Hypoglossal Nerve Stimulation Therapy for the Treatment of Obstructive Sleep Apnea

Outcome Reporting in Prospective Studies Evaluating Neurostimulation for Obstructive Sleep Apnea

OBJECTIVE

Due to the controversy surrounding the appropriate outcomes in neurostimulation, we sought to systematically describe ways in which polysomnography and apnea-hypopnea index are reported in prospective studies involving unilateral hypoglossal nerve stimulation.

DATA SOURCES

MEDLINE (Ovid), Embase (Ovid), Cochrane Library, and Scopus.

REVIEW METHODS

Following the Preferred Reporting items of Systematic Reviews and Meta-analysis (PRISMA) Statement guidelines, a systematic two-reviewer system was used for study screening and quality assessment. Articles that met inclusion criteria were included. Quality was evaluated with either the Newcastle-Ottawa Quality Assessment Scale or the Covidence risk-of-bias tool.

RESULTS

Fifteen studies met the inclusion criteria, which included 14 prospective cohort studies and one randomized controlled trial. Titration polysomnography was the primary sleep study used to acquire data in five of the studies compared to only three studies employing exclusively non-titration polysomnography to report outcomes. Three studies compiled data from two or more sleep studies to report a single apnea-hypopnea index. Within the 15 studies, non-titration apnea-hypopnea index was the most reported type (five studies). Titration apnea-hypopnea index was used to report outcomes in one study. Five studies did not specify what type of apnea-hypopnea index was employed to report treatment effectiveness.

CONCLUSION

The reported sleep studies and corresponding apnea-hypopnea indices were highly variable across the studies. Because of the high degree of heterogeneity, future research would benefit from consistent use of a standardized apnea-hypopnea index to report outcomes related to hypoglossal nerve stimulation.

LEVEL OF EVIDENCE

NA Laryngoscope, 2024.

Are There Hidden Adverse Events in Hypoglossal Nerve Stimulation: Comparing Social Media and a Federal Database

OBJECTIVE

Hypoglossal nerve stimulation (HNS) can be an effective treatment for moderate to severe obstructive sleep apnea (OSA) in positive airway pressure (PAP) intolerant patients. To better understand patient experiences with HNS therapy, we explored reported events from HNS-related Facebook groups and the Manufacturer and User Facility Device Experience (MAUDE) database.

METHODS

A retrospective analysis of HNS-related Facebook posts from three groups pertaining to HNS therapy, from October 1, 2022 to October 1, 2023, was performed. Posts were analyzed for patient-reported adverse events. Concurrently, the MAUDE database was reviewed for HNS-related events during the same timeframe.

RESULTS

From 737 Facebook posts, 132 (17.55%) adverse events were identified. Adverse events included pain (34.85%), stimulation discomfort (14.39%), lip weakness (6.82%) and issues related to lead tethering or tight leads around the neck (3.79%). Analysis of the MAUDE database found 428 adverse events, including pain (24.07%), lip weakness (0.44%), and lead tethering (1.64%).

CONCLUSION

Facebook group members reported higher rates of lip weakness and lead tethering than recorded in the MAUDE database. These findings illustrate how diverse data sources, such as social media, can enhance our understanding of patient experiences and identify gaps in patient education with HNS therapy.

LEVEL OF EVIDENCE

NA Laryngoscope, 2024.

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.

Case report of hypoglossal nerve stimulation therapy failure due to significant underlying central sleep apnea

Hypoglossal nerve stimulation is indicated for obstructive sleep apnea but is ineffective in treating central sleep apnea. We describe 2 patients implanted with hypoglossal nerve stimulation after being diagnosed with obstructive sleep apnea at outside sleep laboratories and failing a trial of continuous positive airway pressure therapy. Despite successful hypoglossal nerve stimulation implantation, the patients continued to have persistent symptoms with residual apnea-hypopnea indices above 25 events/h. Although obstructive sleep apnea was the presenting diagnosis, we discovered a significant central sleep apnea component in the original diagnostic sleep data upon careful review. One patient was confirmed to have a central sleep apnea-predominant sleep disorder and improved with adaptive servo-ventilation therapy. The other was diagnosed with central sleep apnea and severe periodic limb movement disorder, and improved with medication. Based on these sleep apnea cases, we propose guidelines emphasizing the importance of reviewing basic clinical information upon treatment failure and initiating multidisciplinary collaboration early in the treatment course.

