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.

Response to Hypoglossal Nerve Stimulation Changes With Body Mass Index and Supine Sleep

Importance

Hypoglossal nerve stimulation (HGNS) is a potential alternative therapy for obstructive sleep apnea (OSA), but its efficacy in a clinical setting and the impact of body mass index (BMI; calculated as weight in kilograms divided by height in meters squared) on treatment response remain unclear.

Objective

To investigate whether HGNS therapy is effective for patients with OSA, whether HGNS can treat supine OSA, and whether there are associations between BMI and treatment response.

Design, Setting, and Participants

In this cohort study, adult patients with OSA implanted with HGNS at the Washington University Medical Center in St Louis from April 2019 to January 2023 were included. Data were analyzed from January 2023 to January 2024.

Exposure

HGNS.

Main Outcomes and Measures

Multivariable logistic regression was performed to assess associations between HGNS treatment response and both BMI and supine sleep. Treatment response was defined as 50% reduction or greater in preimplantation Apnea-Hypopnea Index (AHI) score and postimplantation AHI of less than 15 events per hour.

Results

Of 76 included patients, 57 (75%) were male, and the median (IQR) age was 61 (51-68) years. A total of 59 patients (78%) achieved a treatment response. There was a clinically meaningful reduction in median (IQR) AHI, from 29.3 (23.1-42.8) events per hour preimplantation to 5.3 (2.6-12.3) events per hour postimplantation (Hodges-Lehman difference of 23.0; 95% CI, 22.6-23.4). In adjusted analyses, patients with BMI of 32 to 35 had 75% lower odds of responding to HGNS compared with those with a BMI of 32 or less (odds ratio, 0.25; 95% CI, 0.07-0.94). Of 44 patients who slept in a supine position, 17 (39%) achieved a treatment response, with a clinically meaningful reduction in median (IQR) supine AHI from 46.3 (33.6-63.2) events per hour preimplantation to 21.8 (4.30-42.6) events per hour postimplantation (Hodges-Lehman difference of 24.6; 95% CI, 23.1-26.5). In adjusted analysis, BMI was associated with lower odds of responding to HGNS with supine AHI treatment response (odds ratio, 0.39; 95% CI, 0.04-2.59), but the imprecision of the estimate prevents making a definitive conclusion.

Conclusions and Relevance

This study adds to the growing body of literature supporting the use of HGNS for OSA treatment. Sleep medicine clinicians should consider informing patients that higher BMI and supine sleeping position may decrease therapeutic response to HGNS. Future research is needed to replicate these findings in larger, more diverse cohorts, which would facilitate the optimization of treatment strategies and patient counseling for HGNS therapy.

Effects of Adaptive Servo-Ventilation on Quality of Life: The READ-ASV Registry

Rationale: Adaptive servo-ventilation (ASV) effectively treats sleep-disordered breathing, including central sleep apnea (CSA) and coexisting obstructive sleep apnea (OSA).Objectives: The prospective, multicenter European READ-ASV (Registry on the Treatment of Central and Complex Sleep-Disordered Breathing with Adaptive Servo-Ventilation) registry investigated the effects of first-time ASV therapy on disease-specific quality of life (QoL).Methods: The registry enrolled adults with CSA with or without OSA who had ASV therapy prescribed between September 2017 and March 2021. The primary endpoint was change in disease-specific QoL (Functional Outcomes of Sleep Questionnaire [FOSQ]) score between baseline and 12-month follow-up. Sleepiness determined using the Epworth Sleepiness Scale (ESS) score was a key secondary outcome. For subgroup analysis, participants were classified as symptomatic (FOSQ score < 17.9 and/or ESS score > 10) or asymptomatic (FOSQ score ⩾ 17.9 and/or ESS score ⩽ 10).Results: A total of 801 individuals (age, 67 ± 12 yr; 14% female; body mass index, 31 ± 5 kg/m2; apnea-hypopnea index, 48 ± 22/h) were enrolled; analyses include those with paired baseline and follow-up data. After 12 ± 3 months on ASV, median (interquartile range) FOSQ score had increased significantly from baseline (+0.8 [-0.2 to 2.2]; P < 0.001; n = 499). This was due to a significantly increased FOSQ score in symptomatic participants (+1.69 [0.38 to 3.05]), with little change in asymptomatic individuals (+0.11 [-0.39 to 0.54]). The median ESS score also improved significantly from baseline during ASV (-2.0 [-5.0 to 0.0]; P < 0.001).Conclusions: ASV treatment of CSA with or without coexisting OSA was associated with improvements in disease-specific QoL and daytime sleepiness, especially in individuals with sleep-disordered breathing symptoms before therapy initiation. These improvements in patient-reported outcomes support the use of ASV in this population.

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.

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.

Should lateral wall collapse be a contraindication for hypoglossal nerve stimulation?

OBJECTIVE

The purpose of this study is to examine how lateral wall collapse affects treatment outcomes for hypoglossal nerve stimulation (HNS) patients.

METHODS

Patients (n = 111) queried from a single surgeon's database of HNS cases were divided into groups based on their degree of oropharyngeal lateral wall collapse noted on drug-induced sleep endoscopy (DISE): Complete, Partial, None. For each group, apnea hypopnea index (AHI) reduction, Epworth Sleepiness Scale (ESS) score, stimulation voltage, average nightly usage, need for alternate device configuration/awake sleep endoscopy, and rate of surgical success were collected. Patients with Complete collapse were compared to those with Partial/None via Student's t-tests and Pearson's Chi-square test.

