Compliance with the provisions in this policy may be monitored and addressed
through post payment data analysis and subsequent medical review audits.

**History/Background and/or General Information**  
Obstructive sleep apnea (OSA) is a disease characterized by recurrent episodes
of upper airway obstruction during sleep. The disruption in airflow caused by
OSA has been associated with multiple comorbidities, including hypertension,
cardiovascular disease, cardiac arrhythmia, cerebrovascular disease, excessive
daytime sleepiness, and mood disorders. Continuous positive airway pressure
(CPAP) has long been the primary treatment modality of choice for OSA, showing
improvements in many comorbidities. Unfortunately, despite attempts to improve
compliance, many people are unable to tolerate treatment with CPAP. Because of
the large percentage of patients not tolerating CPAP, alternative treatment
strategies are necessary.

The hypoglossal nerve is the twelfth cranial nerve, and innervates all the
extrinsic and intrinsic muscles of the tongue, except for the palatoglossus
which is innervated by the vagus nerve. It is a nerve with a solely motor
function. The nerve arises from the hypoglossal nucleus in the brain stem as a
number of small rootlets, passes through the hypoglossal canal and down
through the neck, and eventually branches within the tongue and innervates the
tongue. There are two hypoglossal nerves in the body: one on the left, and one
on the right.

The concept of stimulating the tongue musculature to increase upper airway
size and limit the pathophysiologic obstruction leading to OSA was introduced
in the late 1980s. A variety of strategies were utilized, including
transcutaneous stimulation with placement of electrodes in the submental
region, sublingual mucosa, and soft palate. However, these studies were
limited by their lack of selective stimulation of the primary protrusor of the
tongue, the genioglossus muscle. In 2001, Schwartz et al (1) performed a trial
in which they selectively stimulated the branches of the hypoglossal nerve,
innervating the genioglossus. They noted a significant improvement in the
apnea-hypopnea index (AHI) and O2 desaturation nadir. Although only eight
patients were studied with three remaining free of stimulator malfunction, one
of the important outcomes was that patients could tolerate long-term
stimulation at night. This technology was subsequently refined and Eastwood et
al (2011) (2) conducted a feasibility trial with 21 patients followed for six
months. The AHIs decreased 56% at three months and 55% at six months which was
statistically significant. In 2014, the Stimulation Therapy for Apnea
Reduction (STAR) Trial was published as the initial clinical trial using an
Inspire Medical Systems upper airway stimulation (UAS) device as an
alternative therapy to CPAP for treatment of OSA which led to Food and Drug
Administration (FDA) approval (3).

The only Food and Drug Administration (FDA) - approved hypoglossal nerve
stimulation (HGNS) system has three implantable components: a stimulation lead
that delivers mild stimulation to maintain multilevel airway patency during
sleep, a breathing sensor lead that senses breathing patterns, and a generator
that monitors breathing patterns. The two external components are a patient
sleep remote that provides a noninvasive means for a patient to activate the
generator and a physician programmer that allows the physician to
noninvasively interrogate and configure the generator settings. The system
battery life for the implantable components is 7 to 10 years.

A surgeon implants the system containing a neurostimulator subcutaneously in
the patient's chest, with one lead attached to the patient's hypoglossal nerve
(cranial nerve XII) at the base of the tongue and one lead implanted in the
patient's chest. The lead in the chest consists of a pressure sensor that
detects breathing. Information about respiration rate is relayed to the
device, which stimulates the hypoglossal nerve in the tongue. When stimulated,
the tongue moves forward, opening the airway. The patient can operate the
device by remote control, which the patient activates before going to sleep.
The device turns on after 20 minutes to minimize disrupting the patient's
sleep onset; the device must be manually turned off via remote when the
patient wakes.

