This policy was originally developed in 2009 based on BCBSA’s TEC Assessments from 1998 and 2000, (1, 2) which focused on sacral nerve stimulation (SNS) for urge incontinence and urinary urgency/frequency, respectively. The most recent literature search was conducted through June 2013 using Medline database. This section of the current policy has been substantially revised. The following is a summary of the key literature to date.
Two randomized controlled trials (RCTs) on sacral nerve neuromodulation (SNM) for urinary incontinence have been conducted. The larger study was sponsored by Medtronic and submitted to the U.S. Food and Drug Administration (FDA) as part of the approval process. (3) Findings have not otherwise been published. Based on this RCT, the 1998 TEC Assessment concluded that SNM reduced urge incontinence compared to control patients. (1) 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. 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 2 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.
In the RCT, 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 postimplant, 61% of patients had eliminated the use of catheterization. A total of 220 of 581 (38%) 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 Short Form-36 (SF-36) health survey.
An additional prospective RCT of 44 patients with urge incontinence was published in 2000. (4) At 6 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.
Case series continue to be published. A 2011 series by Groen and colleagues in The Netherlands reported the longest follow-up. (5) A total of 60 patients had at least 5 years of follow-up after SNM for refractory idiopathic urge urinary incontinence. Success was defined as at least a 50% decrease in the number of incontinent episodes or pads used per day. The success rate was 52 of 60 (87%) at 1 month and gradually decreased to 37 (62%) at 5 years. The number of women who were completely continent was 15 (25%) at 1 month and 9 (15%) at 5 years. At the 5-year follow-up, SNM was still used by 48/60 (80%) women. A total of 57 adverse events were reported in 32 of 60 (53%) patients. The most frequent adverse events were hardware-related or pain or discomfort. There were a total of 23 reoperations in 15 patients. In most cases, pain problems were managed conservatively.
Findings from a large prospective series were reported in 2009 by White and colleagues. (6) The study focused on complications associated with SNM in 202 patients with urge incontinence, urinary urgency, or urinary retention. 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.
A 2009 Cochrane review evaluated the literature on implanted devices for urinary storage and voiding dysfunction in adults. (7) The authors stated that, in spite of methodologic 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.” They 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.
In 2011, Tan and colleagues published a meta-analysis of randomized trials and observational studies published between 2000 and 2008 on SNS for treating fecal incontinence. (8) They identified a total of 34 studies that reported on at least one of their outcomes of interest and clearly documented how many patients underwent temporary and permanent SNS. Only one of these studies was an RCT (Tjandra et al. 2008), discussed in more detail below. (9) In the 34 studies, a total of 944 patients underwent temporary SNS and 665 subsequently underwent permanent SNS implantation. There were 279 patients who did not receive permanent implantation, and 154 of these were lost to follow-up. Follow-up in the studies ranged from 2 weeks to 35 weeks. In a pooled analysis of findings of 28 studies, there was a statistically significant decrease in incontinence episodes per week with SNS compared to maximal conservative therapy (weighted mean difference: -6.83; 95% confidence interval [CI]: -8.05 to -5.60, p<0.001). Fourteen studies reported incontinence scores, and when these results were pooled, there was a significantly greater improvement in scores with SNS compared to conservative therapy (weighted mean difference: -10.57, 95% CI: -11.89 to -9.24, p<0.001).
In 2008, Tjandra and colleagues published an RCT with 120 patients with severe fecal incontinence. (9) Patients were randomly assigned to receive SNS or best supportive therapy, consisting of pelvic floor exercises with biofeedback, bulking agents, and dietary management with a team of dieticians. 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. The study was not blinded. 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 1 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%).
Representative observational studies on SNS for fecal incontinence are described below:
In 2008, 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. (10) In 3 patients, the device was removed because of pain or neurologic disease; the remaining 9 patients showed continued efficacy over an average 10-year follow-up (range 7–14 years). Complete continence was achieved in 5 patients (42% of 12), and 3 patients (25%) had less than 10% incontinent episodes. Pulse generator exchange was required in 8 of the 9 patients after a mean of 7 years for battery fatigue.
