What uro-gynecologists should know about sacral neuromodulation (SNM) for the treatment of refractory overactive bladder

To estimate and compare the prevalence and associated bother of lower urinary tract symptoms (LUTS) in the general populations of the USA, UK and Sweden using current International Continence Society (ICS) definitions, as no previous population-based studies evaluating the prevalence of LUTS in the USA, using the 2002 ICS definitions, have been conducted. This cross-sectional, population-representative survey was conducted via the Internet in the USA, the UK and Sweden. Members of Internet-based panels were randomly selected to receive an e-mailed invitation to participate. If interested, respondents selected a link to an informed consent page, followed by the survey. Participants were asked to rate how often they experienced individual LUTS during the previous 4 weeks, on a five-point Likert scale, and, if experienced, how much the symptom bothered them. Descriptive statistics were used to summarize and present the data. Responses rates for the USA, the UK and Sweden were 59.6%, 60.6% and 52.3%, respectively, with a final sample of 30,000 (USA 20,000; UK 7500; Sweden 2500). The mean age (range) of the participants was 56.6 (40-99) years; the mean percentages for race were 82.9% white, 6.7% black, 6.0% Hispanic and 4.4% Asian/other. The prevalence of LUTS was defined by two symptom frequency thresholds, i.e. at least 'sometimes' and at least 'often' for all LUTS except incontinence, where frequency thresholds were at least 'a few times per month' and at least 'a few times per week'. The prevalence of at least one LUTS at least 'sometimes' was 72.3% for men and 76.3% for women, and 47.9% and 52.5% for at least 'often' for men and women, respectively. For most LUTS, at least half of the participants were bothered 'somewhat' or more using a frequency threshold of at least 'sometimes'. For a threshold of at least 'often', 'somewhat' or more bother was reported by > or =70% of participants except for terminal dribble in men and split stream in women. In this large population study of three countries, LUTS are highly prevalent among men and women aged >40 years. In general, LUTS experienced 'often' or more are bothersome to most people.

Neuromodulation of sacral nerves has shown promising results in correcting voiding dysfunction. We report the results of a multicenter trial designed to assess the efficacy of sacral nerve neuromodulation in patients presenting with refractory urinary urgency-frequency. A total of 51 patients from 12 centers underwent baseline assessment, including a detailed voiding diary, urodynamic evaluation and percutaneous test stimulation of the sacral nerves at S3 and/or S4. All patients enrolled in the study had undergone prior conventional treatment, such as pharmacotherapy, hydrodistention and surgical intervention, which failed. All patients demonstrated a satisfactory response to trial stimulation and were randomly divided into a stimulation group (25 patients) and a control group (26). A sacral nerve stimulation device was implanted after 6 months in the control group. Patients were followed at 1, 3 and 6 months, and at 6-month intervals for up to 2 years after implantation of a neuroprosthetic InterStim* system. dagger The study variables included the number of voids daily, volume voided per void and degree of urgency before void. Compared to the control group, 6-month voiding diary results demonstrated statistically significant improvements (p <0.0001) in the stimulation group with respect to the number voids daily (16.9 +/- 9.7 to 9.3 +/- 5.1), volume per void (118 +/- 74 to 226 +/- 124 ml.) and degree of urgency (rank 2.2 +/- 0.6 to 1.6 +/- 0.9). Patients in the control group showed no significant changes in voiding parameters at 6 months. Significant improvements in favor of the stimulation group were noted in various parameters with respect to water cystometry and quality of life (SF-36). At 6 months after implant, neurostimulators were turned off in the stimulation group and urinary symptoms returned to baseline values. After reactivation of stimulation sustained efficacy was documented at 12 and 24 months. Neuromodulation of the sacral nerves is an effective, safe therapy that successfully treats significant symptoms of refractory urgency-frequency.

We systematically reviewed the evidence on the efficacy and safety of sacral nerve stimulation (SNS) for severe urge incontinence. A systematic review was performed of primary studies of SNS for urge incontinence published in English between 1966 and May 2003, and identified in major electronic databases. Two reviewers independently selected studies, assessed their methodological quality and extracted data. Four randomized controlled trials and 30 case series were identified. Evidence from the randomized controlled trials, involving approximately 120 patients, showed that about 80% achieved continence or greater than 50% improvement in their main incontinence symptoms after SNS compared with about 3% of controls receiving conservative treatments while waiting for an implant. While case series were larger, they were methodologically less reliable. However, they showed similar results with 67% of patients becoming dry or achieving a greater than 50% improvement in symptoms after implantation. Incontinence episodes, leakage severity, voiding frequency and pad use were significantly lower after implantation. Benefits were reported to persist 3 to 5 years after implantation. Adverse events were documented in 27 studies. Overall the reoperation rate in implanted cases was 33%. The most common reason for surgical revision was relocation of the generator because of pain and infection. Common complications were pain at the implant or lead site in 25% of patients, lead related problems such as lead migration in 16%, replacement and repositioning of the implanted pulse generator in 15%, wound problems in 7%, adverse effects on bowel function in 6%, infection in 5% and generator problems in 5%. Permanent removal of the electrodes was reported in 9% of patients. Technical changes with time have been associated with decreased complication rates. There is evidence indicating that SNS is effective for decreasing symptoms in patients with urge incontinence. Adverse events occurred in about half of the implanted cases and surgical revision was performed in 33%. No major irreversible complications were reported in the studies reviewed. Further research is required on the long-term effects of and quality of life in patients with SNS.