**Covered Indications**  
FDA-approved hypoglossal nerve neurostimulation is considered medically
reasonable and necessary for the treatment of moderate to severe obstructive
sleep apnea when all of the following criteria are met:

  1. Beneficiary is 22 years of age or older; **and**
  2. Body mass index (BMI) is less than 35 kg/m2; **and**
  3. A polysomnography (PSG) is performed within 24 months of first consultation for HGNS implant; **and**
  4. Beneficiary has predominantly obstructive events (defined as central and mixed apneas less than 25% of the total AHI); **and**
  5. AHI is 15 to 65 events per hour; **and**
  6. Beneficiary has documentation that demonstrates CPAP failure (defined as AHI greater than 15 despite CPAP usage) or CPAP intolerance (defined as less than 4 hours per night, 5 nights per week or the CPAP has been returned) including shared decision making that the patient was intolerant of CPAP despite consultation with a sleep expert; **and**
  7. Absence of complete concentric collapse at the soft palate level as seen on a drug-induced sleep endoscopy (DISE) procedure; **and**
  8. No other anatomical findings that would compromise performance of device (e.g., tonsil size 3 or 4 per standardized tonsillar hypertrophy grading scale).

**Limitations  
** The following are considered not reasonable and necessary and therefore
will be denied:

  1. Use for all other indications. 
  2. Non-FDA-approved hypoglossal nerve neurostimulation.
  3. Presence of any of the following: 
    * Beneficiaries with central and mixed apneas that make up more than one-quarter of the total AHI.
    * Beneficiaries with an implantable device could experience unintended interaction with the HGNS implant system. Limitations are:   

      * BMI equal to or greater than 35
      * Neuromuscular disease affecting the respiratory system
      * Hypoglossal-nerve palsy
      * Severe restrictive or obstructive pulmonary disease
      * Moderate-to-severe pulmonary arterial hypertension
      * Severe valvular heart disease
      * New York Heart Association class III or IV heart failure
      * Recent myocardial infarction or severe cardiac arrhythmias (within the past 6 months)
      * Persistent uncontrolled hypertension despite medication use
      * An active, serious mental illness that reduces the ability to carry out Activities of Daily Living (ADLs) and would interfere with the patient's ability to operate the HNS and report problems to the attending provider
      * Coexisting nonrespiratory sleep disorders that would confound functional sleep assessment
    * Beneficiaries who are, or who plan to become pregnant.
    * Beneficiaries who require magnetic resonance imaging (MRI) with model 3024.
    * Beneficiaries, who require magnetic resonance imaging (MRI) with model 3028, can undergo MRI on the head and extremities if certain conditions and precautions are met. Please refer to the Manufacturer Guidelines for this model and future models for information.
    * Beneficiaries who are unable or do not have the necessary assistance to operate the sleep remote.
    * Beneficiaries with any condition or procedure that has comprised neurological control of the upper airway.  
  

  4. Drug Induced Sleep Endoscopy (DISE):  

    * Due to documented inconsistency in determining if complete concentric collapse (CCC) is present, the inserting provider shall be certified by the FDA approved manufacturer's second opinion service of validation via video clip submissions of at least 80% agreement in at least 15 consecutive studies. Inserting providers shall have documentation to submit to this contractor if necessary.
  5. Shared Decision Making (SDM):
    * SDM, by definition, is any documented conversation between an attending provider and the patient, and not between multiple providers. Providers shall provide these documents if requested by the contractor.

**Place of Service (POS)**  
Hypoglossal nerve stimulation for the treatment of OSA must be furnished in
accordance with the accepted standards of medical practice in a setting
appropriate to the patient's medical needs and condition.

**Provider Qualifications**  
Hypoglossal nerve stimulation for the treatment of OSA must be ordered and
furnished by qualified personnel. The hypoglossal nerve (HN) may be damaged
during neck surgeries. A detailed understanding of the anatomy of the
hypoglossal nerve in relation to various anatomical landmarks and surrounding
structures is important to reduce procedural complications and the risk of
nerve damage.