CITATION

Banerjee D, Lee C-H, Im K. Case report of hypoglossal nerve stimulation therapy failure due to significant underlying central sleep apnea. J Clin Sleep Med. 2024;20(6):1003-1007.

Respiratory Sensing Lead Malfunction in Upper Airway Stimulation: A Single Institution Report

OBJECTIVES

Upper airway stimulation (UAS) is an effective treatment for patients with obstructive sleep apnea. The device consists of a stimulating electrode, an internal pulse generator, and a respiratory sensing lead. The purpose of this study is to characterize the incidence of sensing lead malfunction necessitating revision surgery in a high-volume center in conjunction with a review of the FDA Manufacturer and User Facility Device Experience (MAUDE) database reports on adverse events associated with the sensing lead component.

METHODS

Patients age ≥18 implanted with the device were reviewed between July 2017 and June 2022. Those determined to have sensing lead malfunction were analyzed. The FDA MAUDE database was reviewed for reports associated with "Inspire Model 4323 Respiratory" and "Inspire Model 4340 Respiratory" between January 2014 and September 2022.

RESULTS

One hundred ninety patients underwent UAS at our institution during the study period and four (2.1%) patients were found to have sensing lead malfunction. Analysis of the MAUDE database revealed 122 reports of adverse events associated with the sensing lead component, with 72% (88/122) of these requiring revision surgery. The most frequently reported adverse event was sensing lead tip separation from lead body, noted in 46% of these reports (56/122).

CONCLUSION

The functionality of the sensing lead component is vital to the integrity of the UAS device and is measurable through waveform analysis. To provide optimal care after device implantation, it is essential to have a comprehensive understanding of the scenarios in which this component fails, the incidence of such events, and appropriate management.

LEVEL OF EVIDENCE

4 Laryngoscope, 134:1479-1484, 2024.

Clinical efficacy and mechanism study of mid-frequency anti-snoring device in treating moderate obstructive sleep apnea-hypopnea syndrome

BACKGROUND

Obstructive sleep apnea-hypopnea syndrome (OSAHS) is primarily caused by airway obstruction due to narrowing and blockage in the nasal and nasopharyngeal, oropharyngeal, soft palate, and tongue base areas. The mid-frequency anti-snoring device is a new technology based on sublingual nerve stimulation. Its principle is to improve the degree of oropharyngeal airway stenosis in OSAHS patients under mid-frequency wave stimulation. Nevertheless, there is a lack of clinical application and imaging evidence.

AIM

To investigate the clinical efficacy and mechanisms of a mid-frequency anti-snoring device in treating moderate OSAHS.

METHODS

We selected 50 patients diagnosed with moderate OSAHS in our hospital between July 2022 and August 2023. They underwent a 4-wk treatment regimen involving the mid-frequency anti-snoring device during nighttime sleep. Following the treatment, we monitored and assessed the sleep apnea quality of life index and Epworth Sleepiness Scale scores. Additionally, we performed computed tomography scans of the oropharynx in the awake state, during snoring, and while using the mid-frequency anti-snoring device. Cross-sectional area measurements in different states were taken at the narrowest airway point in the soft palate posterior and retrolingual areas.

RESULTS

Compared to pretreatment measurements, patients exhibited a significant reduction in the apnea-hypopnea index, the percentage of time with oxygen saturation below 90%, snoring frequency, and the duration of the most prolonged apnea event. The lowest oxygen saturation showed a notable increase, and both sleep apnea quality of life index and Epworth Sleepiness Scale scores improved. Oropharyngeal computed tomography scans revealed that in OSAHS patients cross-sectional areas of the oropharyngeal airway in the soft palate posterior area and retrolingual area decreased during snoring compared to the awake state. Conversely, during mid-frequency anti-snoring device treatment, these areas increased compared to snoring.

CONCLUSION

The mid-frequency anti-snoring device demonstrates the potential to enhance various sleep parameters in patients with moderate OSAHS, thereby improving their quality of life and reducing daytime sleepiness. These therapeutic effects are attributed to the device's ability to ameliorate the narrowing of the oropharynx in OSAHS patients.

