Device-related outcomes following hypoglossal nerve stimulator implantation

STUDY OBJECTIVES

Hypoglossal nerve stimulation (HGNS) has been widely used to treat obstructive sleep apnea in selected patients. Here we evaluate rates of revision and explant related to HGNS implantation and assess types of adverse events contributing to revision and explant.

METHODS

Post-market surveillance data for HGNS implanted between January 1, 2018 and March 31, 2022, were collected. Event rates and risk were calculated using the post-market surveillance event counts and sales volume over the same period. Indications were categorized for analysis. Descriptive statistics were reported and freedom from explant or revision curves were grouped by year of implantation.

RESULTS

Of the 20,881 HGNS implants assessed, rates of explant and revision within the first year were 0.723% and 1.542%, respectively. The most common indication for explant was infection (0.378%) and for revision was surgical correction (0.680%). Of the 5,820 devices with three-year post-implantation data, the rate of explant was 2.680% and of revision was 3.557%. During this same interval, elective removal (1.478%) was the most common indication, and for revisions, surgical correction (1.134%).

CONCLUSIONS

The efficacy of HGNS is comparable in the real world setting to published clinical trial data. Rates of explant and revision are low, supporting a satisfactory safety profile for this technology.

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

OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

LEVEL OF EVIDENCE

N/A Laryngoscope, 2024.

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.

Will nasal airway surgery improve my sense of smell? A prospective observational study

BACKGROUND

The effect of nasal airway surgery on olfaction has not been well established. The goal of this study is to assess changes in olfaction after septoplasty with inferior turbinate reduction through both objective and patient-reported measures.

METHODS

Prospective, observational study was conducted of patients with nasal airway obstruction presenting between July 2017 and October 2019 who underwent septoplasty with inferior turbinate reduction. Nasal airflow was characterized with the Nasal Obstruction Symptom Evaluation (NOSE) scale and an 11-point ease-of-breathing (EOB) Likert scale, and olfaction with an 11-point olfactory Likert scale and the 40-item University of Pennsylvania Smell Identification Test (UPSIT), pre- and postoperatively. Pearson correlations were used to assess the relationship between measures of nasal obstruction and olfaction.

RESULTS

Among 80 patients, mean NOSE scores improved from 67.4 preoperatively to 19.6 postoperatively (p < 0.001). EOB Likert scores improved from a mean of 3.9/10 to 8.1/10 after surgery (p < 0.001). Olfactory Likert scores improved from a baseline of 6.1/10 preoperatively to 7.9/10 after surgery (p < 0.001). No statistically significant difference was noted in UPSIT testing pre- versus postoperatively. A moderate correlation was noted between the degree of change in NOSE scores and improved olfactory Likert scores (r = 0.51, p < 0.001), and similarly between the degree of change in EOB Likert scores and improved olfactory Likert scores (r = 0.55, p < 0.0001).

CONCLUSIONS

Based on our data, subjective tests of olfaction may improve with nasal airway surgery in some patients. Changes in olfaction best correlate with the extent to which surgery can improve subjective nasal obstructive symptoms.

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.

Hypoglossal Nerve Stimulation Therapy for Obstructive Sleep Apnea

Obstructive sleep apnea (OSA) is characterized by repetitive episodes of disrupted breathing during sleep. The most effective treatment for OSA is positive pressure ventilation; however, this treatment can be complicated by adherence difficulties. An array of alternative OSA therapies have emerged, including positional therapy, nasal exhalation devices, oral appliances, and various nasal, pharyngeal, and skeletal surgical treatments. One of the newest options, hypoglossal nerve stimulation (HNS) therapy, represents a hybrid medical and surgical treatment. This therapy involves an FDA-approved surgically implanted neuromodulation system that is activated by the patient each night to augment upper airway dilator muscle activity and improve airflow. The implanted components comprise a pulse generator, an electrode on the distal portion of the hypoglossal nerve, and a respiratory sensing lead that allows for synchronization of electrical impulses with the patient's respiratory cycle. Using a representative patient case, the authors describe HNS therapy, including its indications, patient selection, surgical procedure, long-term outpatient management, and outcomes data.

Association of Plasma Biomarkers with Sleep Outcomes and Treatment Response After Mild Traumatic Brain Injury

Sleep disturbances occur in up to 70% of patients with mild traumatic brain injury (mTBI). Modern mTBI management recommends targeted treatment for the patient's unique clinical manifestations (i.e., obstructive sleep apnea, insomnia). The purpose of this study was to evaluate the association of plasma biomarkers with symptom reports, overnight sleep evaluations, and response to treatment for sleep disturbances secondary to mTBI. This study is a secondary analysis of a prospective multiple interventional trial of patients with chronic issues related to mTBI. Pre- and post-intervention assessments were conducted, including overnight sleep apnea evaluation, the Pittsburgh Sleep Quality Index (PSQI), and blinded analysis of blood biomarkers. Bivariate Spearman correlations were conducted for pre-intervention plasma biomarker concentrations and 1) PSQI change scores and 2) pre-intervention sleep apnea outcomes (i.e., oxygen saturation measures). A backward logistic regression model was built to evaluate the association of pre-intervention plasma biomarkers with improvement in PSQI over the treatment period (p < 0.05). Participants were 36.3 ± 8.6 years old and 6.1 ± 3.8 years from their index mTBI. Participants reported subjective improvements (PSQI = -3.7 ± 3.8), whereas 39.3% (n = 11) had improved PSQI scores beyond the minimum clinically important difference (MCID). PSQI change scores correlated with von Willebrand factor (vWF; ρ = -0.50; p = 0.02) and tau (ρ = -0.53; p = 0.01). Hyperphosphorylated tau correlated with average saturation (ρ = -0.29; p = 0.03), lowest desaturation (ρ = -0.27; p = 0.048), and baseline saturation (ρ = -0.31; p = 0.02). The multi-variate model (R ² = 0.33; p = 0.001) retained only pre-intervention vWF as a predictor (odds ratio = 3.41; 95% confidence interval, 1.44-8.08; p = 0.005) of improving PSQI scores beyond the MCID. vWF had good discrimination (area under the curve = 0.83; p = 0.01), with an overall accuracy of 77%, sensitivity of 46.2%, and specificity of 90.0%. Validation of vWF as a potential predictive biomarker of sleep improvement post-mTBI could optimize personalized management and healthcare utilization.

