripheral nerve stimulation still lacks the penetration depth to reach deep nerve targets and the stimulation focality to offer selectivity. It is therefore rarely employed as the primary selected nerve stimulation method. We have previously demonstrated that a new stimulation technique, temporal interference stimulation, can overcome depth and focality issues.

METHODS

Here, we implement a novel form of temporal interference, bilateral temporal interference stimulation, for bilateral hypoglossal nerve stimulation in rodents and humans. Pairs of electrodes are placed alongside both hypoglossal nerves to stimulate them synchronously and thus decrease the stimulation amplitude required to activate hypoglossal-nerve-controlled tongue movement.

RESULTS

Comparing bilateral temporal interference stimulation with unilateral temporal interference stimulation, we show that it can elicit the same behavioral and electrophysiological responses at a reduced stimulation amplitude. Traditional transcutaneous stimulation evokes no response with equivalent amplitudes of stimulation.

CONCLUSIONS

During first-in-man studies, temporal interference stimulation was found to be well-tolerated, and to clinically reduce apnea-hypopnea events in a subgroup of female patients with obstructive sleep apnea. These results suggest a high clinical potential for the use of temporal interference in the treatment of obstructive sleep apnea and other diseases as a safe, effective, and patient-friendly approach.

TRIAL REGISTRATION

The protocol was conducted with the agreement of the International Conference on Harmonisation Good Clinical Practice (ICH GCP), applicable United States Code of Federal Regulations (CFR) and followed the approved BRANY IRB File # 22-02-636-1279.

Obstructive Sleep Apnea

OBJECTIVE

Obstructive sleep apnea (OSA) is the most common type of sleep-disordered breathing. This article describes advances in the diagnosis, testing, treatment, and monitoring of OSA.

LATEST DEVELOPMENTS

Home sleep apnea testing and in-laboratory polysomnography are the most commonly used diagnostic tools in the identification and monitoring of OSA, but new methods for diagnosis and at-home monitoring of treatment response are being developed and validated. While the apnea-hypopnea index is regularly used to define OSA severity, recognition is increasing of its inability to risk-stratify patients. Other sleep study data including arousal threshold, hypoxic burden, and pulse rate variability as well as clinical characteristics can help with risk stratification. The most effective treatment is continuous positive airway pressure (CPAP), which can be limited by adherence and tolerance in some patients. Newer masks and comfort features including heated tubing and expiratory pressure relief may improve tolerance to positive airway pressure (PAP) therapy. Additional treatment options include other PAP modalities, mandibular advancement devices, tongue stimulation therapy, negative inspiratory pressure, nasal expiratory pressure valves, nasal congestion treatments, upper airway surgeries including hypoglossal nerve stimulation, and medications.

ESSENTIAL POINTS

OSA is a common disorder that causes sleep and daytime symptoms and increases the risk of neurologic and medical complications. Neurologists should be aware of atypical presentations and understand the diagnostic and treatment options.

Domiciliary transcutaneous electrical stimulation in patients with obstructive sleep apnoea and limited adherence to continuous positive airway pressure therapy: a single-centre, open-label, randomised, controlled phase III trial

Background

Hypoglossal nerve stimulation (HNS) for obstructive sleep apnoea (OSA) is a novel way to manage the condition. We hypothesised that in patients with OSA and limited adherence to continuous positive airway pressure (CPAP) therapy, domiciliary transcutaneous electrical stimulation (TESLA) would control sleep apnoea and provide health benefits.

Methods

We undertook a single-centre, open-label, randomised, controlled phase III trial in patients with OSA (apnoea-hypopnoea-index [AHI] 5-35 h-1), a BMI of 18.5-32 kg∗m-2, and a documented lack of adherence to CPAP therapy (<4 h∗night-1) at Guy's & St Thomas' NHS Foundation Trust (hospital), UK. Patients were randomly assigned (1:1) using minimisation (gender and OSA severity) to receive TESLA or usual care (CPAP) for at least 3 months; sleep study analysis was provided without knowledge of the assignment arm. The primary outcome was change in AHI at 3-months. The primary outcome and safety were analysed in the intention-to-treat population. Data are reported as median (interquartile range), unless otherwise explained. This trial is registered at ClinicalTrials.gov, NCT03160456.

