Detailed analysis of adverse events and surgical interventions in a large prospective trial of sacral neuromodulation therapy for overactive bladder patients

Treatment of the infected sacral nerve stimulator: A scoping review

BACKGROUND

Sacral nerve stimulators (SNSs) are a widely accepted, efficacious surgical option to treat patients who have failed conservative management for overactive bladder, nonobstructive urinary retention, fecal incontinence, or pelvic pain. As with all implanted devices, there are associated risks for surgical site and implant infections. There are currently no clear published data or guidelines regarding treating such infections.

AIMS

We present a scoping review aiming to examine the existing literature on the treatment approaches of infected SNSs.

METHODS

A scoping review was conducted using Preferred Reporting Items for Systematic Review and Meta-Analysis. The search strategy focused on "sacral modulation," and "infection," and "explantation," and conservative management methods such as "antibiotics." A search was conducted on medical databases, and a grey literature search was performed.

RESULTS

Thirty articles were included for data extraction. Articles were published between 2006 and 2022. Outcomes were reported for 7446 patients. Two hundred and seventy-four infection events were reported, giving an overall 3.7% infection rate. Most infection events were treated with explantation, although there is some discussion on the role of conservative management using oral and intravenous antibiotics in the literature. Articles also discussed considerations for future reimplantation after explantation of SNS.

CONCLUSIONS

There are currently no treatment protocols in the literature to help guide whether a patient is suited to conservative or surgical management. There is future scope for developing treatment algorithms to guide clinicians for optimal treatment of infected sacral neuromodulation devices.

Understanding a decade of safety reporting for sacral neuromodulation in the Food and Drug Administration Manufacturer and User Facility Device Experience database

INTRODUCTION

Over 350 000 sacral neuromodulation (SNM) devices have been implanted since approval by the Food and Drug Administration (FDA) in 1998. SNM technology and clinical applications have evolved, with minimal safety updates after initial trials. We aim to provide an updated overview of real-world SNM safety. These insights will guide informed consent, preoperative counseling, and patient expectation-setting.

MATERIALS AND METHODS

The FDA Manufacturer and User Facility Device Experience (MAUDE) database is a repository for medical device safety reports. We performed MAUDE categorical (1/1/98-12/31/10) and keyword (1/1/11-9/30/21) searches for "Interstim." A random sample of 1000 reports was reviewed and categorized by theme. To corroborate our MAUDE database analysis, a legal librarian searched the Public Access to Court Electronic Records (PACER) database, as well as Bloomberg Law's dockets database for all lawsuits related to SNM devices.

RESULTS

Our search of the MAUDE database returned 44 122 SNM-related adverse events (AEs). The figure illustrates the prevalence of event categories in the random sample. The largest proportion of reports (25.6%) related to a patient's need for assistance with device use, followed by loss/change of efficacy (19.0%). Interestingly, a fall preceded issue onset in 32% of non-shock pain, 30% of lead/device migration, and 27% of painful shock reports. Our legal search revealed only four lawsuits: one for patient complications after an SNM device was used off-label, one case of transverse myelitis after implant, one for device migration or poor placement, and the fourth claimed the device malfunctioned requiring removal and causing permanent injury.

CONCLUSIONS

This review confirms the real-world safety of SNM devices and very low complication rates as seen in the original clinical trials. Our findings indicate that 43.2% (95% confidence interval 40.1%-46.3%) of SNM "complications" are not AEs, per se, but rather reflect a need for improved technical support or more comprehensive informed consent to convey known device limitations to the patient, such as battery life. Similarly, the number of lawsuits is shockingly low for a device that has been in the market for 24 years, reinforcing the safety of the device. Legal cases involving SNM devices seem to relate to inappropriate patient selection-including at least one case in which SNM was used for a non-FDA approved indication-lack of appropriate follow-up, and/or provider inability to assist the patient with utilizing the device after implantation.

