Hypoglossal nerve stimulation improves obstructive sleep apnea: 12-month outcomes

Neurocognitive and Psychosocial Outcomes in Older Adults with Obstructive Sleep Apnea Following Hypoglossal Nerve Stimulation

OBJECTIVES

To assess the impact of hypoglossal nerve stimulation (HNS) on neurocognitive, psychological, and sleep outcomes in older adults with obstructive sleep apnea (OSA).

METHODS

A retrospective analysis of 42 patients aged 50 years and older who underwent HNS for OSA was conducted. Patient-reported outcomes were collected using validated tools, including the Insomnia Severity Index (ISI), PROMIS measures (Sleep-Related Impairment, Cognitive Function, Depression, Anxiety, Anger, Physical Function), Epworth Sleepiness Scale (ESS), Functional Outcomes of Sleep Questionnaire (FOSQ-10), and NIH Toolbox Loneliness survey. Pre- and post-HNS scores were compared using paired t-tests and Wilcoxon tests.

RESULTS

Significant improvements were observed in apnea-hypopnea index (AHI) (-17.6, P < .0001), ISI (-7.02, P < .0001), ESS (-3.4, P < .0001), and FOSQ (4.05, P < .0001). PROMIS measures showed significant posttreatment improvements in sleep impairment, cognitive function, depression, anxiety, anger, and loneliness (all P < .01). Physical function and pain did not change.

CONCLUSION

HNS significantly improves sleep characteristics, cognitive function, and psychosocial outcomes in older adults with OSA. Future studies should include larger and more diverse samples with longer follow-up, as well as a control condition.

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.

Polysomnographic features of hypoglossal nerve stimulation efficacy: Looking deeper than the apnea-hypopnea index

Objectives

Hypoglossal nerve stimulation (HGNS) is a promising surgical option for patients with obstructive sleep apnea (OSA) who are intolerant of continuous positive airway pressure therapy (CPAP). Efficacy studies for HGNS stimulation largely focus on the apnea-hypopnea index and/or oxygen desaturation index. This study's objective was to show the physiological effects of HGNS stimulation on upper airway patency, airflow, and treatment effect during polysomnography (PSG) testing.

Methods

PSG tracings from patients implanted with an Inspire© HGNS device were reviewed for this study. Nasal pressure was utilized as a surrogate for respiratory flow and chin electromyography was used to detect HGNS stimulation, allowing for breath-to-breath analysis. Per our sleep laboratory protocol, the HGNS device was turned on and off at different periods of the night. Respiratory tracings during these periods were visually analyzed.

Results

Analysis of on-off periods of HGNS therapy during PSG allows for a concise assessment of HGNS efficacy. The presence of inspiratory flow limitation and subsequent apneas or hypopneas upon turning off HGNS stimulation with restoration of stable, unobstructed breathing upon resuming HGNS stimulation indicates a positive treatment effect related to HGNS therapy. Despite the respiratory-sensing capacity of the Inspire HGNS device, desynchrony of stimulation and inspiration is observed. Desynchrony yields partially captured inspiratory cycles, allowing for assessment of HGNS effect on an individual breath.

Conclusion

Night-to-night and intranight variability in OSA severity makes assessing the effect of HGNS complex. Strategic testing protocols during postoperative PSG can provide critical insight into the effect of this therapy on upper airway obstruction during sleep. On-off periods of stimulation provide a concise assessment of the effect of HGNS on preventing upper airway collapse and help to account for night-to-night and intranight variability. Respiratory desynchrony associated with HGNS therapy exists. Observing partially-stimulated inspiratory cycles allow for assessment of HGNS's effect on a single breath.

Level of Evidence

4.

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.

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.

Baseline Characteristics Associated with Hypoglossal Nerve Stimulation Treatment Outcomes in Patients with Obstructive Sleep Apnea: A Systematic Review

Hypoglossal nerve stimulation (HGNS) has emerged as an effective treatment for obstructive sleep apnea (OSA). Identifying baseline characteristics that prospectively could predict treatment outcomes even better is crucial for optimizing patient selection and improving therapeutic success in the future. A systematic review was conducted following PRISMA guidelines. Literature searches in Medline, Web of Science, and Cochrane databases identified studies assessing baseline characteristics associated with HGNS treatment outcomes. Inclusion criteria focused on studies with adult patients diagnosed with OSA, treated with HGNS, and assessed using full-night efficacy sleep studies. Risk of bias was evaluated using the NICE tool. Twenty-six studies met the inclusion criteria. Commonly reported baseline characteristics with predictive potential included BMI, site of collapse, and various pathophysiological endotypes. Most studies used the original Sher criteria to define treatment response, though variations were noted. Results suggested that lower BMI, absence of complete concentric collapse at the palatal level, and specific pathophysiological traits were associated with better HGNS outcomes. This review identified several baseline characteristics associated with HGNS outcomes, which may guide future patient selection. Importantly, patients were already preselected for HGNS. Standardizing response criteria is recommended to enhance the evaluation and effectiveness of HGNS therapy in OSA patients.

[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.

Safety of Ambulatory Surgery For Obstructive Sleep Apnea: A Retrospective Review

OBJECTIVE

Assess the safety of ambulatory surgery performed for obstructive sleep apnea.

STUDY DESIGN

Retrospective chart review.

SETTING

Tertiary care hospital.

METHODS

Demographic data including age, gender, race, body mass index, insurance status, socioeconomic status, and distance traveled for surgery was collected, as well as comorbidities, and apnea-hypopnea index (AHI). Outcome variables included continuous positive airway pressure reinitiation, planned/unplanned postoperative admission, emergency department (ED) presentation, or readmission within 7 and 14 days of surgery.