RESULTS

Of the 111 eligible patients, 45 had complete, 30 partial, and 36 had no lateral oropharyngeal wall collapse. There were no statistically significant differences found between the Complete and Partial/None groups in terms of age, BMI, sex, AHI (pre and post-op), ESS (pre and post-op), voltage, alternate device configuration, or nightly adherence. Notably, a significantly greater number of the Partial/None group had surgical success (84.84 % vs 66.67 %, p = 0.024).

CONCLUSIONS

Patients with Partial/None oropharyngeal collapse were significantly more likely than patients with Complete lateral wall collapse to see surgical success. There are many factors to weigh when assessing a patient's surgical candidacy, it is clear that complete lateral wall collapse at the level of the oropharynx is a negative predictor for success in HNS.

Comparison of clinical pathways for hypoglossal nerve stimulation management: in-laboratory titration polysomnography vs home-based efficacy sleep testing

STUDY OBJECTIVES

We conducted this study to evaluate whether laboratory or home-based hypoglossal nerve stimulation (HNS) management would have equivalent objective and subjective obstructive sleep apnea outcomes 6 months after activation.

METHODS

Patients undergoing standard-of-care HNS implantation were randomly assigned in a prospective, multicenter clinical trial to either a 3-month postactivation in-laboratory titration polysomnography (tPSG) or an efficacy home sleep study (eHST) with tPSG by exception for eHST nonresponders at 5 months. Both groups underwent an eHST 6 months postactivation.

RESULTS

Sixty patients were randomly assigned. Patients experienced equivalent decreases in the apnea-hypopnea index (mean difference: -0.01 events/h [-8.75, 8.74]) across both groups with HNS; the selection of tPSG or eHST did not associate with therapy response rates (tPSG vs eHST: 63.2% vs 59.1%). The Epworth Sleepiness Scale (median of differences: 1 [-1, 3]) and device usage (median of differences: 0.0 hours [-1.3, 1.3]) outcomes were similar but did not meet a priori statistical equivalence criteria.

CONCLUSIONS

This prospective, multicenter, randomized clinical trial demonstrated that patients undergoing HNS implantation experienced statistically equivalent improvements in objective obstructive sleep apnea outcomes and similar improvements in daytime sleepiness regardless of whether they underwent tPSG. HNS titration with tPSG may not be required for all postoperative patients.

CLINICAL TRIAL REGISTRATION

Registry: ClinicalTrials.gov; Name: Inspire Home Study: Utilization of Home Monitoring During Therapy Optimization in Patients With an Inspire Upper Airway Stimulation System (Comparison of Home Sleep Testing vs. In-lab Polysomnography Testing) (HOME); URL: https://clinicaltrials.gov/ct2/show/NCT04416542; Identifier: NCT04416542.

CITATION

Kent D, Huyett P, Yu P, et al. Comparison of clinical pathways for hypoglossal nerve stimulation management: in-laboratory titration polysomnography vs home-based efficacy sleep testing. J Clin Sleep Med. 2023;19(11):1905-1912.

Long-Term Generator Replacement Experience in Hypoglossal Nerve Stimulator Therapy Recipients With CPAP-Intolerant Obstructive Sleep Apnea

OBJECTIVE

In the last decade, hypoglossal nerve stimulation (HNS) has emerged as a therapeutic alternative for patients with obstructive sleep apnea. The original clinical trial cohorts are entering the phase of expected battery depletion (8-12 years). This study aimed to examine the surgical experience with implantable pulse generator (IPG) replacements and the associated long-term therapy outcomes.

STUDY DESIGN

Retrospective analysis of patients from the original clinical trial databases (STAR, German post-market) who were followed in the ongoing ADHERE registry.

SETTING

International multicenter HNS registry.

METHODS

The ADHERE registry and clinical trial databases were cross-referenced to identify the serial numbers of IPGs that were replaced. Data collection included demographics, apnea-hypopnea index (AHI), therapy use, operative times, and adverse events.

RESULTS

Fourteen patients underwent IPG replacement 8.3 ± 1.1 years after their initial implantation. Body mass index was unchanged between the original implant and IPG replacement (29 ± 4 vs 28 ± 2 kg/m2 , p = .50). The mean IPG replacement operative time was shorter than the original implant (63 ± 50 vs 154 ± 58 minutes, p < .002); however, 2 patients required stimulation lead replacement which significantly increased operative time. For patients with available AHI and adherence data, the mean change in AHI from baseline to latest follow-up (8.7 ± 1.1 years after de novo implant) was -50.06%, and the mean therapy use was 7.2 hours/night.

CONCLUSION

IPG replacement surgery was associated with low complications and shorter operative time. For patients with available outcomes data, adherence and efficacy remained stable after 9 years of follow-up.

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.

Long-term trends in body mass index throughout upper airway stimulation treatment: does body mass index matter?

STUDY OBJECTIVES

Upper airway stimulation is a surgical option for patients with obstructive sleep apnea who fail other forms of noninvasive treatment. Current guidelines recommend a baseline body mass index (BMI) below 32 kg/m2 for eligibility. In this study, we identify trends in BMI before and after upper airway stimulation to characterize the influence of BMI on treatment success.

METHODS

Patients underwent upper airway stimulation implantation between 2016 and 2021. Sleep study data were collected from preoperative and most recent postoperative sleep study. BMI data were collected and compared across the following time points: preoperative sleep study (BMI-1), initial surgeon consultation (BMI-2), surgery (BMI-3), titration polysomnogram (BMI-4), and second postoperative sleep study (BMI-5). Patients were categorized into groups (BMI ≥32 [BMI32], 25 ≤ BMI <32 [BMI25], BMI <25 [BMI18]) based BMI-1, and clinical outcomes were compared.