Machine learning enables non-Gaussian investigation of changes to peripheral nerves related to electrical stimulation

Electrical stimulation of the peripheral nervous system (PNS) is becoming increasingly important for the therapeutic treatment of numerous disorders. Thus, as peripheral nerves are increasingly the target of electrical stimulation, it is critical to determine how, and when, electrical stimulation results in anatomical changes in neural tissue. We introduce here a convolutional neural network and support vector machines for cell segmentation and analysis of histological samples of the sciatic nerve of rats stimulated with varying current intensities. We describe the methodologies and present results that highlight the validity of the approach: machine learning enabled highly efficient nerve measurement collection, while multivariate analysis revealed notable changes to nerves' anatomy, even when subjected to levels of stimulation thought to be safe according to the Shannon current limits.

Bioelectricity in dental medicine: a narrative review

BACKGROUND

Bioelectric signals, whether exogenous or endogenous, play crucial roles in the life processes of organisms. Recently, the significance of bioelectricity in the field of dentistry is steadily gaining greater attention.

OBJECTIVE

This narrative review aims to comprehensively outline the theory, physiological effects, and practical applications of bioelectricity in dental medicine and to offer insights into its potential future direction. It attempts to provide dental clinicians and researchers with an electrophysiological perspective to enhance their clinical practice or fundamental research endeavors.

METHODS

An online computer search for relevant literature was performed in PubMed, Web of Science and Cochrane Library, with the keywords "bioelectricity, endogenous electric signal, electric stimulation, dental medicine."

RESULTS

Eventually, 288 documents were included for review. The variance in ion concentration between the interior and exterior of the cell membrane, referred to as transmembrane potential, forms the fundamental basis of bioelectricity. Transmembrane potential has been established as an essential regulator of intercellular communication, mechanotransduction, migration, proliferation, and immune responses. Thus, exogenous electric stimulation can significantly alter cellular action by affecting transmembrane potential. In the field of dental medicine, electric stimulation has proven useful for assessing pulp condition, locating root apices, improving the properties of dental biomaterials, expediting orthodontic tooth movement, facilitating implant osteointegration, addressing maxillofacial malignancies, and managing neuromuscular dysfunction. Furthermore, the reprogramming of bioelectric signals holds promise as a means to guide organism development and intervene in disease processes. Besides, the development of high-throughput electrophysiological tools will be imperative for identifying ion channel targets and precisely modulating bioelectricity in the future.

CONCLUSIONS

Bioelectricity has found application in various concepts of dental medicine but large-scale, standardized, randomized controlled clinical trials are still necessary in the future. In addition, the precise, repeatable and predictable measurement and modulation methods of bioelectric signal patterns are essential research direction.

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.

Current state of the art and future directions for implantable sensors in medical technology: Clinical needs and engineering challenges

Implantable sensors have revolutionized the way we monitor biophysical and biochemical parameters by enabling real-time closed-loop intervention or therapy. These technologies align with the new era of healthcare known as healthcare 5.0, which encompasses smart disease control and detection, virtual care, intelligent health management, smart monitoring, and decision-making. This review explores the diverse biomedical applications of implantable temperature, mechanical, electrophysiological, optical, and electrochemical sensors. We delve into the engineering principles that serve as the foundation for their development. We also address the challenges faced by researchers and designers in bridging the gap between implantable sensor research and their clinical adoption by emphasizing the importance of careful consideration of clinical requirements and engineering challenges. We highlight the need for future research to explore issues such as long-term performance, biocompatibility, and power sources, as well as the potential for implantable sensors to transform healthcare across multiple disciplines. It is evident that implantable sensors have immense potential in the field of medical technology. However, the gap between research and clinical adoption remains wide, and there are still major obstacles to overcome before they can become a widely adopted part of medical practice.

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.

Histological and contractile changes in the genioglossus muscle after nasal obstruction in growing rats

