Hypoglossal Stimulator Implantation Research Articles

Cost-Effectiveness of Hypoglossal Nerve Stimulation for Pediatric Severe Obstructive Sleep Apnea in Down Syndrome Patients.

To examine the cost-effectiveness of hypoglossal nerve stimulation (HGNS) implantation at an early age in simulated pediatric cohorts with Down Syndrome (DS) and severe obstructive sleep apnea (OSA). Cost-utility analysis. Hypothetical cohort. A Markov model simulated 3 pediatric cohorts with DS and OSA beginning at age 4 years until 21 years. Cohorts received HGNS implants in early childhood, late childhood, or adulthood at age 4, 13 (current FDA-approved age), or 18 years, respectively. Input model parameters were obtained from the literature and our institution. Outcomes were measured with an incremental cost-effectiveness ratio (ICER), measured in dollars per quality-adjusted life-year (QALY). Deterministic 1-way sensitivity analyses were conducted to evaluate the effects of parameter uncertainty. Results (total costs; total QALYs) across the time horizon were determined for each cohort: early implantation ($83,300.35; 15.79), late ($48,319.09; 14.98), and adult ($38,721.07; 14.55). ICERs were $48,892.47 per QALY for early vs late implantation, $43,471.15 per QALY for early vs adult implantation, and $30,959.58 per QALY for late vs adult implantation. All ICERs were below a willingness-to-pay threshold of $50,000 per QALY. Varying the discount rate and utility expectedly varied the ICERs and cost-effectiveness. Threshold analysis showed early implantation to be cost-effective for a HGNS implantation cost up to $62,230 compared to late implantation. The current study suggests HGNS is a cost-effective treatment strategy for pediatric patients with DS and severe OSA. Our findings also suggest cost-effectiveness at ages younger than 13, the current age of FDA approval.

Upper Airway Stimulation for Children and Adolescents with Down Syndrome: Long-Term Follow-Up.

Hypoglossal nerve stimulation (HGNS) is safe and effective for patients with Down syndrome (DS) and severe persistent obstructive sleep apnea (OSA). Long-term outcomes for this patient population have not been evaluated. A prospective single-group multicenter cohort study with 1-year follow-up was conducted between 2015 and 2021 among 42 adolescent patients with DS and severe persistent OSA. Here, we evaluate long-term outcomes in this patient cohort. Patients were evaluated with polysomnogram (PSG) at three timepoints: pre-implantation (timepoint 1), 1-year post-implantation (timepoint 2), and long-term follow-up (timepoint 3). Long-term follow-up data were available for 33 of 42 patients. Mean (SD) of timepoint 3 was 4.0 (1.9) years after implantation. Using a therapy response definition of a 50% decrease in Apnea Hypopnea INdez (AHI) from timepoint 1, the response rate was 69.7% (23/33) at timepoint 2 and 87.9% (29/33) at timepoint 3. From timepoint 1, there was a mean (SD) decrease in AHI of 12.7 (13.4) events/h at timepoint 2 and 15.7 (13.1) events/h at timepoint 3. The mean percentage change in AHI between timepoints 1 and 2 was -51.1% (95% CI: -32.8% to -69.3%) and between timepoints 1 and 3 was -59.6% (95% CI: -42.0% to -77.3%). Patients with DS and severe persistent OSA who undergo HGNS implantation may continue to experience improvement in PSG parameters at long-term follow-up. Future studies are needed to assess additional long-term outcomes in this patient population, including neurocognition and quality of life. 3 Laryngoscope, 2024.

Implementing a Streamlined Hypoglossal Nerve Stimulator Pathway: Cost, Time to Surgery, and Outcomes.