  * **Provider Specialties**  

    * Insertion of an FDA-approved hypoglossal nerve stimulation device addressed in this LCD must be performed by a qualified physician (MD or DO) who is a board certified or a board eligible  **otolaryngologist** having completed the appropriate AMA or AOA certified residency and/or fellowship program and maintains ongoing certification in otolaryngology. In addition, prior to implanting the system, surgeons will need to receive classroom instruction by an FDA approved device manufacturer or equivalent on device implant techniques as well as cadaver training. Documentation must be provided to support completion of training to an exemplary level by the manufacturer. 
    * Sleep physicians and sleep technicians shall receive classroom instruction from a similar facility on how to titrate the device including hands on operation of the programmer. Doctors must maintain, for the contractor to review, documentation of such training completion to a satisfactory level of completion as established by the device manufacturer or appropriate board approval of competency. Evaluation, referral and post implant evaluation of the hypoglossal nerve stimulator, but not including expected post-op care by the inserting physician, should be performed by board eligible or certified sleep physician with qualifications as outlined in Article A53019, Polysomnography and Sleep Studies - Medical Policy Article. Sleep Technicians shall meet the same qualifications as outlined in the Article A53019, Polysomnography and Sleep Studies - Medical Policy Article, in addition. Likewise, sleep studies shall be performed in an accredited sleep facility as stated in Article A53019.

**Notice** : Services performed for any given diagnosis must meet all of the
indications and limitations stated in this policy, the general requirements
for medical necessity as stated in CMS payment policy manuals, any and all
existing CMS national coverage determinations, and all Medicare payment rules.

Strollo et al (2014) (4) evaluated the clinical safety and effectiveness of
upper-airway stimulation at 12 months for the treatment of moderate-to-severe
obstructive sleep apnea. The study included 126 participants; 83% were men,
17% had had previous uvulopalatopharyngotoplasty. The mean age was 54.5 years,
and the mean BMI was 28.4. Exclusion criteria were a BMI of more than 32.0,
neuromuscular disease, hypoglossal-nerve palsy, severe restrictive or
obstructive pulmonary disease, moderate-to-severe pulmonary arterial
hypertension, severe valvular heart disease, New York Heart Association class
III or IV heart failure, recent myocardial infarction or severe cardiac
arrhythmias (within the past 6 months), persistent uncontrolled hypertension
despite medication use, active psychiatric disease, and coexisting
nonrespiratory sleep disorders that would confound functional sleep
assessment. The study was designed by the sponsor (Inspire Medical Systems),
the investigators, and the FDA as a multicenter, prospective, single-group
trial with participants serving as their own controls. The primary outcome
evaluation was followed by a randomized, controlled therapy-withdrawal study
that included a subgroup of consecutive participants selected from the
population that had a response to therapy. The primary outcome measures were
assessed by means of overnight polysomnography and scored by an independent
core laboratory with the use of standard criteria. The data analysis was
performed by an independent statistician. The study investigators had full
access to the data and the right to submit the results for publication without
input from the sponsor.

Participants underwent screening that included polysomnography, medical and
surgical consultation, and endoscopy during drug-induced sleep (DISE).
Participants were excluded if the AHI score from the screening polysomnography
was less than 20 or more than 50 events per hour, if central or mixed sleep-
disordered breathing events accounted for more than 25% of all apnea and
hypopnea episodes, or if the AHI score while the person was not in a supine
position was less than 10 events per hour. Participants were also excluded if
pronounced anatomical abnormalities preventing the effective use or assessment
of upper-airway stimulation were identified during the surgical consultation
[e.g., tonsil size of 3 or 4 (tonsils visible beyond the pillars or extending
to midline)] or if complete concentric collapse at the retropalatal airway was
observed on endoscopy performed during drug-induced sleep. Qualified
participants underwent a surgical procedure to implant the upper-airway
stimulation system (Inspire Medical Systems). The stimulation electrode was
placed on the hypoglossal nerve to recruit tongue-protrusion function; the
sensing lead was placed between the internal and external intercostal muscles
to detect ventilatory effort; the neurostimulator was implanted in the right
ipsilateral mid-infraclavicular region. Stimulation was initiated one month
after implantation.

The primary outcome was the change in the severity of obstructive sleep apnea
in the study population, as assessed by means of the AHI and the oxygen
desaturation index (ODI: the number of times per hour of sleep that the blood
oxygen level drops by greater than or equal to 4 percentage points from
baseline). The co-primary outcome was the proportion of participants with a
response from baseline to 12 months with respect to the primary outcome
measures of the AHI and ODI scores. A response as measured by means of the AHI
was defined as a reduction of at least 50% from baseline in the AHI score and
an AHI score on the 12-month polysomnography of less than 20 events per hour.
The ODI was chosen as a stable integrative outcome value of all forms of
sleep-disordered breathing. A response as measured by means of the ODI was
defined as a reduction of at least 25% from baseline in the ODI score. The
prespecified primary efficacy objectives were response rates of at least 50%,
as assessed by means of the AHI and ODI. All participants who received an
implant were included in the primary outcome analysis; participants who did
not complete the 12-month visit were considered not to have had a response.