Does race-ethnicity affect upper airway stimulation adherence and treatment outcome of obstructive sleep apnea?

STUDY OBJECTIVES

Untreated obstructive sleep apnea (OSA) is associated with excessive daytime sleepiness, decreased quality of life, and cardiovascular disease. Positive airway pressure is the first-line therapy for OSA; however, adherence is difficult. Upper airway stimulation is a Food and Drug Administration-approved treatment of OSA. The objective of this study was to evaluate for a difference in treatment efficacy and adherence of upper airway stimulation therapy for OSA between individuals who are White and non-White using data from the ADHERE registry.

METHODS

ADHERE registry is a multicenter prospective study of real-world experience of upper airway stimulation for treatment of OSA in the United States and Europe. Propensity score matching was used to create a balanced dataset between the White and non-White groups. t-Tests at a significance level of 5% were used to compare numeric values between groups.

RESULTS

There were 2,755 participants of the ADHERE registry: 27 were excluded due to not having a race identified, 125 participants identified as non-White, 2,603 identify as White, and 27 did not provide race information. Propensity score matching was used to select 110 participants, with 55 White and 55 non-White for the noninferiority analysis. We did not find a difference in adherence, treatment apnea-hypopnea index, changes in Epworth Sleepiness Scale score, or clinical global impression after intervention score between White and non-White individuals.

CONCLUSIONS

Our study found that there was no statistically significant difference in adherence or efficacy with upper airway stimulation therapy between White and non-White individuals. However, the percent of non-White people implanted is low, which suggests a need to expand access to this therapy for non-White populations with OSA who cannot tolerate positive airway pressure therapy.

CITATION

Khan M, Stone A, Soose RJ, et al. Does race-ethnicity affect upper airway stimulation adherence and treatment outcome of obstructive sleep apnea? J Clin Sleep Med. 2022;18(9):2167-2172.

Factors affecting obstructive sleep apnea patients' use of upper airway stimulation treatment

STUDY OBJECTIVES

Upper airway stimulation (UAS) is an alternative treatment for obstructive sleep apnea that must be activated nightly. Although the implanted device offsets the mask- or pressure-related side effects often associated with continuous positive airway pressure therapy, some UAS recipients do not use the therapy consistently. This study qualitatively explored factors associated with UAS usage in obstructive sleep apnea patients.

METHODS

Semistructured interviews were conducted with 24 obstructive sleep apnea patients who received UAS treatment. Twelve patients were categorized as high users with mean usage of ≥ 4 hours/night and 12 were categorized as low users with < 4 hours/night or nonuse. Interviews explored patients' experiences regarding barriers and facilitators to UAS use and their advice for new UAS recipients. Demographic and clinical data including the Insomnia Severity Index and Generalized Anxiety Disorder Scale were collected.

RESULTS

Compared to high users, low users had higher levels of insomnia (mean Insomnia Severity Index: 3.6 vs 15.2, respectively) and anxiety (mean Generalized Anxiety Disorder Scale: 3.4 vs 6.9). High users reported more positive experiences with UAS treatment, such as improvements in symptoms and convenience of treatment, as facilitators of use. Low users tended to focus on the negative aspects of treatment, particularly stimulation-related discomfort and associated sleep disturbance.

CONCLUSIONS

Insomnia with or without anxiety contributes to differing patient-reported experiences in high vs low user groups, with increased insomnia symptoms among low users. Improved understanding of the specific barrier and facilitators of UAS adherence may drive better long-term use and more personalized management strategies, including concomitant insomnia treatment.

CLINICAL TRIALS REGISTRATION

Registry: ClinicalTrials.gov; Name: Stimulation Therapy for Apnea: Reporting Thoughts (START); URL: https://clinicaltrials.gov/ct2/show/NCT04768543; Identifier: NCT04768543.

CITATION

Luyster FS, Ni Q, Lee K, et al. Factors affecting obstructive sleep apnea patients' use of upper airway stimulation treatment. J Clin Sleep Med. 2022;18(9):2207-2215.

Evaluation of Upper Airway Stimulation for Adolescents With Down Syndrome and Obstructive Sleep Apnea

Importance

Patients with Down syndrome have a high incidence of persistent obstructive sleep apnea (OSA) and limited treatment options. Upper airway hypoglossal stimulation has been shown to be effective for adults with OSA but has not yet been evaluated for pediatric populations.

Objective

To evaluate the safety and effectiveness of upper airway stimulation for adolescent patients with Down syndrome and severe OSA.

Design, Setting, and Participants

This prospective single-group multicenter cohort study with 1-year follow-up was conducted between April 1, 2015, and July 31, 2021, among a referred sample of 42 consecutive adolescent patients with Down syndrome and persistent severe OSA after adenotonsillectomy.

Intervention

Upper airway stimulation.

Main Outcomes and Measures

The prespecified primary outcomes were safety and the change in apnea-hypopnea index (AHI) from baseline to 12 months postoperatively. Polysomnographic and quality of life outcomes were assessed at 1, 2, 6, and 12 months postoperatively.

Results

Among the 42 patients (28 male patients [66.7%]; mean [SD] age, 15.1 [3.0] years), there was a mean (SD) decrease in AHI of 12.9 (13.2) events/h (95% CI, -17.0 to -8.7 events/h). With the use of a therapy response definition of a 50% decrease in AHI, the 12-month response rate was 65.9% (27 of 41), and 73.2% of patients (30 of 41) had a 12-month AHI of less than 10 events/h. The most common complication was temporary tongue or oral discomfort, which occurred in 5 patients (11.9%). The reoperation rate was 4.8% (n = 2). The mean (SD) improvement in the OSA-18 total score was 34.8 (20.3) (95% CI, -42.1 to -27.5), and the mean (SD) improvement in the Epworth Sleepiness Scale score was 5.1 (6.9) (95% CI, -7.4 to -2.8). The mean (SD) duration of nightly therapy was 9.0 (1.8) hours, with 40 patients (95.2%) using the device at least 4 hours a night.

Conclusions and Relevance

Upper airway stimulation was able to be safely performed for 42 adolescents who had Down syndrome and persistent severe OSA after adenotonsillectomy with positive airway pressure intolerance. There was an acceptable adverse event profile with high rates of therapy response and quality of life improvement.

