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.

Home Sleep Testing to Direct Upper Airway Stimulation Therapy Optimization for Sleep Apnea.

OBJECTIVES/HYPOTHESIS: Selective upper airway stimulation (sUAS) is a well-established treatment option for obstructive sleep apnea (OSA). This study aimed to determine if there are benefits in performing a home sleep test (HST) to evaluate postoperative sUAS effectiveness after patient acclimatization compared to the generally used polysomnography (PSG) titration, as measured by long-term follow-up outcomes. STUDY DESIGN: Retrospective comparative cohort analysis. METHODS: We conducted an analysis of consecutive patients at our center who had completed a 6-month follow-up (month 6 [M6]) and recorded data from M6, month 12 (M12), and month 24 (M24). After device activation, we performed an HST with the patient's stimulation settings, and measured the apnea-hypopnea index (AHI), Epworth Sleepiness Scale (ESS), and device usage. These values were compared to patients who had undergone PSG-based device titration. RESULTS: Baseline values of the initial 131 patients show high ESS and moderate OSA. At the 2-month time point of the HST, nearly half of the patients (46.2%) reached an AHI ≤15/hr, and approximately a fifth (19.2%) reached <5/hr. The PSG and HST groups differed in median ESS at M24, but no other differences were observed for ESS at M6 and M12. Both groups showed similar AHI, oxygen desaturation, and usage hours per week. CONCLUSIONS: Adjusting therapy by using the HST technique after device activation and acclimatization has clinical and economic advantages. These advantages are contingent on several conditions being met when deviating from the standard device protocol, including precise communication with the referring sleep medicine physicians, especially their role in helping with long-term follow-up. LEVEL OF EVIDENCE: 4 Laryngoscope, 131:E1375-E1379, 2021.

Patient experience with upper airway stimulation in the treatment of obstructive sleep apnea.

OBJECTIVE: Selective upper airway stimulation (sUAS) is a new treatment modality for patients with obstructive sleep apnea (OSA) and continuous positive airway pressure (CPAP) failure. The aim of this study was to analyze therapy adherence and to structure patient experience reports. METHODS: Patients from two German implantation centers were included. Besides demographic and OSA characteristics of that cohort, patients answered a questionnaire on subjective sensation of the stimulation, use of different functions, side effects, and an inventory for the description of the attitude towards sUAS. The use of the sUAS was evaluated as a read-out of the implanted system. RESULTS: The overall apnea-hypopnea-index (AHI) of that 102 assessed patients reduced from initially 32.8/h to 12.6/h at the last available assessment. The responder rate was 75%. There was an objective therapy usage of 5.7 h and subjective reports of 6.8 nights per week. The attitude resulted in strong agreement towards the statement "UAS reduces the problems caused by my sleep apnea". Information on sensing the stimulation and usage habits could be gathered such as that stimulation is only sensed by 67.9% of the patients upon waking in the morning and that 73.6% of the patients do not change the voltage in general. CONCLUSION: This investigation on the sUAS therapy revealed a high adherence to the therapy. The AHI or daytime sleepiness do not have obvious influence on adherence. Patients expressed a positive attitude towards sUAS. These patient reports upon stimulation experiences are of great help to consult candidates for sUAS in future.

Upper-Airway Stimulation Before, After, or Without Uvulopalatopharyngoplasty: A Two-Year Perspective.

OBJECTIVE: Upper airway stimulation (UAS) is an effective second-line treatment for obstructive sleep apnea (OSA). In certain patients, there is a considerable need for advanced programming, notably with inadequate palatal response to therapy. The aim of the study was to investigate the impact of uvulopalatopharyngoplasty and tonsillectomy (UPPP-TE) on UAS therapy outcomes from a 2-year perspective after implantation. METHODS: This study included all consecutive patients implanted with UAS in which a full set of 1- and 2-year follow-up assessments (M12 and M24) were obtained. Cases were analyzed in three groups: patients with UPPP-TE after (group 1) and before (group 2) UAS, and those without UPPP-TE (group 3). RESULTS: Therapy success could be achieved in about 80% of the entire cohort. Groups 2 and 3 did not differ significantly with regard to obesity, Apnea-Hypopnea Index, or Oxygen Desaturation Index. With regard to initial sleep endoscopy, there were fewer patients without any obstruction at the palatal and oropharyngeal levels and higher prevalence of lateral obstruction patterns at oropharynx in group 1 in contrast to groups 2 and 3. Groups 2 and 3 showed similar results, although group 2 patients underwent UPPP-TE before UAS implantation. CONCLUSION: UPPP-TE should be considered in patients with persistent OSA after UAS implantation if the obstruction is identified at the level of velum and oropharynx. Although this approach has higher response rates and better outcomes can be achieved in patients with UAS, there is no indication for patients to routinely undergo UPPP-TE prior to UAS implantation. LEVEL OF EVIDENCE: 4 Laryngoscope, 129:514-518, 2019.