In 2010, Michelsen et al. published a retrospective analysis of all 177 patients who had been seen at their clinic for a percutaneous nerve evaluation test and SNS. (11) Of these, 142 (80%) had a positive test and 126 received a permanent stimulator. All data were presented as the median. At a follow-up of 24 months (range: 3-72 months), 15 patients (12%) had undergone explantation for decreased function, pain, or infection. Of the 107 patients who still had the pulse generator in situ, 87 (81%) had improvement in the Wexner incontinence score (17 at baseline to 9). The Wexner incontinence score improved from 16 to 10 at follow-up; similar changes were observed in subjects followed out to 6 years (n=86 at 2 years, 51 at 3 years, 28 at 4 years, 16 at 5 years, and 10 at 6 years). For those 49 patients who had collected 3-week diaries (stopped in 2006 due to the research burden), episodes of incontinence decreased from a median of 25 at baseline to 2 at 1 year (range: 0-47), and days of soiling decreased from a median of 16 to 5 (range: 0-21).
Also in 2010, Wexner et al. reported results from a 16-site multicenter FDA investigational device exemption (IDE) uncontrolled trial of SNS in 120 patients with fecal incontinence. (12) To be included in the study, patients had to complain of chronic fecal incontinence with duration greater than 6 months or for more than 12 months after vaginal childbirth, defined as greater than 2 incontinent episodes on average per week. All patients had failed or were not candidates for more conservative treatments. Exclusion criteria included congenital anorectal malformation; previous rectal surgery, if performed within the last 12 months (or 24 months in case of cancer); defects of the external anal sphincter over 60 degrees; chronic inflammatory bowel disease; visible sequelae of pelvic radiation; active anal abscesses and fistulae; neurologic diseases such as clinically significant peripheral neuropathy or complete spinal-cord injury; and anatomic limitations preventing the successful placement of an electrode. A total of 285 patients were evaluated for potential enrollment; 133 were enrolled and underwent acute test stimulation, and 120 showed at least 50% improvement during the test phase and received a permanent stimulator. Thirty-four of the 120 patients exited the study for a variety of reasons both related (i.e., lack of efficacy in 6 and implant site infection or skin irritation in 5) and unrelated to the implant (i.e., death of a local principal investigator). Analysis based on the initial 133 patients showed a 66% success rate (>50% improvement), while analysis based on 106 patients who were considered completed cases at 12 months showed an 83% success rate. The success rate based on the 120 patients who received a permanently implanted stimulator would fall between these 2 figures. Of 106 cases included in the 12-month results, perfect continence (100% improvement) was reported in approximately 40%, while an additional 30% of patients achieved 75% or greater improvement in incontinent episodes. Success was lower in patients with an internal anal sphincter defect (65%, n=20) compared with patients without a defect (87%, n=86).
Long-term follow-up of data on the 120 patients who received a permanently implanted stimulator were reported in 2011 by Mellgren and colleagues. (13) Mean length of follow-up among the 120 patients was 3.1 years, and 83 (69%) completed at least part of the 3-year follow-up assessment. In an intention-to-treat analysis using the last observation carried forward, 79% of patients experienced at least a 50% reduction in the number of incontinent episodes per week compared to baseline, and 74% experienced at least a 50% reduction in the number of incontinent days per week. In a per-protocol analysis at 3 years, 86% of patients experienced at least a 50% reduction in the number of incontinent episodes per week, and 78% experienced at least a 50% reduction in the number of incontinent days per week. By the 3-year follow-up, a total of 334 adverse events that were potentially device-related had been reported in 99 patients; 67% of these occurred within the first year. The most frequently reported adverse events among the 120 patients were implant site pain (28%); paresthesia (15%), implant site infection (10%), diarrhea (6%), and extremity pain (6%). Six infections required surgical intervention (5 device removals and 1 device replacement).
In 2011, Maeda and colleagues published a systematic review of studies on complications following permanent implantation of a SNS device for fecal incontinence and constipation. (14) The authors identified 94 articles. The vast majority of studies addressed fecal incontinence. A combined analysis of data from 31 studies on SNS for fecal incontinence reported a 12% suboptimal response to therapy (149 of 1,232 patients). A review of complications reported in the studies found that the most commonly reported complication was pain around the site of implantation, with a pooled rate of13% (81/621 patients). The most common response to this complication was repositioning the stimulator, followed by explantation of the device and reprogramming. The second most common adverse event was infection, with a pooled rate of 4% (40/1025 patients). Twenty-five of the 40 infections (63%) led to explantation of the device.
