Surgery Section - Sacral Nerve Modulation/Stimulation for Pelvic Floor Dysfunction

IMPORTANT REMINDER

This Medical Policy has been developed through consideration of medical necessity, generally accepted standards of medical practice, and review of medical literature and government approval status.

Benefit determinations should be based in all cases on the applicable contract language. To the extent there are any conflicts between these guidelines and the contract language, the contract language will control.

The purpose of medical policy is to provide a guide to coverage. Medical Policy is not intended to dictate to providers how to practice medicine. Providers are expected to exercise their medical judgment in providing the most appropriate care.

Description

Sacral nerve stimulation now more frequently referred to as sacral nerve neuromodulation (SNM), 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 non-obstructive urinary retention, who have failed behavioral and/or pharmacologic therapies. There has also been research interest in using the device as a treatment of fecal incontinence, constipation and chronic pelvic pain.

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 very frequent, small volumes. Urinary retention is the inability to completely empty the bladder of urine. Fecal incontinence is the involuntary passage of stool through the anus.

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 1-2 seconds.

In 1997, the Medtronic® Interstim Sacral Nerve Stimulation (SNS)™ 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.

Note: Sacral nerve neuromodulation should be distinguished from pelvic floor stimulation. Pelvic floor stimulation refers to electrical stimulation of the pudendal nerve. This therapy is addressed separately in Medical Policy, Allied Health, No. 4. Sacral nerve stimulation with associated rhizotomy as a treatment of neurogenic bladder (the Vocare® Bladder System) is addressed separately in Regence Medical Policy, Surgery, No. 112.

Policy/Criteria

Scientific Background

This policy is based in part on 1998 and 2000 BlueCross BlueShield Association Technology Evaluation Center (TEC) assessments (2,3), which focused on sacral nerve neuromodulation for urge incontinence and urinary urgency/frequency respectively:

Urge Incontinence

A multicenter, randomized controlled clinical trial, conducted as part of the FDA approval process, concluded that 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 SNM 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 SNM is reversible. The cohort analysis of the clinical trial provides some evidence that the effect of SNM 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 the patients required surgical revision for pain or infection at the operative sites or migration of the leads.

An additional prospective randomized controlled trial of 44 patients with urge incontinence became available after the 1998 Assessment. (4)  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 SNM for urinary urge incontinence.  Brazzelli and colleagues performed a review of articles published between 1966 and 2003 which included four randomized controlled trials and 30 case series. (5) The authors reported that about 80% of patients in the randomized trials achieved continence or greater than 50% improvement in their main incontinence symptoms after SNS compared with about 3% of controls receiving conservative treatments.  The case series’, which were larger but methodically less reliable, showed similar results.  Benefits were reported to persist 3 to 5 years after implantation.  The authors noted that technical changes over time were associated with decreased complication rates.

Urinary Urgency/Frequency

The data in a 2000 TEC 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. (3) In the multicenter randomized clinical study of 581 patients with a variety of urinary dysfunctions, 220 had significant urgency-frequency symptoms. After 6 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 neuromodulation as a treatment of interstitial cystitis, a condition characterized by painful urinary urgency and frequency. An updated literature search through June 1, 2007 identified three case series of 15, 20, and 25 patients with interstitial cystitis. (6-8) 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.

Urinary Retention

In the randomized clinical study submitted to the FDA as part of the approval process, 177 of 581 patients had urinary retention. (5) 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.

Fecal Incontinence

Only two randomized, trials were found in the current published literature. A small (n=27) randomized crossover trial of sacral nerve stimulation reported decreased episodes of fecal incontinence and improved quality of life. (15) This study is under-powered and, thus, precludes conclusions.  In another study, 120 patients with fecal incontinence were randomized to either a treatment group which received sacral nerve stimulation (n=60) or a control group which received non-operative treatment (n=60). (19) The treatment group had a significant decrease in episodes of incontinence and increased quality of life scores while the control group had no significant improvement in these measures. Additional studies are needed to confirm these results and also to better define patient selection criteria.

The remaining literature consists of numerous small case series of  10-40 patients with fecal incontinence who were treated with sacral neuromodulation as an alternative to anal sphincter surgery.  (10-14, 20-23) These series included patients with a variety of etiologies of fecal incontinence, including obstetric injury, spinal cord injury, prior surgery, or idiopathic incontinence. In addition, the range of follow-up periods within each study was very wide (e.g., 2 – 30 months). Thus, it is difficult to determine the complication rates or the durability of any benefits initially reported. 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. These small case series provide 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.

A Cochrane review reported on three cross-over studies, two for fecal incontinence (n=34 and n=2, respectively) and one for constipation (n=2). (24) This very limited evidence suggested that sacral nerve stimulation can improve continence in selected patients; however, it also reported that temporary, percutaneous stimulation for a 2-3 week period did not always successfully identify patients most likely to benefit from the stimulation. The authors concluded that larger, good quality randomized crossover trials are needed.

