Urinary incontinence refers to the involuntary loss of urine.

The overall prevalence of overactive bladder (OAB) in the total United States
(U.S.) population was 23.3%, with women reporting OAB almost twice as
frequently as men (30.0% vs. 16.4%, respectively).19 Nearly half of nursing
home residents have some degree of incontinence. For noninstitutionalized
persons older than 60 years of age, prevalence ranges from 15-35%, with women
having twice the prevalence of men.17

Sacral nerve stimulation (SNS) delivers nonpainful, electrical pulses to the
sacral nerves to modulate reflexes that influence the bladder, sphincter, and
pelvic floor to improve or restore function.4 SNS has been approved for use in
treating urinary incontinence in the U.S. since 1997.2

In 2011, SNS was U.S. Food and Drug Administration (FDA) approved for the
indication of fecal incontinence (FI).4 The chronic involuntary loss of stool
is a life altering circumstance. In the older population, this represents 1 of
the single most frequent precipitating factors for entrance into a nursing
home.2 FI is a common symptom, with a prevalence that ranges from 7-15% in
community dwelling men and women, but it is often underreported, as providers
seldom screen for FI and patients do not volunteer the symptom, even though
the symptoms can have a devastating impact on quality of life (QOL).The
strongest independent risk factors for FI in the community are bowel
disturbances, especially diarrhea, the symptom of rectal urgency, and burden
of chronic illness.3

Sacral neuromodulation (SNM) is a guideline recommended treatment for voiding
dysfunction including urgency, urge incontinence, and nonobstructive retention
as well as FI.

SNS is covered for the treatment of urinary urge incontinence, urgency-
frequency syndrome, and urinary retention by the Centers for Medicare and
Medicaid Services (CMS) National Coverage Determination (NCD) 230.18 Sacral
Nerve Stimulation for Urinary Incontinence. Direct stimulation of the sacral
nerve(s) via an electrode array implanted at the level of the sacrum is the
only treatment modality covered by the NCD.1

**Covered Indications**

****

**Urinary Incontinence**

SNS is covered for the treatment of urinary urge incontinence, urgency-
frequency syndrome, and nonobstructive urinary retention. SNS involves both a
temporary test stimulation to determine if an implantable stimulator would be
effective and a permanent implantation in appropriate candidates. Both the
test and the permanent implantation are covered.1

**Limitations**

****

NCD 230.18 Sacral Nerve Stimulation for Urinary Incontinence describes the
following limitations for coverage to apply to all 3 indications:

  * Patient must be refractory to conventional therapy (documented behavioral (such as bladder training, or pelvic muscle exercise training), pharmacologic and /or surgical corrective therapy) and be an appropriate surgical candidate such that implantation with anesthesia can occur.
  * Patients with stress incontinence, urinary obstruction, and specific neurologic disease (e.g., diabetes with peripheral nerve involvement, multiple sclerosis, spinal cord injury) which are associated with secondary manifestations of the above 3 indications are excluded.
  * Patient must have had a successful test stimulation in order to support subsequent implantation. Before a patient is eligible for permanent implantation, he/she must demonstrate a 50% or greater improvement through test stimulation. Improvement is measured through voiding diaries.
  * Patient must be able to demonstrate adequate ability to record voiding diary data such that clinical results of the implant procedure can be properly evaluated.1

**Covered Indications /Limitations**

**Fecal Incontinence (FI)**

This A/B Medicare Administrative Contractor (MAC) will cover SNS for FI, when
all of the following criteria are met:

  * Chronic FI with greater than 2 incontinent episodes on average per week and duration of incontinence greater than 6 months or for more than 12 months after vaginal childbirth; AND
  * Documented failure or intolerance to conventional therapy (e.g., dietary modification, the addition of bulking and pharmacologic treatment); AND
  * A successful percutaneous test stimulation, defined as at least 50% sustained (more than 1 week) improvement in symptoms; AND
  * Condition is not related to anorectal malformation (e.g., congenital malformation, defects of the external anal sphincter over 60 degrees, visible sequelae of pelvic radiation, active anal abscesses and fistulae) and /or chronic inflammatory bowel disease; AND
  * Incontinence is not related to another neurologic condition such as peripheral neuropathy or complete spinal cord injury.

SNS is considered experimental, investigational for the treatment of chronic
constipation or chronic pelvic pain (CPP).