RESULTS

A total of 601 patients were included, who underwent sleep surgery between 2017 and 2022. The median age was 55 years [interquartile range: 19]. A total of 437 patients (73%) were male, 502 (84%) were Caucasian, and the median distance traveled was 20 miles [27]. The median AHI was 27.1 [26]. A total of 286 hypoglossal nerve stimulators, 12 tonsillectomies, 160 expansion sphincteroplasties (ESP), and 201 nasal procedures were performed. There were 9 (1%) planned and 23 (4%) total admissions postoperatively. Sixteen patients (2%) presented to ED within 7 days, and 22 (3%) within 14 days. Nine (1%) were readmitted within 7 days, and 12 (2%) within 14 days. There were significantly more planned admissions, unplanned admissions, ED presentations, and readmissions for ESP. There were no significant differences in demographic or clinical data between patients who underwent single versus multiple surgeries.

CONCLUSION

Outpatient sleep surgery is generally safe. Close postoperative monitoring is necessary and overnight observation should be considered in those with very severe sleep apnea and/or significant comorbidities. The distance a patient travels should also be considered for overnight admission.

Use of Hypoglossal Nerve Stimulation for Treating OSA in Military Patient Populations

Background

Failure to effectively treat obstructive sleep apnea (OSA) and its symptoms is incompatible with military readiness. Continuous positive airway pressure (PAP) is the gold standard treatment for OSA, but it is impractical in austere environments. Another OSA treatment, hypoglossal nerve stimulation (HGNS), which is implanted, could have advantages for military patients but is unclear whether HGNS is efficacious.

Methods

We conducted a review of randomized controlled trials and controlled trials published from 2013 to 2023. Primary outcome measures included the Apnea-Hypopnea Index and Epworth Sleepiness Scale. The quality of evidence was assessed using a rating of 1 to 5 based on a modification of the Oxford Centre for Evidence-based Medicine Levels of Evidence and Grades of Recommendation.

Results

We identified 334 studies; 318 did not meet inclusion criteria. The remaining 16 articles were classified into 9 cohorts. Six articles were based on data from the STAR trial and 4 were based on data from a German postmarket long-term follow-up of upper airway stimulation for OSA efficacy. The remaining cohorts were smaller studies that examined moderate-to-severe OSA with nonadherence or failure, a randomized controlled crossover trial, and 1 direct comparator with PAP treatment.

Conclusions

HGNS feasibility in military settings has not been adequately studied, considering the specific demands of operational settings and patient demographics. Understanding risks and benefits specific to military context will help guide practices and determine the suitability of HGNS for OSA in diverse military settings.

Advances in the Use of Hypoglossal Nerve Stimulator in Adolescents With Down Syndrome and Persistent Obstructive Sleep Apnea-A Systematic Review

INTRODUCTION

The Hypoglossal Nerve Stimulator (HNS) is a novel therapy that has been extensively studied in adults and more recently, it has been incorporated in children with Down Syndrome (DS) with persistent obstructive sleep apnea after adenotonsillectomy and trial of continuous positive airway pressure treatment. This systematic review article aims to examine the existing literature on HNS use in children to explore the benefits, efficacy, and parental experiences.

METHODS

MEDLINE, Web of Science and EMBASE were searched to include all studies published up to March 2nd, 2023, on the topic of HNS use in pediatric population under 21 years old.

RESULTS

A total of 179 studies were initially identified from which 10 articles were consistent with the inclusion criteria. Nine articles addressed outcomes after implantation of the HNS device in children with DS and 1 article explored the parental experiences. Findings were similar across studies where after implantation of HNS, there was marked improvement in polysomnographic outcomes and quality of life scores with high level of compliance.

CONCLUSIONS

HNS holds promise as an effective treatment option for pediatric patients with DS and persistent OSA after AT and CPAP trials. It significantly improves sleep-disordered breathing, quality of life, and neurocognitive measures, leading to substantial and sustained benefits for these children. While the findings are encouraging, further research is needed to explore the potential of HNS in other pediatric populations without DS and to raise awareness among healthcare providers about this treatment option. Overall, HNS may offer significant long-term benefits for the overall well-being and health of pediatric patients with DS and persistent OSA.

Upper airway stimulation device failure: A 7-year single center experience

OBJECTIVE

To identify and report a single center experience with upper airway stimulator device-related failures.

STUDY DESIGN

Retrospective case series.

SETTING

Single tertiary academic center.

METHODS

Retrospective data on 352 patients who underwent UAS surgery with an Inspire device from 2016 to 2023 was collected, including demographics, comorbidities, and nature of device failure requiring revision surgery.

RESULTS

Out of the 348 patients included in our analysis, 16 (4.6 %) required revision due to device failure, with an average interval of 772 days (∼2 years) between initial implant and revision. Most failures were attributed to respiratory sensing lead damage (n = 11, 68.8 %), resulting in high system impedance and subsequent device malfunction. Lead fracture causes varied, including idiopathic occurrences and potential trauma. Lead migration was noted in one case (6.3 %), where the hypoglossal electrode detached from the nerve. Two patients (12.3 %) required implantable pulse generator (IPG) replacement, one after experiencing trauma and the other due to unclear source of malfunction. One patient (6.3 %) required complete system replacement following high lead impedance and absent tongue motion. The last patient required replacement of both the IPG and respiratory lead after experiencing high lead impedance (6.3 %).

CONCLUSION

Respiratory sensing lead fracture emerged as the leading cause of device failure in this cohort, underscoring the need to address this under-reported issue, potentially linked to the time lapse after device implantation.

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.

Clinical Characteristics of Older Adults Seeking Hypoglossal Nerve Stimulation for the Treatment of Obstructive Sleep Apnea

OBJECTIVES

Obstructive sleep apnea (OSA) is a common sleep disorder with numerous clinical correlates. Although effective treatments abound, patient acceptance and adherence is low. Hypoglossal nerve stimulation (HNS) is a surgical treatment alternative for the treatment of OSA; however, the demographic and clinical characteristics of individuals seeking HNS are not well categorized. This study sought to determine the clinical characteristics of older adults seeking HNS for the treatment of OSA.

