Relationship of Nocturnal Insomnia Symptoms and Outcomes After Hypoglossal Nerve Stimulation.

Objective: In patients undergoing hypoglossal nerve stimulation (HGNS), we examined the Insomnia Severity Index (ISI) to understand how baseline sleep onset insomnia (SOI), sleep maintenance insomnia (SMI), and early morning awakening (EMA) affected postsurgical outcomes. Study Design: Observational. Setting: Multicenter registry. Methods: We included patients from the Adherence and Outcomes of Upper Airway Stimulation for Obstructive Sleep Apnea International Registry (ADHERE) with a baseline ISI from 2020 to 2023. Regression analysis examined the association of ISI question scores for SOI, SMI, and EMA and outcomes: Apnea-Hypopnea Index (AHI) reduction, device usage, changes in the Epworth Sleepiness Scale (ESS) and overall ISI score, final visit (FV) completion, and satisfaction. Results: No relationship was noted between insomnia subtypes and AHI reduction or FV completion. In the subgroup of patients with baseline moderate/severe insomnia, patients with major impairment for SOI used their device 64 min/day longer than those with minimal impairment. Among all patients, those with baseline major impairment for SOI had a 2.3 points greater improvement in ISI from baseline to FV compared to patients with minimal impairment, while patients with baseline major impairment for SMI had a 2.0 and 3.5 points greater improvement in the ESS and ISI than those with minimal impairment. Patients with EMA and moderate/severe baseline insomnia had decreased odds of being satisfied after surgery. Conclusion: In ADHERE, nocturnal symptoms of insomnia did not limit HGNS efficacy or therapy use. Conversely, those with worse insomnia subtype impairments at baseline had improved outcomes related to adherence, sleepiness, and insomnia at the FV.

Neurostimulation for Obstructive Sleep Apnea.

Neurostimulation of hypoglossal nerve has emerged as an effective treatment option of obstructive sleep apnea (OSA). Since FDA approval in 2014, therapy has been widely used in select patients with moderate-to-severe OSA who do not benefit from positive airway pressure. Ongoing research and technological developments continue to advance the therapy to deliver personalized and efficient treatment to patients with OSA.

Impact of Insomnia on Hypoglossal Nerve Stimulation Outcomes in the ADHERE Registry.

OBJECTIVE: We aimed to determine the preoperative prevalence of insomnia in the Adherence and Outcomes of Upper Airway Stimulation for OSA International Registry (ADHERE) and to examine serial sleep-related data longitudinally, in particular the Insomnia Severity Index (ISI), to compare outcomes between patients with no/subthreshold insomnia (ISI < 15) and moderate/severe insomnia (ISI ≥ 15) at baseline. METHODS: We analyzed observational data from ADHERE between March 2020 and September 2022. Baseline demographic and mental health (MH) data, apnea hypopnea index (AHI), ISI, and ESS (Epworth Sleepiness Scale) were recorded. At post-titration (PT) and final visits, AHI, ISI, ESS and nightly usage were compared between baseline ISI < 15 and ISI ≥ 15 subgroups. RESULTS: A baseline ISI was obtained in 928 patients (62% with ISI ≥ 15). Of the 578 and 141 patients reaching the 12- and 24-month time periods to complete PT and final visits, 292 (50.5%) and 91 (64.5%) completed the ISI, respectively. Baseline MH conditions were higher with ISI ≥ 15 than ISI < 15 (p < 0.001). AHI reduction and adherence did not differ between patients with baseline ISI ≥ 15 and ISI < 15. Patients with ISI ≥ 15 experienced greater improvement in ESS than ISI < 15 at post-titration and final visits (p = 0.014, 0.025). All patients had improved nocturnal, daytime, and overall ISI scores at follow-up visits (p < 0.001), especially for those with baseline ISI ≥ 15 compared with ISI < 15 (p < 0.05). CONCLUSION: HGNS therapy efficacy and adherence were similar between ISI severity subgroups at follow-up visits. Insomnia and sleepiness scores improved in all patients with HGNS therapy and to a greater degree in patients with baseline moderate/severe insomnia. LEVEL OF EVIDENCE: 4 Laryngoscope, 134:471-479, 2024.

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

OBJECTIVE: To describe a novel lateral approach for hypoglossal nerve stimulator (HNS) implantation in women and provide evidence for its safety and efficacy. STUDY DESIGN: Retrospective case series. SETTING: Single academic medical center. METHODS: 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. RESULTS: 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. CONCLUSION: 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.