RESULTS

253 patients were included. The BMI32 group showed a significant decrease in BMI between BMI-1 and BMI-3 (33.9 vs 32.2; P < .001) and a significant increase in BMI between BMI-3 and BMI-5 (32.2 vs 33.0; P = .047). Apnea-hypopnea index improvement and treatment success rate were not significantly different between groups. On univariate and multivariable logistic regression, a lower BMI-5 was significantly predictive of treatment success (odds ratio: 0.88; 95% confidence interval: 0.79-0.97; P = .016). BMI-5 was also significantly associated with improvement in apnea-hypopnea index (P = .002). Other BMI time points were not associated with measures of treatment success.

CONCLUSIONS

Reduced BMI after upper airway stimulation implantation, as opposed to baseline BMI, predicted treatment success. These findings may guide patient counseling, with implications for long-term adherence and therapy success.

CITATION

Renslo B, Virgen CG, Sawaf T, et al. Long-term trends in body mass index throughout upper airway stimulation treatment: does body mass index matter? J Clin Sleep Med. 2023;19(6):1061-1071.

Novel Outcome Analysis Tool for Hypoglossal Nerve Stimulator Sensor Lead Function and Comparison by Incision Type (2 Versus 3)

OBJECTIVE

No reported outcome measures have been established to evaluate sensor lead function in the hypoglossal nerve stimulator (HNS). This study describes the development of novel functional outcome measures for intraoperative sensor electrode function and compares 2-incision and 3-incision outcomes for HNS.

METHODS

A retrospective cohort study of 100 consecutive patients who underwent HNS between June 2019 and September 2021. Demographic information, intraoperative findings, and immediate postoperative outcomes were recorded. Structured parameters were developed to compare intraoperative waveforms with six outcome measures utilized: waveform syncing, waveform amplitude, sensory current leakage, shark-fin morphology, cardiac artifact, and overall impression. Two sleep surgeons and two sleep medicine specialists compared all waveforms in a blinded fashion and assigned scores on the Likert Scale.

RESULTS

The cohort included 50 three-incision and 50 two-incision patients. Age, gender, average body mass index, comorbidity profiles, and sleep endoscopy findings did not significantly differ between the two groups. No major complications occurred. The interclass-correlation-coefficient was greater than 0.7 for all comparisons (good to very good interrater reliability). There was no difference in waveform amplitude, cardiac artifact, sensory current leakage, or shark-fin morphology between the two groups. Waveform syncing and overall impression were statistically better in the 2-incision cohort.

CONCLUSIONS

This study is the first to define a structured method of HNS sensor electrode outcome measurement and showed consistent measures by surgeons and sleep medicine specialists. This article supports the transition to the 2-incision technique among surgeons for placement of the sensor lead. Consideration should be given to utilizing this novel tool in the clinical/research setting and validating these measures moving forward.

LEVEL OF EVIDENCE

3 Laryngoscope, 133:423-430, 2023.

Comparison of readmission and complication rates between traditional sleep surgery and hypoglossal nerve stimulation

Objective

This study aims to compare readmission and complication rates between hypoglossal nerve stimulation (HNS) and traditional sleep surgery (TSS) in the 90‐day postoperative period using a federated electronic health record (EHR) database.

Methods

We queried TriNetX, a global federated health research network providing access to EHR data from approximately 70 million patients in 49 large health care organizations to identify individuals who underwent either HNS or TSS for obstructive sleep apnea (OSA) from April 2014 to March 2021. Propensity scores based on demographics and obesity were used to balance groups. We compared the frequency of readmission/representation and surgical‐related complication rates between cohorts.

Results

After propensity score matching of HNS versus palatal surgery (n = 1014 in each cohort) and HNS versus multilevel surgery (n = 374 in each cohort), we found palatal and multilevel surgery had a significantly higher risk of readmission versus HNS. (12% vs. 4%, p < .0001). Palatal surgery complication rate was also higher than HNS (21% vs. 2%, p < .0001). Multi‐level surgery results were similarly higher (22% vs. 3%, p < .001). The most common diagnoses at ER readmission for TSS were procedural complications and pain, while common diagnoses for HNS readmission were general complaints such as malaise and headache.

Conclusions

Hypoglossal nerve stimulation has lower risk of readmission and postoperative complications than traditional sleep surgery as demonstrated in a large research network database analysis.

Level of Evidence: 3.

This study aims to compare readmission and complication rates between hypoglossal nerve stimulation, a novel implantable neurostimulation system to treat selected CPAP‐intolerant obstructive sleep apnea by stimulating the distal branches of the hypoglossal nerve, against traditional sleep surgery methods in the 90‐day postoperative period using a federated electronic health record database. We found that hypoglossal nerve stimulation has a significantly lower risk of readmission and postoperative complications than traditional sleep surgery.

Upper Airway Stimulation in Patients with Obstructive Sleep Apnea: Long-Term Surgical Success, Respiratory Outcomes, and Patient Experience

Introduction  Upper airway stimulation (UAS) with electric activation of the hypoglossal nerve has emerged as a promising treatment for patients with moderate-to-severe obstructive sleep apnea. Objective  To retrospectively analyze objective and subjective outcome measures after long-term follow-up in obstructive sleep apnea patients receiving upper airway stimulation. Methods  An observational retrospective single-center cohort study including a consecutive series of patients diagnosed with obstructive sleep apnea receiving upper airway stimulation. Results  Twenty-five patients were included. The total median apnea-hypopnea index (AHI) significantly decreased from 37.4 to 8.7 events per hour at the 12-month follow-up ( p  < 0.001). The surgical success rate was 96%. Adverse events were reported by 28% of the patients. Conclusion  Upper airway stimulation is an effective and safe treatment for obstructive sleep apnea in patients with continuous positive airway pressure (CPAP) failure or intolerance. However, it is possible that the existing in and exclusion criteria for UAS therapy in the Netherlands have positively influenced our results.