METHODS

Self-report questionnaires were administered to all patients older than 50 years seeking a HNS consultation at a large university medical center. Questionnaires included validated National Institutes of Health Patient-Reported Outcomes Measurement Information System (NIH PROMIS) measures of physical functioning, sleep-related impairment, cognitive abilities, depression, anxiety, and anger along with the Information extracted from electronic medical records included age, sex, race, and apnea-hypopnea index (AHI).

RESULTS

Patients included 113 adults (mean age 63.30 years, 57% male, 79% white) with severe OSA (AHI = 33.91, standard deviation = 20.63). Overall, 88% of patients reported elevated insomnia symptoms, 30% reported mild difficulty with physical functioning, and 36% indicated that they had experienced moderate-severe daytime impairments attributed to poor sleep. Additionally, we found 28% of sampled individuals reported moderate-severe depressive symptomology, over 19% reported moderate-severe anxiety, and over 17% reported moderate to severe anger issues. Approximately, 38% of the sample reported moderate to severe cognitive difficulties.

CONCLUSIONS

The aim of the study was to better understand the clinical characteristics of older patients with OSA seeking HNS treatment. Utilizing NIH PROMIS questionnaires, we identified unique clinical and psychosocial correlates in this sample, which included higher rates of insomnia symptoms, physical dysfunction, cognitive deficits, and depressive symptoms than the general population. Future studies will be needed to investigate these relationships more thoroughly and throughout the course of the treatment.

Increased Body Mass Index Correlates with Less Favorable Postoperative Outcomes After Hypoglossal Nerve Stimulation for Obstructive Sleep Apnea: A Retrospective Cohort Study

OBJECTIVE

Obstructive sleep apnea is associated with high morbidity. Hypoglossal nerve stimulation (HNS) has become a novel (neuro-) surgical treatment strategy for obstructive sleep apnea, demonstrating good success rates. Beyond predefined inclusion and exclusion criteria, no precise data are available, enabling individual preoperative risk assessment. To improve preoperative risk stratification, this study analyzed individual patient factors that affect outcomes of HNS.

METHODS

Fourteen patients treated with unilateral HNS were analyzed retrospectively. Assessed risk factors included: hypertension, diabetes mellitus, depression, smoking, alcohol consumption, body mass index (BMI), and disease duration. Treatment success was defined as a reduction in the postoperative apnea-hypopnea index (AHI) to ≤20 events/hour, with a relative reduction of at least 50% compared to baseline.

RESULTS

A significant reduction in the postoperative apnea-hypopnea index was observed in all patients (P < 0.0001). BMI correlated significantly with postoperative AHI scores (95% confidence interval, 0.1519-0.8974; P = 0.018). Significant treatment success was observed in 50% of patients. Compared with the "Excellent Responder group," the "Responder group" demonstrated a significantly higher BMI (95% confidence interval, 1.174-6.226; P = 0.0078). Diabetes, hypertension, disease duration, smoking, depression, and alcohol consumption were not significantly associated with AHI reduction.

CONCLUSIONS

Our findings suggest that BMI may be an independent risk factor for the response to HNS, with patients who had less benefit from therapy having significantly higher BMI than "Excellent Responders." Therefore, carefully selecting patients is crucial in obtaining optimal outcomes with HNS therapy, especially those with a high BMI.

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.

Drive versus Pressure Contributions to Genioglossus Activity in Obstructive Sleep Apnea

Rationale: Loss of pharyngeal dilator muscle activity is a key determinant of respiratory events in obstructive sleep apnea (OSA). After the withdrawal of wakefulness stimuli to the genioglossus at sleep onset, mechanoreceptor negative pressure and chemoreceptor ventilatory drive feedback govern genioglossus activation during sleep, but the relative contributions of drive and pressure stimuli to genioglossus activity across progressive obstructive events remain unclear. We recently showed that drive typically falls during events, whereas negative pressures increase, providing a means to assess their individual contributions to the time course of genioglossus activity. Objectives: For the first time, we critically test whether the loss of drive could explain the loss of genioglossus activity observed within events in OSA. Methods: We examined the time course of genioglossus activity (EMGgg; intramuscular electromyography), ventilatory drive (intraesophageal diaphragm electromyography), and esophageal pressure during spontaneous respiratory events (using the ensemble-average method) in 42 patients with OSA (apnea-hypopnea index 5-91 events/h). Results: Multivariable regression demonstrated that the falling-then-rising time course of EMGgg may be well explained by falling-then-rising drive and rising negative pressure stimuli (model R = 0.91 [0.88-0.98] [95% confidence interval]). Overall, EMGgg was 2.9-fold (0.47-∞) more closely associated with drive than pressure stimuli (ratio of standardized coefficients, βdrive:βpressure; ∞ denotes absent pressure contribution). However, individual patient results were heterogeneous: approximately one-half (n = 22 of 42) exhibited drive-dominant responses (i.e., βdrive:βpressure > 2:1), and one-quarter (n = 11 of 42) exhibited pressure-dominant EMGgg responses (i.e., βdrive:βpressure < 1:2). Patients exhibiting more drive-dominant EMGgg responses experienced greater event-related EMGgg declines (12.9 [4.8-21.0] %baseline/standard deviation of βdrive:βpressure; P = 0.004, adjusted analysis). Conclusions: Loss of genioglossus activity precipitating events in patients with OSA is strongly associated with a contemporaneous loss of drive and is greatest in those whose activity tracks drive rather than pressure stimuli. These findings were upheld for events without prior arousal. Responding to falling drive rather than rising negative pressure during events may be deleterious; future therapeutic strategies whose aim is to sustain genioglossus activity by preferentially enhancing responses to rising pressure rather than falling drive are of interest.

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.

International Consensus Statement on Obstructive Sleep Apnea

BACKGROUND

Evaluation and interpretation of the literature on obstructive sleep apnea (OSA) allows for consolidation and determination of the key factors important for clinical management of the adult OSA patient. Toward this goal, an international collaborative of multidisciplinary experts in sleep apnea evaluation and treatment have produced the International Consensus statement on Obstructive Sleep Apnea (ICS:OSA).