To evaluate the costs, time to surgery, and clinical outcomes associated with implementing a streamlined hypoglossal nerve stimulator (HGNS) implantation pathway. Retrospective cohort study. Single tertiary care center in the United States from 2016 to 2023. Patients with a lack of complete concentric collapse of the velum during volitional snore on in-office laryngoscopy qualified for the streamlined HGNS pathway. This pathway consisted of confirmatory drug-induced sleep endoscopy (DISE) followed immediately by HGNS implantation during the same surgical encounter. Outcomes were compared to patients in the traditional pathway (standalone DISE followed by HGNS implantation on a later date). A total of 68 patients (13 streamlined, 55 traditional) with obstructive sleep apnea who underwent HGNS implantation were included. Patients were predominately male (70.6%) and White (95.6%) and had a mean (SD) age of 63.5 (10.0) years. The streamlined pathway was associated with a significant reduction in both hospital costs (mean difference $9258, 95% confidence interval [CI]: 3690-14,825; P = .002) and time to surgery (mean decrease of 3.82 months, 95% CI: 0.83-6.80 months; P = .013) compared to the traditional pathway. Patients in both groups had reduction in apnea-hypopnea index and Epworth Sleepiness Scale score, with no significant differences in comparisons between groups. In select patients, the streamlined HGNS pathway may expedite time to surgery and reduce hospital costs with comparable clinical outcomes to a traditional 2-stage pathway. Further research is warranted to validate patient selection and better understand longitudinal outcomes.

Characteristic Pressure Waveforms Can Distinguish Airway Collapse Patterns in Sleep Apnea Patients: A Pilot Study.

To use pharyngeal pressure recordings to distinguish different upper airway collapse patterns in obstructive sleep apnea (OSA) patients, and to assess whether these pressure recordings correlate with candidacy assessment for hypoglossal nerve stimulator (HGNS) implantation. Prospective case series. Single tertiary-quaternary care academic center. Subjects with OSA prospectively underwent simultaneous drug-induced sleep endoscopy (DISE) and transnasal pharyngeal pressure recording with a pressure-transducing catheter. Pressure was recorded in the nasopharynx and oropharynx, and endoscopic collapse patterns were classified based on site, extent, and direction of collapse. Pressure recordings were classified categorically by waveform shape as well as numerically by inspiratory and expiratory amplitudes and slopes. Waveform shape, amplitude, and slope were then compared with the endoscopic findings. Twenty-five subjects with OSA were included. Nasopharyngeal waveform shape was associated with the extent of collapse at the level of the palate (P = .001). Oropharyngeal waveform shape was associated with anatomical site of collapse (P < .001) and direction of collapse (P = .019) below the level of the palate. Pressure amplitudes and slopes were also associated with the extent of collapse at various sites. Waveform shape was also associated with favorable collapse pattern on endoscopy for HGNS implantation (P = .043), as well as surgical candidacy for HGNS (P = .004). Characteristic pharyngeal pressure waveforms are associated with different airway collapse patterns. Pharyngeal pressure is a promising adjunct to DISE in the sleep surgery candidacy evaluation.

Comprehensive Analysis of Adverse Events Associated With Hypoglossal Nerve Stimulators: Insights From the MAUDE Database

AbstractObjectiveThis study aims to examine the adverse events associated with hypoglossal nerve stimulator (HNS) implantation for treating obstructive sleep apnea (OSA), drawing data from the Manufacturer and User Facility Device Experience (MAUDE) database. We aim to provide a comprehensive and updated account of these adverse events.Study DesignRetrospective analysis.SettingMAUDE Database review.MethodsA retrospective analysis was performed on the MAUDE database to collect all HNS‐related reports from May 2014 to December 2023. Variables collected included date of event, event description, nature of event, iatrogenic injuries, required interventions, and, if available, root causes. Each event description was analyzed to classify the adverse event, the postevent intervention, and device model number.ResultsOut of 1178 reports fulfilling the inclusion criteria, 1312 adverse events were identified. Common adverse events included infection (24.0%), pain (19.7%), and hematoma/seroma (10.2%). Approximately 83.1% of these adverse events necessitated medical and/or surgical intervention. The most frequent procedures included explantation (29.4%) and device repositioning (15.8%). Pneumothorax was reported in 50 cases, with 41 (82.0%) requiring a chest tube to be inserted. Three adverse events described overstimulation in the setting of magnetic resonance imaging (MRI) despite the implantation of MRI‐compatible second‐generation internal pulse generators.ConclusionWhile HNS implantation has been established as a reliable intervention for OSA in cases of continuous positive airway pressure failure or intolerance, this study highlights several perioperative and postoperative difficulties and complications. Understanding these challenges is essential for refining surgical practices and enhancing patient consent processes, ultimately aiming to improve therapeutic outcomes.