Constipation

Two small case series were identified that focused on patients with slow transit constipation. (16,17) While both reported promising results, these case series of four and eight patients, respectively, are inadequate to permit scientific conclusions.

Chronic Pelvic Pain

Siegel and colleagues reported on a case series of ten patients with chronic pelvic pain. (18) 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.

References

1. BCBSA Medical Policy Reference Manual, Policy No. 7.01.69
2. TEC Assessment: Sacral Nerve Simulation for the Treatment of Urge Incontinence, 1998; BlueCross and BlueShield Association Technology Evaluation Center, Vol.  Tab 18
3. TEC Assessment: Sacral Nerve Stimulation for Urinary Urge/Frequency Disorders, 2000; BlueCross and BlueShield Association Technology Evaluation Center, Vol. Tab 7
4. Weil EH, Ruiz-Cerda JL, Eerdmans PH et al. Sacral root neuromodulation in the treatment of refractory urinary urge incontinence: a prospective randomized clinical trial. Eur Urol 2000; 37(2):161-71
5. Brazzelli M, Murray A, Fraser C.  Efficacy and safety of sacral nerve stimulation for urinary urge incontinence: a systematic review. J Urol. 2006;175(3 Pt 1):835-41
6. Maher CF, Carey MP, Dwyer PL et al. Percutaneous sacral nerve root neuromodulation for intractable interstitial cystitis. J Urol 2001;165(3):884-6
7. Payne CK, Whitmore KE, Diokno AC et al. Sacral neuromodulation in patients with interstitial cystitis: a multicenter clinical trial. Neurourol Urodyn 2001;20:554-5
8. Comiter CV. Sacral neuromodulation for the symptomatic treatment of refractory interstitial cystitis: a prospective study. J Urol 2003;169(4):1369-73
9. Medtronic. Summary of Multi-Center Clinical Study. Medtronic Neurological, Minneapolis, MN. See also Web site: www.interstim.com  (Verified 9/23/08)
10. Kenefick NJ, Vaizey CJ, Cohen RC et al. Medium term results of permanent sacral nerve stimulation for faecal incontinence. Br J Surg 2002;89(7):896-901
11. Rosen HR, Urbarz C, Holzer B et al. Sacral nerve stimulation as a treatment for fecal incontinence. Gastroenterology 2001;121(3):536-41
12. Ganio E, Ratto C, Masin A et al. Neuromodulation for fecal incontinence: outcome in 16 patients with definitive implant. Dis Colon Rectum 2001;44(7):965-71
13. Ganio E, Luc AR, Clerioco G et al. Sacral nerve stimulation for treatment of fecal incontinence. Dis Colon Rectum 2001;44(5):619-31
14. Matzel KE, Kamm MA, Stosser M et al. Sacral spinal nerve stimulation for faecal incontinence: multicenter study. Lancet 2004;363:1270-76
15. Leroi AM, Parc Y, Lehur PA, et al. Efficacy of sacral nerve stimulation for fecal incontinence: results of a multicenter double-blind crossover study. Ann Surg. 2005;242(5):662-9
16. Kenefick NJ, Nicholls RJ, Cohen RC et al. Permanent sacral nerve stimulation for treatment of idiopathic constipation. Br J Surg 2002;89(7):882-88
17. Malouf AJ, Wiesel PH, Nicholls T et al. Short-term effects of sacral nerve stimulation for idiopathic slow transit constipation. World J Surg 2002;26(2):166-70
18. Siegel S, Paszkievics E, Kirkpatrick C et al. Sacral nerve stimulation in patients with chronic intractable pelvic pain. J Urol 2001;166(5):1742-45
19. Tjandra JJ, Chan MK, Yeh CH, et al. Sacral nerve stimulation is more effective than optimal medical therapy for severe fecal incontinence: a randomized, controlled study. Dis Colon Rectum. 2008;51(5):494-502. Epub 2008 Feb 16
20. Meurette G, La Torre M, Regenet N, et al. Value of Sacral Nerve Stimulation in the treatment of server faecal incontinence: a comparison to the Artificial Bowel Sphincter. Colorectal Dis. 2008; [Epub ahead of print]
21. Holzer B, Rosen HR, Novi G, et al. Sacral nerve stimulation for neurogenic faecal incontinence. Br J Surg. 2007;94(6):749-53
22. Holzer B, Rosen HR, Novi G, et al. Sacral nerve stimulation in patients with severe constipation. Dis Colon Rectum. 2008;51(5):524-9
23. Melenhorst J, Koch SM, Uludag O, et al. Sacral neuromodulation in patients with faecal incontinence: results of the first 100 permanent implantations. Colorectal Dis. 2007;9(8):725-30. Epub 2007 May 17
24. Mowatt G, Glazener C, Jarrett M. Sacral nerve stimulation for fecal incontinence and constipation in adults; a short version Cochrane review. Neurourol Urodyn 2008;27(3):155-61

Cross References

Pelvic Floor Stimulation as a Treatment of Urinary Incontinence, Allied Health, Regence Medical Policy Manual, Policy No. 4

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