Findings

Between 6 June 2018 and 7 February 2023, 56 participants were enrolled and randomly assigned (29 patients in the intervention group and 27 in the usual care group). Patients were followed up for a median of 3.0 months (IQR 3.0; 10.0). The groups were similar in terms of age (55.8 (48.2; 66.0) vs 59.3 (47.8; 64.4) years), gender (male:female, 19:10 vs 18:9) and BMI (28.7 (26.4; 31.9) vs 28.4 (24.4; 31.9) kg∗m-2). The unadjusted group difference in the Δ AHI was -11.5 (95% CI -20.7; -2.3) h-1 (p = 0.016). Adjusted for the baseline value, the difference was Δ AHI -7.0 (-15.7; 1.8) h-1 (p = 0.12), in favour of the intervention. Minor adverse events were found in one of the participants who developed mild headaches related to the intervention.

Interpretation

Domiciliary TESLA can be used safely and effectively in OSA patients with poor adherence to CPAP, with favourable impact on sleepiness and sleep fragmentation. Despite pandemic-related limitations of the amended protocol this trial provides the evidence that TESLA improves clinically meaningful outcomes over the observed follow up period, and the transcutaneous approach is likely to offer an affordable alternative for responders to electrical stimulation in clinical practice.

Funding

British Lung Foundation, United Kingdom Clinical Research Collaboration-registered King's Clinical Trials Unit at King's Health Partners.

Beyond CPAP: modifying upper airway output for the treatment of OSA

Obstructive Sleep Apnea (OSA) is exceedingly common but often under-treated. Continuous positive airway pressure (CPAP) has long been considered the gold standard of OSA therapy. Limitations to CPAP therapy include adherence and availability. The 2021 global CPAP shortage highlighted the need to tailor patient treatments beyond CPAP alone. Common CPAP alternative approaches include positional therapy, mandibular advancement devices, and upper airway surgery. Upper airway training consists of a variety of therapies, including exercise regimens, external neuromuscular electrical stimulation, and woodwind instruments. More invasive approaches include hypoglossal nerve stimulation devices. This review will focus on the approaches for modifying upper airway muscle behavior as a therapeutic modality in OSA.

The assessment and management of obstructive sleep apnoea-hypopnoea syndrome and obesity hypoventilation syndrome in obesity

Obesity is associated with respiratory dysfunction. It is a key risk and contributory factor in the sleep related breathing disorders, obstructive sleep apnoea/hypopnoea syndrome (OSAHS) and obesity hypoventilation syndrome (OHS). Weight management is an integral part of the management of these disorders, in addition to continuous positive airways pressure (CPAP) and non-invasive ventilation (NIV). Untreated, these conditions are associated with a high disease burden and as treatment is effective, early recognition and referral is critical. Best practice in on-going care is multidisciplinary.

Targeted Hypoglossal Nerve Stimulation for Patients With Obstructive Sleep Apnea: A Randomized Clinical Trial

Importance

Evidence is lacking from randomized clinical trials of hypoglossal nerve stimulation in obstructive sleep apnea (OSA).

Objective

To evaluate the safety and effectiveness of targeted hypoglossal nerve stimulation (THN) of the proximal hypoglossal nerve in patients with OSA.

Design, Setting, and Participants

This randomized clinical trial (THN3) was conducted at 20 centers and included 138 patients with moderate to severe OSA with an apnea-hypopnea index (AHI) of 20 to 65 events per hour and body mass index (calculated as weight in kilograms divided by height in meters squared) of 35 or less. The trial was conducted from May 2015 through June 2018. Data were analyzed from January 2022 through January 2023.

Intervention

Implant with THN system; randomized 2:1 to activation at month 1 (treatment) or month 4 (control). All received 11 months of THN with follow-up at months 12 and 15, respectively.

Main Outcomes and Measures

Primary effectiveness end points comprised AHI and oxygen desaturation index (ODI) responder rates (RRs). Treatment responses at months 4 and 12/15 were defined as a 50% or greater reduction in AHI to 20 or less per hour and an ODI decrease of 25% or greater. Coprimary end points comprised (1) month 4 AHI and ODI RR in the treatment greater than the control group and (2) month 12/15 AHI and ODI RR in the entire cohort exceeding 50%. Secondary end points included sleep apnea severity (AHI and ODI) and patient-reported outcomes (Epworth Sleepiness Scale, Functional Outcomes of Sleep Questionnaire, and EQ-5D visual analog scale).