METHODS

Using previously defined methodology, focal topics in OSA were assigned as literature review (LR), evidence-based review (EBR), or evidence-based review with recommendations (EBR-R) formats. Each topic incorporated the available and relevant evidence which was summarized and graded on study quality. Each topic and section underwent iterative review and the ICS:OSA was created and reviewed by all authors for consensus.

RESULTS

The ICS:OSA addresses OSA syndrome definitions, pathophysiology, epidemiology, risk factors for disease, screening methods, diagnostic testing types, multiple treatment modalities, and effects of OSA treatment on multiple OSA-associated comorbidities. Specific focus on outcomes with positive airway pressure (PAP) and surgical treatments were evaluated.

CONCLUSION

This review of the literature consolidates the available knowledge and identifies the limitations of the current evidence on OSA. This effort aims to create a resource for OSA evidence-based practice and identify future research needs. Knowledge gaps and research opportunities include improving the metrics of OSA disease, determining the optimal OSA screening paradigms, developing strategies for PAP adherence and longitudinal care, enhancing selection of PAP alternatives and surgery, understanding health risk outcomes, and translating evidence into individualized approaches to therapy.

Changes in tongue morphology predict responses in pharyngeal patency to selective hypoglossal nerve stimulation

STUDY OBJECTIVES

The major goal of the study was to determine whether changes in tongue morphology under selective hypoglossal nerve therapy for obstructive sleep apnea were associated with alterations in airway patency during sleep when specific portions of the hypoglossal nerve were stimulated.

METHODS

This case series was conducted at the Johns Hopkins Sleep Disorders Center at Johns Hopkins Bayview Medical Center. Twelve patients with apnea implanted with a multichannel targeted hypoglossal nerve-stimulating system underwent midsagittal ultrasound tongue imaging during wakefulness. Changes in tongue shape were characterized by measuring the vertical height and polar dimensions between tongue surface and genioglossi origin in the mandible. Changes in patency were characterized by comparing airflow responses between stimulated and adjacent unstimulated breaths during non-rapid eye movement sleep.

RESULTS

Two distinct morphologic responses were observed. Anterior tongue base and hyoid-bone movement (5.4 [0.4] to 4.1 [1.0] cm (median and [interquartile range]) with concomitant increases in tongue height (5.0 [0.9] to 5.6 [0.7] cm) were associated with decreases in airflow during stimulation. In contrast, comparable anterior hyoid movement (tongue protrusion from 5.8 [0.5] to 4.5 [0.9] cm) without significant increases in height (5.2 [1.6] to 4.6 [0.8] cm) were associated with marked increases in airflow during sleep.

CONCLUSIONS

Tongue protrusion with preservation of tongue shape predicted increases in patency, whereas anterior movement with concomitant increases in height were associated with decreased pharyngeal patency. These findings suggest that pharyngeal patency can be best stabilized by stimulating lingual muscles that maintain tongue shape while protruding the tongue, thereby preventing it from prolapsing posteriorly during sleep.

CITATION

Fleury Curado T, Pham L, Otvos T, et al. Changes in tongue morphology predict responses in pharyngeal patency to selective hypoglossal nerve stimulation. J Clin Sleep Med. 2023;19(5):947-955.

OMS residents’ obstructive sleep apnea‐related education, knowledge, and professional behavior: A national survey

OBJECTIVES

Oral and maxillofacial surgeons (OMS) treat adult and pediatric patients with obstructive sleep apnea (OSA). Objective 1 assessed sleep apnea-related education, knowledge, and professional behavior of OMS residents in the United States. Objective 2 was to compare the responses of junior versus senior residents and residents in single- versus dual-degree programs.

METHODS

OMS residents in the United States received a recruitment email with a link to an anonymous online survey; 81 residents responded. The survey included 20 questions to assess respondents' OSA-related education, knowledge, attitudes, and professional behavior.

RESULTS

Respondents generally agreed that they had received OSA-related didactic-based education (5-point scale with "5" = agree strongly: mean = 3.62) and clinical training (mean = 3.75). Clinical and classroom educational gaps were identified in relation to treatment with oral appliances and hypoglossal nerve stimulation. The residents scored on average 10.38 out of 18 (58%) possible correct answer points for the knowledge questions. Findings about pediatric OSA suggest that only 43.8% of residents understand diagnostic criteria for pediatric OSA, with only 26.6% screening pediatric patients for OSA. A case analysis showed that only 1.5% of residents correctly identified an apnea-hypopnea index of 17 as moderate sleep apnea.

CONCLUSION(S)

This survey found knowledge gaps in several areas that can be improved upon. It identifies deficiency in objective knowledge about OSA among OMS residents and a specific lack of clinical training and confidence with hypoglossal nerve stimulation and management of pediatric patients with OSA. Junior and senior residents and single- and dual-degree residents showed no statistically significant differences in any category except senior residents in regard to surgical management of OSA, particularly with maxillomandibular advancement.

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.

Management of Obstructive Sleep Apnea in Patients With Heart Failure

Sleep apnea is traditionally classified as obstructive sleep apnea (OSA), which occurs when the upper airway collapses due to the relaxation of oropharyngeal musculature, and central sleep apnea occurs when the brainstem cannot stimulate breathing. Most sleep apnea in patients with heart failure (HF) results from coexisting OSA and central sleep apnea (CSA), or complex sleep apnea syndrome. OSA and CSA are common in HF and can be involved in its progression by exposure to the heart to intermittent hypoxia, increased preload and afterload, activating sympathetic, and decreased vascular endothelial function. A majority of treatments have been investigated in patients with CSA and HF; however, less or short-term randomized trials demonstrated whether treating OSA in patients with HF could improve morbidity and mortality. OSA could directly influence the patient's recovery. This review will focus on past and present studies on the various therapies for OSA in patients with HF and summarize CSA treatment options for reasons of reference and completeness. More specifically, the treatment covered include surgical and non-surgical treatments and reported the positive and negative consequences for these treatment options, highlighting possible implications for clinical practice and future research directions.