The aim of the study was to address the genioglossus muscle physiological and histological changes after unilateral nasal obstruction in growing rats. Fifty-four 6-day-old male Wistar albino rats were randomly divided into control (n = 27) and experimental (n = 27) groups. Unilateral nasal obstruction was performed at 8 days old. Contractile properties of the genioglossus whole muscle were measured at 5-, 7- and 9-week-old, including the twitch and tetanic forces, contraction time, half-decay time, and fatigue index. The histological characteristics of the genioglossus were also evaluated at 5-, 7- and 9-week-old, analyzing the myosin heavy chain composition of the slow, fast, IIa and IIb muscle fiber type, by measuring the number, rate, diameter and cross-sectional area. The maximal twitch force, and tetanic force at 60 Hz and 80 Hz force was significantly increased at all ages after nasal obstruction. The fatigue index was decreased at 5 weeks-old after nasal obstruction. The diameter and cross-sectional area of the fast, IIa and IIb muscle fiber types were increased at 7 and 9 weeks after nasal obstruction, while only the diameter of IIa type and cross-sectional area of IIb type were increased at 5 weeks-old after nasal obstruction. Nasal obstruction during growth affects the whole genioglossus muscle contractile properties and histological characteristics, increasing its force, the diameter and area of its muscle fibers. These changes in the genioglossus muscle may affect the normal growth, development and function of the craniofacial complex.

Oxytocin mediated excitation of hypoglossal motoneurons: implications for treating obstructive sleep apnea

Clinical studies have shown that oxytocin administered intranasally (IN) decreased the incidence and duration of obstructive events in patients with obstructive sleep apnea (OSA). Although the mechanisms by which oxytocin promotes these beneficial effects are unknown, one possible target of oxytocin could be the excitation of tongue-projecting hypoglossal motoneurons in the medulla, that exert central control of upper airway patency. This study tested the hypothesis that IN oxytocin enhances tongue muscle activity via the excitation of hypoglossal motoneurons projecting to tongue protrudor muscles (PMNs). To test this hypothesis we performed in vivo and in vitro electrophysiological studies in C57BL6/J mice as well as fluorescent imaging studies in transgenic mice in which neurons that express oxytocin receptors co-express fluorescent protein. IN oxytocin significantly increased the amplitude of inspiratory-related tongue muscle activity. This effect was abolished by severing the medial branch of hypoglossal nerve that innervates PMNs of the tongue. Oxytocin receptor-positive neurons were more prevalent in the population of PMNs than in retractor-projecting hypoglossal motoneurons (RMNs). Oxytocin administration increased action potential firing in PMNs, but had no significant effect on firing activity in RMNs. In conclusion, IN oxytocin stimulates respiratory-relating tongue muscle activity likely acting on central hypoglossal motoneurons that provide tongue protrusion and upper airway opening. This mechanism may play a role in oxytocin-induced reductions in upper airway obstructions in patients with OSA.

Perioperative and Perianesthesia Considerations for Hypoglossal Nerve Stimulator Implantation in Obstructive Sleep Apnea Patients

Hypoglossal nerve stimulation (Inspire Medical Systems, Maple Grove, Minnesota) is an innovative treatment option for eligible patients with moderate to severe obstructive sleep apnea (OSA). Since U.S. Food and Drug Administration approval in 2014, over 18,000 patients have been implanted. The device includes an implanted pacemaker-sized pulse generator, one sensing lead, and one stimulation lead. During sleep, inspirations and expirations are detected by the sensing lead. At end expiration, the stimulation lead triggers the hypoglossal nerve to contract and stiffen the tongue thus preventing airway obstruction and improving OSA. Perioperative and perianesthesia nurses have an important role in caring for these patients during all aspects of the surgical insertion process: evaluation for eligibility, device implantation, and future visits to the perioperative area for related and unrelated procedures. This article reviews anatomic and physiologic factors contributing to airway collapse in OSA, function of the hypoglossal nerve stimulation device, the evaluation, implantation, and activation process, and considerations for patient care in the perioperative and perianesthesia periods. Precautions needed for other therapies, including Magnetic Resonance Imaging, diathermy, and radiation are also discussed.

Hypoglossal nerve stimulation in adolescents with down syndrome and obstructive sleep apnea: A systematic review and meta-analysis

Objective

To evaluate the efficacy and adverse effects of hypoglossal nerve stimulation in adolescents with down syndrome and obstructive sleep apnea.

Methods

A systematic search was conducted using PubMed, Web of Science, Embase, and Scopus databases. The systematic review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. A comprehensive search strategy used a combination of Medical Subject Headings and free words with “OR” and “AND.” Articles were screened to extract data reporting apnea-hypopnea index, quality of life, voltage, follow-up duration, and complications. All included participants were adolescents with down syndrome and obstructive sleep apnea.

