Archived Policies - Surgery

Sacral Nerve Neuromodulation/Stimulation for Pelvic Floor Dysfunction


Effective Date:12-01-2009

End Date:10-31-2010


Sacral nerve neuromodulation (SNM) may be considered medically necessary in patients with urge incontinence, urgency-frequency, and non-obstructive urinary retention that is not related to a neurologic condition and has not responded to prior behavioral and pharmacologic interventions.

Other urinary/voiding applications of sacral nerve neuromodulation are considered experimental, investigational and unproven including but not limited to treatment of stress incontinence or urge incontinence due to a neurologic condition, (e.g., detrusor hyperreflexia, multiple sclerosis, spinal cord injury), or other types of chronic voiding dysfunction.

Sacral nerve neuromodulation is considered experimental, investigational and unproven in the treatment of fecal incontinence, chronic constipation, or chronic pelvic pain.


Sacral nerve stimulation (SNS), now more frequently referred to as sacral nerve neuromodulation is defined as the implantation of a permanent device that modulates the neural pathways controlling bladder function.  This treatment is one of several alternative modalities for patients with either urinary urge incontinence, significant symptoms of urgency-frequency, or nonobstructive urinary retention who have failed behavioral and/or pharmacologic therapies. Urge incontinence is defined as leakage of urine when there is a strong urge to void.  Urgency-frequency is an uncontrollable urge to urinate, resulting in voiding very frequent, small volumes. Urgency-frequency is a prominent symptom of interstitial cystitis.  Urinary retention is the inability to completely empty the bladder of urine.

The SNM device consists of an implantable pulse generator that delivers controlled electrical impulses.  This pulse generator is attached to wire leads that connect to the sacral nerves, most commonly the S3 nerve root.

Two external components of the system help control the electrical stimulation:

  • A control magnet is kept by the patient and can be used to turn the device on or off.
  • A console programmer is kept by the physician and used to adjust the settings of the pulse generator.

Prior to implantation of the permanent device, patients undergo a peripheral nerve stimulation test to estimate potential response to SNM.  This procedure is done under local anesthesia, using a test needle to identify the appropriate sacral nerve(s).  Once identified, a temporary wire lead is inserted through the test needle and left in place for several days.  This lead is connected to an external stimulator, which is carried by patients in their pocket or on their belt.  Patients then keep track of voiding symptoms while the temporary device is functioning.  The results of this test phase are used to determine whether patients are appropriate candidates for the permanent device.  If patients show a 50% or greater reduction in incontinence frequency, they are deemed eligible for the permanent device.  According to data from the manufacturer, approximately 63% of patients have a successful peripheral nerve evaluation and are thus candidates for the permanent SNM.

The permanent device is implanted with the patient under general anesthesia.  An incision is made over the lower back, and the electrical leads are placed in contact with the sacral nerve root(s).   The wire leads are extended through a second incision underneath the skin across the flank to the lower abdomen.  Finally, a third incision is made in the lower abdomen where the pulse generator is inserted and connected to the wire leads.  Following implantation, the physician programs the pulse generator to the optimal settings for that patient.  The patient can switch the pulse generator between on and off by placing the control magnet over the area of the pulse generator for one to two seconds.

In 1997, the Medtronic Interstim Sacral Nerve Stimulation system received U.S. Food and Drug Administration (FDA) approval for marketing for the indication of urinary urge incontinence in patients who have failed or could not tolerate more conservative treatments.  In 1999, the device received FDA approval for the additional indications of urgency-frequency and urinary retention in patients without mechanical obstruction.  There has also been research interest in using the device as a treatment of fecal incontinence, constipation, and chronic pelvic pain.

In 2006, the Medtronic Interstim® II System received FDA approval for treatment of intractable cases of overactive bladder and urinary retention.  The new device is smaller and lighter than the original system and is reported to be suited for those with lower energy requirements or small stature.  The device also includes updated software and programming options.

NOTE: Pelvic floor stimulation refers to electrical stimulation of the pudendal nerve.  This therapy is addressed separately in medical policy DME101.037.


This policy was originally based on Blue Cross Blue Shield Association Technology Evaluation Center Assessment Program (TEC) Assessments from 1998 and 2000, which focused on sacral nerve stimulation (SNS) for urge incontinence and urinary urgency/frequency, respectively.  The literature published since these Assessments, has been periodically updated.