Similar effect of hypoglossal nerve stimulation for obstructive sleep apnea in 5 disease severity categories

STUDY OBJECTIVES

Data on adherence and outcome of upper airway stimulation (UAS) for patients with obstructive sleep apnea (OSA) are collected in an international registry (ADHERE). Previous publications report significant improvement in self-reported and objective OSA outcomes, durable effectiveness, and high adherence. Debate remains whether the effectiveness of UAS is influenced by preoperative OSA severity; therefore, we aimed to evaluate this using data from the ADHERE Registry.

METHODS

ADHERE is a postmarket, ongoing, international multicenter registry. Adult patients were included if they had undergone UAS implantation and had at least 1 follow-up visit recorded in the database on June 8, 2021. We divided the patients into 5 subgroups, based on OSA severity at baseline (AHI in events/h): subgroup 1 (0-15), 2 (15-30), 3 (≥ 30-50), 4 (> 50-65), and 5 (> 65). We compared results regarding objective and self-reported treatment outcomes.

RESULTS

A total of 1,963 patients were included. Twelve months after implantation, there was a significant (P < .0001) improvement in objective sleep parameters in all subgroups with an AHI above 15 events/h. Patients in subgroup 1 had the lowest AHI at the final visit and the AHI reduction in patients in subgroup 5 was the largest (P < .0001). No significant difference was found between the subgroups in overall treatment success (66.6%) and improvement in self-reported outcomes.

CONCLUSIONS

Our results suggest that UAS is an effective treatment for patients with an AHI ≥ 15 events/h, independent of preoperative OSA severity. Self-reported outcomes and treatment success did not differ significantly between the 5 subgroups. These results clearly support that the indication of UAS could be broadened for patients with an AHI above 65 events/h, which, to date, is not common practice.

CLINICAL TRIAL REGISTRATION

Registry: ClinicalTrials.gov; Title: Adherence and Outcome of Upper Airway Stimulation (UAS) for OSA International Registry (ADHERE Registry); Identifier: NCT02907398; URL: https://www.clinicaltrials.gov/ct2/show/NCT02907398.

CITATION

Bosschieter PFN, de Vries N, Mehra R, et al. Similar effect of hypoglossal nerve stimulation for obstructive sleep apnea in 5 disease severity categories. J Clin Sleep Med. 2022;18(6):1657-1665.

Early objective adherence to hypoglossal nerve stimulation therapy

STUDY OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

CITATION

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

Hypoglossal Nerve Stimulation Therapy

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

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

OBJECTIVE

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

STUDY DESIGN

Noninferiority cohort analysis of a retrospective and prospective registry study.

SETTING

Tertiary care and community surgical centers.

METHODS

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

RESULTS

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

CONCLUSION

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

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

PURPOSE OF REVIEW

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

RECENT FINDINGS

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

SUMMARY

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

ATS Core Curriculum 2021. Adult Sleep Medicine: Sleep Apnea

The American Thoracic Society Sleep Core Curriculum updates clinicians on important sleep topics, presented during the annual meeting, and appearing in summary here. This year’s sleep core theme is sleep-disordered breathing and its management. Topics range from pathophysiological mechanisms for the association of obstructive sleep apnea (OSA) and metabolic syndrome, surgical modalities of OSA treatment, comorbid insomnia and OSA, central sleep apnea, and sleep practices during a pandemic. OSA has been associated with metabolic syndrome, independent of the role of obesity, and the pathophysiology suggests a role for sleep fragmentation and intermittent hypoxia in observed metabolic outcomes. In specific patient populations, surgical treatment modalities for OSA have demonstrated large reductions in objective disease severity compared with no treatment and may facilitate adherence to positive airway pressure treatment. Patient-centered approaches to comorbid insomnia and sleep apnea include evaluating for both OSA and insomnia simultaneously and using shared-decision making to determine the order and timing of positive airway pressure therapy and cognitive behavioral therapy for insomnia. The pathophysiology of central sleep apnea is complex and may be due to the loss of drive to breathe or instability in the regulatory pathways that control ventilation. Pandemic-era sleep practices have evolved rapidly to balance safety and sustainability of care for patients with sleep-disordered breathing.

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

OBJECTIVES/HYPOTHESIS

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

STUDY DESIGN

Prospective observational study.

METHODS

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

RESULTS

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

CONCLUSIONS

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

LEVEL OF EVIDENCE

4 Laryngoscope, 131:2616-2624, 2021.

Breathing Synchronised Hypoglossal Nerve Stimulation with Inspire for Untreated Severe Obstructive Sleep Apnoea/Hypopnoea Syndrome: A Simulated Cost-Utility Analysis from a National Health Service Perspective

BACKGROUND

Hypoglossal nerve stimulation (HNS) with Inspire is a novel treatment indicated for moderate or severe obstructive sleep apnoea/hypopnoea syndrome (OSAHS), intolerant to or unable to be treated with continuous positive airway pressure (CPAP).

OBJECTIVE

The aim of this study was to assess the cost effectiveness of treating moderate or severe OSAHS, in patients intolerant to CPAP, with HNS, compared with standard care, from a National Health Service (NHS) perspective.

METHODS

A cohort state transition model was developed to compare HNS with Inspire with no treatment in UK adult patients with moderate or severe OSAHS who have previously tried and have not responded to CPAP therapy. Published literature was applied in the model to estimate incremental cost-effectiveness ratios (ICERs; 2019 Great British pounds per quality-adjusted life-year [QALY] gained), from an NHS and personal social services (PSS) perspective, over a cohort's lifetime.