Results

A total of 92 articles were identified, of which 9 articles met the inclusion criteria. A total of 106 patients were included. All the studies showed that patients receiving hypoglossal nerve stimulation experienced a significant decrease in apnea-hypopnea index (at least 50%). The pooled AHI was significantly lower in patients following treatment (mean AHI reduction 17.43 events/h, 95% confidence interval 13.98–20.88 events/h, P < 0.001) after 2 case reports were excluded. The pooled OSA-18 were significantly decreased in 88 patients after treatment (mean OSA-18 reduction 1.67, 95% confidence interval 1.27–2.08, P < 0.001) after excluding 5 studies. Four investigations examined the necessity to optimize stimulation voltage for arousal during treatment. The most common complication was pain or discomfort in the tongue or mouth. Most studies had relatively short patient follow-up periods, with the most extended follow-up being 44–58 months.

Conclusion

Hypoglossal nerve stimulation significantly reduces apnea-hypopnea index and improves the quality of life; and thus, could be a potential alternative therapy for obstructive sleep apnea in adolescents with down syndrome. The adolescent's age, potential complications, adverse events, long-term efficacy, and comfort, needs to be considered while performing hypoglossal nerve stimulation.

Obstructive Sleep Apnea and Cardiovascular Diseases: Sad Realities and Untold Truths regarding Care of Patients in 2022

Obstructive sleep apnea (OSA) is one of the most common and serious sleep-related breathing disorders with a high prevalence among patients with cardiovascular (CV) diseases. Despite its widespread presence, OSA remains severely undiagnosed and untreated. CV mortality and morbidity are significantly increased in the presence of OSA as it is associated with an increased risk of resistant hypertension, heart failure, arrhythmias, and coronary artery disease. Evaluation and treatment of OSA should focus on recognizing patients at risk of developing OSA. The use of screening questionnaires should be routine, but a formal polysomnography sleep study is fundamental in establishing and classifying OSA. Recognition of OSA patients will allow for the institution of appropriate therapy that should alleviate OSA-related symptoms with the intent of decreasing adverse CV risk. In this review, we focus on the impact OSA has on CV disease and evaluate contemporary OSA treatments. Our goal is to heighten awareness among CV practitioners.

Anesthetic Management of a Patient With an Implantable Hypoglossal Nerve Stimulator: A Case Report

Obstructive sleep apnea (OSA) is a common condition, particularly in obese men and in those with an increased neck circumference. Management with a continuous positive airway pressure (CPAP) machine has been the mainstay of treatment over many years; although, it is not acceptable to all. Recently, innovative medical devices, such as hypoglossal nerve stimulators, have emerged and are now being increasingly utilized. We present a case report of a patient undergoing rotator cuff repair on the same side as the implanted device and our recommendations on the anesthetic management.

Sleep Neurology's Toolkit at the Crossroads: Challenges and Opportunities in Neurotherapeutics Lost and Found in Translation

We find ourselves at our present crossroads with a well-traveled toolkit, perhaps too well worn but with aspirational hopes and dreams for the field of sleep neurotherapeutics. This volume is organized thematically into six topical domains that parallel the major subspecialty areas of contemporary clinical sleep neurology practice, as well as novel directions and opportunities. The issue begins with an overview of the central disorders of hypersomnolence, including narcolepsy, idiopathic hypersomnia and other hypersomnia disorders, and the related use of the entire broad range of stimulant and wake-promoting pharmacotherapies. Next, the range of behavioral therapies, application of light and light restriction and melatonin therapies, and hypnotic pharmacotherapies useful in insomnia and circadian sleep-wake rhythm disorders are reviewed, followed by an overview of treatment options for sleep-related breathing disorders including positive airway pressure and the novel approach of hypoglossal neurostimulation for obstructive sleep apnea. The parasomnias and sleep-related movement disorders, including NREM disorders of arousal, REM parasomnias (nightmares and isolated sleep paralysis and idiopathic/isolated REM sleep behavior disorder, and restless legs syndrome are then discussed, and the applications of sleep neurotherapeutics in sleep and neurological disease are reviewed, including neurodevelopmental, epileptic, autoimmune encephalopathies, and neurodegenerative diseases. Last, the novel directions and opportunities in sleep neurology offered by cannabinoid therapies and machine learning/artificial intelligence methodology conclude this comprehensive survey of contemporary sleep neurology. We hope that you find this volume to be a useful and inspirational support tool for the work that matters most, your care of all our sleep neurology patients in the clinics.