Results

Among 138 participants, the mean (SD) age was 56 (9) years, and 19 (13.8%) were women. Month 4 THN RRs were substantially greater in those in the treatment vs control group (AHI, 52.3% vs 19.6%; ODI, 62.5% vs 41.3%, respectively) with treatment-control standardized mean differences of 0.725 (95% CI, 0.360-1.163) and 0.434 (95% CI, 0.070-0.843) for AHI and ODI RRs, respectively. Months 12/15 RRs were 42.5% and 60.4% for AHI and ODI, respectively. Improvements in AHI, ODI, Epworth Sleepiness Scale, Functional Outcomes of Sleep Questionnaire, and EQ-5D visual analog scale scores were all clinically meaningful (medium to large effect size). Two serious adverse events and 100 nonserious related adverse events were observed from the implant procedure or study protocol.

Conclusions and Relevance

This randomized clinical trial found that THN demonstrated improvements in sleep apnea, sleepiness, and quality of life in patients with OSAs over an extended AHI and body mass index range without prior knowledge of pharyngeal collapse pattern. Clinically meaningful improvements in AHI and patient-reported responses compared favorably with those of distal hypoglossal nerve stimulation trials, although clinically meaningful differences were not definitive for ODI.

Trial Registration

ClinicalTrials.gov Identifier: NCT02263859.

Pathophysiological mechanisms and therapeutic approaches in obstructive sleep apnea syndrome

Obstructive sleep apnea syndrome (OSAS) is a common breathing disorder in sleep in which the airways narrow or collapse during sleep, causing obstructive sleep apnea. The prevalence of OSAS continues to rise worldwide, particularly in middle-aged and elderly individuals. The mechanism of upper airway collapse is incompletely understood but is associated with several factors, including obesity, craniofacial changes, altered muscle function in the upper airway, pharyngeal neuropathy, and fluid shifts to the neck. The main characteristics of OSAS are recurrent pauses in respiration, which lead to intermittent hypoxia (IH) and hypercapnia, accompanied by blood oxygen desaturation and arousal during sleep, which sharply increases the risk of several diseases. This paper first briefly describes the epidemiology, incidence, and pathophysiological mechanisms of OSAS. Next, the alterations in relevant signaling pathways induced by IH are systematically reviewed and discussed. For example, IH can induce gut microbiota (GM) dysbiosis, impair the intestinal barrier, and alter intestinal metabolites. These mechanisms ultimately lead to secondary oxidative stress, systemic inflammation, and sympathetic activation. We then summarize the effects of IH on disease pathogenesis, including cardiocerebrovascular disorders, neurological disorders, metabolic diseases, cancer, reproductive disorders, and COVID-19. Finally, different therapeutic strategies for OSAS caused by different causes are proposed. Multidisciplinary approaches and shared decision-making are necessary for the successful treatment of OSAS in the future, but more randomized controlled trials are needed for further evaluation to define what treatments are best for specific OSAS patients.

Effects of Soft Tissue Sleep Surgery on Morbidly Obese Patients

INTRODUCTION

Morbidly obese patients with obstructive sleep apnea (OSA) are often intolerant of continuous positive airway pressure (CPAP). The effects of sleep surgery in this population is not well documented, and sleep surgery is generally avoided due to the expectation of poor outcomes, leaving these patients untreated.

METHODS

This retrospective study included 42 patients with a body mass index (BMI) ≥40.0 and OSA with a preoperative apnea hypopnea index (AHI) ≥5. Preoperative BMI ranged from 40.0 to 69.0 kg/m². Preoperative AHI ranged from 7.2 to 130.0. Of 42 patients, 12 (28.6%) underwent concurrent pharyngeal and retrolingual surgery. Subgroup analysis of change in AHI was measured with respect to preoperative OSA severity, change in preoperative BMI, and BMI severity. Univariate linear and logistic regression was performed assessing change in AHI and surgical success with respect to age, sex, preoperative AHI, preoperative BMI, change in BMI, total procedures, palatal procedure, retrolingual procedure, nasal procedure, and multilevel procedures.