RESULTS

The model base-case predicts that patients undergoing HNS will incur lifetime costs of £65,026 compared with £36,727 among untreated patients. The HNS cohort would gain 12.72 QALYs compared with 11.15 QALYs in the no-treatment arm. The ICER of treating severe OSAHS with HNS is therefore estimated to be £17,989 per QALYs gained. Probabilistic sensitivity analysis found that at a threshold of £30,000/QALY, HNS has a 69% probability of being cost effective. Limitations of the model include uncertainty around the utility data that were not sourced directly from HNS clinical trials. There is further uncertainty in the relationship between change in the Apnoea-Hypopnoea Index (AHI) and reduction in ischaemic heart disease and stroke because of difficulty capturing the reduction in risk over a long time horizon in studies.

CONCLUSIONS

Over a patient's lifetime, HNS with Inspire is expected to be cost effective when compared with no treatment in patients with severe OSAHS who have tried and have not responded to CPAP, from an NHS perspective.

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

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

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

INTRODUCTION

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

METHODS

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

RESULTS

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

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

Purpose

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

Methods

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

Results

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

Conclusion

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

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

STUDY OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

CLINICAL TRIAL REGISTRATION

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

Noninvasive electrical stimulation of oropharyngeal muscles in obstructive sleep apnea

Introduction: Continuous positive airway pressure (CPAP) therapy remains the standard treatment for obstructive sleep apnea. However, its proven effect is useless if the patient does not tolerate the treatment. The electrical stimulation approach has been investigated for several decades now and it seems that the implantable devices for invasive electrical stimulation of hypoglossal nerve are viewed as effective with some of them already approved for human use.Areas covered: in this review, we intent to summarize the existing records of noninvasive stimulation in sleep apnea to make the scientific community aware of the details before deciding on its future. We believe that this is a battle still to fight and more could be done bearing in mind the safety of this method.Expertopinion: noninvasive electrical stimulation has been left behind based on few, small and inconsistent studies using different stimulation parameters. These studies are difficult to compare and to draw conclusions.Electrical stimulation is a field for research in the treatment of obstructive sleep apnea, with many aspects still to be discovered, and which may become a therapeutic alternative to the use of CPAP in certain patients.

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.

Model-based analysis of implanted hypoglossal nerve stimulation for the treatment of obstructive sleep apnea

STUDY OBJECTIVES

Individuals with obstructive sleep apnea (OSA), characterized by frequent sleep disruptions from tongue muscle relaxation and airway blockage, are known to benefit from on-demand electrical stimulation of the hypoglossal nerve. Hypoglossal nerve stimulation (HNS) therapy, which activates the protrusor muscles of the tongue during inspiration, has been established in multiple clinical studies as safe and effective, but the mechanistic understanding for why some stimulation parameters work better than others has not been thoroughly investigated.

METHODS

In this study, we developed a detailed biophysical model that can predict the spatial recruitment of hypoglossal nerve fascicles and axons within these fascicles during stimulation through nerve cuff electrodes. Using this model, three HNS programming scenarios were investigated including grouped cathode (---), single cathode (o-o), and guarded cathode bipolar (+-+) electrode configurations.

RESULTS

Regardless of electrode configuration, nearly all hypoglossal nerve axons circumscribed by the nerve cuff were recruited for stimulation amplitudes <3 V. Within this range, monopolar configurations required lower stimulation amplitudes than the guarded bipolar configuration to elicit action potentials within hypoglossal nerve axons. Further, the spatial distribution of the activated axons was more uniform for monopolar versus guarded bipolar configurations.

CONCLUSIONS

The computational models predicted that monopolar HNS provided the lowest threshold and the least sensitivity to rotational angle of the nerve cuff around the hypoglossal nerve; however, this setting also increased the likelihood for current leakage outside the nerve cuff, which could potentially activate axons in unintended branches of the hypoglossal nerve.

CLINICAL TRIAL REGISTRATION

NCT01161420.

Surgical management of obstructive sleep apnoea: A position statement of the Australasian Sleep Association. Respirology 2020;25:1292-1308. [PMID: 33190389 PMCID: PMC7839593 DOI: 10.1111/resp.13967]

Surgery for adult obstructive sleep apnoea (OSA) plays a key role in contemporary management paradigms, most frequently as either a second‐line treatment or in a facilitatory capacity. This committee, comprising two sleep surgeons and three sleep physicians, was established to give clarity to that role and expand upon its appropriate use in Australasia. This position statement has been reviewed and approved by the Australasian Sleep Association (ASA) Clinical Committee.

Ansa Cervicalis Stimulation: A New Direction in Neurostimulation for OSA

BACKGROUND

Hypoglossal nerve stimulation (HNS) is an alternative treatment option for patients with OSA unable to tolerate positive airway pressure but implant criteria limit treatment candidacy. Previous research indicates that caudal tracheal traction plays an important role in stabilizing upper airway patency.

RESEARCH QUESTION

Does contraction of the sternothyroid muscle with ansa cervicalis stimulation (ACS), which pulls the pharynx caudally via thyroid cartilage insertions, increase maximum inspiratory airflow (V_Imax)?

STUDY DESIGN AND METHODS

Hook-wire percutaneous electrodes were used to stimulate the medial branch of the right hypoglossal nerve and right branch of the ansa cervicalis innervating the sternothyroid muscle during propofol sedation. V_Imax was assessed during flow-limited inspiration with a pneumotachometer.