Electric field aspects in hypoglossal nerve stimulation for obstructive sleep apnea: A bilateral electrophysiological evaluation of unilateral electrode configuration changes.

Hypoglossal nerve stimulation is an established treatment option for obstructive sleep apnea in selected patients. A unilateral hypoglossal nerve stimulation system was approved a decade ago, yet the physiological effect of unilateral hypoglossal stimulation on bilateral tongue motion remains unclear. This study examined how electrode configuration, stimulation cuff position, or body mass index influenced the contralateral genioglossus electromyography (EMG) signal. Twenty-nine patients underwent three EMG recordings in a polysomnographic setting after being implanted with a unilateral hypoglossal nerve stimulator for at least 6 months. The ratio of EMG signals between the ipsi- and contralateral sides was evaluated. No difference in EMG signals was demonstrated based on electrode configurations, stimulation-cuff position, body-mass-index, or sleep apnea severity, even in patients with right tongue protrusion only. Our findings may be explained by a significant level of cross-innervation and by a smaller and less variable circumferential electric field than expected based on prior biophysical models. A patient's individual anatomy needs to be considered during therapy titration in order to achieve an optimal response.

Cervical cancer screening history among women diagnosed with cervical cancer in Estonia 2017-18.

BACKGROUND: Despite the national cervical cancer screening programme launched in 2006, Estonia has one of the highest cervical cancer incidence rates in Europe. While the overall coverage of cervical cytology is high, the factors related to cancer screening history prior to cancer diagnosis need to be studied. METHODS: In this study, we aimed to examine the 10-year screening history of women diagnosed with cervical cancer in Estonia in 2017-18, using data collected from laboratory reports from 2007 to 2018. From each report, we extracted information on the date and result of cytology and on the laboratory where the sample was assessed. We analysed these data across cancer histology, the time interval between the last test result and cancer diagnosis and the laboratory type (local or regional). RESULTS: Among 319 women with cervical cancer, 181 (56.7%) did not have any cytology reports available. Among 138 women with at least one cytology, 60% had 1-3, 24% 4-6 and 16% ≥7 tests (mean 3.7) before cancer. In 78% of women, the last test was performed less than 5 years before cancer diagnosis and 62% of these tests did not report any abnormalities. The last cytology results differed significantly between the regional and local laboratories (P = 0.028). CONCLUSION: Women received the cervical cancer diagnosis in Estonia despite having several screening tests 10 years prior to the diagnosis. The proportion of cytology tests without any abnormalities less than 5 years before the diagnosis was worryingly high and needs further investigation together with the difference between laboratory types.

Inequalities in reported use of cervical screening in Estonia: results from cross-sectional studies in 2004-2020.

BACKGROUND: Despite the national cervical cancer (CC) screening program established in 2006, the CC incidence in Estonia in 2020 was still one of the highest in Europe. To better understand the possible barriers among women, the aim of this study was to describe the inequalities in the Pap smear uptake trend in 2004-2020 and to analyse the associations between different factors in Estonia. METHODS: Weighted data of 25-64-year-old women (N = 6685) from population-based cross-sectional studies of Health Behaviour among Estonian Adult Population in 2004-2020 was used. Linear trends in uptake of Pap smear over time were tested using the Cochrane-Armitage test. Binary logistic regression with interactions was performed to analyse associations between the uptake of Pap smear and sociodemographic, socioeconomic, health-related and lifestyle factors. Crude and adjusted odds ratios with 95% confidence intervals were calculated. RESULTS: Prevalence of lifetime uptake of Pap smear increased in 2004-2020 from 50.6 to 86.7% (P < 0.001). From 2004 to 2020, uptake of Pap smear increased significantly among women aged 25-34, 35-44, 45-54 and 55-64, in both ethnicity groups and among women with basic, secondary and higher education (P < 0.001). The gap in Pap smear uptake increased between Estonians and non-Estonians but decreased between education levels over time. Lower lifetime uptake of Pap smear was associated from sociodemographic factors with younger age, being non-Estonian and single, from socioeconomic factors with lower educational level and unemployment, from health indicators with higher body mass index indicating overweight and obesity, presence of chronic disease and depressiveness, and from lifestyle factors with non-smoking. CONCLUSIONS: Although Pap smear uptake among 25-64 year old women increased significantly in Estonia in 2004-2020, inequalities were found indicating an opportunity for development of targeted CC prevention strategies.

Quality Assessment of Cervical Cytology Practices in Estonia From 2007 to 2018.