Several case series have been published; no controlled studies were identified. Earlier series had very small sample sizes (i.e. fewer than 10 patients) and focused on individuals with slow transit constipation. For example, in 2008, Holzer and colleagues reported on a prospectively recruited cohort of 19 patients with either pathologic colonic transit time with less than 2 bowel movements per week or rectal outlet obstruction requiring digital manipulation for defecation. (15) Eight of the patients (42%) reported improvement during the test period, defined as a 50% reduction in laxative intake with more than 2 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); 1 patient lost stimulation after a trauma dislodged an electrode. All component scores of the SF-36 evaluation showed significant improvements from pre-stimulation (n=19) to 6 months’ follow-up (n=7); baseline to post-treatment changes in the 7 subjects who were successfully treated was not reported.
In 2010, Kamm and colleagues published findings of an uncontrolled prospective study conducted at multiple sites in Europe. (16) The study included 62 patients who had idiopathic chronic constipation lasting at least 1 year and had failed medical and behavioral treatments. Constipation was defined as at least one of the following: fewer than 2 bowel movements per week, straining to evacuate in at least 25% of attempts or a sensation of incomplete evacuation on at least 25% of occasions. Forty-five of the 62 (73%) met criteria for permanent implantation during the 3-week trial period. Criteria included an increase in evacuation frequency to at least 3 per week, or a 50% reduction in either frequency of straining during evacuation or in episodes with sensation of incomplete evacuation. After a median follow-up of 28 months (range 1-55 months) after permanent implantation, 39 of 45 (87%) patients were classified as treatment successes (i.e., met same improvement criteria as were used to evaluate temporary stimulation). There was a significant increase in the frequency of bowel movements from a median of 2.3 per week at baseline to 6.6 per week at latest follow-up (p<0.001). The frequency of spontaneous bowel movements (i.e., without use of laxatives or other stimulation) increased from a median of 1.7 per week at baseline to 4.3 per week at last follow-up; p=0.0004. A total of 101 adverse events were reported; 40 (40%) of these were attributed to the underlying constipation or an unrelated diagnosis. Eleven serious adverse events related to treatment were reported (the authors did not specify whether any patients experienced more than 1 serious event). The serious adverse events included a deep postoperative infection (n=2), superficial erosion of lead through the skin (n=1), persistent postoperative pain at the site of implantation (n=2), conditions leading to lead revision (n=4), and device failure (n=2). The study has been criticized for including a large number of patients who had more than 2 bowel movements per week at study entry.
In 2010, Maeda and colleagues published a retrospective review of 38 patients with constipation who received permanent SNS after a successful trial period. (17) The study focused on reportable events, defined as suboptimal outcomes (lack of or loss of efficacy) or adverse events. The authors did not report detailed criteria for temporary or permanent placement of an SNS device. At the time of chart review, a mean of 25.7 months had elapsed since implantation. A total of 58 reportable events were identified in 22 of the 38 (58%) patients. A median of 2 (range 1-9) events per patient were reported; 26 of 58 events (45%) were reported in the first 6 months after device implantation. The most common reportable events were lack or loss of efficacy (26 of 58 events, 45%), and pain (16 events, 28%). Twenty-eight (48%) of the events were resolved by reprogramming. Surgical interventions were required for 19 (33%) of the events, most commonly permanent electrode replacement (14 events). Three of 38 (8%) patients discontinued use of the device due to reportable events.
Due to the availability of only a small number of uncontrolled trials with a limited number of patients, inconsistent or unclear definitions of chronic constipation, data are insufficient to permit scientific conclusions about the efficacy and safety of SNM for patients with constipation.
Chronic Pelvic Pain
Several case series have evaluated sacral neuromodulation for treating chronic pelvic pain. For example, Siegel and colleagues reported on a case series of 10 patients with chronic pelvic pain. (18) Their research interest was prompted by the concomitant decrease in pain reported by patients receiving SNM for urinary disorders. The authors did not detail the etiology of the pain syndromes in their case series but reported that 9 of the 10 patients had a decrease in pain. These data are inadequate to permit scientific conclusions.
