Sacral Neuromodulation Can Ease Refractory Overactive Bladder in the Elderly
This x-ray of the pelvis shows an electronic nerve-stimulating device in the right iliac fossa.
Overactive bladder (OAB) is estimated to affect more than 33 million adults in the United States alone. Standard treatments for this disorder comprise behavioral modifications, Kegel exercises, anticholinergic medications, and fluid management. However, simple first-line measures, including trials of one or more drugs, often fail, leaving patients with refractory OAB.
In the geriatric population, other concerns arise with first-line treatments, including polypharmacy and cognitive side effects from the medications. Neuromodulation represents an ideal therapy for refractory OAB in the geriatric population because of the procedure's minimal invasiveness and high efficacy.
To be considered a candidate for sacral neuromodulation (SNM), individuals should not have any true cognitive defects, should be able to understand the therapy, should not be in imminent need for an MRI (current contraindication), and should be a satisfactory medical candidate for a short-term anesthetic.
In preparation for SNM, the patient should undergo a thorough history and physical examination to ensure that the patient's incontinence has no other etiology that could be treated with alternate modalities. Having patients keep a three-day voiding diary will provide a fluid intake and output log that also tracks for objective urinary frequency and includes leakage measurements. This process is repeated after a lead is placed for SNM.
SNM is approved by the FDA for urge/frequency incontinence, urge incontinence, and nonobstructive urinary retention. The outpatient procedure is usually performed under monitored anesthesia care (MAC). Physicians may elect to perform an in-office percutaneous nerve evaluation (PNE), but the fine wire lead that is introduced into the sacral nerve foramen (S3) is not durable and often is displaced before adequate efficacy can be established.
Thus, most implanting physicians perform the staged approach with a durable tined lead placed under MAC in the operating room. If the patient experiences greater than 50 percent improvement based on objective (voiding diary) and subjective (questionnaire) evaluation, an implantable pulse generator or pacemaker can be placed within one to two weeks.
While no prospective studies have been done in geriatric patients, retrospective data show slightly diminished efficacy compared with nongeriatric patients, as advancing age seems to be a negative predictive factor in overall success. Estimated success rates for geriatric patients with idiopathic refractory OAB can range between 70% and 80%.
Nevertheless, SNM may be too invasive for some elderly patients. In these patients, percutaneous tibial nerve stimulation (PTNS) may provide relief. This office-based procedure involves placement of a 34G needle into the posterior tibial nerve (terminal branch of S3) located just above the medial malleolus near the ankle, with low-dose stimulation being given on a weekly basis for approximately 12 weeks.
Subsequent carryover effects result in improvement in bladder overactivity, but patients need continued “boost” therapy once a month to maintain the treatment benefit. Advantages of this approach include the office-based nature of the therapy, minimal pain, and no need for anesthesia. However, questions remain regarding the efficacy of PTNS compared with SNM.
Data showing that SNM does not work as well in geriatric voiding dysfunction as it does in younger patients should not deter a referral for consideration of this procedure or PTNS for treatment of the refractory OAB. These therapies can be very beneficial and can significantly improve patients' quality of life.
Dr. Vasavada is Urologic Director of the Cleveland Clinic's Center for Female Pelvic Medicine and Genitourinary Reconstructive Surgery and Associate Professor of Surgery (Urology) at Cleveland Clinic Lerner College of Medicine of Case Western Reserve University in Cleveland, Ohio.