Wexner, et al.2 conducted a multicentered prospective trial to determine the
safety and efficacy of SNS in a large population under the rigors of FDA
approved investigational protocol. Patients showing 50% improvement during
test stimulation received chronic implantation of the InterStimTM Therapy
(Medtronic; Minneapolis MN). The primary efficacy objective was to demonstrate
that 50% of subjects would achieve therapeutic success, defined as 50%
reduction of incontinent episodes per week at 12 months compared with
baseline. At 12 months, 83% of subjects achieved therapeutic success (95%
confidence interval: 74%-90%; __ P<0.0001), and 41% achieved 100% continence.
Therapeutic success was 85% at 24 months. Incontinent episodes decreased from
a mean of 9.4 per week at baseline to 1.9 at 12 months and 2.9 at 2 years.
There were no reported unanticipated adverse device effects associated with
InterStimTM Therapy. They concluded that SNS using InterStimTM Therapy is a
safe and effective treatment for patients with FI.

Noblett, et al.4 reviewed the history, mechanism of action, evolution, and
landmark literature for this treatment modality. They concluded that the
treatment of neuromodulation for the treatment of refractory voiding and bowel
dysfunction has provided an effective alternative therapy for patients who
have failed more conservative treatments. Data supports the long-term efficacy
and safety of SNS for the treatment of bladder and bowel dysfunction.

Siegel, et al.7 conducted a multicenter clinical trial to measure the
effectiveness of SNS in 10 patients with chronic intractable pelvic pain. They
performed a prospective nonrandomized study to characterize the safety and
efficacy of SNS for chronic intractable pelvic and /or urogenital pain in 10
patients with a history of pelvic pain that persisted for at least 6 months
and was refractory to conventional treatment. Due to their small sample size
they did not anticipate that the data from this study would be suitable for
statistical analysis. They concluded that the data in their feasibility study
implied that transforaminal SNS decreases the severity, number of hours, and
rate of pain in patients with chronic intractable pelvic pain. From a clinical
viewpoint, 6 of 10 patients reported substantial benefit from treatment. A
multicenter, statistically powered study should be performed to evaluate the
validity of these trends.

Paquette, et al.8 conducted an organized search of Medline, PubMed, Embase,
and the Cochrane Database of Collected Reviews. The scope of this updated
practice parameter was to address the evaluation and management of patients
with FI based on a thorough review of the published literature. SNM is thought
to modulate rectal sensation by activating or deactivating chemical mediating
receptors, stimulating the afferent pathway, and changing brain activity
relevant to the continence mechanism. SNM has been consistently shown to
result in a reduction in frequency of FI episodes. Pooled analysis of all
studies to date indicates that 79% (69-83%) of patients experience 50%
improvements in weekly FI episodes in the short term (0-12 months) and 84% of
patients experience 50% improvement at long-term (>36 month) follow-up when a
per protocol analysis is followed (only patients who received a full system
implant are analyzed). SNM may be considered as a first line surgical option
for incontinent patients. Grade of Recommendation: Strong recommendation based
on moderate quality evidence, 1B.

Mahran, et al.9 performed a systematic review study that comprised a
systematic search and summary of the literature related to the use of SNM in
improving the symptoms of CPP. The search was conducted using online
databases: Medline, Embase, Cochrane, Web of Science, and Scopus for articles
that studied the efficacy of SNM in treating CPP. The primary outcome was pain
improvement on a 10-point visual analog scale (VAS) in patients with CPP.
Fourteen of 2175 studies, evaluating 210 patients were eligible for further
analysis. The main finding of this systematic review is that SNM is an
acceptable treatment option for CPP in selected patients. While the
implantation rate is lower than it is for other indications, based on their
analysis, the improvement in VAS pain score obtained by using SNM ranges
between 35-52%. Pain improvement was better in patients with CPP due to
etiologies other than interstitial cystitis/bladder pain syndrome (IC/BPS).
They concluded, SNM is a promising treatment option for refractory CPP.
Randomized prospective studies are warranted to compare SNM versus other
modalities for CPP treatment.