A novel sacral neuromodulation protocol is associated with reduction in removal for device infection

INTRODUCTION AND HYPOTHESIS

Sacral neuromodulation (SNM) has been established as an effective third-line therapy for non-obstructive urinary retention and urinary urgency-frequency syndrome. Device infection, ranging from 2-10%, is a severe complication usually necessitating device explanation. This study sought to demonstrate an infection protocol founded upon established device implantation risk factors and novel approaches to reduce the incidence of device infection, while maintaining good antibiotic stewardship following best practice statements.

METHODS

A single-surgeon protocol was enacted from 2013 to 2022. Preoperatively, nasal swabs were cultured from each patient. If positive for methicillin-resistant Staphylococcus aureus or methicillin-sensitive Staphylococcus aureus, preoperative treatment with intranasal mupirocin was employed. Preoperative cefazolin was administered in patients with negative cultures or MSSA-positive. All protocol patients were given chlorhexidine wipes before surgery and prepped with a chlorhexidine scrub followed by alcohol/iodine paint. Post-procedural antibiotics were not given. Pre-protocol patients from 2011 to 2013 served as controls.

RESULTS

Pre-protocol (n = 87) patients had a significantly higher rate of device infection compared to protocol patients (n = 444) in both the percentage of patients experiencing device infection (4.6% vs 0.9%, p = 0.01) and percentage of procedures associated with device infection (2.9% vs 0.5%, p < 0.05). A successful culture of the nares was achieved in 91.4% of protocol patients, with 11.6% MRSA-positive. Risk ratio for infection of pre-protocol/protocol patients was 0.19 (0.05-0.77) with odds ratio 5.1 (1.3-20.0).

CONCLUSIONS

Utilization of a novel SNM infection protocol tailored to a patient's preoperative MRSA colonization is associated with a reduction in the overall incidence of explant for device infection while avoiding prolonged postoperative antibiotic regimens.

CLINICAL TRIAL REGISTRATION

The study was initiated prior to January 18, 2017 and does not meet the definition of an applicable clinical trial (ACT) as defined in section 402 (J) of the US PHS Act.

Microbial colonization of sacral nerve stimulators pseudo-capsule: A single institution experience

PURPOSE

To evaluate the incidence and type of microbial colonization of the pseudo-capsule (PC) that forms around sacral nerve stimulators (SNS) and consequently the significance of surgical excision of this PC at time of SNS revision or removal.

MATERIALS AND METHODS

A cohort of 31 patients who underwent SNS revision or removal from January 2018 to June 2021 were retrospectively reviewed. The baseline demographics, rate and type of PC microbial colonization and development of SNS insertion site infection were reported.

RESULTS

A cohort of 31 patients who underwent "InterStim device (Medtronic)" revision or removal were included. The majority were females (93.5%). The most common indication for SNS insertion was refractory overactive bladder (67.7%). Nine patients (29.0%) underwent SNS revision due to malfunctional device, and 9 patients had SNS removal for the need of MRI procedures. Four patients (12.9%) had positive tissue culture growing Coryneform bacillus (50.0%), Cutibacterium acnes (25.0%) and Pseudomonas aeruginosa (25.0%).

CONCLUSIONS

PC colonization was uncommon at the time of SNS explant. However, more research is needed to better understand the role of PC-positive culture in increasing the risk of SNS device infections if strict adherence to sterile techniques is adopted.

Cost-effectiveness of overactive bladder treatments from a US commercial and payer perspective

Aim: The cost-effectiveness of treatment options (anticholinergics, β3-adrenoceptor agonists, onabotulinumtoxinA, sacral nerve stimulation and percutaneous tibial stimulation [the latter two including new rechargeable neurostimulators]) for the management of overactive bladder (OAB) were compared with best supportive care (BSC) using a previously published Markov model. Materials & methods: Cost-effectiveness was evaluated over a 15-year time horizon, and sensitivity analyses were performed using 2- and 5-year horizons. Discontinuation rates, resource utilization, and costs were derived from published sources. Results: Using Medicare and commercial costs over a 15-year time period, onabotulinumtoxinA 100U had incremental cost-effectiveness ratios (ICERs) gained of $39,591/quality-adjusted life-year (QALY) and $42,255/QALY, respectively, versus BSC, which were the lowest ICERs of all assessed treatments. The sensitivity analyses at 2- and 5-year horizons also showed onabotulinumtoxinA to be the most cost-effective of all assessed treatments versus BSC. Conclusion: OnabotulinumtoxinA 100U is currently the most cost-effective treatment for OAB.

