For the management of refractory urge incontinence, non-pharmacologic options can be used alone or in combination with anticholinergic medications will be adequate treatment for many patients, but some will need further therapy.
The PNE is appealing to patients because it is minimally invasive and can be performed in the office. They view it more like a test than a surgical procedure. The use of fluoroscopy for this technique has greatly improved its value and relevance to the eventual intraoperative tined lead placement. It is also very cost effective to administer in an office setting. Still, a staged approach, with its quadripolar lead configuration and longer trial period, is a better overall predictor of successful treatment.
Present and future indications. In the U.S., FDA-approved indications for SNM include refractory overactive bladder and idiopathic, nonobstructive urinary retention. It may be successfully used for both indications since it is not a bladder-specific therapy and works at a central level on the "on-off" switch for bladder reflexes. While FDA labeling stipulates that SNM is only approved for non-neurogenic patients, patients with a neurogenic basis of complaint have been successfully treated (Eur Urol 2010; 58:865-74).
In Europe, where SNM is approved for both bladder and bowel (fecal urgency/frequency, fecal incontinence, and nonobstructive constipation/obstipation), the technique is used more commonly for bowel indications. A successful U.S. clinical trial of SNM for fecal incontinence has been submitted and reviewed by the FDA, and may be acted upon definitively in the near future (Ann Surg 2010; 251:441-9). In the meantime, many of our patients with refractory urinary complaints also have very significant and disabling bowel complaints (Neurourol Urodyn 2007; 26:19-28, Neurourol Urodyn 2010; 29:545-50), and selection of SNM is likely to have a beneficial effect on both conditions (Int J Colorectal Dis 2009; 24:1377-81). Thus, the therapy should be appropriately weighed against intravesical botulinum toxin for this potential benefit in patients who are also bothered by gastrointestinal symptoms.
Efficacy and complications. SNM has been the subject of hundreds of publications in the peer-reviewed literature. In general, randomized, controlled trials and case series reports show approximately 80% and 70% success rates, respectively, defined as at least a 50% decrease in relevant voiding parameters. Studies also demonstrate significant improvement in quality of life, decreased use and cost of therapeutic alternatives, and long-term benefit (Eur Urol 2010; 58:865-74; J Urol 2006; 175:835-41; Urology 2007; 70:1069-73). The degree of improvement, even among patients with the most severe baseline symptoms, has been shown to be greater than among patients successfully treated in OAB drug trials (based on package inserts/FDA-submitted trials).
Complications of SNM include infection, discomfort from the lead or implantable pulse generator placement, change or lack of efficacy over time, and inability to undergo magnetic resonance imaging once the device has been implanted. The most common reason for re-operation is change in efficacy over time, and recent reports indicate the re-operation rate is about 20% (Int Urogynecol J Pelvic Floor Dysfunct 2010; 21:491-6). Of course, even if everything is perfect, all patients who outlive the device's battery life are likely to need a re-operation for a new battery unless or until a better therapeutic option is available.