BACKGROUND: Cervical cancer incidence and mortality in Estonia are among the highest in Europe, although the overall coverage with cervical cytology is high. This indicates potential issues with the quality of collection and/or laboratory evaluation of cervical cytology. OBJECTIVES: The aim of the retrospective observational study was to assess the quality of cervical cytology specimen collection, evaluation, and reporting using laboratory reports in Estonia. METHODS: The study included women with a cervical cancer diagnosis in 2017-2018. Cervical cytology and histology reports for these women in 2007-2018 were obtained from ten laboratories. We described the quality of cytology specimen collection and reporting of cytology results. Multivariate logistic regression was used to calculate odds ratios (OR) with 95% confidence intervals (CI) to identify factors associated with NILM as the last cervical cytology result within 5 or 2 years before the cervical cancer diagnosis. Also, we calculated cytology-histology correlation (CHC). RESULTS: We identified 503 cytology and 100 histology reports from 138 women. The laboratories differed greatly regarding human resources, work capacity and volume. Differences between local and regional laboratories were observed in reporting specimen adequacy (P < .001). We found that local laboratories had 3 times higher odds (OR = 2.95, 95% CI: 1.05-8.33) of reporting normal results 2 years before cancer diagnosis than regional laboratories. According to the CHC, 58.9% of pairs were in agreement. CONCLUSIONS: The study showed considerable heterogeneity and suboptimal performance of cervical cytology practices in Estonia, particularly at local laboratories. Efforts to improve laboratory quality assurance are crucial.

Hypoglossal nerve stimulator patient usage: Patterns and trends over time.

Objective: Hypoglossal nerve stimulation (HNS) is an effective treatment for obstructive sleep apnea (OSA) patients intolerant of continuous positive airway pressure but is only effective if used regularly. Usage patterns have not been studied in detail. In this study, we aimed to characterize granular HNS usage patterns. Methods: Patients implanted by a single surgeon at an academic medical center from August 2016 to January 2021 were identified from a prospective database, which was merged with the Inspire Cloud usage database. Patient, OSA, and usage characteristics were summarized, and patient- and OSA-related characteristics were associated with usage characteristics by Wilcoxon rank-sum analyses. Usage trends over time were summarized in the overall cohort and stratified by initial usage. Results: Fifty patients were included. Median usage was 94% of nights (interquartile range [IQR]: 82%-98%) for 5.8 h per night (IQR: 4.9-6.4). Higher post-operative apnea-hypopnea index predicted fewer nights used (92% [IQR: 82%-97%] vs. 96% [IQR: 91%-99%]). No other characteristics examined were significantly associated with usage. Median hours used per night decreased from 6.80 h (IQR: 5.32-7.94) on Day 1 to 5.76 (IQR: 1.81-7.13) on Day 361. This decrease was most pronounced in the quartile with the lowest initial usage. Conclusion: This study found that most patient and OSA characteristics were not associated with HNS usage, and that usage generally decreased over time. This decrease in usage over time was most pronounced in patients with the lowest initial usage. Further work should identify interventions to improve usage patterns to optimize clinical outcomes. Level of Evidence: 4.

Neurophysiological profiles of responders and nonresponders to hypoglossal nerve stimulation: a single-institution study.

STUDY OBJECTIVES: Hypoglossal nerve stimulation (HGNS) is an effective alternative treatment for obstructive sleep apnea that acts by opening the airway via selective stimulation of nerve fibers that innervate tongue muscles that protrude (genioglossus) and stiffen the tongue (transverse and vertical) while avoiding nerve fibers that innervate tongue muscles that retract the tongue (styloglossus and hyoglossus). There remains a subset of postoperative patients who fail to adequately respond to HGNS, in some cases due to mixed activation of muscles that simultaneously protrude and retract the tongue. This study aims to characterize the relationship between neurophysiological data from individual tongue muscle activation during intraoperative electromyographic recordings and postoperative apnea-hypopnea index responses to HGNS. METHODS: A single-institution review of 46 patients undergoing unilateral HGNS implantation for obstructive sleep apnea. Patients were separated into responders and nonresponders through comparison of pre and postoperative apnea-hypopnea index. Neurophysiological data included electromyographic responses of the genioglossus, styloglossus/hyoglossus, intrinsic/vertical, and hyoglossus (neck) muscles to intraoperative stimulation using unipolar (- to - and o to o) and bipolar (+ to +) settings. RESULTS: The overall treatment success rate was 61% as determined by a postoperative apnea-hypopnea index < 20 events/h with a greater than 50% AHI reduction. We observed no statistically significant relationships between treatment response and individual muscle responses. However, we did note that increasing body mass index was correlated with worse postoperative responses. CONCLUSIONS: Although we noted a significant subgroup of clinical nonresponders to HGNS postoperatively, these patients were not found to exhibit significant inclusion of tongue retractors intraoperatively on neurophysiological analysis. Further research is needed to delineate additional phenotypic factors that may contribute to HGNS treatment responses. CITATION: Wang D, Modik O, Sturm JJ, et al. Neurophysiological profiles of responders and nonresponders to hypoglossal nerve stimulation: a single-institution study. J Clin Sleep Med. 2022;18(5):1327-1333.