Trial Registration

ClinicalTrials.gov Identifier: NCT02344108.

Cluster analysis of upper airway stimulation adherence patterns and implications on clinical care

Study Objectives

Upper airway stimulation (UAS) therapy is effective for a subset of obstructive sleep apnea (OSA) patients with continuous positive airway pressure (CPAP) intolerance. While overall adherence is high, some patients have suboptimal adherence, which limits efficacy. Our goal was to identify therapy usage patterns during the first 3 months of therapy to enable targeted strategies for improved adherence.

Methods

Therapy data was retrieved from 2098 patients for three months after device activation. Data included mean and standard deviation (SD) of hours of use, therapy pauses, hours from midnight the therapy was turned ON and OFF, percentage of missing days, and stimulation amplitude. Cluster analysis was performed using Gaussian mixture models that categorized patients into six main groups.

Results

The six groups and their prevalence can be summarized as Cluster 1A: Excellent Use (34%); Cluster 1B: Excellent Use with variable timing (23%); Cluster 2A: Good Use with missing days and late therapy ON (16%), Cluster 2B: Good Use with missing days, late therapy ON, and early therapy OFF (12%); Cluster 3A: Variable Use with frequent missing days (8%); Cluster 3B: Variable Use with frequent pauses (7%). Most patients (85%) are excellent or good users with mean therapy use &gt;6 hours per night.

Conclusions

Cluster analysis of early UAS usage patterns identified six distinct groups that may enable personalized interventions for improved long-term management. Differentiation of the patient clusters may have clinical implications with regard to sleep hygiene education, therapy discomfort, comorbid insomnia, and other conditions that impact adherence.

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

OBJECTIVES

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSION

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

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

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

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.

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

OBJECTIVES/HYPOTHESIS

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

STUDY DESIGN

Cohort study.

METHODS

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

RESULTS

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

CONCLUSIONS

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

LEVEL OF EVIDENCE

3 Laryngoscope, 131:1676-1682, 2021.

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

OBJECTIVES/HYPOTHESIS

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

STUDY DESIGN

Prospective longitudinal trial.

METHODS

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

RESULTS

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

CONCLUSIONS

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

LEVEL OF EVIDENCE

4 Laryngoscope, 131:1663-1669, 2021.

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.

DISE-PAP: a method for troubleshooting residual AHI elevation despite positive pressure therapy

None

Despite excellent positive airway pressure (PAP) adherence, a subset of patients with obstructive sleep apnea experience residual elevation of the apnea-hypopnea index (AHI). Drug-induced sleep endoscopy during PAP application provides an opportunity to examine the anatomic effect of PAP therapy on the upper airway and to troubleshoot refractory residual AHI elevation. We present a patient who demonstrated persistent moderate-severe AHI elevation during titration polysomnogram and subsequent data download reports despite numerous mask refits, chin strap, positional modifications, and multiple pressure and mode adjustments in both the clinic and sleep laboratory settings. Drug-induced sleep endoscopy was performed with the flexible endoscope passed through the PAP circuit into the upper airway. Jaw laxity and associated mandibular retrusion at sleep onset was found to result in a complete fixed tongue base obstruction that PAP therapy, delivered via the patient's oronasal interface, was unable to overcome. Various strategies to overcome these obstacles are discussed.

Immune Landscape of Viral- and Carcinogen-Driven Head and Neck Cancer

Head and neck squamous cell carcinoma (HNSCC) arises through exposure to environmental carcinogens or malignant transformation by human papillomavirus (HPV). Here, we assessed the transcriptional profiles of 131,224 single cells from peripheral and intra-tumoral immune populations from patients with HPV^- and HPV⁺ HNSCC and healthy donors. Immune cells within tumors of HPV^- and HPV⁺ HNSCC displayed a spectrum of transcriptional signatures, with helper CD4⁺ T cells and B cells being relatively divergent and CD8+ T cells and CD4+ regulatory T cells being relatively similar. Transcriptional results were contextualized through multispectral immunofluorescence analyses and evaluating putative cell-cell communication based on spatial proximity. These analyses defined a gene expression signature associated with CD4⁺ T follicular helper cells that is associated with longer progression-free survival in HNSCC patients. The datasets and analytical approaches herein provide a resource for the further study of the impact of immune cells on viral- and carcinogen-induced cancers.

Previous Surgery and Hypoglossal Nerve Stimulation for Obstructive Sleep Apnea

Objective

To examine whether previous palate or hypopharyngeal surgery was associated with efficacy of treatment of obstructive sleep apnea with hypoglossal nerve stimulation.

Study Design

Cohort (retrospective and prospective).

Setting

Eleven academic medical centers.

Subjects and Methods

Adults treated with hypoglossal nerve stimulation were enrolled in the ADHERE Registry. Outcomes were defined by the apnea-hypopnea index (AHI), in 3 ways: change in the AHI and 2 definitions of therapy response requiring ≥50% reduction in the AHI to a level <20 events/h (Response20) or 15 events/h (Response15). Previous palate and hypopharyngeal (tongue, epiglottis, or maxillofacial) procedures were documented. Linear and logistic regression examined the association between previous palate or hypopharyngeal surgery and outcomes, with adjustment for age, sex, and body mass index.

Results

The majority (73%, 217 of 299) had no previous palate or hypopharyngeal surgery, while 25% and 9% had previous palate or hypopharyngeal surgery, respectively, including 6% with previous palate and hypopharyngeal surgery. Baseline AHI (36.0 ± 15.6 events/h) decreased to 12.0 ± 13.3 at therapy titration ( P < .001) and 11.4 ± 12.6 at final follow-up ( P < .001). Any previous surgery, previous palate surgery, and previous hypopharyngeal surgery were not clearly associated with treatment response; for example, any previous surgery was associated with a 0.69 (95% CI: 0.37, 1.27) odds of response (Response20 measure) at therapy titration and a 0.55 (95% CI: 0.22, 1.34) odds of response (Response20 measure) at final follow-up.

Conclusion

Previous upper airway surgery was not clearly associated with efficacy of hypoglossal nerve stimulation.