Dinning, et al.12 conducted the first randomized, dual center, controlled
trial to evaluate the efficacy of permanent SNS in patients with slow transit
constipation. Using the specific primary outcome of the proportion of patients
who, on more than 2 days/week for at least 2 of 3 weeks, report a bowel
movement associated with a feeling of complete evacuation during suprasensory
stimulation, they found no significant difference in the response rate between
permanent suprasensory SNS (30%) and sham stimulation (21%). They found no
significant difference in response rate between subsensory permanent SNS (25%)
and sham (25%). When compared with sham, active stimulation had no significant
impact on any of the tertiary outcome measures (QOL, stool frequency, global
satisfaction and bothersome scores, days/week laxative use, number of
defecating episodes associated with straining, and /or a feeling of complete
evacuation). They found a response rate of 21-30% in each treatment arm
whether it be subsensory, suprasensory, or sham, which are rates that are
traditionally expected from a placebo response. They concluded in patients
with refractory slow transit constipation SNS did not improve the frequency of
complete bowel movements over the 3-week active period.

Amundsen, et al.13 assessed whether onabotulinumtoxinA is superior to SNM in
controlling refractory episodes of urgency urinary incontinence. They
conducted a multicenter open-label randomized trial (February 2012 - January
2015) at 9 U.S. medical centers involving 381 women with refractory urgency
urinary incontinence. In this comparative effectiveness trial,
onabotulinumtoxinA had a greater mean daily urgency urinary incontinence
episode reduction over 6 months than did the SNM group, -3.9 vs. -3.3 episodes
per day, a statistically significant but small difference. Urinary tract
infections and need for self-catheterization were more frequent among women
who received onabotulinumtoxinA. They concluded among women with refractory
urgency urinary incontinence, treatment with onabotulinumtoxinA compared with
SNM resulted in a small daily improvement in episodes that although
statistically significant is of uncertain clinical importance. In addition, it
resulted in a higher risk of urinary tract infections and need for transient
self-catheterizations.

Hull, et al.14 conducted a study to assess the outcome of SNS, or SNM,
focusing on the long-term durability of the therapy. Five-year data were
analyzed. This prospective, nonrandomized, U.S. FDA - regulated study was
conducted in 14 centers in the US, 1 in Canada, and 1 in Australia from 2002
through 2012. Patients with chronic FI in whom conservative treatments had
failed or who were not candidates for more conservative treatments received
SNS with the use of InterStimTM Therapy (FDA-approved in March 2011,
Medtronic, Minneapolis, MN) and were thereafter followed at predetermined
intervals to evaluate the efficacy and safety of the therapy. Patients were
assessed with a 14-day bowel diary and Fecal Incontinence Quality of Life and
Fecal Incontinence Severity Index questionnaires. Therapeutic success was
defined as 50% improvement over baseline in FI episodes per week. At 5 years
post implantation, 89% (64/72) of patients contributing bowel diary data had
at least a 50% improvement from baseline in weekly incontinent episodes
(p<0.0001). In addition, 35% (26/72) of patients at 5 years post implantation
had achieved total continence. The average number of weekly incontinent
episodes decreased from 9.1 at baseline to 1.7 at 5 years (p<0.0001). This
improvement from baseline was observed past 5 years. This study has multiple
strengths including its long-term follow-up, the number of patients, the
quality of the data, and the use of accepted tools to objectively study the
patients before and after therapy. A limitation of this study is that it was
not a randomized study with a control arm. Although that would have added to
the credibility of the data, the present FDA-sanctioned study still used a
rigorous design with strict collection of data at baseline and then regularly
through and past 5 years. Another limitation of this study is that there were
no prescribed program settings for the device. Patients were able to adjust
the stimulation as they needed with portable programmers between visits. They
concluded that this prospective study looking at the durability of SNS therapy
has shown that the therapeutic effect and improvements in QOL are maintained
through 5 years post implantation.