Sacral neuromodulation for overactive bladder using the InterStim and BetterStim systems

This study aimed to evaluate differences in the clinical outcomes of different sacral neuromodulation systems (InterStim and BetterStim) used in the treatment of overactive bladder. Data from a previously established database of sacral neuromodulation in China (the InterStim system) and a 2020 clinical trial of the BetterStim system were screened. Patients with overactive bladder undergoing stage II implanted pulse generator implantation were selected for analysis and divided into InterStim and BetterStim system groups. Voiding diaries and subjective scores obtained preoperatively, after stage I tined-lead implantation (experience period), and after stage II implanted pulse generator implantation were compared between the two groups. This study included 113 patients with overactive bladder (43, InterStim system group; 70, BetterStim system group). Voiding diaries and subjective scores significantly improved in both the InterStim and BetterStim system groups over the treatment period. Specifically, the urination frequency (all P < 0.001), average voiding volume (all P < 0.001), and average urinary leakage (InterStim, P < 0.05; BetterStim, P < 0.01) in both groups significantly improved at different periods during treatment. At the same time, the urgency perception scale (P < 0.001) and OAB-related quality of life score (InterStim, P < 0.05; BetterStim, P < 0.01) also significantly improved. There was no significant difference in urination frequency at baseline between the two groups (P = 0.169). Urination frequency was significantly higher in the BetterStim system group than in the InterStim group during the experience period and at follow-up (P = 0.031, P = 0.006). There was no significant difference in the number of urinary leakages between the different systems at baseline (P = 0.662), although this was higher in the InterStim system group during the experience period (P = 0.016), and the difference disappeared at the last follow-up (P = 0.565). There were significant differences in baseline urgency perception scale (P = 0.001) and OAB-related quality of life score (P < 0.001) between the two groups; however, these differences were not maintained at follow-up (P = 0.81, P = 0.479). Both sacral neuromodulation systems are safe and effective in treating overactive bladder. The InterStim system may be more beneficial for patients with dry overactive bladder. Satisfactory outcomes may be achieved with the BetterStim system in patients with wet overactive bladder. However, further studies are required to confirm this finding.

Posterior Tibial Nerve Stimulation for Overactive Bladder: Mechanism, Classification, and Management Outlines

Purpose of the Review. Posterior tibial nerve stimulation (PTNS) techniques have dramatically grown after approval to manage overactive bladder (OAB). The present review will focus on the most current data on PTNS types (percutaneous, transcutaneous, and implant) and their mechanism of action, safety, efficacy, advantages, drawbacks, limitation, and clinical applications. Recent Findings. The present review described the recent studies that addressed the tibial nerve stimulation role in OAB management. BlueWind RENOVA system, Bioness StimRouter, and eCoin are examples of emerging technologies that have evolved from interval sessions (percutaneous PTNS and transcutaneous PTNS) to continuous stimulation (implants). These can be efficiently managed at home by patients with minimum burden on the health system and fewer visits, especially in the COVID-19 pandemic. Summary. Our review shows that the tibial nerve stimulation advancements in OAB treatment have been rapidly increasing over the recent years. It is minimally invasive and effective, similar to sacral nerve stimulation (SNM), but less aggressive. Implantable PTNS has been promised in terms of efficacy, safety, and high acceptance rate. However, evidence is still limited to short-term trials, and tolerability, method, and drawbacks remain challenges.