Predicting Therapeutic Response to Hypoglossal Nerve Stimulation Using Deep Learning.

To develop and validate machine learning (ML) and deep learning (DL) models using drug-induced sleep endoscopy (DISE) images to predict the therapeutic efficacy of hypoglossal nerve stimulator (HGNS) implantation. Patients who underwent DISE and subsequent HGNS implantation at a tertiary care referral center were included. Six DL models and five ML algorithms were trained on images from the base of tongue (BOT) and velopharynx (VP) from patients classified as responders or non-responders as defined by Sher's criteria (50% reduction in apnea-hypopnea index (AHI) and AHI < 15 events/h). Precision, recall, F1 score, and overall accuracy were evaluated as measures of performance. In total, 25,040 images from 127 patients were included, of which 16,515 (69.3%) were from responders and 8,262 (30.7%) from non-responders. Models trained on the VP dataset had greater overall accuracy when compared to BOT alone and combined VP and BOT image sets, suggesting that VP images contain discriminative features for identifying therapeutic efficacy. The VCG-16 DL model had the best overall performance on the VP image set with high training accuracy (0.833), F1 score (0.78), and recall (0.883). Among ML models, the logistic regression model had the greatest accuracy (0.685) and F1 score (0.813). Deep neural networks have potential to predict HGNS therapeutic efficacy using images from DISE, facilitating better patient selection for implantation. Development of multi-institutional data and image sets will allow for development of generalizable predictive models. N/A Laryngoscope, 2024.

The impact of neck circumference on hypoglossal nerve stimulator therapy outcomes.

Hypoglossal nerve stimulation (HGNS) therapy has historically had strict eligibility requirements including a body mass index (BMI) < 32 kg/m2. However, recent Food and Drug Administration approval expanded indications to a BMI < 40 kg/m2. There is a wide variability in body fat distribution. This study sought to determine if neck circumference is a better surrogate predictive variable for HGNS outcomes than BMI. A retrospective chart review was conducted at a tertiary care center on adults who underwent HGNS implantation by a single surgeon from March 2017 to October 2021. Baseline demographic data including neck circumference, diagnostic sleep studies and post-implantation HGNS titration studies were collected. Linear regression and Spearman's Correlation Coefficient (SCC) analysis were utilized to compare neck circumference (NC), percentage of predicted neck circumference (PPNC) and BMI with the apnea-hypopnea index at effective voltage (AHI-v). This study included 43 patients who were middle aged (61.1 years), predominantly male (76.7%), with severe obstructive sleep apnea (median AHI 35) and mean neck circumference of 15.3 inches. Utilizing the NC and PPNC, positive correlations with AHI-v were observed (p = 0.0033, SCC = .438, and p = 0.0029, SCC = .444). While controlling for BMI, a 1-inch increase in neck circumference was associated with a 35% increase in AHI-v (p = 0.0411). A larger neck circumference was independently associated with worse HGNS outcomes. Further research is needed to support and confirm these findings, particularly across sexes.

Difficulty Falling Asleep is Associated with Poorer Therapeutic Outcomes in Unilateral Hypoglossal Nerve Stimulation.