RESULTS

The mean AHI improved from 45.9 ± 31.8 to 31.9 ± 31.6 (P = .007). Epworth sleepiness score (ESS) improved from 13.2 ± 5.5 to 9.6 ± 5.4 (P = .00006). Lowest oxygen saturation (LSAT) improved from 74.4 ± 10.7 to 79.9 ± 10.4 (P = .002). About 33.3% of patients had surgical success (AHI < 20 with at least 50% reduction in AHI). Preoperative AHI was the most significant factor for change in AHI in univariate and multivariate models (P = .015).

CONCLUSION

Sleep surgery is effective in reducing OSA burden in most morbidly obese patients and can result in surgical cure for a third of patients.

Trends in Volumetric-Energy Efficiency of Implantable Neurostimulators: A Review From a Circuits and Systems Perspective

This paper presents a comprehensive review of state-of-the-art, commercially available neurostimulators. We analyse key design parameters and performance metrics of 45 implantable medical devices across six neural target categories: deep brain, vagus nerve, spinal cord, phrenic nerve, sacral nerve and hypoglossal nerve. We then benchmark these alongside modern cardiac pacemaker devices that represent a more established market. This work studies trends in device size, electrode number, battery technology (i.e., primary and secondary use and chemistry), power consumption and longevity. This information is analysed to show the course of design decisions adopted by industry and identifying opportunity for further innovation. We identify fundamental limits in power consumption, longevity and size as well as the interdependencies and trade-offs. We propose a figure of merit to quantify volumetric efficiency within specific therapeutic targets, battery technologies/capacities, charging capabilities and electrode count. Finally, we compare commercially available implantable medical devices with recently developed systems in the research community. We envisage this analysis to aid circuit and system designers in system optimisation and identifying innovation opportunities, particularly those related to low power circuit design techniques.

Combination CPAP and bilateral hypoglossal nerve stimulation for obstructive sleep apnea in Treacher Collins syndrome: first case report

We report the first case of bilateral hypoglossal nerve stimulator implantation in a patient with Treacher Collins syndrome and very severe obstructive sleep apnea, who was initially intolerant of continuous positive airway pressure (CPAP) treatment. Novel bilateral hypoglossal nerve stimulation in combination with CPAP allowed near obliteration of snoring, improved sleep quality, and ability to maintain the CPAP mask in position in the setting of craniofacial changes associated with this condition.

CITATION

Wong ACL, Jones A, Stone A, MacKay SG. Combination CPAP and bilateral hypoglossal nerve stimulation for obstructive sleep apnea in Treacher Collins syndrome: first case report. J Clin Sleep Med. 2023;19(1):197-199.

Transcutaneous electrical stimulation in obstructive sleep apnoea: current developments and concepts of the TESLA-home programme

PURPOSE OF REVIEW

Obstructive sleep apnoea (OSA) is a highly prevalent condition affecting about 1 billion people worldwide. The first line therapy for most patients with OSA is continuous positive airway pressure (CPAP) therapy. However, there are significant limitations with long-term adherence to CPAP therapy, which may be as low as 30-60%.

RECENT FINDING

Electrical stimulation of the hypoglossal nerve has been studied in recent years. It achieves upper airway patency by causing a contraction of the genioglossus muscle, the strongest dilator of the upper airway, and by maintaining its neuromuscular tone in the asleep patient with OSA. Electrical stimulation can be delivered invasively, hypoglossal nerve stimulation (HNS), and noninvasively, transcutaneous electrical stimulation in OSA (TESLA). However, randomised controlled trials, the STAR and the TESLA trial, have provided promising results on efficacy and safety of the methods.

SUMMARY

Patient and public involvement underlines the interest in TESLA and HNS and highlights the need to provide non-CPAP therapeutic options to those who may find it difficult to cope with first line therapies. The relatively low costs and the favourable safety profile of the TESLA approach provide the chance to offer this treatment to patients with OSA following further development of the evidence.

