Predictive Factors in Sacral Neuromodulation: A Systematic Review.

INTRODUCTION: Sacral neuromodulation (SNM) is an effective treatment in patients with overactive bladder syndrome or nonobstructive urinary retention when conservative treatment fails. Several factors that could impact outcome with SNM have been studied. This systematic review investigated these predictive factors and their relevance for clinical practice. METHODS: Systematic review according to the PRISMA guidelines was conducted. This review is registered in the PROSPERO register (CRD42015016256). RESULTS: Seventy-eight studies (of which 11 abstracts) were included. Females, younger patients, and a tined lead procedure tend to be predictive in successful SNM outcome. Factors that did not influence SNM outcome were prior back surgery, surgery for stress urinary incontinence, affective symptoms, and duration of complaints. Reduced detrusor contractility is associated with a lower success rate. The level of evidence of most studies (graded according to the Centre for Evidence-Based Medicine) was 3b. CONCLUSION: Even though this systematic review investigated predictive factors (gender, age, type of procedure, type of lead, and detrusor contractility), no general consensus on predictive factors could be made. Most studies are small, retrospective, and involve a heterogeneous population. Therefore, prospective research in larger specific patient groups remains necessary to find predictors of SNM outcome.

A prospective, multicenter study of a novel, miniaturized rechargeable sacral neuromodulation system: 12-month results from the RELAX-OAB study.

AIMS: Historically, providing SNM therapy required use of a non-rechargeable implantable pulse generator (IPG) with an average device lifespan of 4.4 years. Multiple device replacement surgeries are necessary with this device for long-term overactive bladder (OAB) management. A longer-lived device can reduce and potentially eliminate the need for replacement surgeries, thereby improving the long-term safety and cost-effectiveness of SNM therapy. The objective of this study was to evaluate the safety and efficacy of a miniaturized, rechargeable SNM system. METHODS: This prospective, multi-center study implanted 51 subjects with the SNM system in a single stage procedure without an external trial period. Subjects had overactive bladder as demonstrated on a 3-day voiding diary (≥8 voids/day and/or ≥2 incontinence episodes over 72-h). Outcome measures at 1-year follow-up included quality of life (evaluated by ICIQ-OABqol questionnaire), therapy responder rates (≥50% reduction in voids and/or leaks or <8 voids per day), subject satisfaction questionnaire, and adverse events (AEs). RESULTS: At 1-year, 94% of Test Responders continued to respond to r-SNM therapy based on bladder diary criteria. Subjects experienced significant improvement of 21.1 points on the ICIQ-OABqol. 84% of subjects were satisfied with r-SNM therapy and 98% found their charging experience acceptable. Device-related AEs occurred in 21% of subjects, with discomfort due to stimulation occurring in 20% of subjects. This AE was resolved with reprogramming in all instances. CONCLUSIONS: The Axonics r-SNM System provides sustained clinically significant improvements in OAB subjects after 1-year. Subjects were satisfied with r-SNM therapy and reported an easy and acceptable recharging experience.

Affective symptoms and quality of life in patients with voiding or storage dysfunction: Results before and after sacral neuromodulation: A prospective follow-up study.

AIMS: Sacral neuromodulation (SNM) is an effective treatment for patients with overactive bladder syndrome (OAB) or non-obstructive urinary retention (NOR). These lower urinary tract symptoms (LUTS) are the result of a functional urological cause but often coincide with psychological and/or psychiatric factors. It has been stated that there is an association between LUTS, depression and anxiety disorders. With this study we will investigate whether affective symptoms and quality of life (QoL) improve after successful SNM. METHODS: All patients eligible for SNM between March 2013 and March 2016, filled out the HADS (Hospital Anxiety and Depression Scale), SF-36 (Short Form-36) and either the International Consultation on Incontinence Modular Questionnaire (ICIQ) on Male/Female Lower Urinary Tract Symptoms (M/F-LUTS), or the OAB-q questionnaire, before and after the test procedure. Symptom improvement of ≥50% was considered as success. Results were analyzed by paired T-tests and the Wilcoxon signed-rank test. RESULTS: In total 95 patients were included. Mean age was 52.1 (SD 13.9). Fifty-six patients (59%) were implanted. Successful OAB patients reported a significant improvement in all domains of OAB-q, health change and affective symptoms. Successful NOR patients showed a significant improvement in voiding symptoms (P = 0.04) and health change (P = 0.03). However, they did not report significant improvement in affective symptoms. CONCLUSION: QoL and affective symptoms can significantly improve in LUTS patients who are successfully treated with SNM. When divided per indication, a significant improvement in affective symptoms together with QoL was only reported in successful OAB patients and not in successfully treated NOR patients.