RESULTS

Eight participants with OSA were studied using ACS with and without HNS. Compared with baseline, the mean V_Imax increase with isolated ACS was 298%, or 473 mL/s (95% CI, 407-539). Isolated HNS increased mean V_Imax from baseline by 285%, or 260 mL/s (95% CI, 216-303). Adding ACS to HNS during flow-limited inspiration increased mean V_Imax by 151%, or 205 mL/s (95% CI, 174-236) over isolated HNS. Stimulation was significantly associated with increase in V_Imax in both experiments (P < .001).

INTERPRETATION

ACS independently increased V_Imax during propofol sedation and drove further increases in V_Imax when combined with HNS. The branch of the ansa cervicalis innervating the sternothyroid muscle is easily accessed. Confirmation of the ansa cervicalis as a viable neurostimulation target may enable caudal pharyngeal traction as a novel respiratory neurostimulation strategy for treating OSA.

Evaluation of Surgical Learning Curve Effect on Obstructive Sleep Apnea Outcomes in Upper Airway Stimulation

OBJECTIVE

An increasing number of facilities offer Upper Airway Stimulation (UAS) with varying levels of experience. The goal was to quantify whether a surgical learning curve exists in operative or sleep outcomes in UAS.

METHODS

International multi-center retrospective review of the ADHERE registry, a prospective international multi-center study collecting UAS outcomes. ADHERE registry centers with at least 20 implants and outcomes data through at least 6-month follow-up were reviewed. Cases were divided into two groups based on implant order (the first 10 or second 10 consecutive implants at a given site). Group differences were assessed using Mann-Whitney U-tests, Chi-squared tests, or Fisher's Exact tests, as appropriate. A Mann-Kendall trend test was used to detect if there was a monotonic trend in operative time. Sleep outcome equivalence between experience groups was assessed using the two one-sided tests approach.

RESULTS

Thirteen facilities met inclusion criteria, contributing 260 patients. Complication rates did not significantly differ between groups (P = .808). Operative time exhibited a significant downward trend (P < .001), with the median operative time dropping from 150 minutes for the first 10 implants to 134 minutes for the subsequent 10 implants. The decrease in AHI from baseline to 12-month follow-up was equivalent between the first and second ten (22.8 vs 21.2 events/hour, respectively, P < .001). Similarly, the first and second ten groups had equivalent ESS decreases at 6 months (2.0 vs 2.0, respectively, P < .001). ESS outcomes remained equivalent for those with data through 12-months.

CONCLUSIONS

Across the centers' first 20 implants, an approximately 11% reduction operative time was identified, however, no learning curve effect was seen for 6-month or 12-month AHI or ESS over the first twenty implants. Ongoing monitoring through the ADHERE registry will help measure the impact of evolving provider and patient specific characteristics as the number of implant centers increases.

The practicality of a two-incision surgical approach for hypoglossal nerve stimulator implantation

INTRODUCTION

Determine the feasibility of a two-incision surgical approach to hypoglossal nerve stimulator implantation based on anatomic considerations.

METHODS

Upper airway stimulation (UAS) using the Inspire system uses three implanted devices-the implantable pulse generator (IPG), stimulation lead and sensing chest wall lead. The traditional surgical approach requires three skin incisions located on the submandibular neck, anterosuperior chest wall and inferolateral chest wall. Our surgical team sought to determine the anatomic considerations of combining the two chest wall incisions into one. In order to minimize morbidity and reduce operative time, the chest wall sensing lead was placed posterolateral to the IPG site via the same incision.

RESULTS

Using an adult cadaver for anatomical analysis, access to the third and fourth intercostal spaces was made more difficult by the pectoralis major humeral head and upper arm. The intercostal space was narrower, the musculature along the anterior axillary line and anterior chest wall was devoid of the innermost intercostal muscle group found more laterally. Furthermore, there were much thinner external and internal intercostal muscle components as they transitioned to a membranous layer anteriorly in comparison to the inferolateral chest wall.

CONCLUSION

Lack of the innermost intercostal muscle and thinning of the external and internal intercostal muscles lateral to the IPG site leaves little barrier between the thoracic musculature and parietal pleural increasing the risk of complications such as pleurisy and pneumothorax. Given the anatomical findings, a two-incision surgical approach for UAS therapy is at higher risk for complications.

Comparison of Traditional Upper Airway Surgery and Upper Airway Stimulation for Obstructive Sleep Apnea

OBJECTIVE

To compare patients with moderate-severe obstructive sleep apnea (OSA) undergoing traditional single and multilevel sleep surgery to those undergoing upper airway stimulation (UAS).

STUDY DESIGN

Case control study comparing retrospective cohort of patients undergoing traditional sleep surgery to patients undergoing UAS enrolled in the ADHERE registry.

SETTING

8 multinational academic medical centers.

SUBJECTS AND METHODS

233 patients undergoing prior single or multilevel traditional sleep surgery and meeting study inclusion criteria were compared to 465 patients from the ADHERE registry who underwent UAS. We compared preoperative and postoperative demographic, quality of life, and polysomnographic data. We also evaluated treatment response rates.

RESULTS

The pre and postoperative apnea hypopnea index (AHI) was 33.5 and 15 in the traditional sleep surgery group and 32 and 10 in the UAS group. The postoperative AHI in the UAS group was significantly lower. The pre and postoperative Epworth sleepiness scores (ESS) were 12 and 6 in both the traditional sleep surgery and UAS groups. Subgroup analysis evaluated those patients undergoing single level palate and multilevel palate and tongue base traditional sleep surgeries. The UAS group had a significantly lower postoperive AHI than both traditional sleep surgery subgroups. The UAS group had a higher percentage of patients reaching surgical success, defined as a postoperative AHI <20 with a 50% reduction from preoperative severity.