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

OBJECTIVE: The only hypoglossal nerve stimulation (HNS) device available for US clinical use is implanted through 3 incisions. A recently proposed 2-incision modification moved the respiratory sensing lead from the fifth to the second intercostal space to eliminate the third lower chest incision. This study compared perioperative data and therapeutic outcomes between the techniques. STUDY DESIGN: Noninferiority cohort analysis of a retrospective and prospective registry study. SETTING: Tertiary care and community surgical centers. METHODS: Patients with obstructive sleep apnea underwent HNS implantation via a modified 2-incision technique (I2). A cohort previously implanted via the standard 3-incision technique (I3) were 1:1 propensity score matched for a noninferiority analysis of postoperative outcomes. RESULTS: There were 404 I3 patients and 223 I2 patients across 6 participating centers. Operative time decreased from 128.7 minutes (95% CI, 124.5-132.9) in I3 patients to 86.6 minutes (95% CI, 83.7-97.6) in I2 patients (P < .001). Postoperative sleep study data were available for 76 I2 patients who were matched to I3 patients. The change in apnea-hypopnea index between the cohorts was statistically noninferior (a priori noninferiority margin: 7.5 events/h; mean difference, 1.51 [97.5% CI upper bound, 5.86]). There were no significant differences between the cohorts for baseline characteristics, perioperative adverse event rates, or change in Epworth Sleepiness Score (P > .05). CONCLUSION: In a multicenter registry, a 2-incision implant technique for a commercially available HNS device had a statistically noninferior therapeutic efficacy profile when compared with the standard 3-incision approach. The 2-incision technique is safe and effective for HNS implantation.

Underrepresented Women Leaders: Lasting Impact of Gender Homophily in Surgical Faculty Networks.

OBJECTIVE: Despite the increase of women in surgical fields and resources toward advancing women, there is no corresponding increased representation of women in higher academic ranks and leadership. The following hypotheses are explored: 1) men and women build/maintain different relationship networks and 2) women are not similarly included within the organization and do not receive the same sponsorship as male counterparts. STUDY DESIGN: Prospective observational study. METHODS: Three months of prospective, passive organizational network data of full-time faculty at an academic medical center were collected by analysis of deidentified internal email communication logs. Data were analyzed and strength of network relationships was assessed using algorithms measuring the tie, or connection, score. Data analysis was performed with standard statistical methods and multivariable regression models, comparing network relationships based on gender and academic rank. RESULTS: Among 345 full-time faculties from surgical departments, 45.2% were female Assistant Professors, but only 9.8% were female full Professors. Men had 55% more network relationships with other men than women had with men. Gender homophily was particularly pronounced at the higher academic ranks. Men compared to women in higher ranks had 157% more network relationships to other men in lower ranks. Multivariable regression models suggested direct association of these gender differences in relationships with more women in lower academic ranks. CONCLUSION: Higher academic rank can be predicted by male gender, tenure, and number of meaningful relationships. Women are underrepresented at the leadership level in surgical departments. Gender homophily is present in collaboration networks among academic surgeons and is associated with impeded female career advancement. LEVEL OF EVIDENCE: 2 Laryngoscope, 132:20-25, 2022.

Hypoglossal Nerve Stimulator Implantation in an Ambulatory Surgery Center Versus Hospital.