Programming settings and recharge interval in a prospective study of a rechargeable sacral neuromodulation system for the treatment of overactive bladder.

AIMS: The RELAX-OAB study is designed to confirm the safety, efficacy, and technical performance of the Axonics r-SNM System, a miniaturized, rechargeable SNM system approved in Europe and Canada for the treatment of bladder and bowel dysfunction. The purpose of this article is to describe study subjects' ability to charge the rechargeable neurostimulator and to document their neurostimulator program settings and recharge interval over time. METHODS: Fifty-one OAB patients were implanted in a single-stage procedure. These results represent the 3-month charging experience for 48 subjects who completed the 3-month follow-up. Recharge intervals were estimated using therapy stimulation settings and subject experience was evaluated using questionnaires. RESULTS: Forty-seven of forty-eight (98%) subjects were able to successfully charge their device prior to follow-up within 1-month post-implant. At 3-month post-implant, 98% of subjects were able to charge prior to their follow-up visit. Average stimulation amplitude across all subjects was 1.8 mA (±1.1 mA). A total of 69% of subjects had ≥14-day recharge intervals (time between charging) and 98% of subjects had ≥7-day recharge interval. No charging related adverse events occurred. CONCLUSIONS: Study subjects were able to charge the Axonics r-SNM System and stimulation settings provided 2 weeks of therapy between recharging for most subjects. Subject satisfaction indicates that subjects are satisfied with rechargeable SNM therapy.

Three month clinical results with a rechargeable sacral neuromodulation system for the treatment of overactive bladder.

AIMS: The primary aim of the RELAX-OAB study is to confirm the safety and efficacy of the Axonics r-SNM System, a miniaturized, rechargeable SNM system. METHODS: A total of 51 OAB patients were implanted in a single-stage implant procedure. These results represent the 3-month outcomes. Subject outcomes were evaluated using 3-day bladder diaries and quality of life questionnaires. RESULTS: A total of 31 of 34 patients (91%) that responded during an initial trial period ("Test Responders") continued to benefit from therapy with the Axonics r-SNM System at 3-months, defined as symptom improvement of ≥50% reduction in urinary voids or incontinence episodes or a return to <8 voids per day. Subjects who were Test Responders showed a statistically and clinically meaningful improvement in all aspects of quality of life (ICIQ-OABqol). No serious device-related adverse events (SADEs) occurred, and there were no unanticipated adverse events (UAEs). One subject was explanted due to an infection at the implant site and 19.6% of subjects experienced device related adverse events, most notably discomfort due to stimulation, which was resolved with reprogramming. CONCLUSIONS: The Axonics r-SNM System provides safe and effective SNM therapy with objective improvement in 91% of subjects. The data also demonstrates a significant improvement in all domains of quality of life. This miniaturized, rechargeable system is designed to last 15 or more years and is expected to provide clinical and cost benefits over current non-rechargeable systems by eliminating replacement surgeries.

Onset of Action of Sacral Neuromodulation in Lower Urinary Tract Dysfunction-What is the Optimal Duration of Test Stimulation?