Drug-Induced Sleep Endoscopy and Surgical Outcomes: A Multicenter Cohort Study

OBJECTIVE

To evaluate the association between findings of blinded reviews of preoperative drug-induced sleep endoscopy (DISE) examinations using the VOTE Classification and obstructive sleep apnea (OSA) surgical outcomes in a large multicenter, international cohort.

METHODS

Retrospective, multi-center cohort study of adults without tonsillar hypertrophy who underwent pharyngeal surgery for OSA. The study included only participants without enlarged tonsils. Four independent reviewers performed blinded review of preoperative DISE videos using the VOTE Classification system and scoring of a primary structure contributing to airway obstruction. DISE findings were examined for an association with surgical outcomes with univariate analyses and multiple regression.

RESULTS

Two hundred seventy-five study participants were included from 14 centers. Mean age was 51.4 ± 11.8 years, and body mass index was 30.1 ± 5.2 kg/m² . There was moderate interrater reliability (kappa = 0.40-0.60) for DISE findings. Oropharyngeal lateral wall-related obstruction was associated with poorer surgical outcomes (adjusted odds ratio (AOR) 0.51; 95% CI 0.27, 0.93). Complete tongue-related obstruction was associated with a lower odds of surgical response in moderate to severe OSA (AOR 0.52; 95% CI 0.28, 0.98), with findings that were similar but not statistically significant in other analyses. Surgical outcomes were not clearly associated with the degree and configuration of velum-related obstruction or the degree of epiglottis-related obstruction. Surgical response was associated with tonsil size and body mass index (inversely).

CONCLUSION

DISE findings concerning the oropharyngeal lateral walls and tongue may be the most important findings of this evaluation technique.

LEVEL OF EVIDENCE

2B Laryngoscope, 129:761-770, 2019.

Dysfunctional hypoglossal nerve stimulator after electrical cardioversion: A case series

OBJECTIVES/HYPOTHESIS

Upper airway stimulation has demonstrated marked improvements in apnea-hypopnea index, oxygen desaturation index, and quality-of-life measures in patients with moderate to severe obstructive sleep apnea (OSA) who cannot tolerate continuous positive airway pressure. Cardiac arrhythmias are common in patients with OSA and can require electrical cardioversion. We describe the first four reported cases of hypoglossal nerve stimulator (HGNS) dysfunction after electrical cardioversion and illustrate our operative approach to device troubleshooting and repair.

STUDY DESIGN

Retrospective case series.

METHODS

A retrospective review of 201 HGNS implantations performed at two academic institutions revealed four cases of HGNS device dysfunction after electrical cardioversion requiring surgical revision. Preoperative and postoperative device performance metrics and electrical cardioversion specifications were retrospectively assessed and compiled for this case series. The senior authors (R.J.S., M.S.B.) detail operative planning and approach for HGNS implantable pulse generator (IPG) replacement.

RESULTS

At least two patients with HGNS device dysfunction had received cardioversion via anterolateral electrode pad placement. Three patients had received multiple shocks. All four patients experienced a change in device functionality or complete cessation of functionality after electrocardioversion. Operatively, each patient required replacement of the IPG, with subsequent intraoperative interrogation revealing proper device functionality.

CONCLUSION

Counseling for patients with HGNS undergoing external electrical cardioversion should include possible device damage and need for operative replacement. Anteroposterior electrode pad placement should be considered for patients with HGNS who require electrocardioversion. Operative replacement of an HGNS system damaged by electrocardioversion begins with IPG replacement and intraoperative device interrogation.

LEVEL OF EVIDENCE

4 Laryngoscope, 129:1949-1953, 2019.

Risk of Postoperative Complications in Patients with Obstructive Sleep Apnea following Skull Base Surgery

Objectives

Obstructive sleep apnea (OSA) presents several challenges in skull base surgery, including increased intracranial pressure, worsened OSA with nasal packing, and avoidance of positive airway pressure (PAP) therapy postoperatively. The objective of this study was to examine the risk of postoperative complications in a skull base population with OSA in which PAP therapy is withheld.

Study Design

Retrospective cohort study.

Setting

Tertiary care hospital.

Subjects and Methods

Medical records of 414 adult patients undergoing anterior skull base procedures between January 1, 2014, and January 7, 2017, were retrospectively reviewed. Revision surgeries, skull base infections, sinus surgery, and orbital cases were excluded.

Results

Fifty-four (13.0%) patients with a diagnosis of OSA were identified. While the known patients with OSA were more likely to require postoperative supplemental oxygen (odds ratio [OR], 4.29; 95% confidence interval [CI], 2.38-7.75; P < .001), there was no increased risk of serious respiratory events or cerebrospinal fluid leak (CSF). To address the likely underdiagnosis of OSA in this cohort, subgroup analyses were performed of patients at high risk for OSA (body mass index >30 kg/m2 and hypertension) and demonstrated an increased risk of serious respiratory events (OR, 4.41; 95% CI, 1.24-15.7; P = .034) and CSF leak (13.6% vs 4.7%; P = .018).

Conclusions

Skull base patients with known OSA can be successfully managed with diligent care in the perioperative period when PAP therapy is withheld. However, OSA is likely underdiagnosed in the skull base population, and patients at high risk for undiagnosed OSA may be at the greatest risk for respiratory complications and CSF leak. Increased presurgical awareness and implementation of a perioperative management algorithm is needed.

Upper Airway Stimulation for Obstructive Sleep Apnea: 5-Year Outcomes

Objective To present 5-year outcomes from a prospective cohort of patients with obstructive sleep apnea (OSA) who were treated with upper airway stimulation (UAS) via a unilateral hypoglossal nerve implant. Study Design A multicenter prospective cohort study. Setting Industry-supported multicenter academic and clinical trial. Methods From a cohort of 126 patients, 97 completed protocol, and 71 consented to a voluntary polysomnogram. Those having continuous positive airway pressure failure with moderate to severe OSA, body mass index <32 kg/m², and no unfavorable collapse on drug-induced sleep endoscopy were enrolled in a phase 3 trial. Prospective outcomes included apnea-hypopnea index (AHI), oxygen desaturation index, and adverse events, as well as measures of sleepiness, quality of life, and snoring. Results Patients who did and did not complete the protocol differed in baseline AHI, oxygen desaturation index, and Functional Outcomes of Sleep Questionnaire scores but not in any other demographics or treatment response measures. Improvement in sleepiness (Epworth Sleepiness Scale) and quality of life was observed, with normalization of scores increasing from 33% to 78% and 15% to 67%, respectively. AHI response rate (AHI <20 events per hour and >50% reduction) was 75% (n = 71). When a last observation carried forward analysis was applied, the responder rate was 63% at 5 years. Serious device-related events all related to lead/device adjustments were reported in 6% of patients. Conclusions Improvements in sleepiness, quality of life, and respiratory outcomes are observed with 5 years of UAS. Serious adverse events are uncommon. UAS is a nonanatomic surgical treatment with long-term benefit for individuals with moderate to severe OSA who have failed nasal continuous positive airway pressure.