The coexistence of insomnia and obstructive sleep apnea (OSA) is very prevalent. Hypoglossal nerve stimulation (HGNS) is an established second-line therapy for patients suffering OSA. Studies investigating the effect of the different aspects of insomnia on the therapeutic outcome are largely missing. Therefore, this study aimed to understand the impact of the different aspects of insomnia on the therapeutic outcome under HGNS therapy in clinical routine. This is a retrospective study including 30 consecutive patients aged 55.40 ± 8.83 years (8 female; 22 male) undergoing an HGNS implantation in our tertiary medical center between 2020 and 2023. All patients underwent preoperative polysomnography (PSG) according to AASM. First follow-up PSG was performed 95.40 ± 39.44 days after activation (30 patients) and second follow-up PSG was performed 409.89 ± 122.52 days after activation (18 patients). Among others, the following PSG-related parameters were evaluated: apnea-hypopnea index (n/h) (AHI) and oxygen desaturation index (n/h) (ODI). Insomnia was assessed by the insomnia severity index (ISI) questionnaire. Preoperatively, all patients included filled out each ISI item. Spearman's-rho correlation coefficient was calculated for correlations. Preoperative score of ISI item 1 (difficulty falling asleep) was 1.93 ± 1.34 and preoperative cumulative ISI score (item1-7) was 18.67 ± 5.32. Preoperative AHI was 40.61 ± 12.02 (n/h) and preoperative ODI was 38.72 ± 14.28 (n/h). In the second follow-up, the mean difference in AHI was ∆ 10.47 ± 15.38 (n/h) and the mean difference in ODI was ∆ 8.17 ± 15.67 (n/h). Strong significant correlations were observed between ISI item 1 (difficulty falling asleep) and both ∆ AHI (r: -0.65, p=0.004) and ∆ ODI (r: -0.7; p=0.001) in the second follow-up. Difficulty falling asleep may hence negatively influence HGNS therapeutic outcome. Insomnia-related symptoms should be considered in the preoperative patient evaluation for HGNS.

Device-related outcomes following hypoglossal nerve stimulator implantation.

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. Postmarket surveillance data for HGNS implanted between January 1, 2018 and March 31, 2022, were collected. Event rates and risk were calculated using the postmarket 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. 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 3-year postimplantation 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%). 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. Moroco AE, Wei Z, Byrd I, etal. Device-related outcomes following hypoglossal nerve stimulator implantation. J Clin Sleep Med. 2024;20(9):1497-1503.

Hypoglossal Nerve Stimulation for Obstructive Sleep Apnea in a Young Child With Down Syndrome.

Obstructive sleep apnea (OSA) is common in children with Down syndrome (DS). Adenoidectomy and/or tonsillectomy are the usual first interventions employed to treat OSA in children with DS but sometimes do not achieve adequate resolution of clinical signs. Positive airway pressure treatment is often used next, but this treatment is poorly tolerated by this population. Persistent OSA can adversely affect a child's health and cognitive development. Hypoglossal nerve stimulation (HGNS), previously shown to be safe and effective in adults with OSA, has been used in children as young as 10 years old with DS and has achieved measurable neurocognitive benefits. The US Food and Drug Administration recently lowered the age for HGNS implantation to 13 years for children with DS. However, questions remain regarding treatment of refractory OSA in younger children. Here, we report the case of a 4-year-old boy with DS and treatment-refractory OSA who underwent successful HGNS implantation. The decision to proceed with HGNS implantation in such a young child involved discussions about anatomic feasibility and potential neurocognitive benefits. The device was implanted without complication and with minimal postoperative bulk. This case suggests a possible treatment option that can be discussed in the course of shared decision-making between clinicians and families of young children with DS and treatment-refractory OSA.

Hypoglossal Nerve Stimulation and Cardiovascular Outcomes for Patients With Obstructive Sleep Apnea