The 1998 TEC Assessment on urge incontinence included a multicenter, randomized controlled clinical trial, conducted as part of the FDA approval process, which concluded that sacral nerve neuromodulation (SNM) reduced urge incontinence compared to control patients.  This well-designed trial, using standardized clinical and functional status outcomes measurements, enrolled patients with severe urge incontinence who had failed extensive prior treatments.  The magnitude of effect (approximately one half of the patients became dry, three quarters experienced at least 50% reduction in incontinence) was fairly large, probably at least as great as with surgical procedures, and larger than expected from a placebo effect or from conservative measures such as behavioral therapy or drugs.  However, due to the protocol that selects patients who are likely to benefit based on the peripheral nerve evaluation test, this magnitude of effect is overestimated relative to the total pool of patients with refractory urge incontinence.  On the other hand, this screening step avoids an invasive procedure and implantation of the SNS device in patients who are less likely to benefit, thus reducing morbidity and unnecessary treatment.  The therapy evaluation test, in which the device is turned off and patients thus serve as their own controls, provided further evidence that the effect on incontinence is due to electrical stimulation, and demonstrates that the effect of SNS is reversible.  The cohort analysis of the clinical trial provides some evidence that the effect of SNS is maintained for up to two years. There was a high rate of adverse events reported in this clinical trial.  Most of the adverse events were minor and reversible; however, approximately one third of patients required surgical revision for pain at the operative sites or migration of the leads.  Data were inadequate on the other indications for SNS, including treatment of urge incontinence due to neurologic conditions, stress incontinence, or other chronic voiding dysfunctions.

An additional prospective randomized controlled trial of 44 patients with urge incontinence became available after the 1998 Assessment.  At six months, the implant group showed significantly greater improvement on standardized clinical outcomes, as compared to those receiving conservative therapy.  The magnitude of effect was substantial.  This study provides further evidence of the beneficial effect of SNS for urinary urge incontinence.

Sacral nerve neuromodulation for the treatment of urinary urgency and frequency was the subject of a 2000 TEC Assessment.  The data considered in this Assessment consisted of one published randomized controlled trial, a long-term, single-arm cohort study, and additional data submitted to the FDA as part of the approval process.  In the multicenter randomized clinical study of 581 patients with a variety of urinary dysfunctions, 220 had significant urgency-frequency symptoms. After six months, 83% of patients with urgency-frequency symptoms reported increased voiding volumes with the same or reduced degree of frequency.  At 12 months, 81% of patients had reached normal voiding frequency.  Compared to a control group, patients with implants reported significant improvements in quality of life, as evaluated by the SF-36 health survey.  There has also been interest in the use of sacral nerve stimulation as a treatment of interstitial cystitis, a condition characterized by painful urinary urgency and frequency.  A literature search identified three cases series of 15, 20, and 25 patients with interstitial cystitis.  These studies reported a decrease in both urgency/frequency and pain.  There is no separate policy statement for patients with interstitial cystitis, as they would be considered candidates for sacral neuromodulation therapy based on the presence of urgency and frequency alone.

A systematic review again found substantial improvement for use of SNS in treating urinary urge incontinence, with about 80% of patients achieving continence or at least a 50% improvement in incontinence symptoms.  This review also noted a repeated operation rate of 33% of implanted cases; pain and infection were the two most frequent causes.  The authors also noted that over time technical changes have been associated with decreased complication rates.

In the randomized clinical study submitted to the FDA as part of the approval process, 177 of 581 patients had urinary retention.  Patients with urinary retention reported significant improvements in terms of volume catheterized per catheterization, a decrease in the number of catheterizations per day, and increased total voided volume per day.  At 12 months post-implant, 61% of patients had eliminated the use of catheterization.  Patients with implants also reported improved quality of life.