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.

High Frequency-Low Amplitude Oscillometry: Continuous Unobtrusive Monitoring of Respiratory Function on PAP Machines

Oscillometry or Forced Oscillation Technique, traditionally used in intermittent clinical measurements, has recently gained substantial attention from its application as a continuous monitoring tool for large and small airways. However, low frequency (< 8 Hz) continuous oscillometry faces high breathing noise, and hence requires high oscillation amplitudes to maintain an acceptable signal-to-noise ratio. Therefore, PAP machines that utilize low frequency oscillometry do so intermittently to distinguish airway patency several seconds after a breathing pause has occurred. We hypothesized that high frequency and low amplitude (HFLA) oscillometry may be as sensitive and applicable for monitoring upper airway patency to distinguish between central and obstructive apnea and hypopnea events, and for monitoring respiratory impedance. An inline oscillometry prototype device was developed and connected to commercial PAP machines to test whether oscillometry at 17, 43, and 79 Hz are as sensitive to airway patency as oscillometry at 4 Hz. Analysis of 11 patients with 171 apneas and hypopneas showed that all frequency oscillometry inputs were equally sensitive in distinguishing between central and obstructive apneas, while 17 Hz and 43 Hz oscillometry were most sensitive in distinguishing between central and obstructive hypopneas. Observations during normal breathing also showed the same periodicity and cross-correlation between impedance measurements from HFLA oscillometry compared to 4 Hz. Our findings provide an unobtrusive means of distinguishing airway patency during sleep and a means of continuous monitoring of respiratory function, with the potential for detection and prediction of developing respiratory diseases and significantly richer context for data analytics.

Neuromodulation in Obstructive Sleep Apnea

Epidemiological studies show a steady rise in the prevalence of obstructive sleep apnea (OSA). Untreated OSA is responsible for numerous chronic health conditions, motor vehicle, and workplace-related accidents leading to substantial economic burden both to the individual and society. Multiple causes for OSA and a wide range of consequences has made its diagnosis and treatment difficult. Obstructive sleep apnea may be caused by anatomical variation, increased collapsibility of the upper airway, low sleep arousal threshold, and exaggerated response to desaturation. Lifestyle changes, anatomical corrective surgeries, and oral appliances have been used but patient compliance is poor as it interferes in the daily routine. Neuromodulation is a promising functional modifying option that addresses the cause of obstructive sleep apnea at multiple levels.

Obstructive Sleep Apnea: Non-positive Airway Pressure Treatments

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

Upper airway stimulation vs other upper airway surgical procedures for OSA: a meta-analysis

PURPOSE

The aim was to compare the outcomes of upper airway stimulation (Stim) and other upper airway surgical procedures (Surg) in the treatment of obstructive sleep apnea (OSA).

METHODS

Data sources included PubMed, Ovid MEDLINE, Cochrane Library, Web of Science, Scopus, and reference lists. Relevant articles were identified from various databases according to the PRISMA guidelines.

RESULTS

Five articles with a total of 990 patients were included. The mean cure rates in the Stim group and the Surg group was 63% and 22%, and the mean success rates was 86% and 51% which were higher in the Stim group (p < 0.001). The apnea-hypopnea index reduction was -23.9 events/ hour (MD, 95% CI -25.53, -22.29) in the Stim group and -15.5 events/hour (MD, 95% CI -17.50, -13.45) in the Surg group which was greater in the Stim group (P < 0.001). Epworth Sleepiness Scale decreased -4.9 (MD, 95% CI -5.45, -4.32) in the Stim group and -5.1 (MD 95% CI -5.88, -4.37) in the Surg group without significant difference between the groups (P = 0.62). Oxygen saturation nadir improvement was 8.5% (MD 95% CI 7.05%, 9.92%) in the Stim group and 2.2% (MD 95% CI-0.22%, 4.58%) in the Surg group which was higher in the Stim group (P < 0.001). Hospital stay and readmission rate were lower in the Stim group. The timing of follow-up ranged from 2 to 13 months.

CONCLUSION

Upper airway stimulation provides improved objective and similar subjective outcomes compared to other upper airway surgical procedures for selected patients with moderate to severe OSA with difficulty adhering to CPAP treatment. However, further studies are essential to confirm outcomes in the long term.

The Hypoglossal Nerve Stimulation as a Novel Therapy for Treating Obstructive Sleep Apnea-A Literature Review

Obstructive sleep apnea (OSA) is a common sleep disorder that affects all age groups and is associated with many co-morbid diseases (especially cardiovascular diseases). Continuous positive airway pressure (CPAP) is the gold standard for treating OSA. However, adherence to PAP therapy has been a major challenge with an estimated adherence between 20% and 80%. Mandibular advancement devices (MAD) are a good alternative option if used in the appropriate patient. MAD are most effective in mild and moderate OSA but not severe OSA. Surgical options are invasive, not appropriate for severe OSA, and associated with pain and long healing time. Hypoglossal nerve stimulation (HGNS), or upper airway stimulation (UAS), is a novel therapy in treating moderate and severe degrees of OSA in patients who cannot tolerate CPAP therapy. We reviewed the MEDLINE (PubMed) database. The search process yielded 303 articles; 31 met the inclusion and exclusion criteria and were included. We concluded that hypoglossal nerve stimulation is a very effective and novel alternative therapy for moderate and severe OSA in patients who cannot tolerate CPAP therapy. Adherence to HGNS is superior to CPAP. However, more developments are needed to ensure the highest safety profile.

Considering the Role of Adherence in New and Emerging Sleep Treatments

There are several novel and emerging treatments for obstructive sleep apnea (OSA), including new devices and pharmacotherapies. Long-term efficacy and adherence data for these interventions in the sleep context are lacking. Future studies exploring the long-term adherence and efficacy in novel and emerging treatments of OSA are required to fully understand the place of these treatments in treatment hierarchies. Such research also should aim to evaluate the use of these novel therapies in real-world clinical settings, because many of the studies performed to date have been done under closely monitored research populations and relatively small sample sizes.

