Sacral nerve stimulation for treatment of fecal incontinence does not meet member benefit certificate primary coverage criteria that there be scientific evidence of effectiveness in improving health outcomes.  This treatment is under study in a clinical trial to determine effectiveness.

 

For contracts without primary coverage criteria, sacral nerve stimulation for treatment of fecal incontinence is considered investigational.  Investigational services are an exclusion in the member certificate of coverage.

The device is recommended for those patients with fecal incontinence who have an intact or repaired anal sphincter, who have failed conservative treatment or for whom conventional treatment is inappropriate.  Sacral nerve neurostimulation for fecal incontinence has shown improvement in multiple outcome measures (e.g., patient satisfaction, physical functioning, social functioning, coping & behavior, depression and self-perception, and embarrassment) at 24 & 36 months post implantation. Patients undergo a staged procedure with placement of a temporary, percutaneously placed test stimulation lead, followed by operative placement of a permanent quadripolar lead and pacer.  The device is approved by the appropriate regulatory agencies in Europe; it is not yet approved for marketing in the United States, but is under study to determine effectiveness and safety.

 

A small randomized trial of SNS reported decreased episodes of fecal incontinence and improved quality of life (Leroi, 2005).  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 5 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 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 2 controlled trials (2 subjects each) in addition to the study of 27 patients described (Mowatt, 2008).  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.

 

In 2008, 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 (Tjandra, 2008).  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 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%). Matzel and colleagues reported long-term outcomes from 12 patients with severe incontinence (average of 54% incontinent episodes per week) who underwent SNS between 1994 and 1999 (Matzel, 2008).  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. Although promising, additional studies with longer-term results are needed.

 

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 SNS (Rao, 2004).  The ACG concluded that the precise indication for SNS, its comorbidity, its long-term outcome, and efficacy remain to be defined.

 

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.

 

In 2010, Wexner et al. reported results from a 16-site multicenter FDA investigational device exemption (IDE) trial of sacral nerve stimulation in 120 patients with fecal incontinence (Wexner, 2010). 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 such as dietary modification, the addition of bulking and antidiarrheal agents, and biofeedback therapy. 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 between 2002 and 2008; 133 were enrolled and underwent acute test stimulation, 129 of the 133 patients progressed to the 2-week subchronic test stimulation, and 120 showed > 50% improvement during the test phase. Of the 120 patients who received a permanent stimulator, 34 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). At the time of data cut-off for the manuscript, 111 patients had completed 12 months follow-up, 76 patients completed 2 years, and 34 patients completed 3 years. Conservative 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 two figures. Out of 106 completed cases (88% of 120) included in the 12-month results, perfect continence (100% improvement) was reported in about 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). There were 307 adverse events reported in 96 patients related to the device or therapy, including infection, implant site pain, hematomas, lead fractures or migrations, extremity pain or skin irritation; 26 were considered serious adverse events that were life threatening, required hospitalization, or resulted in persistent or significant disability.

 

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 sacral nerve stimulation (Michelson, 2010). 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, 15 patients (12%) had undergone explantation for decreased function, pain, or infection. Out 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 and days of soiling decreased from a median of 16 to 5.

 

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, (Leroi, 2009):

 

Indications:

 

Contraindications:

Potential Contraindications:

 

Guidance from the United Kingdom’s National Institute for Clinical Excellence (NICE) concluded in 2004 that the safety and efficacy of sacral nerve stimulation for fecal incontinence appears adequate to support the use of this procedure.

 

With consistent and longer-term results from 2 large trials in 2010 (a prospective multicenter investigational trial with 120 patients and a European cohort of 177 patients), together with a randomized controlled trial with 12-month follow-up from 2008, 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.

 

It should be emphasized that not all patients will benefit, and that the adverse event rate for this procedure, including serious adverse events, is high. Patients should therefore be provided with adequate information to make an informed choice regarding the potential risks and benefits of this procedure. As concluded in the 2009 Cochrane review of sacral nerve stimulation for urinary incontinence (Herbison, 2009), 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 literature on sacral nerve stimulation for constipation or chronic pelvic pain remains insufficient to evaluate the effect of this technology on health outcomes.

 

 

 

 

 

 

 

    

 

 

 

 

 

Thaha and colleagues published a Cochrane review on sacral nerve stimulation for fecal incontinence and constipation in adults, which included randomized, quasi-randomized, and crossover trials (Thaha, 2015). For fecal incontinence, the review included 6 trials of SNM (n=219), 2 of which used a parallel group design (Thin et al [2015], Tjandra et al [2008]) and the remaining of which used a crossover design. The primary methodological quality issue noted was related to lack of clarity around randomization techniques and allocation concealment. The review concluded, “The limited evidence from the included trials suggests that SNS can improve continence in a proportion of patients with fecal incontinence.”

 

In the 2015 Cochrane review by Thaha and colleagues on sacral nerve stimulation for fecal incontinence and constipation in adults, 2 trials on SNM for constipation were included (Dinning et al [2015], along with an additional crossover trial) (Thaha, 2015). In one trial, the time with abdominal pain and bloating decreased during the “on” period from 79% to 33%. However, in the larger Dinning et al study, there was no improvement with SNM during the “on” period. The review concluded, “SNS did not improve symptoms in patients with constipation.”

 

Zerbib and colleagues reported on a double-blind crossover RCT of SNS in 36 women with refractory constipation (Zerbib, 2016). Subjects were eligible if they had chronic constipation (>1 year), with 2 or fewer bowel movements per week, straining to evacuate with more than 25% of attempts, or sensation of incomplete evacuation with more than 25% of attempts, with lack of response to standard therapies. Thirty-six subjects meeting inclusion criteria underwent an initial peripheral nerve evaluation; those who had adequate symptom improvement to a predefined level were offered permanent SNS implant. After a 2 week washout, subjects were randomized to “on” or “off” for 8 weeks, followed by a 2-week washout, when the groups crossed over. Of the 36 patients enrolled, 20 responded and underwent randomization. Four were excluded; 2 due to wound infection, and 1 each to withdrawal of consent and lack of compliance. At 1-year follow-up, a positive response was observed in 12/20 and 11/20 patients after active and sham stimulation periods, respectively (P=0.746).