The 2007 update identified an industry-funded study that reported 11-year (3 to 162 months) follow-up on 234 patients who had undergone placement of an implantable pulse generator.  Fifty-four percent of the patients consented and returned a mailed questionnaire.  Of these, 104 charts were available for review (44% of the total patient population).  Patients presenting with urinary frequency and/or urinary incontinence (n=83) showed significant improvements in the standard outcome measures (voids, leaks, pads).  In contrast, the 21 patients presenting with non-obstructive urinary retention, half of which were attributable to a neurological disorder, showed improvement in only one of five outcome measures (from 1.7 voids per night to 1.0).  Another retrospective case series reported 4- to 32-month follow-up on 33 patients with neurologic disease (16 multiple sclerosis, six Parkinson’s disease, two spina bifida, two cerebrovascular accident, one cerebral palsy, or six other) who underwent sacral nerve stimulation for neurogenic lower urinary tract dysfunction.  Twenty-eight of the patients (85%) had a successful test stimulation trial (> 50% reduction in leakage episodes, nocturnal, or pad usage over a period of one to three weeks) with subsequent implantation of the pulse generator.  Sacral stimulation resulted in an average 68% decrease in incontinence episodes (from 4 to 1.3 per 24 hours) and night-time voids (from 2.6 to 0.8 per night), and a 72% reduction in the number of pads used per 24 hours (from 3.5 to 1.0).  These results suggest that sacral nerve stimulation may have short-term efficacy in patients with underlying neurologic disease who have had successful test stimulation.  However, as the authors noted, “long-term efficacy of sacral nerve neuromodulation in these patients needs further research because neurologic diseases, such as multiple sclerosis (MS) and Parkinson disease are typically progressive and hence may have variable responses over time.”  Thus, longer follow-up in a larger number of patients is needed.  

White et al reported complications from a prospective longitudinal analysis of 202 patients with urge incontinence, urinary urgency, or urinary retention that had been treated with sacral nerve stimulation between 2001 and 2008.  At a mean follow-up of 37 months (range 7–84), 67 patients (30%) had experienced adverse events that required either lead or implantable pulse generator revisions.  Complications included pain (3%), device malfunction secondary to trauma (9%), infection (4%), postoperative hematoma (2%), and lead migration (6%).  In addition, 5% of patients underwent elective removal, 4% had device removal due to lack of efficacy, and 2% required removal due to battery expiration.  At the last follow-up, 172 patients (85%) had functional implanted units.

Fecal Incontinence

At the time this policy was created, a literature search identified five cases series of 15, 16, 20, 23, and 37 patients, respectively, with fecal incontinence that were treated with sacral neuromodulation as an alternative to anal sphincter surgery.  All series included patients with a variety of etiologies of fecal incontinence, including obstetric injury, spinal cord injury, prior surgery, or idiopathic incontinence.  While sacral neuromodulation for urinary disorders focuses on patients with urinary tracts that appear to be structurally intact but functionally impaired, in contrast, the majority of patients with fecal incontinence have structural impairment of the anal sphincter.  In general, the case series reported improvements in episodes of incontinence and improvements in quality of life in those undergoing permanent implantation.  There were also improvements in objective measures, such as anal sphincter resting pressure.  The longest follow-up was 24 months.  These small case series provided inadequate data to permit scientific conclusions.  The trials of patients with urinary incontinence have typically included an arm in which symptoms were evaluated with the device turned off in a blinded manner to evaluate a placebo effect.  No such component was included in these case series of fecal incontinence.

In 2005, a small (27 patients) randomized trial of SNS reported decreased episodes of fecal incontinence and improved quality of life.  Following the crossover period, the blinded participants chose the period of stimulation (on or off) that they had preferred.  For the 19 who preferred the “on” period, episodes of incontinence fell from 1.7 to 0.7 per week.  However, for the other five subjects incontinence episodes increased from 1.7 per week during the “off” period to 3.7 during the “on” period.  Four of the 27 participants (15%) experienced an adverse event requiring removal.  These results suggest that temporary percutaneous stimulation for a 2- to 3-week period does not always successfully identify those for whom a permanent implant will be beneficial.  A 2007 Cochrane review identified only two controlled trials (two subjects each) in addition to the study of 27 patients described.  The authors concluded that SNS can improve continence in selected individuals, but additional studies are needed to confirm these results and also to better define patient selection criteria.