Sham-controlled trials are needed to characterize the effect of hypoglossal nerve stimulation (HGNS) therapy on cardiovascular end points in patients with moderate-severe obstructive sleep apnea (OSA). To determine the effect of therapeutic levels of HGNS, compared to sham levels, on blood pressure, sympathetic activity, and vascular function. This double-blind, sham-controlled, randomized crossover therapy trial was conducted from 2018 to 2022 at 3 separate academic medical centers. Adult patients with OSA who already had an HGNS device implanted and were adherent and clinically optimized to HGNS therapy were included. Participants who had fallen asleep while driving within 1 year prior to HGNS implantation were excluded from the trial. Data analysis was performed from January to September 2022. Participants underwent a 4-week period of active HGNS therapy and a 4-week period of sham HGNS therapy in a randomized order. Each 4-week period concluded with collection of 24-hour ambulatory blood pressure monitoring (ABPM), pre-ejection period (PEP), and flow-mediated dilation (FMD) values. The change in mean 24-hour systolic blood pressure was the primary outcome, with other ABPM end points exploratory, and PEP and FMD were cosecondary end points. Participants (n = 60) were older (mean [SD] age, 67.3 [9.9] years), overweight (mean [SD] body mass index, calculated as weight in kilograms divided by height in meters squared, 28.7 [4.6]), predominantly male (38 [63%]), and had severe OSA at baseline (mean [SD] apnea-hypopnea index, 33.1 [14.9] events/h). There were no differences observed between active and sham therapy in 24-hour systolic blood pressure (mean change on active therapy, -0.18 [95% CI, -2.21 to 1.84] mm Hg), PEP (mean change on active therapy, 0.11 [95% CI, -5.43 to 5.66] milliseconds), or FMD (mean change on active therapy, -0.17% [95% CI, -1.88% to 1.54%]). Larger differences between active and sham therapy were observed in a per-protocol analysis set (n = 20) defined as experiencing at least a 50% reduction in apnea-hypopnea index between sham and active treatment. In this sham-controlled HGNS randomized clinical trial, mean 24-hour systolic blood pressure and other cardiovascular measures were not significantly different between sham and active HGNS therapy. Several methodologic lessons can be gleaned to inform future HGNS randomized clinical trials. ClinicalTrials.gov Identifier: NCT03359096.

Hypoglossal Nerve Stimulator in the Active Duty Population: Military Readiness and Satisfaction.

Because inadequate sleep impairs mission performance, the U.S. Army regards sleep as a core pillar of soldier readiness. There is an increasing incidence of obstructive sleep apnea (OSA) among active duty (AD) service members, which is a disqualifying condition for initial enlistment. Moreover, a new diagnosis of OSA in the AD population often prompts a medical evaluation board, and if symptomatic OSA proves refractory to treatment, this may result in medical retirement. Hypoglossal nerve stimulator implantation (HNSI) is a newer implantable treatment option, which requires minimal ancillary equipment to function and may provide a useful treatment modality to support AD service members while maintaining readiness in appropriate candidates. Because of a perception among AD service members that HNSI results in mandatory medical discharge, we aimed to evaluate the impact of HNSI on military career progression, maintenance of deployment readiness, and patient satisfaction. The Department of Research Programs at the Walter Reed National Military Medical Center provided institutional review board approval for this project. This is a retrospective, observational study and telephonic survey of AD HNSI recipients. Military service information, demographics, surgical data, and postoperative sleep study results were collected from each patient.Additional survey questions assessed each service member's experience with the device. Fifteen AD service members who underwent HNSI between 2016 and 2021 were identified. Thirteen subjects completed the survey. The mean age was 44.8 years (range 33-61), and all were men. Six subjects (46%) were officers. All subjects maintained AD status following HNSI yielding 14.5 person-years of continued AD service with the implant. One subject underwent formal assessment for medical retention. One subject transferred from a combat role to a support role. Six subjects have since voluntarily separated from AD service following HNSI. These subjects spent an average of 360 (37-1,039) days on AD service. Seven subjects currently remain on AD and have served for an average of 441 (243-882) days. Two subjects deployed following HNSI. Two subjects felt that HSNI negatively affected their career. Ten subjects would recommend HSNI to other AD personnel. Following HNSI, of the eight subjects with postoperative sleep study data, five achieved surgical success defined as >50% reduction of apnea-hypopnea index and absolute apnea-hypopnea index value of <20. Hypoglossal nerve stimulator implantation for AD service members offers an effective treatment modality for OSA, which generally allows for the ability to maintain AD status, however: The impact on deployment readiness should be seriously considered and tailored to each service member based on their unique duties before implantation. Seventy-seven percent of HNSI patients would recommend it to other AD service members suffering from OSA.

Upper Airway Stimulation in Female Patients: Safety and Efficacy of a Novel Lateral Approach.