Non-CPAP therapy for obstructive sleep apnoea

Treatment of obstructive sleep apnoea in adults is evolving, from a "one treatment fits all" to a more individualised approach. The spectrum of treatment options is broad and heterogeneous, including conservative, technological and pharmaceutical modalities. This raises the questions of which patients these modalities might be useful for, and if there are specific criteria for single or combined treatment. The most commonly used non-CPAP treatment is a mandibular advancement device. Furthermore, it appears from the available evidence that upper airway surgery, bariatric surgery, and maxillomandibular advancement can be effective in particular patient groups and should be indicated more readily in clinical practice. Technically, a tracheotomy is the most effective surgical treatment, but is not socially acceptable and is associated with major side-effects. Other treatment options are emerging, like positional therapy, hypoglossal nerve stimulation, and myofunctional exercises. Drug therapy is also promising when pathophysiological traits are considered. The range of currently available treatment options will be discussed in this review, with emphasis on the selection of appropriate patients, therapeutic efficacy and compliance, and reference to recent guidelines. In the selection process, routine application of drug-induced sleep endoscopy to assess the site(s) of collapse during sleep can increase the success rate of both surgical interventions and oral appliance therapy.

Educational aims

To outline recommendations concerning the proper management of obstructive sleep apnoea (OSA) patients that cannot be treated adequately with continuous positive airway pressure (CPAP) due to intolerance, poor adherence or compliance, or CPAP refusal.To provide information about the selection of appropriate patients for alternative non-CPAP treatment options.To better understand the different aspects of OSA treatment with noninvasive approaches, such as oral appliances, positional therapy, drug treatment and myofunctional therapy, including indications, contraindications, and expected short- and long-term results.To discuss the different surgical options for the treatment of OSA and to provide information on the important issue of proper patient selection for surgery, as most OSA surgical outcomes are associated with the pre-operative assessment of the level(s) of upper airway collapse.

Obstructive sleep apnea: personalizing CPAP alternative therapies to individual physiology

Introduction The recent continuous positive airway pressure (CPAP) crisis has highlighted the need for alternative obstructive sleep apnea (OSA) therapies. This article serves to review OSA pathophysiology and how sleep apnea mechanisms may be utilized to individualize alternative treatment options.Areas covered: The research highlighted below focuses on 1) mechanisms of OSA pathogenesis and 2) CPAP alternative therapies based on mechanism of disease. We reviewed PubMed from inception to July 2022 for relevant articles pertaining to OSA pathogenesis, sleep apnea surgery, as well as sleep apnea alternative therapies.Expert opinion: Although the field of individualized OSA treatment is still in its infancy, much has been learned about OSA traits and how they may be targeted based on a patient's physiology and preferences. While CPAP remains the gold-standard for OSA management, several novel alternatives are emerging. CPAP is a universal treatment approach for all severities of OSA. We believe that a personalized approach to OSA treatment beyond CPAP lies ahead. Additional research is needed with respect to implementation and combination of therapies longitudinally, but we are enthusiastic about the future of OSA treatment based on the data presented here.

Design and rationale for the treating Obstructive Sleep Apnea using Targeted Hypoglossal Nerve Stimulation (OSPREY) trial

Obstructive sleep apnea (OSA) affects nearly 1 billion people worldwide, including approximately 35 million US residents. OSA has detrimental cardiovascular and neurocognitive consequences. Positive airway pressure corrects sleep disordered breathing but is not always tolerated or used sufficiently. Oral appliances and surgery provide alternatives in select populations but are variably effective. Hypoglossal nerve stimulation can effectively treat obstructive sleep apnea. Targeted hypoglossal nerve stimulation (THN) is simpler than incumbent technology with no sensor and an easier, proximal electrode implantation. The third clinical study of THN, THN3, was the first randomized, controlled trial of hypoglossal nerve stimulation to demonstrate significant improvement of sleep disordered breathing in OSA. The present investigation reports the design of a novel trial of targeted stimulation to provide additional Level 1 evidence in moderate to severe obstructive apnea. OSPREY is a randomized, parallel-arm, 13-month trial wherein all subjects are implanted, 2/3 are activated at Month 1 ("Treatment") and 1/3 are activated at Month 7 ("Control"). The primary endpoint is the difference in apnea-hypopnea index response rates between Treatment and Control groups at Month 7. Secondary endpoints include quality of life and oximetry metrics. OSPREY follows an adaptive "Goldilocks" design which optimizes the number of subjects with the need for high-confidence results. A maximum of 150 subjects is allowed, at which study power of >95% is predicted. Interim analyses begin once 50 patients are randomized and recur after each 20 additional randomizations to detect early success or futility. OSPREY is a unique, efficient trial that should provide high-confidence confirmation of the safety and efficacy of targeted hypoglossal nerve stimulation for moderate to severe obstructive sleep apnea.