Does CPAP Affect Patient-Reported Voice Outcomes?

Upper aerodigestive tract symptoms are common in patients with obstructive sleep apnea (OSA). It remains unclear whether continuous positive airway pressure (CPAP) improves or worsens these otolaryngology symptoms. As therapy-related side effects limit CPAP adherence, this study aimed to determine if CPAP negatively affects voice, sinonasal, and reflux symptoms of the upper airway. Case series with planned data collection was performed at an academic otolaryngology sleep center. Newly diagnosed patients with OSA were evaluated before and 6 months after initiating CPAP therapy. Data collected included CPAP data download, Reflux Symptom Index (RSI), Epworth Sleepiness Scale (ESS), Voice Handicap Index 10 (VHI-10), Sino-Nasal Questionnaire (SNQ), and oral dryness visual analog scale (VAS). For the 11 CPAP-adherent participants, the RSI significantly improved with CPAP (mean RSI, 22.0-9.5; P = .002); however, the VAS, VHI-10, and SNQ did not change after 6 months of CPAP therapy. In a small sample size, patient-reported voice outcomes (VHI-10) and other upper aerodigestive tract symptoms did not worsen with CPAP; rather, CPAP therapy was associated with a reduction in reflux symptoms.

Updates of operative techniques for upper airway stimulation

Selective upper airway stimulation has been established as an additional treatment for obstructive sleep apnea (OSA). Essential for the treatment is the precise placement of the cuff electrode for select branches of the hypoglossal nerve, which innervate the protrusors and stiffeners of the tongue. A direct approach to the distal hypoglossal nerve has been established to achieve this goal. For surgeons, detailed knowledge of this anatomy is vital. Another decisive step is the placement of the sensing lead between the intercostal muscles. Also, the complexity of follow-up care postoperatively should be kept in mind. The aim of this article is to provide the latest knowledge on the neuroanatomy of the hypoglossal nerve and to give surgeons a step-by-step guide on the current operative technique. Laryngoscope, 126:S12-S16, 2016.

Updated Nasal Surgery for Obstructive Sleep Apnea

Numerous studies report that difficulty breathing through the nose is associated with reduced sleep quality, increased daytime dysfunction, and increased risk of snoring and obstructive sleep apnea (OSA). Additionally, chronic nasal obstruction often complicates and limits successful medical device therapy for OSA, particularly with continuous positive airway pressure (CPAP). When medical evaluation and management of the nose is inadequate, surgical therapy to lower nasal resistance has been shown to substantially improve sleep and breathing outcome measures. Although nasal surgery in isolation does not have a consistent effect on the apnea-hypopnea index in OSA patients, it does have robust evidence on improving snoring, subjective sleep quality, daytime sleepiness, sleep-related quality of life measures, and other important OSA outcome measures. Furthermore, in OSA patients with sinonasal disease who are struggling with CPAP and other medical devices, sinonasal surgery also has the potential to lower pressure requirements and improve adherence rates. Nasal surgery plays a key adjunctive role in the management of an OSA patient population.

OSA treatment history in an upper airway stimulation trial cohort

Objectives

Analyze the obstructive sleep apnea (OSA) treatment history in a group of participants who enrolled in a hypoglossal nerve stimulation trial.

Methods

Moderate-severe OSA patients with difficulty adhering to CPAP presented for enrollment in a multicenter trial. Self-reported history on prior OSA medical therapy was collected at enrollment, including OSA diagnosis date, CPAP start and stop dates, oral appliance trial, and reasons for discontinuation or non-adherence.

Results

The cohort consisted of 929 participants, 83% male, with a mean age (53.9 ± 10.5) years. Ninety percent (n = 835) had complete CPAP information including 47% (n = 435) who discontinued therapy prior to enrollment and 43% (n = 400) who were still attempting CPAP but had inadequate adherence. Abandonment rates were 60% at 1-year, 73% at 3-years, and 86% at 5-years. Oral appliance therapy was attempted by 171 patients for mean (1.8 ± 2.3) years, with 81% abandonment at 1 year, 89% at 3-years, and 94% at 5-years.

Conclusions

In this CPAP-refractory cohort, high rates of CPAP abandonment were reported in the first several years with approximately half of the participants not receiving any treatment despite being diagnosed for >5 years. Close clinical follow-up and consideration of alternative treatment options is indicated in all OSA patients in order to ensure adequate longitudinal care.

Positive airway pressure adherence and mask interface in the setting of sinonasal symptoms

OBJECTIVES/HYPOTHESIS

Despite reports of lower positive pressure adherence rates with oronasal masks, patients with sinonasal problems are often prescribed this interface over a nasal interface. The aim of this study was to characterize the relationship between mask type and therapy adherence in the setting of sinonasal symptoms.

STUDY DESIGN

Retrospective case series with chart review.

METHODS

We reviewed 328 patients who underwent positive pressure titration between January 2012 and May 2015. Follow-up adherence data were available for 218 patients (66.5%). Multivariate analysis examined whether patients with sinonasal symptoms have improved adherence with oronasal masks compared to nasal or nasal pillow interfaces.

RESULTS

At a median follow-up of 95 days, positive pressure adherence in patients with sinonasal symptoms was highest with the nasal pillow interface. When compared with oronasal interfaces, the odds of adequate therapy adherence were >5 times greater with nasal pillow interfaces (odds ratio [OR] = 5.20, 95% confidence interval [CI] = 1.61-16.80, P = .006) and >3 times greater with nasal interfaces (OR = 3.67, 95% CI = 1.20-11.26, P = .02) in these symptomatic patients.