PURPOSE: Since the development of sacral neuromodulation, a large number of patients with lower urinary tract symptoms have been treated with this procedure. A test stimulation is performed prior to implantation. At centers worldwide the duration of this test stimulation varies considerably since it is not certain when the onset of the therapy effect can be expected. The objective of this prospective study was to evaluate the average onset time of sacral neuromodulation in patients with lower urinary tract symptoms. MATERIALS AND METHODS: All patients who were eligible for treatment with sacral neuromodulation were asked to participate in this study. A voiding diary was filled out prior to and during test stimulation using an implanted tined lead. Success was defined as a 50% or greater improvement compared to baseline in any of the main complaint parameters. The Mann-Whitney U test was used to compare the mean time to success between patients with overactive bladder syndrome and patients with nonobstructive urinary retention. RESULTS: Of the 45 patients 24 with nonobstructive urinary retention and 21 with overactive bladder syndrome agreed to participate and were included in study. Test stimulation was successful in 29 patients (64%). Mean time to success in all patients was 3.3 days (range 1 to 9). There was no significant difference in mean time to success between cases of overactive bladder syndrome and nonobstructive urinary retention (3.25 and 3.5 days, respectively, p = 0.76). CONCLUSIONS: The results imply that a test stimulation of more than 2 weeks is not necessary if a cutoff of 50% or greater improvement is adopted. However, further improvement can be expected with prolonged test stimulation. This might be important since it might have implications for long-term results.

Optimal Lead Positioning in Sacral Neuromodulation: Which Factors Are Related to Treatment Outcome?

OBJECTIVES: Sacral neuromodulation (SNM) is a well-established treatment for overactive bladder (OAB) and non-obstructive urinary retention (NOR). During test stimulation, the lead is positioned along the third sacral nerve, which ideally results in a response in all four contact points (active electrodes). However, it is unclear whether the position of the lead (depth, angle, deflection) and the number of active electrodes is related to the outcome of SNM. METHODS: All patients who underwent test stimulation using the tined lead between January 2011 and September 2016 were included in this retrospective study. Success was defined as >50% improvement in voiding diary parameters compared to baseline. The correlation between lead position and outcome of test stimulation was evaluated. The lead position was determined by evaluating the depth, angle and deflection with respect to the sacral foramen. Binary logistic regression was used in order to determine the predictive value of these factors. RESULTS: We included 189 patients of whom 105 were diagnosed with OAB and 84 with NOR. After a SNM test period of 4 weeks, 111 patients (59%) were successful and received a permanent implant. The position of the lead and the number of active electrodes did not predict success of test stimulation in neither the OAB group nor the NOR. However, lateral deflection of the lead was associated with finding more active electrodes (p = 0.01). CONCLUSION: In our study, the position of the lead or the number of active electrodes did not predict the outcome of SNM test stimulation. However, the impact of lead positioning and number of active electrodes on long-term outcome remains to be proven.

The Impact of Duration of Complaints on Successful Outcome of Sacral Neuromodulation.

OBJECTIVES: The study aimed to evaluate whether the duration of complaints in patients with overactive bladder syndrome or non-obstructive urinary retention predicts the outcome of sacral neuromodulation (SNM). METHODS: All patients that underwent a SNM test period evaluation between 2011 and 2014, were included in this study. The duration of complaints was listed in 3 categories: (a) 0-5 years, (b) 5-10 years and (c) 10 years or longer. Analyses with chi square tests were performed to evaluate whether the duration of complaints are associated with outcome of SNM. RESULTS: In total, 130 patients were included. Most patients had a complaint duration of 0-5 years (n = 60). The test period was successful in 56% (n = 74) of the total group. Analyses showed that the duration of complaints is not significantly associated with outcome of SNM (p = 0.752), even when subdivided per indication, and also when possible confounders such as age at test and indication are taken into account (p = 0.720). CONCLUSION: Based on the results of this study, there is no relationship between duration of complaints and SNM outcome. SNM seems to remain a feasible treatment option, despite of possible anatomical or physiological changes within the lower urinary tract.