OBJECTIVES/HYPOTHESIS: Hypoglossal nerve stimulator (HGNS) implantation is highly effective in treating obstructive sleep apnea (OSA) in select patient populations that are intolerant of continuous positive airway pressure. Implantation surgery is traditionally performed in hospital outpatient departments (HOPD) due to concern about anesthetic effects and airway manipulation in an OSA population. In this study, we examined complications and efficiency of HGNS implantation in an ambulatory surgery center (ASC) versus HOPD. STUDY DESIGN: Retrospective cohort study. METHODS: Patients with HGNS implantation performed between May 2015-January 2021 at our HOPD or ACS were included. Patient-related characteristics, surgical times, and postoperative complications were obtained via chart review. Reimbursement data on a national level for Medicare patients were calculated based on publicly available data from the Center for Medicare Services. Patient characteristics, surgical times, and complications were summarized as medians with interquartile ranges (IQRs) and proportions in each surgical setting group as appropriate. These were compared between surgical setting groups via Wilcoxon rank-sum testing and χ2 testing. RESULTS: A total of 122 patients were included. Patients in the HOPD group had significantly higher median apnea-hypopnea index (AHI) (42.0 [IQR 27.9-51.0]) compared to the ASC group (31.0 [IQR 21.0-44.2], P = .005). The intervals between in-room and case start, case finish and out-of-room, and time in the postoperative area were significantly shorter in the ASC group compared to the HOPD group. Reimbursement on a national level was estimated at 18% lower for patients with surgery performed at the ASC. There was no significant difference in postoperative complications. CONCLUSIONS: HGNS implantation in an ASC is safe and more efficient than in a HOPD, and may also be more cost-effective. LEVEL OF EVIDENCE: 3 Laryngoscope, 132:706-710, 2022.

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

OBJECTIVES/HYPOTHESIS: To provide the ADHERE registry Upper Airway Stimulation (UAS) outcomes update, including analyses grouped by body mass index (BMI) and therapy discomfort. STUDY DESIGN: Prospective observational study. METHODS: ADHERE captures UAS outcomes including apnea-hypopnea index (AHI), Epworth sleepiness scale (ESS), therapy usage, patient satisfaction, clinician assessment, and safety over a 1-year period. BMI ≤32 kg/m2 (BMI32 ) and 32 < BMI ≤35 kg/m2 (BMI35 ) group outcomes were examined. RESULTS: One thousand eight hundred forty-nine patients enrolled in ADHERE, 1,019 reached final visit, 843 completed the visit. Significant changes in AHI (-20.9, P < .0001) and ESS (- 4.4, P < .0001) were demonstrated. Mean therapy usage was 5.6 ± 2.2 hr/day. Significant therapy use difference was present in patients with reported discomfort versus no discomfort (4.9 ± 2.5 vs. 5.7 ± 2.1 hr/day, P = .01). Patients with discomfort had higher final visit mean AHI versus without discomfort (18.9 ± 18.5 vs. 13.5 ± 13.7 events/hr, P = .01). Changes in AHI and ESS were not significantly different. Serious adverse events reported in 2.3% of patients. Device revision rate was 1.9%. Surgical success was less likely in BMI35 versus BMI32 patients (59.8% vs. 72.2%, P = .02). There was a significant therapy use difference: 5.8 ± 2.0 hr/day in BMI32 versus 5.2 ± 2.2 hr/day in BMI35 (P = .028). CONCLUSIONS: Data from ADHERE demonstrate high efficacy rates for UAS. Although surgical response rate differs between BMI32 and BMI35 patient groups, the AHI and ESS reduction is similar. Discomfort affects therapy adherence and efficacy. Thus, proper therapy settings adjustment to ensure comfort is imperative to improve outcomes. LEVEL OF EVIDENCE: 4 Laryngoscope, 131:2616-2624, 2021.

Obstructive Sleep Apnea: Non-positive Airway Pressure Treatments.

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

Improving outcomes of hypoglossal nerve stimulation therapy: current practice, future directions, and research gaps. Proceedings of the 2019 International Sleep Surgery Society Research Forum.

Hypoglossal nerve stimulation (HGNS) has evolved as a novel and effective therapy for patients with moderate-to-severe obstructive sleep apnea. Despite positive published outcomes of HGNS, there exist uncertainties regarding proper patient selection, surgical technique, and the reporting of outcomes and individual factors that impact therapy effectiveness. According to current guidelines, this therapy is indicated for select patients, and recommendations are based on the Stimulation Therapy for Apnea Reduction or STAR trial. Ongoing research and physician experiences continuously improve methods to optimize the therapy. An understanding of the way in which airway anatomy, obstructive sleep apnea phenotypes, individual health status, psychological conditions, and comorbid sleep disorders influence the effectiveness of HGNS is essential to improve outcomes and expand therapy indications. This article presents discussions on current evidence, future directions, and research gaps for HGNS therapy from the 10th International Surgical Sleep Society expert research panel. CITATION: Suurna MV, Jacobowitz O, Chang J, et al. Improving outcomes of hypoglossal nerve stimulation therapy: current practice, future directions and research gaps. Proceedings of the 2019 International Sleep Surgery Society Research Forum. J Clin Sleep Med. 2021;17(12):2477-2487.

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.