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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

Technical tips during implantation of selective upper airway stimulation.

OBJECTIVE: Selective upper airway stimulation is now well-established in the United States and in several European countries, with more than 1,000 patients implanted since U.S. Food and Drug Administration approval in April 2014. The authors herein, all head and neck surgeons, account for approximately one of every five implants completed to date. Several of the authors also provide comprehensive longitudinal care of their patients as dual-specialty sleep medicine physicians. STUDY DESIGN: Multi-center, retrospective clinical analysis. METHODS: More than 300 implants have been evaluated and reviewed in five different implant centers (Germany, United States). RESULTS: This analysis shares tips and techniques from the collective experiences with more than 300 implants, which can help newer implanters learn vicariously both for standard practices in executing routine implants through activation and, importantly, for working through more challenging encounters with anatomy, special patient phenotypes, system testing, and troubleshooting. CONCLUSION: These tips should help new implanters handle most of the situations arising during implantation and avoid common pitfalls. Laryngoscope, 128:756-762, 2018.

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.

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.

Upper airway stimulation therapy: A novel approach to managing obstructive sleep apnea.

OBJECTIVES: Review the role of upper airway stimulation (UAS) therapy in the management of moderate to severe obstructive sleep apnea (OSA). DATA SOURCES: A literature search was performed of PubMed and Medline using the search terms clinical trial; obstructive sleep apnea; upper airway stimulation; hypoglossal stimulation; hypoglossal nerve; Inspire; and ImThera. REVIEW METHODS: All published clinical trials of currently available devices were reviewed. Unpublished data were excluded. RESULTS: UAS therapy results in surgical success (AHI decrease of >50% and overall AHI <= 20) in 66% of implanted subjects. In addition, UAS therapy results in significant improvement in daytime sleepiness, snoring, and sleep-related quality of life. CONCLUSION: UAS therapy is a valid alternative for select patients with moderate to severe OSA who are unsuccessful users of CPAP therapy. Laryngoscope, 126:S5-S8, 2016.

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.

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.