Selective upper airway stimulation in older patients.

OBJECTIVE: Selective stimulation of the hypoglossal nerve has proven to be an effective therapy for patients with obstructive sleep apnea (OSA). The aim of the study is to investigate the efficacy of selective upper airway stimulation (sUAS) in older adults. METHODS: All consecutive patients older than 64 years and who received an implant for sUAS were enrolled. As a control group, an equal number of patients younger than 65 years with matched apnea hypopnea index (AHI) and body-mass-index (BMI) were selected. Treatment outcome data were collected including daytime sleepiness as well as demographics with co-morbidities, BMI, adverse events and adherence to therapy. RESULTS: 62 patients were included. Both the control and study group did not differ significantly for AHI, BMI, and Epworth Sleepiness Scale (ESS) (28.7-28.4/h; 30.1 to 28.4 kg/m2; 14.6 to 12.0 points); but co-morbidities were significantly higher in the study group. Our data showed no significant difference between the outcomes of study and control group for AHI, Oxygen desaturation index (ODI) and ESS (6.0-6.0/h; 7.9 to 5.5/h; 5.0 to 7.0 points). Serious adverse events did not occur in both groups and surgical implantation time did not differ. CONCLUSION: sUAS leads to significant reductions of AHI, ODI and ESS in older patients. Despite higher age and more co-morbidities, surgical implantation time was not affected. Older patients showed higher usage of sUAS. Advanced age seems not to be a limiting factor for treatment outcomes of sUAS, thus indication for this treatment can also be applied to older people.

Patient-reported outcome: results of the multicenter German post-market study.

PURPOSE: Upper airway stimulation (UAS) is an alternative second-line treatment option for patients with obstructive sleep apnea (OSA). In our substudy of a previous multicentre study of patients implanted with UAS, we focused on patient-related outcomes like Epworth Sleepiness Scale (ESS), the Functional Outcomes of Sleep Questionnaire (FOSQ), snoring and personal satisfaction 6 and 12 months after the implantation. METHODS: 60 patients, who were initially non-adherent to CPAP and implanted with UAS, were included in a prospective multicentre study. Data were collected preoperative, 6 and 12 months after implantation regarding FOSQ, ESS, snoring, and their experience with the UAS device. RESULTS: Besides relevant Apnoea-Hypopnea Index (AHI) reduction, we saw significant improvements in ESS (p < 0.001), FOSQ (p < 0.001) and snoring under UAS therapy. A strong correlation between AHI results postoperative and the personal satisfaction of the patients after implantation was found as well as between usage results and AHI compared to the preoperative results. CONCLUSION: The more the patients benefit from UAS according to their self-reported outcome, the higher is the therapy use.

Outcome after one year of upper airway stimulation for obstructive sleep apnea in a multicenter German post-market study.

OBJECTIVE/HYPOTHESIS: Upper airway stimulation (UAS) of the hypoglossal nerve has been implemented in the routine clinical practice for patients with moderate-to-severe obstructive sleep apnea (OSA) who could not adhere to continuous positive airway pressure. This study reports objective and patient-reported outcome after 12 months of implantation. STUDY DESIGN: Multicenter prospective single-arm study. METHODS: Consecutive patients who received the UAS system (Inspire Medical Systems, Inc., Minneapolis, Minnesota, Maple Grove, MN, U.S.A.) were enrolled in three German centers. Key study exclusion criteria included body mass index > 35 kg/m2 , apnea-hypopnea index (AHI) < 15 or > 65, or complete concentric collapse at the soft palate during sedated endoscopy. Data collection at 6- and 12-month visit include home sleep test and patient-reported outcome measures. RESULTS: Among the total of 60 participants, the median AHI reduced from 28.6 to 9.5 from baseline to 12 months. Patient-reported outcome measured in Epworth Sleepiness Scale and Functional Outcomes of Sleep Questionnaire both improved significantly from baseline to 12 months. The average usage time was 39.1 ± 14.9 hours per week among all participants based on recordings by the implanted device. One patient requested a removal of the device for cosmetic and other personal reasons and was completed without sequelae. CONCLUSION: This study supported that UAS is a safe and effective treatment option for patients with OSA in routine clinical practice. LEVEL OF EVIDENCE: 4. Laryngoscope, 128:509-515, 2018.