Predictors of success in hypoglossal nerve stimulator implantation for obstructive sleep apnea

Objective

Current guidelines for hypoglossal nerve stimulator (HGNS) implantation eligibility include drug-induced sleep endoscopy (DISE) findings and other patient characteristics but lead to highly variable rates of surgical success across institutions. Our objective was to determine whether additional factors seen on preoperative evaluation could be used as predictors of surgical success.

Study design

Retrospective chart review.

Setting

Single-institution academic tertiary care medical center.

Subjects

and Methods:This study included patients with obstructive sleep apnea (OSA) who underwent HGNS implantation between 2015 and 2018. Surgical success was defined as a postoperative apnea-hypopnea index (AHI) of less than 20 events per hour and an AHI reduction of at least 50%. Preoperative polysomnogram (PSG) results, DISE findings, and physical parameters were compared between surgical successes and failures.

Results

A total of 68 patients were included in the analysis. The overall surgical success rate was 79.4% (54/68). Elevated preoperative AHI was associated with an increased likelihood of treatment failure, with an AHI of (36.9 ± 16.8) events/hour in the success group compared to (49.4 ± 19.6) events/hour in the failure group (P = 0.05). Patients observed to have partial lateral oropharyngeal collapse on DISE was more frequently associated with the treatment failure group than in the success group (P = 0.04).

Conclusion

Patients who underwent HGNS implantation overall had a very high treatment response rate at our institution. Factors that may predispose patients to surgical failure included the presence of lateral oropharyngeal collapse and a significantly elevated preoperative AHI. These should be considered when determining surgical candidacy for HGNS implantation.

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

PURPOSE

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

PATIENTS AND METHODS

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

RESULTS

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

CONCLUSION

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

Update on Research and Practices in Major Sleep Disorders: Part I. Obstructive Sleep Apnea Syndrome

PURPOSE

The purpose of this first of two review articles providing an update on sleep disorders was to examine the pathophysiology, epidemiology, and treatment of obstructive sleep apnea (OSA). OSA is a common sleep disorder whose prevalence is similar to asthma. As with other sleep disorders, OSA has a broad impact on individuals, affecting their daily behaviors, cognitive abilities, and performance, and putting them at increased risk for accidents, mood disorders, cancer, cardiovascular disease, and hypertension. Thus, early recognition and management, much of which can be implemented by nurses, can reduce health and accident risks and improve daily functioning.

METHODS

This narrative review utilized medical databases such as PubMed to identify relevant English language original and systematic review articles predominantly from peer-reviewed journals from 2012 to 2018. However, as background, findings from classic articles prior to 2012 were also included.

CLINICAL RELEVANCE

OSA is a common condition with considerable impact on daily functioning and potential for accidents and serious comorbidities such as hypertension, cardiovascular disease, diabetes, and depressed mood. The impairments and comorbidities associated with OSA can be reduced through early detection, encouraging treatment, providing education about sleep and OSA, and, importantly, promoting adherence to the predominant therapy, positive airway pressure.

Cross motor innervation of the hypoglossal nerve-a pilot study of predictors for successful opening of the soft palate

PURPOSE

Selective hypoglossal nerve stimulation has proven to be a successful treatment option in patients with obstructive sleep apnea. The aim of this pilot study was to investigate if there is a cross-innervation of the hypoglossal nerve in humans and if patients with this phenotype show a different response to hypoglossal nerve stimulation compared to those with ipsilateral-only innervation METHODS: Nineteen patients who previously received a selective hypoglossal nerve stimulation system (Inspire Medical Systems, Golden Valley, USA) were implanted with a nerve integrity system placing electrodes on both sides of the tongue. Tongue motions were recorded one and two months after surgery from transoral and transnasal views. Polysomnography (PSG) was also performed at two months. Electromyogram (EMG) signals and tongue motions after activation were compared with PSG findings.

RESULTS

Cross-innervation showed significant correlation with bilateral tongue movement and bilateral tongue base opening, which were associated with better PSG outcomes.

CONCLUSION

Cross motor innervation of the hypoglossal nerve occurs in approximately 50% of humans, which is associated with a positive effect on PSG outcomes. Bilateral stimulation of the hypoglossal nerve may be a solution for non-responding patients with pronounced collapse at the soft palate during drug-induced sleep endoscopy.

Electrical stimulation as a therapeutic approach in obstructive sleep apnea - a meta-analysis

PURPOSE

Electrical stimulation of the upper airway dilator muscles is an emerging treatment for obstructive sleep apnea (OSA). Invasive hypoglossal nerve stimulation (HNS) has been accepted as treatment alternative to continuous positive airway pressure (CPAP) for selected patients, while transcutaneous electrical stimulation (TES) of the upper airway is being investigated as non-invasive alternative.

METHODS

A meta-analysis (CRD42017074674) on the effects of both HNS and TES on the apnea-hypopnea index (AHI) and the Epworth Sleepiness Scale (ESS) in OSA was conducted including published evidence up to May 2018. Random-effects models were used. Heterogeneity and between-study variance were assessed by I² and τ², respectively.

RESULTS

Of 41 identified clinical trials, 20 interventional trials (n = 895) could be pooled in a meta-analysis (15 HNS [n = 808], 5 TES [n = 87]). Middle-aged (mean ± SD 56.9 ± 5.5 years) and overweight (body mass index 29.1 ± 1.5 kg/m²) patients with severe OSA (AHI 37.5 ± 7.0/h) were followed-up for 6.9 ± 4.0 months (HNS) and 0.2 ± 0.4 months (TES), respectively. The AHI improved by - 24.9 h^-1 [95%CI - 28.5, - 21.2] in HNS (χ² 79%, I² 82%) and by - 16.5 h^-1 [95%CI - 25.1, - 7.8] in TES (χ² 7%, I² 43%; both p < 0.001). The ESS was reduced by - 5.0 (95%CI - 5.9, - 4.1) (p < 0.001).