CONCLUSIONS

The presence of nasal problems does not predict the need for an oronasal mask. Positive pressure adherence rates are higher with nasal and nasal pillow interfaces compared to oronasal masks, even in patients with sinonasal complaints.

LEVEL OF EVIDENCE

4. Laryngoscope, 127:2418-2422, 2017.

Upper Airway Stimulation for Obstructive Sleep Apnea: Patient-Reported Outcomes after 48 Months of Follow-up

Objective To assess patient-based outcomes of participants in a large cohort study-the STAR trial (Stimulation Therapy for Apnea Reduction)-48 months after implantation with an upper airway stimulation system for moderate to severe obstructive sleep apnea. Study Design A multicenter prospective cohort study. Setting Industry-supported multicenter academic and clinical setting. Subjects Participants (n = 91) at 48 months from a cohort of 126 implanted participants. Methods A total of 126 participants received an implanted upper airway stimulation system in a prospective phase III trial. Patient-reported outcomes at 48 months, including Epworth Sleepiness Scale (ESS), Functional Outcomes of Sleep Questionnaire (FOSQ), and snoring level, were compared with preimplantation baseline. Results A total of 91 subjects completed the 48-month visit. Daytime sleepiness as measured by ESS was significantly reduced ( P = .01), and sleep-related quality of life as measured by FOSQ significantly improved ( P = .01) when compared with baseline. Soft to no snoring was reported by 85% of bed partners. Two patients required additional surgery without complication for lead malfunction. Conclusion Upper airway stimulation maintained a sustained benefit on patient-reported outcomes (ESS, FOSQ, snoring) at 48 months in select patients with moderate to severe obstructive sleep apnea.

Upper Airway Stimulation for Obstructive Sleep Apnea: Self-Reported Outcomes at 24 Months

OBJECTIVES

To evaluate the long-term (24-mo) effect of cranial nerve upper airway stimulation (UAS) therapy on patient-centered obstructive sleep apnea (OSA) outcome measures.

METHODS

Prospective, multicenter, cohort study of 126 patients with moderate to severe OSA who had difficulty adhering to positive pressure therapy and received the surgically implanted UAS system. Outcomes were measured at baseline and postoperatively at 12 mo and 24 mo, and included self- and bedpartner-report of snoring intensity, Epworth Sleepiness Scale (ESS), and Functional Outcomes of Sleep Questionnaire (FOSQ). Additional analysis included FOSQ subscales, FOSQ-10, and treatment effect size.

RESULTS

Significant improvement in mean FOSQ score was observed from baseline (14.3) to 12 mo (17.3), and the effect was maintained at 24 mo (17.2). Similar improvements and maintenance of effect were seen with all FOSQ subscales and FOSQ-10. Subjective daytime sleepiness, as measured by mean ESS, improved significantly from baseline (11.6) to 12 mo (7.0) and 24 mo (7.1). Self-reported snoring severity showed increased percentage of "no" or "soft" snoring from 22% at baseline to 88% at 12 mo and 91% at 24 mo. UAS demonstrated large effect size (> 0.8) at 12 and 24 mo for overall ESS and FOSQ measures, and the effect size compared favorably to previously published effect size with other sleep apnea treatments.

CONCLUSIONS

In a selected group of patients with moderate to severe OSA and body mass index ≤ 32 kg/m2, hypoglossal cranial nerve stimulation therapy can provide significant improvement in important sleep related quality-of-life outcome measures and the effect is maintained across a 2-y follow-up period.

Upper Airway Stimulation for OSA: Early Adherence and Outcome Results of One Center

OBJECTIVE

To review outcome measures and objective adherence data for patients treated with hypoglossal nerve stimulation (HNS) therapy for moderate to severe obstructive sleep apnea (OSA).

STUDY DESIGN

Case series with chart review.

SETTING

Academic sleep medicine center.

SUBJECTS AND METHODS

The first 20 implanted patients to complete postoperative sleep laboratory testing were assessed. All patients had moderate to severe OSA, were unable to adhere to positive pressure therapy, and met previously published inclusion criteria for the commercially available implantable HNS system. Data included demographics, body mass index (BMI), apnea-hypopnea index (AHI), Epworth Sleepiness Score (ESS), nightly hours of device usage, and procedure- and therapy-related complications.

RESULTS

Mean age was 64.8 ± 12.0 years, with 50% female. Mean BMI was unchanged postoperatively (26.5 ± 4.2 to 26.8 ± 4.5 kg/m(2); P > .05). Mean AHI (33.3 ± 13.0 to 5.1 ± 4.3; P < .0001) and mean ESS (10.3 ± 5.2 to 6.0 ± 4.4; P < .01) decreased significantly. Seventy percent (14/20) of patients achieved a treatment AHI <5, 85% (17/20) an AHI <10, and 95% (19/20) an AHI <15. Average stimulation amplitude was 1.89 ± 0.50 V after titration. Adherence monitoring via device interrogation showed high rates of voluntary device use (mean 7.0 ± 2.2 h/night).

CONCLUSION

For a clinical and anatomical subset of patients with OSA, HNS therapy is associated with good objective adherence, low morbidity, and improved OSA outcome measures. Early results at one institution suggest that HNS therapy can be implemented successfully into routine clinical practice, outside of a trial setting.

Efficacy of Upper Airway Stimulation on Collapse Patterns Observed during Drug-Induced Sedation Endoscopy

OBJECTIVE

To describe upper airway collapse patterns observed on drug-induced sedation endoscopy (DISE) during screening for a clinical trial and to evaluate the impact of collapse patterns found on preoperative DISE on response rates to upper airway stimulation (UAS) therapy.

STUDY DESIGN

Retrospective review of an ongoing prospective multi-institutional cohort study.

SETTING

Twenty-two participating institutions of the STAR trial.

SUBJECTS AND METHOD

In total, 222 subjects were screened with DISE to determine eligibility for an implantable UAS device. Supine laryngoscopy was performed during moderate sedation (propofol and/or midazolam). Airway collapse pattern and severity were graded at 4 levels, including velum, oropharynx, tongue base, and epiglottis (VOTE classification). Patients with complete concentric collapse (CCC) at the velum were excluded from implantation.