Trial Stimulation Techniques
As described in the background section above, there are 2 types of trial stimulation before permanent implantation of a neuromodulation device. These are percutaneous nerve evaluation (PNE) and stage 1 (lead implantation) of a 2-stage surgical procedure. The PNE was the initial method of trial stimulation and has been the standard of care prior to permanent implantation of the device. There are concerns about possible suboptimal sensitivity of the PNE test due to lead migration, and the stage-1 lead implantation is an alternate trial stimulation modality.
Comparative rates of lead migration and rates of progressing to permanent implantation are useful outcomes in that there may be reduced sensitivity of the PNE test due to lead dislodgement. However, due to the potential placebo effect of testing, it is also important to compare the long-term efficacy of SNM after these 2 trial stimulation techniques. In addition, it would be useful to have data on the optimal approach to using the 2-stage surgical procedure. As mentioned previously in the background section, the 2-stage surgical procedure has been used in various ways including instead of PNE, for patients who failed PNE, for patients with an inconclusive PNE, and for patients who had a successful PNE to further refine patient selection.
No RCTs were identified that evaluated long-term health outcomes (e.g., reduction in incontinence symptoms) after trial stimulation with PNE versus stage-1 lead implantation. There are limited data on the issue of rates of failure after SNM in patients selected using the 2-stage test. Leong and colleagues, in a single-center prospective study published in 2011, evaluated 100 urge incontinence patients with both PNE and the first stage of the 2-stage technique (i.e., patients served as their own controls). (19) Patients were first screened with the PNE and, afterwards, with lead implantation. Response to testing was based on diary data for 3 consecutive days after receiving each type of lead. In the test phase, 47 patients (47%) had a positive response to PNE, and 69 (69%) had a positive response to the first-stage lead placement test. All patients who responded to PNE also responded to stage-1 testing. The 69 patients who responded to stage-1 testing underwent implantation. They were then followed for a mean of 26 months, and 2 patients (3% of those with a positive test) had failed therapy. Although this study showed a low rate of failure, only 22 individuals had a successful test with the stage-1 technique but not with PNE. This is a small number of patients on which to base conclusions about the comparative efficacy of the 2 techniques. In addition, the order of testing could have impacted findings. All patients had PNE testing prior to first-stage lead implantation and could have been biased by their first test. Stronger study designs would be to randomize the order of testing or to randomize patients to receive one type of testing or the other.
In 2002, Scheepens and colleagues conducted an analysis of 15 patients with urinary incontinence or retention who had a good initial response to PNE but then failed PNE in the longer term (i.e., days 4-7 of testing). (20) These 15 patients underwent stage 1 of the 2-stage technique. One patient failed the first stage and was explanted. Of the remaining 14 patients, 2 were explanted later due to lack of efficacy of sacral neuromodulation. The other 12 patients were followed for a mean of 4.9 years and voiding diary data showed improvement in nearly all incontinence symptoms. There was a low failure rate after stage-1 testing, but this is a small sample size, and stage-1 testing was not compared to another trial stimulation method, e.g., PNE.
In 2010, Marcelissen and colleagues published findings in 92 patients with urinary symptoms who underwent trial evaluation for SNM treatment. (21) Patients initially underwent PNE (n=76) or stage-1 surgery (n=16). Patients who had a negative PNE (n=41) then underwent stage-1 evaluation. A total of 11 of 16 (63%) patients had a positive initial stage-1 test and were implanted with a SNM device. Thirty-five of 76 (46%) patients had a positive initial PNE test and underwent permanent implantation. There were 41 patients (54% of those undergoing PNE) who had a negative test and then had stage-1 surgical evaluation. Eighteen of 41 (44%) had a positive stage-1 test and underwent implantation. Altogether there were 64 patients who underwent implantation of an SNM device. Mean follow-up was 51 months. Thirty-eight of 64 patients (59%) implanted experienced clinical success at last follow-up, defined as greater than 50% improvement in symptoms reported in a voiding diary. Clinical success rate was not reported separately by trial stimulation method.
Several studies, e.g., Borawski and colleagues (2006) (22) and Bannowsky and colleagues (2008), (23) compared the response rates during the test phase in patients with urinary incontinence symptoms and found higher rates of response with the stage-1 test than with PNE. (22, 23) In these studies, more people who received the stage-1 test went on to undergo implantation. The Borawski et al. study was an RCT with 30 patients (13 received PNE and 17 received the stage-1 test). The Bannowsky et al. study was not randomized; 42 patients received a PNE, and 11 patients received a stage-1 test. Neither study, however, followed patients once they had a device implanted so they do not provide data on the relative success rate of SNM after these 2 test procedures. With this type of study (i.e., without follow-up after implantation), it is not possible to conclude whether the 2-stage procedure reduced false-negatives (i.e., selected more people who might benefit) or increased false-negatives (i.e., selected more people who might go on to fail).