2009 Update

The 2009 literature update identified one randomized controlled trial and a number of case series from outside of the United States.  Tjandra and colleagues randomized 120 patients with severe fecal incontinence to SNS or best supportive therapy, consisting of pelvic floor exercises with biofeedback, bulking agents, and dietary management with a team of dieticians.   Due to the differences in treatments, this study was not blinded.  Exclusion criteria included neurologic disorders and external anal sphincter defects of more than 120 degrees of the circumference, although a “high proportion” of the patients had pudendal neuropathy.  Of the 60 patients randomized to SNS, 54 (90%) had successful test stimulation and 53 decided to proceed with implant of the pulse generator.  At baseline, the SNS group had an average of 9.5 incontinent episodes per week, and the controls had 9.2.  Both groups had an average of 3.3 days per week with incontinence.  At 12-month follow-up, episodes had decreased to one day per week with 3.1 episodes in the SNS group, but had not changed in the control group (mean 3.1 days per week with 9.4 episodes).  Complete continence was achieved in 22 of the 53 SNS patients (42%) and 13 patients (24%) improved by 75% to 99%.  None of the patients had worsening of fecal continence.  Adverse events included pain at implant site (6%), seroma (2%), and excessive tingling in the vaginal region (9%).  Matzel and colleagues reported long-term outcomes from 12 patients with severe incontinence (average of 54% incontinent episodes per week) that underwent SNS between 1994 and 1999.  In three patients the device was removed because of pain or neurologic disease; the remaining nine patients showed continued efficacy over an average 10-year follow-up (range 7–14 years).  Complete continence was achieved in five patients (42% of 12), and three patients (25%) had less than 10% incontinent episodes.  Pulse generator exchange was required in eight of the nine patients after a mean of seven years for battery fatigue. Although promising, additional studies with longer-term results are needed.

A 2009 Cochrane review described eight randomized studies on implanted devices for urinary storage and voiding dysfunction in adults.  In spite of methodological problems (generally poor quality studies), the evidence “seems clear that continuous stimulation offers benefits for carefully selected people with overactive bladder syndrome and for those with urinary retention but no structural obstruction.”   The authors concluded that while some people benefit, more research is needed to improve patient selection, to carry out the implant, and to find why so many fail.


The 2002 literature update identified two small case series that focused on patients with slow transit constipation.  While both reported promising results, these case series of four and eight patients, respectively, were inadequate to permit scientific conclusions.  

The 2009 update identified a prospectively recruited cohort of 19 patients with either pathologic colonic transit time with less than two bowel movements per week or rectal outlet obstruction requiring digital manipulation for defecation.  Eight of the patients (42%) reported improvement during the test period, defined as a 50% reduction in laxative intake with more than two bowel movements per week (n=4) or rectal emptying with digital manipulation or 50% reduction in irrigation procedures (n=4).  The median follow-up was 11 months (range 2–20 months); one patient lost stimulation after a trauma dislodged an electrode.  All component scores of the Short Form (SF-36) evaluation showed significant improvements from prestimulation (n=19) to six months follow-up (n=7); baseline to post-treatment changes in the seven subjects who were successfully treated was not reported.

Chronic Pelvic Pain

Siegel and colleagues reported on a case series of ten patients with chronic pelvic pain.  Their research interest was prompted by the concomitant decrease in pain reported by patients receiving sacral neuromodulation for urinary disorders.  The authors did not detail the etiology of the pain syndromes in their case series, but reported that nine of the ten patients had a decrease in pain.  These data are inadequate to permit scientific conclusions.

2009 Summary

Recent literature indicates increasing study of SNS for the treatment of fecal incontinence and constipation, particularly from outside of the United States.  Identification of patients who will respond to SNS remains problematic, and the evidence remains insufficient to determine the effect of this technology on net health outcomes.


Each benefit plan, summary plan description or contract defines which services are covered, which services are excluded, and which services are subject to dollar caps or other limitations, conditions or exclusions. Members and their providers have the responsibility for consulting the member's benefit plan, summary plan description or contract to determine if there are any exclusions or other benefit limitations applicable to this service or supply. If there is a discrepancy between a Medical Policy and a member's benefit plan, summary plan description or contract, the benefit plan, summary plan description or contract will govern.



Medicare Coverage:

The information contained in this section is for informational purposes only.  HCSC makes no representation as to the accuracy of this information.  It is not to be used for claims adjudication for HCSC Plans.

The Centers for Medicare and Medicaid Services (CMS) does have a national Medicare coverage position.

A national coverage position for Medicare may have been developed or changed since this medical policy document was written.  See Medicare's National Coverage at <>.


Sacral Nerve Stimulation for Urinary Incontinence.  Chicago, Illinois: Blue Cross Blue Shield Association Technology Evaluation Center Assessment Program (1998 October) 13(18):1-28.

Sacral Nerve Stimulation for Urinary Urge/Frequency Disorders.  Chicago, Illinois: Blue Cross Blue Shield Association Technology Evaluation Center Assessment Program (2000 August) 15(7):1-18.

Weil, E.H., Ruiz-Cerda, J.L., et al.  Sacral root neuromodulation in the treatment of refractory urinary urge incontinence: a prospective randomized clinical trial.  European Urology (2000) 37(2):161-71.