RESULTS

The CCC at the velum was observed in 52 (23%) of screened subjects, and these subjects were subsequently excluded from implantation. Of the 170 subjects without CCC at the velum, 126 (77%) underwent implantation: 121 (96%) had multilevel collapse and 5 (4%) had single-level collapse. When comparing preimplantation DISE findings, UAS responders at 12 months had lower baseline VOTE scores compared with therapy nonresponders.

CONCLUSION

Drug-induced sedation endoscopy is an efficient and safe method for determining UAS eligibility and has the potential to identify UAS nonresponders. Most patients had multilevel airway collapse, illustrating the limitations of single-level upper airway surgery in treating obstructive sleep apnea. Upper airway stimulation is effective therapy for most patients with multilevel airway collapse; however, patients with complete anterior-posterior or lateral soft palate and/or epiglottic collapse may be at increased risk of therapy failure.

Novel Surgical Approaches for the Treatment of Obstructive Sleep Apnea

Novel approaches to upper airway anatomic phenotyping, more reconstructive upper airway surgical techniques, and new implantable hypoglossal neurostimulation technology have very favorable potential to improve symptoms and quality-of-life measures, to reduce obstructive sleep apnea (OSA) disease severity and associated cardiovascular risk, and to serve as an adjunct to continuous positive airway pressure, oral appliances, and other forms of OSA medical therapy. Successful surgical therapy depends critically on accurate diagnosis, skillful knowledge and examination of the upper airway anatomy, proper procedure selection, and proficient technical application.

Three-Year Outcomes of Cranial Nerve Stimulation for Obstructive Sleep Apnea: The STAR Trial

OBJECTIVE

To describe the 36-month clinical and polysomnography (PSG) outcomes in an obstructive sleep apnea (OSA) cohort treated with hypoglossal cranial nerve upper airway stimulation (UAS).

STUDY DESIGN

A multicenter prospective cohort study.

SETTING

Industry-supported multicenter academic and clinical setting.

SUBJECTS

Participants (n = 116) at 36 months from a cohort of 126 implanted participants.

METHODS

Participants were enrolled in a prospective phase III trial evaluating the efficacy of UAS for moderated to severe OSA. Prospective outcomes included apnea-hypopnea index, oxygen desaturation index, other PSG measures, self-reported measures of sleepiness, sleep-related quality of life, and snoring.

RESULTS

Of 126 enrolled participants, 116 (92%) completed 36-month follow-up evaluation per protocol; 98 participants additionally agreed to a voluntary 36-month PSG. Self-report daily device usage was 81%. In the PSG group, 74% met the a priori definition of success with the primary outcomes of apnea-hypopnea index, reduced from the median value of 28.2 events per hour at baseline to 8.7 and 6.2 at 12 and 36 months, respectively. Similarly, self-reported outcomes improved from baseline to 12 months and were maintained at 36 months. Soft or no snoring reported by bed partner increased from 17% at baseline to 80% at 36 months. Serious device-related adverse events were rare, with 1 elective device explantation from 12 to 36 months.

CONCLUSION

Long-term 3-year improvements in objective respiratory and subjective quality-of-life outcome measures are maintained. Adverse events are uncommon. UAS is a successful and appropriate long-term treatment for individuals with moderate to severe OSA.

Upper Airway Stimulation for Obstructive Sleep Apnea: Durability of the Treatment Effect at 18 Months

OBJECTIVE

To determine the stability of improvement in polysomnographic measures of sleep disordered breathing, patient reported outcomes, the durability of hypoglossal nerve recruitment and safety at 18 months in the Stimulation Treatment for Apnea Reduction (STAR) trial participants.

DESIGN

Prospective multicenter single group trial with participants serving as their own controls.

SETTING

Twenty-two community and academic sleep medicine and otolaryngology practices.

MEASUREMENTS

Primary outcome measures were the apnea-hypopnea index (AHI) and the 4% oxygen desaturation index (ODI). Secondary outcome measures were the Epworth Sleepiness Scale (ESS), the Functional Outcomes of Sleep Questionnaire (FOSQ), and oxygen saturation percent time < 90% during sleep. Stimulation level for each participant was collected at three predefined thresholds during awake testing. Procedure- and/or device-related adverse events were reviewed and coded by the Clinical Events Committee.

RESULTS

The median AHI was reduced by 67.4% from the baseline of 29.3 to 9.7/h at 18 mo. The median ODI was reduced by 67.5% from 25.4 to 8.6/h at 18 mo. The FOSQ and ESS improved significantly at 18 mo compared to baseline values. The functional threshold was unchanged from baseline at 18 mo. Two participants experienced a serious device-related adverse event requiring neurostimulator repositioning and fixation. No tongue weakness reported at 18 mo.

CONCLUSION

Upper airway stimulation via the hypoglossal nerve maintained a durable effect of improving airway stability during sleep and improved patient reported outcomes (Epworth Sleepiness Scale and Functional Outcomes of Sleep Questionnaire) without an increase of the stimulation thresholds or tongue injury at 18 mo of follow-up.

Drug-Induced Sedation Endoscopy in the Evaluation of OSA Patients with Incomplete Oral Appliance Therapy Response

Objective

To use drug-induced sedation endoscopy (DISE) to identify locations and patterns of residual collapse in patients with obstructive sleep apnea (OSA) with incomplete response to oral appliance therapy (OAT).

Study Design

Case series with chart review.

Setting

Academic multidisciplinary sleep practice.

Subjects and Methods

Thirty-five consecutively screened adult patients with OSA with continuous positive airway pressure (CPAP) intolerance and incomplete response to OAT (apnea-hypopnea index [AHI] >15 or AHI >5 with persistent subjective symptoms) who underwent DISE with and without the oral appliance. Data collected included demographics, body mass index, polysomnography data, and management decisions after DISE. Each DISE video pair was retrospectively scored using the VOTE classification system by the same blinded reviewer (R.J.S.).

Results

All patients had multilevel airway collapse at baseline. The palate was the most common location of OAT failure. Fifteen (42.9%) had persistent collapse of the velum during DISE with OAT, and 7 (20%) had persistent collapse of the epiglottis. Twenty-three (65.7%) patients were offered targeted surgery based on DISE findings to augment OAT effectiveness. Twenty (57.1%) patients underwent additional medical therapy such as OAT adjustment or cervical positional therapy. Mean AHI was reduced from 37.4 at baseline, to 16.4 with OAT ( P < .01), and to 10.7 after post-DISE intervention ( P < .78).