In review articles (e.g., Baxter and Kim 2010), (24) lead migration was described as a potential problem with the PNE technique, but no studies were identified that quantified the rate of lead migration in large numbers of patients. No published studies were available comparing trial stimulation techniques in patients with non-urinary conditions e.g., fecal incontinence.
Evidence from RCTs and case series with long-term follow-up provides sufficient evidence to conclude that sacral nerve neuromodulation is effective and safe in selected patients with urge incontinence, urgency-frequency, and non-obstructive urinary retention. With consistent and longer term results from randomized controlled trials and prospective case series and findings of a 2011 meta-analysis, evidence is considered sufficient for sacral nerve stimulation to be an option for the treatment for chronic fecal incontinence in well-selected patients who have failed conservative therapy. Therefore, it may be considered medically necessary under specific conditions. Not all patients will benefit, and the adverse event rate for this procedure is high. Patients should therefore be provided with adequate information to make an informed choice regarding the potential risks and benefits of this procedure.
Limited evidence reports that more patients have a positive stimulation trial when stage-1 surgery is used compared to PNE and that the majority of patients with a positive stage-1 test experience a reduction in symptoms after permanent implantation. This evidence does not determine with certainty that health outcomes are improved with the stage-1 trial stimulation. However, due to the available evidence, as well as strong clinical support for surgical lead placement as an alternative to percutaneous test stimulation, surgical lead placement may be considered medically necessary for otherwise eligible patients.
The literature on sacral nerve stimulation for constipation or chronic pelvic pain remains insufficient to evaluate the effect of this technology on health outcomes.
Practice Guidelines and Position Statements
French implant centers provided a 2010 position statement on sacral nerve stimulation for the management of patients with fecal incontinence based on review of the evidence and a formal consensus process. (25)
- Severe fecal incontinence, i.e., at least one or more episodes of fecal incontinence per week and/or a significant change in the patient’s quality of life.
- Without any significant damage (>30% of the anal circumference) to the external anal sphincter, with or without previous repair.
- Failed conservative therapy (diet, antidiarrheals and bulking agents, treatment of incomplete rectal evacuation by any means, and rehabilitation with biofeedback training.
- Double fecal and urinary incontinence (excluding stress urinary incontinence).
- Congenital anorectal malformation
- Flatus incontinence alone
- Recent rectal surgery
- Present external rectal prolapse
- Chronic bowel diseases
- Chronic diarrhea
- Altered bowel habit associated with abdominal pain
- Stoma present
- Complete bilateral or spinal nerve lesions
- Inappropriate surgical candidate (i.e., bleeding, pregnancy, anatomical limitations, skin disease risking infection, psychiatric disease)
- Fecal incontinence associated with constipation
- Non-active inflammatory bowel disease
- Progressive incomplete neurological disease
In 2007, the National Institute for Clinical Evidence (NICE) guideline on management of fecal incontinence recommended, “a trial of temporary sacral nerve stimulation should be considered for people with faecal incontinence in whom sphincter surgery is deemed inappropriate…All individuals should be informed of the potential benefits and limitations of this procedure and should undergo a trial stimulation period of at least 2 weeks to determine if they are likely to benefit. People with faecal incontinence should be offered sacral nerve stimulation on the basis of their response to percutaneous nerve evaluation during specialist assessment, which is predictive of therapy success.” (26)
Practice Guidelines from the American College of Gastroenterology (ACG) in 2004 on the diagnosis and management of fecal incontinence found limited evidence in favor of sacral nerve stimulation. (27) The ACG concluded that the precise indication for SNS, its comorbidity, its long-term outcome, and efficacy remain to be defined.
In 2004 (reaffirmed 2008), the American College of Obstetricians and Gynecologists (ACOG) recommended that sacral nerve stimulation be considered as a treatment option for chronic pelvic pain. This was rated a Level B recommendation, meaning that it was based on limited or inconsistent scientific evidence. (28)
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