Secondary outcome measures included self-reported sleepiness and disease-
specific quality of life as assessed with the use of the Epworth Sleepiness
Scale (scores range from 0.0 to 24.0, with higher scores indicating more
daytime sleepiness); disease-specific quality of life, as assessed with the
use of the Functional Outcomes of Sleep Questionnaire (FOSQ - scores range
from 5.0 to 20.0, with higher scores indicating greater functioning); and the
percentage of sleep time with the oxygen saturation less than 90%.

At the 12-month visit, 124/126 (98 %) patients were available for evaluation.
The first 46 consecutive participants who met the criterion of having a
response to therapy were randomly assigned, in a 1:1 ratio, to the therapy-
maintenance group or the therapy-withdrawal group. This design filtered out
persons who had not had a response to therapy. The therapy-withdrawal group
had the device turned off for 7 days, whereas the therapy-maintenance group
continued with the device turned on. Polysomnography was performed after the
randomization period to measure the effects of therapy withdrawal, as compared
with continued use of the therapy.

The scores on the AHI and ODI (primary outcome measures) were lower
(indicating fewer episodes of sleep apnea) at 12 months than at baseline. The
median AHI score decreased 68%, from the baseline value of 29.3 events per
hour to 9.0 events per hour. The median ODI score decreased 70%, from 25.4
events per hour to 7.4 events per hour. At the 12-month visit, the criteria
for the coprimary outcome of a reduction of at least 50% in the AHI score from
baseline and an AHI score of less than 20 events per hour were met by 66% of
the participants [83 of 126 participants; lower boundary of the 97.5%
confidence interval (CI), 57]. The criterion for the coprimary outcome of a
reduction of at least 25% in the ODI score from baseline was met by 75% of
participants [94 of 126; lower boundary of the 97.5% (CI), 66]. Both primary
efficacy outcomes exceeded the predefined study objectives. However, reviewing
the supplementary data, at 12 months there were 37/126 (29%) participants with
an AHI <5/hr, 67 (53%) with an AHI < 10, and 80 (63%) with an AHI <15.

Scores on the FOSQ and Epworth Sleepiness Scale indicated significant
improvement at 12 months, as compared with baseline. The median percentage of
sleep time with the oxygen saturation less than 90% decreased from a baseline
value of 5.4% to 0.9% at 12 months. The average increase in the AHI score in
the therapy-withdrawal group was 18.2 events per hour, whereas the average
increase in the therapy-maintenance group was 1.7 events per hour (difference
in changes in mean scores, 16.412.0 events per hour; P less than 0.001). A
similar effect was observed with respect to the mean ODI scores.

Two participants had a serious device-related adverse event requiring
repositioning and fixation of the neurostimulator to resolve discomfort. No
permanent tongue weakness was reported during the study. Most of the device-
related events that were not considered to be serious resolved after the
participants acclimated to the upper-airway stimulation therapy or after the
device was reprogrammed to adjust the stimulation variables.

The daily use of upper-airway stimulation was 86%, as assessed on the basis of
self-report. A control group of therapeutic CPAP users (i.e., a comparative-
effectiveness design) would be impractical, given the current study design.

The randomized, controlled therapy-withdrawal study in which some participants
had the therapy turned off for 1 week provided evidence that the therapeutic
effect established at 12 months was attributable to the upper-airway
stimulation therapy, rather than variability in the AHI score.

The STAR Trial group evaluated the stability of improvement of 123/126 (98%)
subjects using polysomnographic measures of sleep disordered breathing,
patient reported outcomes, the durability of hypoglossal nerve recruitment and
safety at 18 months [Dedhia et al (2015)] (5). Procedure- and/or device-
related adverse events were reviewed and coded by the Clinical Events
Committee. The median AHI was reduced by 67.4% from the baseline of 29.3 to
9.7/h at 18 months. The median ODI was reduced by 67.5% from 25.4 to 8.6/h at
18 months. The FOSQ and ESS improved significantly at 18 months compared to
baseline values. The functional threshold was unchanged from baseline at 18
months. No tongue weakness reported at 18 months.