Siegel, et al.16 evaluated the therapeutic success rate, and changes in the
QOL and safety in subjects using SNM (InterStimTM System) at 36 months. The
InSite trial was designed to be implemented in 2 phases. Phase 1 was a
prospective, multicenter, randomized trial comparing SNM to standard medical
therapy with a 6-month follow-up period. It provided level 1 evidence for the
objective and subjective superiority of SNM over standard medical therapy
among OAB refractory patients and confirmed the safety of currently used
devices and techniques for SNM. The second phase of the InSite trial is a
prospective evaluation of the safety and efficacy of SNM in 5 years. They
concluded the 36-month follow-up data from the multicenter study demonstrate
sustained safety, effectiveness and improved QOL in subjects implanted with
InterStimTM, without requiring failure of all medications. They reported
results for all implanted subjects up to 3 years. Subjects will continue to be
followed for 5 years to collect additional long-term data. The InSite trial is
an ongoing, large, prospective multicenter study designed to evaluate the
long-term safety and efficacy of SNM for subjects with refractory symptoms of
OAB. They reported the results after 3 years of therapy demonstrating that
implanted subjects maintained improvements in OAB symptoms with QOL. The
strength of the InSite study include the large number of subjects with
protocol mandated follow-up, and the rigorous modified completer analysis with
ongoing inclusion of subjects withdrawn for lack of benefit or device related
complications as failures. The weaknesses of this InSite study include the
homogeneous population, with a minority of male subjects, which could detract
from generalizability. Furthermore, centers were allowed to follow individual
protocols regarding perioperative antibiotics, lead choice, and procedure
techniques.

Benson, et al.18 conducted the ARTISAN-SNM study a single-arm, prospective,
multi-center, pivotal study that was designed to evaluate the safety and
efficacy of the Axonics System for the treatment of urinary urgency
incontinence (UUI). The Axonics System provides SNM therapy for the treatment
of OAB, nonobstructive urinary retention, and FI. With an approved functional
life of at least 15 years, the Axonics System is the first rechargeable SNM
system available for use in the U.S. The Axonics System is approved for full
body magnetic resonance imaging (MRI) scans. A total of 129 eligible
participants were implanted with a quadripolar tined-lead and neurostimulator
in a single procedure. Efficacy data were collected using a 3-day bladder
diary, a validated QOL questionnaire (ICIQ-OABqol), and a participant
satisfaction questionnaire. At 1 year, 89% of the participants were therapy
responders. The average UUI episodes per day reduced from 5.6  0.3 at
baseline to 1.4  0.2. Participants experienced an overall clinically
meaningful improvement of 34 points on the ICIQ-OABqol questionnaire. All
study participants (100%) were able to recharge their device at 1 year, and
96% of participants reported that the frequency and duration of recharging was
acceptable. The strengths of this study include the conservative data analysis
methods. In addition, the collection of recharging usability data provides
insight into the patient charging experience, showing high patient
satisfaction. Study limitations include that this was a nonrandomized study,
with no comparator or placebo arm. However, given that SNM is a widely
accepted treatment with well-known efficacy, the use of a placebo was
considered unnecessary.

Siegel, et al.20 evaluated the therapeutic success rate, changes in QOL, and
safety of SNM 5 years after InterStimTM implantation. This prospective study
demonstrated the sustained efficacy and safety of SNM in subjects with OAB
after 5 years of treatment. The therapeutic success rate was 82% at 5 years
and 85% at 1 year, which strongly demonstrates long-term durability in
patients with SNM in clinical practice. Limitations include the homogeneous
population with a minority of male subjects. Centers could follow individual
protocols regarding perioperative antibiotics, lead choice, and procedure
techniques. Although this approximates what is occurring in general practice
with SNM therapy, this lack of standardization along with the potential impact
on infection rates, device related complications, and ultimate therapy success
or failure rates may have impacted the overall study results. They concluded
statistically significant treatment effects from baseline to 5 years were
found in the cardinal symptoms of OAB (leaks and/or voids) and in QOL. In
addition, the InSite for OAB study showed an InterStimTM therapy safety
profile that indicates a low rate of serious device related AEs (adverse
events) and types of devices related AEs that are consistent with product
labeling and the published literature.

The analysis of evidence reviewed for the SNS for the treatment of urinary and
FI included a multicentered prospective nonrandomized trial, a systematic
review study that comprised a systematic search and summary of the literature,
randomized dual center-controlled trial, multicenter open-label randomized
trial, and single-arm prospective multi-center pivotal study.

The literature supports the long-term efficacy and safety of SNS for the
treatment of bladder and bowel dysfunction. The InSite trial for OAB success
rate was 82% at 5 years and 85% at 1 year, which strongly demonstrates long-
term durability in patients with SNM in clinical practice.

The literature reviewed concluded that SNS is a safe and effective treatment
for patients with FI. A Grade 1B recommendation.

The literature did not support the use of SNM for chronic intractable pelvic
pain. Further studies are warranted to compare SNM versus other modalities for
CPP treatment.

The literature reviewed did not support the use of sacral neurostimulation for
chronic constipation.