To describe a novel lateral approach for hypoglossal nerve stimulator (HNS) implantation in women and provide evidence for its safety and efficacy. Retrospective case series. Single academic medical center. We identified patients implanted with HNS by a single surgeon from January 2017 to December 2021. Patient characteristics, postoperative complications, surgical duration, response to therapy, and need for revision surgery were recorded. One hundred four patients were included, including 93 males and 11 females. The lateral approach for HNS implantation involves placing the chest incision for the implantable pulse generator and respiratory sensor lead vertically in the anterior axillary line instead of horizontally in the infraclavicular area. No changes are made to the stimulator lead placement. All female patients were implanted using a lateral approach and all male patients were implanted via the standard anterior approach. Half of the patients were implanted via a 2-incision technique. The median surgical time duration was equivalent in male and female patients (119 [interquartile range (IQR): 105-138] vs 126 [IQR: 115-141], respectively). Revision was required in 2 (18%) females versus 6 (6%) males (p = .17). There were equivalent rates of therapy response as well as postoperative complications. A more cosmetic lateral approach is feasible for HNS in female patients and has a similar rate of adverse events and therapy responsiveness. Additional considerations in female patients include the ability to tolerate mammography as well as HNS implantation in the setting of existing breast implants.

Hypoglossal Nerve Stimulator Explantation Technique and Outcomes: A Retrospective Case Series

Introduction: Upper airway stimulation via the hypoglossal nerve stimulator (HGNS) implant is a surgical method for treating obstructive sleep apnea. However, patients may need the implant removed for a variety of reasons. The purpose of this case series is to assess surgical experiences with HGNS explantation at our institution. We report on surgical approach, overall operative times, operative and postoperative complications, and discuss relevant patient-specific surgical findings when removing the HGNS. Methods: We performed a retrospective case series of all patients that underwent HGNS implantation at a single tertiary medical center between January 9, 2021, and January 9, 2022. Subjects included adult patients who presented to the sleep surgery clinic of the senior author for surgical management of previously implanted HGNS. Patient clinical history was reviewed to determine the timing of the patient’s implant, reasons for explant, and postoperative recovery course. Operative reports were reviewed to determine overall duration of surgery and any associated difficulties or deviations from the general approach. Results: Between January 9, 2021, and January 9, 2022, 5 patients had an explantation of their HGNS implant. Explantation occurred between 8 and 63 months of their original implant surgery. The average operative time from incisional start time to close was 162 min for all cases with a range of 96–345 min. No significant complications were reported including pneumothorax and nerve palsy. Conclusion: This reported case series outlines the general steps for Inspire HGNS explantation as well as details the experiences in a case series of 5 subjects explanted over the year at a single institution. The results from the cases suggest that the explantation of the device can be performed efficiently and safely.

Supine Pharyngeal Width Is Associated With Complete Concentric Palatal Collapse During Drug-Induced Sleep Endoscopy and Hypoglossal Nerve Stimulator Outcomes.

Hypoglossal nerve stimulation (HNS) implantation in the US requires preoperative drug-induced sleep endoscopy (DISE) screening for complete concentric palatal collapse (CCC) to establish treatment candidacy. We hypothesized that supine pharyngeal width (SPW) in awake patients is associated with CCC and HNS therapy outcomes. Adults with moderate to severe obstructive sleep apnea underwent awake measurement of SPW followed by DISE screening for CCC. Eligible patients electing for HNS implantation underwent postoperative polysomnography per standard of care. SPW was measured in 73 patients. For SPW >20mm, the positive likelihood ratio for absence of CCC was 6.67 with pre- and post-test odds of 6.3 and 42.0, respectively. Postoperative PSG data were available from 31 of 44 (70.5%) patients subsequently implanted with HNS. Patients with SPW >20mm had a greater rate of HNS response than those with SPW ≤20 (62 vs 30%; P < .05). Only SPW and BMI were significantly associated with CCC and HNS response in regression models. In a retrospective cohort study, SPW was significantly associated with CCC and postoperative apnea-hypopnea index following HNS implantation. SPW may be a viable screening tool for HNS candidacy.