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

Soose et al (2016) (6) reported the 24-month evaluation of 111/126 (88%) of
the STAR Trial patients. Outcomes measured 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.

Significant improvement in mean FOSQ score was observed from baseline (14.3)
to 12 months (17.3), and the effect was maintained at 24 months (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 months (7.0) and 24 months
(7.1). Self-reported snoring severity showed an increased percentage of "no"
or "soft" snoring from 22% at baseline to 88% at 12 months and 91% at 24
months. UAS demonstrated large effect size (greater than 0.8) at 12 and 24
months for overall ESS and FOSQ measures, and the effect size compared
favorably to previously published effect size with other sleep apnea
treatments.

The authors concluded that in a selected group of patients with moderate to
severe OSA and body mass index less than or equal to 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-year follow-up period.

Woodson et al (2016) (7) reported the 36-month evaluations of the STAR
clinical trial patients performed by the investigators. Of the 126 enrolled
participants, 116 (92%) completed 36-month follow-up evaluations per protocol;
98 participants additionally agreed to a voluntary 36-month PSG. Self-report
daily device usage was 81%. In the PSG group, 74% met the prior definition of
success with the primary outcomes of apnea-hypopnea index, reduced from the
median value of 28.2 events per hour at baseline to 8.7 and 6.2 at 12 and 36
months, respectively. Similarly, self-reported outcomes improved from baseline
to 12 months and were maintained at 36 months.

The authors concluded that long-term 3-year improvements in objective
respiratory and subjective quality-of-life outcome measures were maintained
and adverse events were uncommon.

The 48-month STAR Trial outcomes were reported by Gillespie et al (2017) (8).
A total of 91 subjects (72%) completed the 48-month visit. Daytime sleepiness
as measured by ESS was significantly reduced (P equal to .01), and sleep-
related quality of life as measured by FOSQ significantly improved (P equal to
.01) when compared with baseline. Soft to no snoring was reported by 85% of
bed partners.

The authors concluded that upper airway stimulation benefits had been
maintained.  

Finally, Woodson et al (2018) (9) published the STAR investigators' 5-year
patient outcomes. From a cohort of 126 patients, 97 (77 %) completed the
protocol, and 71 (56 %) consented to a voluntary polysomnogram. 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 were observed, with
normalization of scores increasing from 33% to 78% and 15% to 67%,
respectively. AHI response rate (AHI less than 20 events per hour and greater
than 50% reduction) was 75% (n equal to 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.

The authors concluded that there were improvements in sleepiness, quality of
life, and respiratory outcomes observed with 5 years of UAS and serious
adverse events were uncommon. Nearly all of the STAR investigators variously
reported personal fees, research support, and advisory panel memberships from
Inspire Medical Systems, Inc. and several other related companies.

Studies in Europe and Australia with or without participation by investigators
in the United States have generally had the same inclusion and exclusion
criteria as the STAR Trial but inclusion criteria for AHI and BMI have been
broadened. The FDA initially approved the device for individuals with an AHI
equal to or greater than 20 and less than or equal to 65 events per hour (3).
The AHI range was changed by the FDA in June 2017 to 15 to 65 AHI events per
hour. (10) The FDA did not address BMI in its approvals. Overall results were
similar to those in the STAR Trial.

Heiser et al (2017) (11) prospectively studied HGS UAS outcomes in 31
consecutive patients with moderate to severe OSA (AHI >15/h to <65/h) treated
at a single tertiary referral center. There was no BMI set for
inclusion/exclusion criteria but the mean BMI was reported as 28.8 kg/m2.
Follow-up visits at 1, 2, 3, 6, and 12 months were performed with PSGs at
months 2 and 3 and home sleep polygraphy (PG) at 6 and 12 months. Mean AHI
decreased 65% at month 2 and was also significantly reduced at 3 months. At 6
months, 30/31 (96.8%) had greater than a 50% decrease from their baseline AHI.
Results were maintained at 12 months. Mean baseline AHIs were 32.9  11.2/h.
AHIs at 6 months were 7.7  3 and 7.1  5.9 at 12 months. ODI and ESS results
also showed statistically significant improvements. The senior author was a
study investigator and consultant for Inspire Medical System.