CONCLUSION

UAS offers significantly better control of AHI severity than traditional sleep surgery. Quality life improvements were similar between groups.

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.

Short-term results of upper airway stimulation in obstructive sleep apnoea patients: the Amsterdam experience

OBJECTIVES

This paper aimed to: retrospectively analyse single-centre results in terms of surgical success, respiratory outcomes and adverse events after short-term follow up in obstructive sleep apnoea patients treated with upper airway stimulation; and evaluate the correlation between pre-operative drug-induced sleep endoscopy findings and surgical success.

METHODS

A retrospective descriptive cohort study was conducted, including a consecutive series of obstructive sleep apnoea patients undergoing implantation of an upper airway stimulation system.

RESULTS

Forty-four patients were included. The total median Apnoea-Hypopnea Index and oxygen desaturation index significantly decreased from 37.6 to 8.3 events per hour (p < 0.001) and from 37.1 to 15.9 events per hour (p < 0.001), respectively. The surgical success rate was 88.6 per cent, and did not significantly differ between patients with or without complete collapse at the retropalatal level (p = 0.784). The most common therapy-related adverse event reported was (temporary) stimulation-related discomfort.

CONCLUSION

Upper airway stimulation is an effective and safe treatment in obstructive sleep apnoea patients with continuous positive airway pressure intolerance or failure. There was no significant difference in surgical outcome between patients with tongue base collapse with or without complete anteroposterior collapse at the level of the palate.

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.

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.

Evaluation of Hypoglossal Nerve Stimulation Treatment in Obstructive Sleep Apnea

Importance

Hypoglossal nerve stimulation is a treatment option for patients with obstructive sleep apnea unable to tolerate continuous positive airway pressure. This study evaluates demographic factors that may be associated with greater improvements in postoperative outcomes of interest.

Objective

To examine the association of hypoglossal nerve stimulation with obstructive sleep apnea severity, daytime sleepiness, and sleep-related quality of life.

Design, Setting, and Participants

Patient-level data were pooled from 3 prospective cohorts and 1 retrospective observational cohort comprising 584 adults with moderate to severe obstructive sleep apnea unable to tolerate or benefit from continuous positive airway pressure. The data were gathered from the Stimulation Therapy for Apnea Reduction Trial; a postmarket approval study conducted in Germany; the multicenter, international Adherence and Outcome of Upper Airway Stimulation for OSA Registry; and a retrospective cohort study from 2 sites in the United States.

Exposure

Hypoglossal nerve stimulation.

Main Outcomes and Measures

Severity of obstructive sleep apnea was the primary outcome. The apnea-hypopnea index (AHI) (<5, normal; 5-15, mild; 15-30, moderate, and >30, severe) and Epworth Sleepiness Scale (range, 0-24; score >10 indicates pathologic sleepiness) outcomes were available at 2 to 6 months from 2 cohorts (n = 398), at 12 months from 1 cohort (n = 126), and at both times from 1 cohort (n = 60). Sleep-related quality of life and oxygen saturation nadir data were collected where available. Linear mixed-effects models were constructed to examine associations between clinical variables and reported postoperative outcomes at 6 and 12 months with study included as a random effect.

Results

Of the 584 patients included in the study, 472 were men (80.8%); mean (SD) age was 58.5 (11.0) years. Greater improvement in the postoperative AHI was associated with a higher preoperative AHI (-0.74 events/h; 95% CI, -0.82 to -0.67), older patient age (-0.10 events/h; 95% CI, -0.20 to -0.00), and lower body mass index (0.52; 95% CI, 0.22-0.83). After adjusting for these variables and considering all patients in the analysis, the AHI was statistically higher at 12 months than at 6 months (3.24 events/h; 95% CI, 1.67-4.82 events/h).

Conclusions and Relevance

Hypoglossal nerve stimulation demonstrated clinically significant improvements in obstructive sleep apnea severity, daytime sleepiness, and sleep-related quality of life in this pooled cohort of patient-level results. Age, body mass index, and preoperative AHI appeared to be associated with treatment outcomes, and these variables may explain some of the difference between 2- to 6-month and 12-month outcomes.

Does Insurance Status Impact Delivery of Care with Upper Airway Stimulation for OSA?

OBJECTIVE

To understand differences in patient demographics, insurance-related treatment delays, and average waiting times for Medicare and private insurance patients undergoing upper airway stimulation (UAS) for treatment of obstructive sleep apnea (OSA).

METHODS

Retrospective chart review of all Medicare and private insurance patients undergoing upper airway stimulation (UAS) from 2015 to 2018 at a single academic center. Primary outcomes were insurance-related procedure cancellation rate and time from drug induced sleep endoscopy (DISE) and UAS treatment recommendation to UAS surgery in Medicare versus private insurance patients.

RESULTS

In our cohort 207 underwent DISE and were recommended treatment with UAS. Forty-four patients with Medicare and 30 patients with private insurance underwent UAS procedure. Patients with Medicare undergoing UAS were older (67.4 ± 11.1 years) than patients with private insurance (54.9 ± 8.1 years). Medicare patients had a shorter mean wait time of 121.9 ± 75.8 days (range, 15-331 days) from the time of UAS treatment recommendation to UAS surgery when compared to patients with private insurance (201.3 ± 102.2 days; range, 33-477 days). Three patients with Medicare (6.4%) and 8 patients with private insurance (21.1%) were ultimately denied UAS.

CONCLUSION

Medicare patients undergoing UAS have shorter waiting periods, fewer insurance-related treatment delays and may experience fewer procedure cancellations when compared to patients with private insurance. The investigational status of UAS by private insurance companies delays care for patients with OSA.