Abstract 11871: Hypoglossal Nerve Stimulation as a Treatment for Sleep Apnea Does Not Lower Blood Pressure

Introduction: Obstructive sleep apnea (OSA) effects up to 30% of men and 15% of women in North America. Untreated, OSA is associated with the development of hypertension, heart failure, coronary artery disease, cardiac arrhythmia, and stroke. Treatment reduces these risks. The American Academy of Sleep Medicine outlines the first line treatment of OSA as continuous positive airway pressure (CPAP). However, many patients are unable to tolerate CPAP. One of the newest therapies approved in 2014 is implantation of a hypoglossal nerve stimulator (HNS) which functions by stimulating the tongue protrudor muscles to reduce upper airway obstruction. However, there is minimal research investigating HNS's effects on comorbidities. Currently there are two published studies showing improved blood pressure control and heart rate variability, but each study only included 46 patients. Several factors warrant a comparison including the lack of data, procedural risks, and procedural cost; especially, when considering the proven efficacy and low cost of CPAP. We present a retrospective analysis of blood pressure after HNS implantation. Hypothesis: We hypothesize that HNS implantation will improve blood pressure control. Methods: All cases of HNS implantation at MercyOne North Iowa Mason City, Iowa were retrospectively reviewed. Each case was manually reviewed for pre- and post-surgery blood pressure, heart failure exacerbations, arrhythmia, hemoglobin A1c, stroke, and acute coronary syndrome. Results: Fifty-nine patients had a mean change in blood pressure of +1.76 systolic and +0.76 diastolic with a standard error of 2.10 and 1.29 respectively. The mean follow-up time was 5.7 months after the fine-tuning sleep titration study. Five patients needed one less blood pressure medication and 6 patients needed one more. Preliminary regression analysis does not support gender, age, apnea-hypopnea index, or body mass index being predictive of change in blood pressure with HNS implantation. There was no statistically significant effect on other comorbidities. Conclusion: This study showed no clinically significant change in blood pressure after HNS implantation. Limitations include the small sample size and only one follow-up blood pressure.

Parental experience of hypoglossal nerve stimulator implantation in adolescents with Down Syndrome and obstructive sleep apnea

PurposeThe purpose of this study is to explore the experience of parents in deciding whether to participate in a clinical trial of the insertion of the Hypoglossal Nerve Stimulator (HNS) to treat their adolescent with Down Syndrome (DS) and Obstructive Sleep Apnea (OSA). Design and methodsA qualitative descriptive design with interviews was used to gather parental experiences from those who consented to HNS for their adolescent with DS and OSA. Interviews were conducted, audiotaped, and transcribed. Basic content analysis was followed to interpret the data. Using a process of data debriefing/engagement, codes were generated, and field/reflective notes were used to assure trustworthiness of the data. ResultsParents, 13 mothers/2 fathers, participated. Three themes were identified: Parents experience desperation about acceptance of standard of care for their adolescent with DS and OSA. This desperation led parents to seek information/insights from social media and they came to rely on those sites to explore options, ultimately leading them to HNS clinical trial. Finally, parents had a desire to share experience with HNS implantation. ConclusionsParents described being desperate at acceptance of standards of care for OSA. They shifted reliance on experts and parents by searching social media pages to explore options for treatment of OSA. Parents wished to share experiences with the HNS implantation. Practice implicationsNurses play a role in preparing for the HNS by instructing/educating parents. Nurses can identify supportive social media sites for parents during the HNS decision and suggest ways to measure outcomes of HNS.

Iatrogenic Pneumothorax During Hypoglossal Nerve Stimulator Implantation: A Large Database Analysis.

There have been case reports of adverse events of hypoglossal nerve stimulator (HNS) implantation not seen in previous clinical trials, including pneumothorax and pleural effusion. The purpose of this study was to determine the rates of these complications and potential risk factors. Retrospective case-control study during 2014 to 2021. Twenty-five health care organizations across the United States. The TriNetX Research Network was queried by using disease codes to retrospectively identify patients with obstructive sleep apnea who underwent HNS implantation. Rates of pneumothorax, pleural effusion, other complications, and need for revision/replacement or explant were determined. We identified 1813 patients from 25 health care organizations who underwent HNS implantation. The average age was 60 years, and there were 68% males and 32% females. Of the cohort, 2.4% (n = 44 from 7 implant centers) experienced a pneumothorax, and 0.6% (n = 11) were diagnosed with a pleural effusion on the day of surgery. Patients who experienced pneumothorax were more likely to have a history of chronic lower respiratory diseases when compared with those who did not (odds ratio, 2.2; 95% CI, 1.1-4.1; P = .02). The incidence of intraoperative pneumothorax and pleural effusion during HNS implantation may be greater than initially thought. Patients with chronic lower respiratory diseases may be at increased risk. This should be communicated with patients during the informed consent process.