CONCLUSION

Both invasive and transcutaneous electrical stimulation reduce OSA severity by a clinically relevant margin. HNS results in a clinically relevant improvement of symptoms. While HNS represents an invasive treatment for selected patients with moderate to severe OSA, TES should be further investigated as potential non-invasive approach for OSA.

Implantable Neurostimulation for Treatment of Sleep Apnea: Present and Future

Hypoglossal nerve stimulation (HNS) therapy represents a novel approach and a paradigm shift in the evolution of obstructive sleep apnea (OSA) treatment as a hybrid surgically implanted, medically titratable device. Unlike traditional sleep apnea surgical procedures, HNS augments the neuromuscular activity of the pharynx, preserves upper airway structure and function, and has the potential to provide multilevel upper airway improvement with one procedure. The early success of HNS sets the stage for new technology development, further investigation into optimal patient selection and therapy titration, and application to other subsets of the OSA population.

Preoperative Predictors of Response to Hypoglossal Nerve Stimulation for Obstructive Sleep Apnea

Objective

Hypoglossal nerve stimulation (HGNS) is an effective treatment for patients with obstructive sleep apnea (OSA) who fail continuous positive airway pressure (CPAP). We assessed the relationship between patient characteristics and response to HGNS.

Study Design

Retrospective cohort study.

Setting

Single tertiary care institution.

Subjects and Methods

This study included CPAP-intolerant patients with moderate to severe OSA after HGNS system implantation from November 2015 to December 2017. Patient measures, drug-induced sleep endoscopy (DISE) findings, and apnea-hypopnea indices (AHIs) were recorded.

Results

Forty-eight patients underwent implantation with the following median measures: age, 66 years; body mass index, 28.6; and neck circumference, 41.0 cm. Patients were classified by Friedman tongue position (II, 27%; III, 56%; IV, 17%) and Mallampati grade (I, 25%; II, 50%; III, 23%; IV, 2%). By DISE, 71% had anterior-posterior palatal collapse. Additionally, 38% had lateral oropharynx collapse; 50%, tongue base collapse; and 27%, epiglottis collapse. Following implantation, median AHI improved from 38.5 to 2.7 ( P < .001), and 92% of patients had no worse than mild OSA (8% moderate). Patients with Friedman tongue position grade II/III experienced greater change in AHI as compared with grade IV (94.2% vs 73.8%, P < .001). Patients with Mallampati score I/II experienced greater improvement versus score III/IV (94.7% vs 66.5%, P < .001). No DISE findings, including any obstruction or collapse, were associated with change in AHI.

Conclusion

This study further confirms HGNS as an effective treatment of CPAP-intolerant OSA. Office measures such as Friedman tongue position IV and Mallampati III/IV were associated with mildly decreased response. DISE findings were not associated with patient response.

Bilateral hypoglossal nerve stimulation for treatment of adult obstructive sleep apnoea

BACKGROUND AND AIM

Hypoglossal nerve stimulation (HNS) decreases obstructive sleep apnoea (OSA) severity via genioglossus muscle activation and decreased upper airway collapsibility. This study assessed the safety and effectiveness at 6 months post-implantation of a novel device delivering bilateral HNS via a small implanted electrode activated by a unit worn externally, to treat OSA: the Genio™ system.

METHODS

This prospective, open-label, non-randomised, single-arm treatment study was conducted at eight centres in three countries (Australia, France and the UK). Primary outcomes were incidence of device-related serious adverse events and change in the apnoea-hypopnoea index (AHI). The secondary outcome was the change in the 4% oxygen desaturation index (ODI). Additional outcomes included measures of sleepiness, quality of life, snoring and device use. This trial was registered with ClinicalTrials.gov, number NCT03048604.

RESULTS

22 out of 27 implanted participants (63% male, aged 55.9±12.0 years, body mass index (BMI) 27.4±3.0 kg·m^-2) completed the protocol. At 6 months BMI was unchanged (p=0.85); AHI decreased from 23.7±12.2 to 12.9±10.1 events·h^-1, a mean change of 10.8 events·h^-1 (p<0.001); and ODI decreased from 19.1±11.2 to 9.8±6.9 events·h^-1, a mean change of 9.3 events·h^-1 (p<0.001). Daytime sleepiness (Epworth Sleepiness Scale; p=0.01) and sleep-related quality of life (Functional Outcomes of Sleep Questionnaire-10; p=0.02) both improved significantly. The number of bed partners reporting loud, very intense snoring, or leaving the bedroom due to participant snoring decreased from 96% to 35%. 91% of participants reported device use >5 days per week, and 77% reported use for >5 h per night. No device-related serious adverse events occurred during the 6-month post-implantation period.

CONCLUSIONS

Bilateral HNS using the Genio™ system reduces OSA severity and improves quality of life without device-related complications. The results are comparable with previously published HNS systems despite minimal implanted components and a simple stimulation algorithm.

Nerve Stimulation for the Treatment of Obstructive Sleep Apnea

Purpose

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

Methods

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

Results

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

Conclusions

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

Upper airway stimulation as an alternative to maxillomandibular advancement for obstructive sleep apnoea in a patient with dentofacial deformity: case report with literature review

Obstructive sleep apnoea (OSA) is characterized by repeated upper airway collapse leading to oxygen desaturation resulting in cardiovascular and neurocognitive sequelae. Upper airway surgeries such as palatopharyngoplasty, tongue base surgery, and maxillomandibular advancement can improve patient tolerance of continuous positive airway pressure, quality of life, and the severity of OSA. Upper airway stimulation (UAS) of the hypoglossal nerve is a contemporary US Food and Drug Administration-approved treatment modality for OSA with a fundamentally different mechanism. We report the case of a 65-year-old male with a high body mass index, hypertension, diabetes, dentofacial deformity, and severe OSA. He presented with a respiratory distress index (RDI) of 89.1 events per hour, apnoea-hypopnoea index (AHI) of 82.7 events per hour, and minimum oxygen saturation of 75%. He chose to undergo UAS. Initially, complete concentric collapse of the velum was found during drug-induced sedation endoscopy, which was converted by palatopharyngoplasty to meet inclusion criteria for UAS. The patient achieved surgical cure with postoperative RDI and AHI of 2 events per hour with minimum oxygen saturation of 83%, and resolution of daytime somnolence. UAS is an effective surgical option to broaden the surgeon's ability to treat OSA, especially if facial skeletal surgery is contraindicated or declined by the patient with dentofacial deformity.