Heiser et al (2017) (12) also reported on 60 patients treated at three
tertiary hospitals in Germany. The AHI inclusion criteria were >15/hr and
<65/hr and a BMI <35 mg/kg2. Two-night home sleep tests were performed before
and six months after surgery. The average AHI prior to surgery was 31.6 
13.4/h with a range of 13.4 - 64.5. Six-month evaluations were performed on 56
of the 60 patients. The other four patients had a uvulopalatoplasty (UPPP)
after the two-month titration studies. Of the 56, an average reduction of 61%
 24% occurred with 25% achieving an AHI 5, 59% 10, and 70% 15\.
Statistically significant reductions occurred in ODI, apnea index, hyponea
index, and ESS. All but one of the authors had received personal fees, travel
expenses, and/or research fee support from Inspire Medical Systems.

Hasselbacher et al (2018) (13) gathered patient reported outcomes of 56 of the
above 60 patients. Results showed a high correlation between AHI improvement;
a favorable comparison of UAS to CPAP; whether UAS would be chosen again and
would be recommended to a friend or family member; and overall satisfaction.
Each author reported potential conflicts of interest.

Records of 78 patients were reviewed at a US and a German facility by Huntley
et al (2018) (14). Patients were divided into two groups: 32 kg/m2 (113
patients) and > 32 kg/m2 (40 patients). The BMI average in the first group was
27.63  2.48 kg/m2 and 34.37  3.08 kg/m2 in the second. There was no
statistically significant difference between the two groups for postoperative
AHI, oxygen desaturation nadir, ESS score, rate of surgical success or rate of
patients reaching an AHI less than 15 or 5/h. Surgical success defined as a
decrease in postoperative AHI by 50% and less than 20/h was attained by 95.4%
in the smaller BMI group and 92.3% in the larger BMI group (p = 0.345). A
postoperative AHI of <15/h was attained by 93.6% and 89.7% (p = 0.316).
Postoperative AHI <5% was achieved by 63.6% and 56.4% (p = 0.271). (Results
for the smaller group are listed first.) The authors noted that UAS was only
offered to patients with an elevated BMI who had readily palpable cervical
landmarks and carried most of their weight in the waist and hips. Limitations
of the study were the retrospective design and post-treatment assessment
through titration PSG. The authors declared no potential conflicts of
interest.

Heiser et al (2019) (15) developed an international ADHERE multinational
registry to identify predictors of UAS therapy response. Five hundred and
eight patients were enrolled. The AHI data prior to implementation, the
treatment AHI post-titration, and the "final" visit at about 12 months were
collected. At the final visit, the AHI decreased by _>_ 50% and to 20/h in
81%. Those with an ESS <10 increased from a baseline of 37% to 76% at the
final visit. Satisfaction was 94% at the final visit. BMI was a predictor of
lower UAS therapy adherence with each unit of BMI increase having an odds
ratio of 10% lower adherence. Age was associated with an increased odds ratio
of 9% for each year of additional age. Two-thirds of the authors reported a
potential conflict of interest.

Two review articles have been published. Certal et al (2015) (16) reviewed six
prospective studies with 200 patients. Devices varied but were all implanted
hypoglossal nerve stimulators. Overall, at 12 months the AHI was reduced
between 50% and 57%. The ODI was reduced between 48% and 52%. Kompelli et al
(2019) (17) reviewed 16 studies with 381 patients. At 12 months the mean AHI
was reduced by 21.1 (95% CI, 2.6-3.7) and the mean ODI was reduced by 15.0
(95% CI, 12.7-17.4). The ESS improved by 5.0 (95% CI, 4.2-5.8) with a mean
FQSQ improvement of 3.1 (95% CI, 2.6-3.4). Each author concluded that
hypoglossal nerve stimulation of the upper airway could be considered for
patients with obstructive sleep apnea who did not respond to medical therapy.