Efficacy of expansion pharyngoplasty and hypoglossal nerve stimulation in treating sleep apnea

ObjectiveWe investigated whether a palatal conversion procedure combined with a second-stage hypoglossal nerve stimulator (HGNS) insertion can be beneficial for those patients who have a complete concentric velopharyngeal collapse and may initially not meet the criteria for use of HGNS. MethodsA retrospective chart review included all patients who underwent a planned multi-level sleep surgery including expansion sphincter pharyngoplasty (ESP) followed by HGNS. All patients had a complete concentric collapse (CCC) of the velopharynx (VP) on pre-intervention drug-induced sleep endoscopy (DISE) and were initially not a candidate for HGNS. These patients then underwent ESP followed by a DISE to confirm elimination of the CCC of the VP. They then went on to HGNS implantation several months later followed by a sleep study. ResultsA total of 20 patients were identified and included in the retrospective chart analysis. All patients who underwent ESP successfully converted their VP from CCC to an anterior-posterior collapse pattern and thus met inclusion criteria for HGNS. After the HGNS was implanted, patients showed a significant reduction of the mean AHI from 53.9 before ESP to 8.2 after ESP and HGNS and a decrease in the Epworth Sleep Score (ESS) from a mean of 13.3 to 5.7. ConclusionESP can be effective in eliminating the CCC of the VP thus making patients become HGNS candidates. In selected OSA patients, who have multilevel upper airway obstruction with complete concentric VP collapse, the combination of ESP and HGNS insertion should be considered as a planned 2-staged approach.Level of evidence: 4.

Association of hypoglossal nerve stimulator response with machine learning identified negative effort dependence patterns.

Background Hypoglossal nerve stimulator (HGNS) is a therapeutic option for moderate to severe obstructive sleep apnea (OSA). Improved patient selection criteria are needed to target those most likely to benefit. We hypothesized that the pattern of negative effort dependence (NED) on inspiratory flow limited waveforms recorded during sleep, which has been correlated with the site of upper airway collapse, would contribute to the prediction of HGNS outcome. We developed a machine learning (ML) algorithm to identify NED patterns in pre-treatment sleep studies. We hypothesized that the predominant NED pattern would differ between HGNS responders and non-responders.MethodsAn ML algorithm to identify NED patterns on the inspiratory portion of the nasal pressure waveform was derived from 5 development set polysomnograms. The algorithm was applied to pre-treatment sleep studies of subjects who underwent HGNS implantation to determine the percentage of each NED pattern. HGNS response was defined by STAR trial criteria for success (apnea–hypopnea index (AHI) reduced by > 50% and < 20/h) as well as by a change in AHI and oxygenation metrics. The predominant NED pattern in HGNS responders and non-responders was determined. Other variables including demographics and oxygenation metrics were also assessed between responders and non-responders.ResultsOf 45 subjects, 4 were excluded due to technically inadequate polysomnograms. In the remaining 41 subjects, ML accurately distinguished three NED patterns (minimal, non-discontinuous, and discontinuous). The percentage of NED minimal breaths was significantly greater in responders compared with non-responders (p = 0.01) when the response was defined based on STAR trial criteria, change in AHI, and oxygenation metrics.ConclusionML can accurately identify NED patterns in pre-treatment sleep studies. There was a statistically significant difference in the predominant NED pattern between HGNS responders and non-responders with a greater NED minimal pattern in responders. Prospective studies incorporating NED patterns into predictive modeling of factors determining HGNS outcomes are needed.Supplementary InformationThe online version contains supplementary material available at 10.1007/s11325-022-02641-y.