Conclusion

In patients with incomplete response to OAT, DISE with and without the appliance can identify residual anatomical locations of collapse, which may direct additional medical and surgical treatment options to augment OAT effectiveness. Further work is needed to determine if DISE affects outcomes.

Upper Airway Stimulation for Obstructive Sleep Apnea: Past, Present, and Future

ABSTRACT

Obstructive sleep apnea (OSA) is an increasingly prevalent clinical problem with significant effects on both personal and public health. Continuous positive airway pressure (CPAP) has demonstrated excellent efficacy and low morbidity; long-term adherence rates approach 50%. Although traditional upper airway surgical procedures target the anatomic component of obstruction, upper airway stimulation tackles the twin goals of improving anatomic and neuromuscular pathology. After decades of trials demonstrating proof of concept of hypoglossal nerve stimulation in animal and human subjects, the results of a large multicenter, prospective trial were recently published. The trial demonstrated that hypoglossal nerve stimulation led to significant improvements in objective and subjective measurements of the severity of OSA. This novel approach is the first to combine sleep surgery techniques with a titratable medical device for the treatment of OSA. Further research is required to define optimal patient selection and device performance and to demonstrate long-term effectiveness.

Randomized controlled withdrawal study of upper airway stimulation on OSA: short- and long-term effect

OBJECTIVE

To assess the efficacy and durability of upper airway stimulation via the hypoglossal nerve on obstructive sleep apnea (OSA) severity including objective and subjective clinical outcome measures.

STUDY DESIGN

A randomized controlled therapy withdrawal study.

SETTING

Industry-supported multicenter academic and clinical setting.

SUBJECTS

A consecutive cohort of 46 responders at 12 months from a prospective phase III trial of 126 implanted participants.

METHODS

Participants were randomized to either therapy maintenance ("ON") group or therapy withdrawal ("OFF") group for a minimum of 1 week. Short-term withdrawal effect as well as durability at 18 months of primary (apnea hypopnea index and oxygen desaturation index) and secondary outcomes (arousal index, oxygen desaturation metrics, Epworth Sleepiness Scale, Functional Outcomes of Sleep Questionnaire, snoring, and blood pressure) were assessed.

RESULTS

Both therapy withdrawal group and maintenance group demonstrated significant improvements in outcomes at 12 months compared to study baseline. In the randomized assessment, therapy withdrawal group returned to baseline, and therapy maintenance group demonstrated no change. At 18 months with therapy on in both groups, all objective respiratory and subjective outcome measures showed sustained improvement similar to those observed at 12 months.

CONCLUSION

Withdrawal of therapeutic upper airway stimulation results in worsening of both objective and subjective measures of sleep and breathing, which when resumed results in sustained effect at 18 months. Reduction of obstructive sleep apnea severity and improvement of quality of life were attributed directly to the effects of the electrical stimulation of the hypoglossal nerve.

Procedure Selection with Drug-Induced Sleep Endoscopy

Program Description:

Drug-induced sleep endoscopy (DISE) is a novel technique to identify sites of anatomic obstruction that may be amenable to surgery. Although the technical aspect of the procedure is straight forward, the interpretation and management is not. The science of DISE is rapidly expanding, but there are still many gaps. This miniseminar will present a variety of DISE videos. After audience polling, an expert panel will provide their interpretation and management. Both the art and science behind the decision process will be discussed.

Educational Objectives:

(1) Evaluate a DISE video and classify the obstruction. (2) Formulate a management plan for a variety of anatomic sites of obstruction. (3) Predict the best OSA surgical candidates.

Randomized Treatment Withdrawal of Hypoglossal Nerve Stimulation for Obstructive Sleep Apnea

Objectives:

Describe the therapeutic effect of upper airway stimulation (UAS) therapy withdrawal on objective and subjective measures of sleep apnea severity.

Methods:

From a cohort of 126 participants in a prospective therapy effectiveness trial, 46 subjects were randomized to therapy “ON” and “OFF” groups. Primary outcomes measures were apnea-hypopnea index (AHI) and oxygen desaturation index (ODI) changes and secondary outcome measures included Epworth Sleepiness Scale (ESS), Functional Outcomes of Sleep Questionnaire (FOSQ), sleep architecture, hypoxemia, snoring, and blood pressure.

Results:

Groups did not differ at pretreatment baseline or at 12 months of therapy in polysomnography or self-reported measures. Following randomized controlled trial (RCT) therapy withdrawal, change in AHI and ODI significantly differed in “ON” and “OFF” groups (1.7 versus 18.2 and 1.6 versus 17.0 events/hour P < .0001). Therapy withdrawal worsened ESS, FOSQ, snoring, hypoxemia, and arousal index in the therapy “OFF” but no change was observed in the “ON” group ( P < .001). The therapy “ON” group demonstrated a reduction in blood pressure at 12 months compared to baseline which was maintained through the RCT.

Conclusions:

Withdrawal of therapeutic UAS results in relapse of both subjective and objective measures of OSA.

Hypoglossal Nerve Stimulation Therapy for Obstructive Sleep Apnea

Program Description:

Obstructive sleep apnea (OSA) significantly affects sleep, daytime function, quality of life, public safety, and cardiovascular risk. Although positive pressure remains the primary treatment, suboptimal adherence rates necessitate alternative treatment strategies. Hypoglossal nerve stimulation is a new and emerging treatment option with published prospective clinical trial data. Sleep-boarded otolaryngologists will review the physiology and basic science of upper airway stimulation, demonstrate the current technology and surgical procedure, present safety and efficacy data from recent multicenter clinical trials, and discuss patient selection and cost-effectiveness. A panel will explore future directions and the advantages/disadvantages of this technology as it compares to other sleep apnea treatment options.

Educational Objectives:

(1) Examine the pathophysiology of OSA with a particular focus on the neuromuscular control mechanisms. (2) Interpret the basic science and feasibility studies on hypoglossal nerve stimulation and describe the current technology and surgical procedure. (3) Report the safety, efficacy, and cost-effectiveness data from published prospective multicenter clinical trials.