Bilateral vs Unilateral Hypoglossal Nerve Stimulation in Patients With Obstructive Sleep Apnea

Objective

Unilateral hypoglossal nerve stimulation (uniHNS) is an effective treatment for obstructive sleep apnea. Bilateral hypoglossal nerve stimulation (biHNS) is a novel therapeutic option and a different approach to hypoglossal nerve stimulation. The aim of this study was to analyze the clinical outcome of the first 10 biHNS cases vs the first 10 uniHNS cases ever implanted.

Study Design

Prospective data analysis.

Setting

International multicenter comparative clinical trial.

Methods

The first 10 patients in 2020 who received a biHNS device (Genio System; Nyxoah) and the first 10 patients in 2014 who received a uniHNS system (Inspire II; Inspire Medical Systems) were included. Treatment outcome was evaluated at 3 months after surgery. Data collection included demographics, apnea hypopnea index (AHI), oxygen saturation and desaturation index, Epworth Sleepiness Scale, and adverse events.

Results

The mean ± SD age was 52.1 ± 9.6 years (biHNS) and 58.3 ± 8.6 years (uniHNS). The mean body mass index was 26.4 ± 5.6 kg/m² (biHNS) and 26.2 ± 2.2 kg/m² (uniHNS). The mean preimplantation AHI (biHNS, 39.9 ± 14.8/h; uniHNS, 32.2 ± 11.0/h) decreased in both groups after 3 months (biHNS, 19.2 ± 14.0/h, P = .008; uniHNS, 13.1 ± 16.8/h, P = .037) with no significant difference between groups (P = .720). The mean preimplantation Epworth Sleepiness Scale (biHNS, 11.8 ± 6.2; uniHNS, 11.1 ± 4.9) decreased as well after 3 months (biHNS, 9.4 ± 6.3; uniHNS, 6.0 ± 5.0).

Conclusion

Preliminary postmarket data suggest that biHNS may be as safe and effective as uniHNS. Long-term follow-up in a larger sample size is required to assess the stability of biHNS.

Current and Novel Treatment Options for OSA

Obstructive sleep apnoea is a challenging medical problem due to its prevalence, its impact on quality of life and performance in school and professionally, the implications for risk of accidents, and comorbidities and mortality. Current research has carved out a broad spectrum of clinical phenotypes and defined major pathophysiological components. These findings point to the concept of personalised therapy, oriented on both the distinct clinical presentation and the most relevant pathophysiology in the individual patient. This leads to questions of whether sufficient therapeutic options other than positive airway pressure (PAP) alone are available, for which patients they may be useful, if there are specific indications for single or combined treatment, and whether there is solid scientific evidence for recommendations. This review describes our knowledge on PAP and non-PAP therapies to address upper airway collapsibility, muscle responsiveness, arousability and respiratory drive. The spectrum is broad and heterogeneous, including technical and pharmaceutical options already in clinical use or at an advanced experimental stage. Although there is an obvious need for more research on single or combined therapies, the available data demonstrate the variety of effective options, which should replace the unidirectional focus on PAP therapy.

The analysis of individual pathophysiological composition opens new directions towards personalised treatment of OSA, focusing not only on pharyngeal dilation, but also on technical or pharmaceutical interventions on muscle function or breathing regulationhttps://bit.ly/3sayhkd

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.