Evidence-Based Practice Guidelines and Position Statements  
  
The American Academy of Sleep Medicine (AASM) (18) Clinical Practice Guideline
for Diagnostic Testing for Adult OSA states that the third edition of the
International Classification of Sleep Disorders (ICSD-3) defines OSA as a PSG-
determined obstructive respiratory disturbance index (RDI) greater than or
equal to 5 events/hour associated with the typical symptoms of OSA (e.g.,
unrefreshing sleep, daytime sleepiness, fatigue or insomnia, awakening with a
gasping or choking sensation, loud snoring, or witnessed apneas), or an
obstructive RDI greater than or equal to 15 events/hour (even in the absence
of symptoms). There is no current statement regarding hypoglossal nerve
stimulation for upper airway stimulation.

In 2016, the American Academy of Otolaryngology Head and Neck Surgery (19)
issued a position statement on hypoglossal nerve stimulation for treatment of
obstructive sleep apnea (OSA) which states "The American Academy of
Otolaryngology Head and Neck Surgery considers upper airway stimulation (UAS)
via the hypoglossal nerve for the treatment of adult obstructive sleep apnea
syndrome to be an effective second-line treatment of moderate to severe
obstructive sleep apnea in patients who are intolerant or unable to achieve
benefit with positive pressure therapy (PAP). Not all adult patients are
candidates for UAS therapy and appropriate polysomnographic, age, BMI and
objective upper airway evaluation measures are required for proper patient
selection." AAO-HNS position statements include an important disclaimer, "In
no sense do they represent a standard of care."

International Society for Sleep Surgery (20) states that cranial nerve
(hypoglossal nerve) stimulation is among surgical treatments and procedures
that "have been shown to be effective in the treatment of sleep disordered
breathing/obstructive sleep apnea syndrome in adults (and/or children) when
applied to selected patients based on their anatomy, physiology, body mass
index and neck size, prior therapy and co-morbidities. Patient should have
undergone an appropriate evaluation(s) prior to treatment which may include
polysomnography, home sleep testing, awake or drug induced sleep endoscopy,
and possible cephalometric or other radiographic evaluations."

In 2017, National Institute for Health and Clinical Excellence (NICE) (21)
issued an interventional procedure guidance (IPG598) which states: "Current
evidence on the safety and efficacy of hypoglossal nerve stimulation for
moderate to severe obstructive sleep apnea is limited in quantity and quality.
Therefore, this procedure should only be used with special arrangements for
clinical governance, consent and audit for research."

The evidence on hypoglossal nerve stimulation for the treatment of obstructive
sleep apnea (OSA) includes case series and a multicenter, prospective, single
group, cohort design study (STAR) that were surgically implanted with an upper
airway stimulation device with obstructive sleep apnea who had difficulty
either accepting or adhering to CPAP therapy and were followed for 5 years.
Prospective cohort study is gold standard for epidemiologic studies. The study
strengths included measuring primary and secondary outcomes and at 12-month
visits, a second randomized study within the study where participants were
randomly assigned into two groups with one group having the device turned off
for 7 days and the other continued with the device turned on. Polysomnography
was performed after the randomization period to measure the effects of therapy
withdrawal as compared to continued use of the therapy. (4)

Hypoglossal nerve stimulation has shown improved outcomes in the STAR Trial
when used in a select group of patients. For the patients that met the
inclusion criteria for AHI, BMI and favorable pattern for palatal collapse
about two-thirds met the study definition of success. Results observed at the
12 month follow-up were maintained at 3 years. Patient based outcomes at 48
months, concluded these patients maintained a sustained benefit on patient
reported outcomes (Epworth Sleepiness Score, Functional Outcomes of Sleep
Questionnaire and snoring). Conclusions from the 5 year outcomes were that 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. Safety and effectiveness were evaluated using multiple outcome
measures.

There are also other studies showing patient improvement but none followed
patients longer than 12 months. Limitations of the studies are that few gave
results of the AHI improvement in terms of how many patients achieved an AHI
<5 (normal), 5 - <15 (mild), _>_ 15 - < 30 (moderate) and 30 (severe). The
improved mean AHIs were usually in the mild to moderate range leaving the
patient with mild to moderate sleep apnea.

For individuals with obstructive sleep apnea who are treated with hypoglossal
nerve stimulation, the evidence is sufficient to determine that the technology
results in a meaningful improvement in the net health outcome when utilized
for carefully selected patients as outlined in this LCD.