LEVEL OF EVIDENCE

4.

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

Objective/Hypothesis

The ADHERE Registry is a multicenter prospective observational study following outcomes of upper airway stimulation (UAS) therapy in patients who have failed continuous positive airway pressure therapy for obstructive sleep apnea (OSA). The aim of this registry and purpose of this article were to examine the outcomes of patients receiving UAS for treatment of OSA.

Study Design

Cohort Study.

Methods

Demographic and sleep study data collection occurred at baseline, implantation visit, post‐titration (6 months), and final visit (12 months). Patient and physician reported outcomes were also collected. Post hoc univariate and multivariate analysis was used to identify predictors of therapy response, defined as ≥50% decrease in Apnea‐Hypopnea Index (AHI) and AHI ≤20 at the 12‐month visit.

Results

The registry has enrolled 1,017 patients from October 2016 through February 2019. Thus far, 640 patients have completed their 6‐month follow‐up and 382 have completed the 12‐month follow‐up. After 12 months, median AHI was reduced from 32.8 (interquartile range [IQR], 23.6–45.0) to 9.5 (IQR, 4.0–18.5); mean, 35.8 ± 15.4 to 14.2 ± 15.0, P < .0001. Epworth Sleepiness Scale was similarly improved from 11.0 (IQR, 7–16) to 7.0 (IQR, 4–11); mean, 11.4 ± 5.6 to 7.2 ± 4.8, P < .0001. Therapy usage was 5.6 ± 2.1 hours per night after 12 months. In a multivariate model, only female sex and lower baseline body mass index remained as significant predictors of therapy response.

Conclusions

Across a multi‐institutional study, UAS therapy continues to show significant improvement in subjective and objective OSA outcomes. This analysis shows that the therapy effect is durable and adherence is high.

Level of Evidence

2

Laryngoscope, 130:1333–1338, 2020

Long-term follow-up of the German post-market study for upper airway stimulation for obstructive sleep apnea

PURPOSE

Upper airway stimulation (UAS) is an effective treatment for obstructive sleep apnea (OSA) in positive airway pressure (PAP) failure. Most reports have presented short-term data, so long-term safety and efficacy reports are rare. The German post-market study (G-PMS) has followed approximately 60 patients from three implanting centers for several years.

METHODS

Patients with OSA and PAP failure qualified for the G-PMS by the absence of obesity class 2 an AHI between 15 and 65 events/h and absence of complete concentric collapse at the velum during drug-induced sleep endoscopy. Optional 2- and 3-year follow-ups after implantation were collected during routine clinical practice. We measured respiratory parameters such as apnea-hypopnea index (AHI) and oxygen desaturation index (ODI) and daytime sleepiness using the Epworth sleepiness scale (ESS) in a per protocol analysis. Usage was calculated from device-downloaded reports. Device-related complications were documented.

RESULTS

Of the 60 original patients, 41 returned for 2-year follow-up, and 38 for 3 years. About 76% at 2 years and 68% at 3 years met the criterion of therapy success defined as an AHI below 15/h. The median AHI was reduced from 28.6/h (baseline) to 9.0/h (2 years) and 10.0/h (3 years); whereas median ODI decreased from 27.0 to 6.3/h (2 years), and 8.3/h (3 years). Median ESS improved from baseline 13 points to 4 (2 years) and 6 (3 years). Usage was stable at approximately 45 h per week at 2 and 3 years. Serious device-related adverse events were rare, with two-device explantation between 12 to 36 months postoperatively.

CONCLUSIONS

The German multi-center long-term outcomes compare favorably with previously published studies. Respiratory and sleepiness efficacy outcomes were sustained over 2 and 3 years, with a favorable safety profile, supporting the safety and efficacy of a chronic implantable therapy.

Inclusion of the first cervical nerve does not influence outcomes in upper airway stimulation for treatment of obstructive sleep apnea

OBJECTIVES/HYPOTHESIS

Upper airway stimulation (UAS) has demonstrated efficacy in the management of obstructive sleep apnea (OSA). Branches of the hypoglossal nerve that selectively activate tongue protrusor and stiffener muscles are included within the stimulation cuff electrode. The first cervical nerve (C1) is often also included to stimulate additional muscles contributing to tongue protrusion and stabilization. The purpose of this study was to determine whether inclusion of the C1 translates into treatment efficacy, decreased voltage requirement, and improved outcomes in patients utilizing UAS.

STUDY DESIGN

Single-center, retrospective cohort study.

METHODS

One hundred fourteen patients who received a UAS implant at our institution and underwent posttreatment polysomnography were evaluated. Stimulation cuff electrodes in 87 patients included the C1; those in the remaining 27 patients did not include the C1. Demographic data, voltage data, and pre- and posttreatment apnea-hypopnea index (AHI), O₂ nadir, and Epworth Sleepiness Scale (ESS) data were collected for all patients.

RESULTS

There was no significant difference in stimulation voltage, or posttreatment AHI, O₂ nadir, and ESS between the two cohorts. Treatment success, as measured by posttreatment AHI < 20 with a 50% reduction, was similar regardless of C1 inclusion. The same was seen for the percent of patients with AHI < 15 and AHI < 5 after treatment. The distributions of age and body mass index, as well as pre-treatment AHI, O₂ nadir, and ESS were also not significantly different between treatment groups.

CONCLUSIONS

The current study has demonstrated that inclusion of the C1 in the stimulation cuff electrode of the upper airway stimulator may not provide any additional benefit in therapy for OSA.

LEVEL OF EVIDENCE

4 Laryngoscope, 130:E382-E385, 2020.