Maher, C.F., Carey, M.P., et al.  Percutaneous sacral nerve root neuromodulation for intractable interstitial cystitis.  Journal of Urology (2001) 165(3):884-6.

Rosen, H.R., Urbarz, C., et al.  Sacral nerve stimulation as a treatment for fecal incontinence. Gastroenterology (2001) 121(3):536-41.

Ganio, E., Ratto, C., et al.  Neuromodulation for fecal incontinence: outcome in 16 patients with definitive implant.  Diseases of the Colon and Rectum (2001) 44(7):965-70.

Ganio, E., Luc, A.R., et al.  Sacral nerve stimulation for treatment of fecal incontinence.  Diseases of the Colon and Rectum (2001) 44(5):619-31.

Payne, C.K., Whitmore, K.E., et al.  Sacral neuromodulation in patients with interstitial cystitis: a multicenter clinical trial.  Neurourological Urodynamics (2001) 20:554-5.

Siegel, S., Paszkiewicz, E., et al.  Sacral nerve stimulation in patient with chronic intractable pelvic pain.  Journal of Urology (2001) 166(5):1742-5.

Kenefick, N.J., Nicholls, R.J., et al.  Permanent sacral nerve stimulation for treatment of idiopathic constipation.  British Journal of Surgery (2002) 89(7):882-8.

Medtronic.  Summary of Multi-Center Clinical Study. Medtronic Neurological, Minneapolis, Minnesota: <>.

Malouf, A.J., Wiesel, P.H., et al.  Short-term effects of sacral nerve stimulation for idiopathic slow transit constipation.  World Journal of Surgery (2002) 26(2):166-70.

Kenefick, N.J., Vaizey, C.J., et al.  Medium term results of permanent sacral nerve stimulation for faecal incontinence.  British Journal of Surgery (2002) 89(7):896-901.

Comiter, C.V.  Sacral neuromodulation for the symptomatic treatment of refractory interstitial cystitis: a prospective study.  Journal of Urology (2003) 169(4):1369-73.

Matzel, K.E., Kamm, M.A., et al.  Sacral spinal nerve stimulation for faecal incontinence: multicentre study.  Lancet (2004) 363(9417):1270-6.

Leroi, A.M., Parc, Y., et al.  Efficacy of sacral nerve stimulation for fecal incontinence: results of a multicenter double-blind crossover study.  Annals of Surgery (2005) 242(5):662-9.

Brazzelli, M., and A. Murray.  Efficacy and safety of sacral nerve stimulation for urinary urge incontinence: a systematic review.  Journal of Urology (2006) 175(3 pt 1):835-41.

Sutherland, S.E., Lavers, A., et al.  Sacral nerve stimulation for voiding dysfunction: One institution's 11-year experience.  Neurourology and Urodynamics (2007) 26(1):19-28.

Wallace, P.A., Lane, F.L., et al.  Sacral nerve neuromodulation in patients with underlying neurologic disease.  American Journal of Obstetrics and Gynecology (2007) 197(1):96.

Mowatt, G., Glazener, C., et al.   Sacral nerve stimulation for fecal incontinence and constipation in adults: a short version.  Cochrane review.  Neurourological Urodynamics (2008)27(3):155-61.

Matzel, K.E., Lux, P., et al.  Sacral nerve stimulation for faecal incontinence: Long-term outcome.  Colorectal Disease (2008 August 21). [Epub ahead of print].

Tjandra, J.J., Chan, M.K., et al.  Sacral nerve stimulation is more effective than optimal medical therapy for severe fecal incontinence: a randomized, controlled study.  Diseases of the Colon Rectum (2008) 51(5):494-502.

White, W.M., Mobley, J.D., 3rd et al.  Incidence and Predictors of Complications with Sacral Neuromodulation.  Urology (2009 February 3). [Epub ahead of print].

Herbison, G.P., and E.P. Arnold.  Sacral neuromodulation with implanted devices for urinary storage and voiding dysfunction in adults.  Cochrane Database Systems Review (2009) (2):CD004202.

Sacral Nerve Neuromodulation/Stimulation for Pelvic Floor Dysfunction.  Chicago, Illinois: Blue Cross Blue Shield Association Medical Policy Reference Manual (2009 May) 7.01.69.

Policy History:

12/1/2009        Policy reviewed and references updated; no change in coverage position.

12/1/2007        Revised/updated entire document

8/15/2003        Revised/updated entire document

5/2002             Revised/updated entire document

1/2000             Revised/updated entire document

9/1999             New Medical Document

Archived Document(s):

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