The specific branches leading to the genioglossus muscle: three-dimensional localisation using skin reference points

INTRODUCTION

Supra-selective stimulation of the branches destined for the horizontal part of genioglossus muscle (GGh) could be a target of choice in the treatment of mild-to-severe obstructive sleep apnea syndrome. The main aim of our study was to assess a percutaneous method for the three-dimensional localisation of the terminal branches destined to GGh.

MATERIALS AND METHODS

Twenty cadaveric hypoglossal nerves were dissected and included in the injection protocol. The distance between the posterior edge of the mandibular symphysis and the hyoid bone on the sagittal midline as the approximated distance of the geniohyoid muscle (dGH) was measured before any dissection. Methylene blue mixed with a thickening agent, was injected. The injection point was defined in relation to dGH, in an orthonormal coordinate system. For each dissection, we recorded the theoretical and the real (X, Y, Z) coordinates of GGh motor points and measured their distance to each other.

RESULTS

X was accurately estimated. Y and Z were overestimated by + 5.34 ± 5.21 mm ([Formula: see text]) and + 4.79 ± 3.99 mm ([Formula: see text]) on average, respectively. We found a more significant difference between the theoretical and real Y and Z coordinates in the subgroup BMI < 25 kg/m² (8.6 ± 4.5 mm and 6.9 ± 2.5 mm, respectively, p = 0.0009), and of Z in subgroup with dGH ≥ 50 mm (6.89 ± 3.26 mm, p = 0.0494).

CONCLUSIONS

X can be estimated accurately using the relationship [Formula: see text]. Y seems to be related to BMI and Z may be estimated with the relationship [Formula: see text]. This three-dimensional localisation could be very helpful to facilitate placement of cuff electrodes to manage refractory sleep apnea.

Genioglossus muscle responses to resistive loads in severe OSA patients and healthy control subjects

This study aimed to determine whether there is impairment of genioglossus neuromuscular responses to small negative pressure respiratory stimuli, close to the conscious detection threshold, in obstructive sleep apnea (OSA). We compared genioglossus electromyogram (EMGgg) responses to midinspiratory resistive loads of varying intensity (≈1.2-6.2 cmH₂O·L^-1·s), delivered via a nasal mask, between 16 severe OSA and 17 control participants while the subjects were awake and in a seated upright position. We examined the relationship between stimulus intensity and peak EMGgg amplitude in a 200-ms poststimulus window and hypothesized that OSA patients would have an increased activation threshold and reduced sensitivity in the relationship between EMGgg activation and stimulus intensity. There was no significant difference between control and OSA participants in the threshold (P = 0.545) or the sensitivity (P = 0.482) of the EMGgg amplitude vs. stimulus intensity relationship, where change in epiglottic pressure relative to background epiglottic pressure represented stimulus intensity. These results do not support the hypothesis that deficits in neuromuscular response to negative upper airway pressure exist in OSA during wakefulness; however, the results are likely influenced by a counterintuitive and novel genioglossus muscle suppression response observed in a significant proportion of both OSA and healthy control participants. This suppression response may relate to the inhibition seen in inspiratory muscles such as the diaphragm in response to sudden-onset negative pressure, and its presence provides new insight into the upper airway neuromuscular response to the collapsing force of negative pressure.NEW & NOTEWORTHY Our study used a novel midinspiratory resistive load stimulus to study upper airway neuromuscular responses to negative pressure during wakefulness in obstructive sleep apnea (OSA). Although no differences were found between OSA and healthy groups, the study uncovered a novel and unexpected suppression of neuromuscular activity in a large proportion of both OSA and healthy participants. The unusual response provides new insight into the upper airway neuromuscular response to the collapsing force of negative pressure.

Development of a standardized evaluation of endobuccal adverse events induced by repeated tongue protrusion with both a dedicated questionnaire and an endobuccal examination

INTRODUCTION

A new approach to treat obstructive sleep apnea (OSA) is upper airway stimulation therapy (UAS). Electrical pulses applied to the hypoglossal nerve induce tongue protrusion, increase airway patency and decrease the frequency of apneic and hypopneic events. Thus, the main objective of this study was to design a standardized evaluation of endobuccal adverse events induced by repeated tongue protrusion with both a dedicated questionnaire and an endobuccal examination.

METHOD

This study has designed the Tongue Adverse Event and Satisfaction Questionnaire (TAESQ) and an endobuccal examinations divided into an endobuccal lesion examination (ELE) and an endobuccal risk factor examination (ERFE). Evaluations were conducted at month 6 post-implantation.

RESULTS

The study population after implantation of UAS device consisted of ten Caucasian males with a mean age of 51.9 ± 11.8 years, and a mean BMI of 28.6 ± 3.3. The AHI of the ten participants ranged from 46.7 ± 12.2/h at baseline to 14.5 ± 8.9/h with the Inspire therapy at the 6-month follow-up. The TAESQ revealed pain (30%), followed by less tongue sensitivity (20%) and tongue weakness (10%). The ELE did not reveal any lesions. The ERFE revealed that some participants had tissue and dental risk factors but not associated to more adverse events.

CONCLUSION

The TAESQ, ELE and ERFE have been designed and studied on a small number of participants. These evaluations could systematically be included in the care pathway of patients treated by UAS to better investigate tongue discomfort and tongue lesion for patients treated with this technology.