Obstructive sleep apnea

Obstructive sleep apnea (OSA) is a disease that results from loss of upper airway muscle tone leading to upper airway collapse during sleep in anatomically susceptible persons, leading to recurrent periods of hypoventilation, hypoxia, and arousals from sleep. Significant clinical consequences of the disorder cover a wide spectrum and include daytime hypersomnolence, neurocognitive dysfunction, cardiovascular disease, metabolic dysfunction, respiratory failure, and pulmonary hypertension. With escalating rates of obesity a major risk factor for OSA, the public health burden from OSA and its sequalae are expected to increase, as well. In this chapter, we review the mechanisms responsible for the development of OSA and associated neurocognitive and cardiometabolic comorbidities. Emphasis is placed on the neural control of the striated muscles that control the pharyngeal passages, especially regulation of hypoglossal motoneuron activity throughout the sleep/wake cycle, the neurocognitive complications of OSA, and the therapeutic options available to treat OSA including recent pharmacotherapeutic developments.

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.

Hypoglossal nerve stimulation for obstructive sleep apnea: updated position paper of the German Society of Oto-Rhino-Laryngology, Head and Neck Surgery

Since the first statement of the German Society of Oto-Rhino-Laryngology, hypoglossal nerve stimulation (HNS) is meanwhile an established treatment option for obstructive sleep apnea (OSA). There are three HNS systems available in Germany which differ in their technical details of the underlying comparable basic principle. For the unilateral HNS with respiratory sensing, several comparative studies, high-volume register analysis and long-term reports exist. The continuous HNS without respiratory sensing does not require a sleep endoscopy for indication. For the bilateral continuous HNS as the single partially implantable device, a feasibility study exists. For indication, the assessment of positive airway pressure failure by sleep medicine is crucial, and the decision for HNS should be made in discussion of other treatment options for at least moderate OSA. The implantation center holds primarily responsibility among the interdisciplinary sleep team and is primary contact for the patient in problems. This depicts why structural processes are required to secure outcome quality and minimize the complications. The aftercare of HNS patients can be provided interdisciplinary and by different medical institutions, whereat, minimal reporting standards to document outcome and usage are recommended.

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.

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.

Upper airway muscles: influence on obstructive sleep apnoea pathophysiology and pharmacological and technical treatment options

PURPOSE OF REVIEW

Obstructive sleep apnoea (OSA) is highly prevalent with numerous deleterious effects on neurocognitive and cardiovascular health. It is characterized by collapse of the upper airway during sleep, due to the decrease in both basal and compensatory UA muscle activities. However, the leading treatment, continuous positive airway pressure, is often poorly tolerated. This review presents latest works focusing on novel interventions targeting upper airway muscles to alleviate OSA severity.

RECENT FINDINGS

In the last years, researchers have focused on the development of alternative treatment strategies targeting UA muscle activation, including pharmacological and nonpharmacological interventions.

SUMMARY

Among the nonpharmacological treatments, hypoglossal nerve stimulation aims to increase upper airway muscle phasic activity during sleep through electrical stimulation, while myofunctional therapy improves the activity and coordination of upper airway dilator muscles.Regarding OSA pharmacotherapy, recent findings strongly suggest that selective norepinephrine reuptake inhibitors such as atomoxetine and reboxetine, when administered with antimuscarinics such as oxybutynin, can alleviate OSA in most patients increasing pharyngeal dilator muscles activity during sleep. New combinations of norepinephrine reuptake inhibitors and antimuscarinics have further been explored with variable success and animal models showed that leptin, thyrothropin releasing hormone analogues and gene therapy hold potential for the future of OSA pharmacotherapy.

[Hypoglossal Nerve Stimulation in the Treatment of Obstructive Sleep Apnea]

Reduced genioglossus muscle tone is considered one of the major causes for obstructive sleep apnea (OSA). Hypoglossal nerve stimulation (HNS) keeps the upper airway patent by increasing the muscle tone of the genioglossus muscle being the major airway opener. According to the German S3-Guideline on Sleep Disordered Breathing this treatment is indicated in patients with OSA failing or rejecting positive airway pressure, showing an AHI between 15 and 65, in particular when anatomy is normal and the BMI below 35. In 2021 it has been made available for regular patient care in Germany. However, breathing synchronized, continuous, and bilateral HNS differ in parts relevantly regarding their patient selection criteria, technical features, surgical technique, therapy setting and programming, and daily use for the patient. There are many publications showing the safety, efficacy, and patient satisfaction of breathing synchronized HNS. Less but promising data are available for continuous and the most recent bilateral HNS.