Reprogramming Sacral Neuromodulation for Sub-Optimal Outcomes: Evidence and Recommendations for Clinical Practice

Objectives

In some patients treated for urinary or fecal incontinence with sacral neuromodulation (SNM) persistence of symptoms, a reduction in efficacy or adverse effects of stimulation can occur. In such situations, further programming of the SNM device can help resolve problems. Infrequently hardware failure is detected. This article aims to provide practical guidance to solve sub‐optimal outcomes (troubleshooting) occurring in the course of SNM therapy.

Materials and Methods

A systematic literature review was performed. Collective clinical experience from an expert multidisciplinary group was used to form opinion where evidence was lacking.

Results

Circumstances in which reprogramming is required are described. Actions to undertake include changes of electrode configuration, stimulation amplitude, pulse frequency, and pulse width. Guidance in case of loss of efficacy and adverse effects of stimulation, developed by a group of European experts, is presented. In addition, various hardware failure scenarios and their management are described.

Conclusions

Reprogramming aims to further improve patient symptoms or ensure a comfortable delivery of the therapy. Initial changes of electrode configuration and adjustment of stimulation parameters can be performed at home to avoid unnecessary hospital visits. A logical and stepwise approach to reprogramming can improve the outcome of therapy and restore patient satisfaction.

Intermediate-term results of a prospective, multicenter study on remote programming sacral neuromodulation for refractory overactive bladder

Background

To evaluate the efficacy and safety of a novel remote programming sacral neuromodulation (SNM) system (BetterStim system) in the treatment of patients with refractory overactive bladder (OAB) for 3 years.

Methods

A total of 8 centers in China enrolled 84 patients with OAB. Following test stimulation 70 patients underwent implantation using BetterStim. All patients returned for follow-up at 3 and 6 months postoperatively. After that, the visits were conducted by telephone. Outcomes of voiding diaries, the overactive bladder symptom score (OABSS), questionnaires regarding OAB-related quality of life (OAB-qol), and adverse events (AEs) were evaluated at each visit. The clinical therapeutic success was defined as ≥50% improvement from baseline in any of the voiding diary variables or average voids/day return to normal voiding (<8 voids/day). The analysis is a modified Completers analysis.

Results

At the 36-month follow-up, the success rate was 79% for overall OAB symptoms, 69% for urge urinary incontinence (UUI) and 42% for urgency frequency (UF). The average number of voids/day decreased from 29.2±14.9 at baseline to 17.6±11.2 at 3 years, the average volume/void increased from 94.7±54.2 to 151.4±80.8 mL, the urgency reduced from 3.0±1.4 to 1.8±1.7 (all P<0.001). For patients with urge incontinence, mean leaking episodes/day decreased from 8.1±7.6 at baseline to 2.1±3.5 at three years (P<0.05). The devices were explanted in 8 (11.4%) patients. There were no remote programming-related AEs or device-related serious AEs that occurred.

Conclusions

The Intermediate-term results demonstrated that BetterStim SNM system with remote programming is safe and effective for patients with refractory OAB.

A prospective, multicenter, international study to explore the effect of three different amplitude settings in female subjects with urinary urge incontinence receiving interstim therapy

AIMS

The aim of this study is to evaluate the effect of sub-sensory amplitude settings of sacral neuromodulation therapy on overactive bladder symptoms in subjects with urinary urge incontinence.

METHODS

Subjects who qualified for a neurostimulator device implant were randomized to one of three amplitude settings (50% of sensory threshold [ST], 80% of ST, and ST). Subjects completed urinary voiding diaries (3-day), International consultation on incontinence modular questionnaire-overactive bladder symptoms quality of life questionnaire, and patient global impression of improvement (PGI-I) to assess change in voiding symptoms and quality of life (QoL) from baseline through 12 weeks.

RESULTS

Forty-eight subjects had a successful test stimulation, 46 were implanted with a neurostimulator device and 43 completed the 12-week follow-up visit. The change from baseline to 12 weeks is -3.0 urinary incontinence (UI) episodes/day (95% confidence interval [CI]: -4.4 to -1.7) for the 50% of sensory threshold group, -2.9 UI episodes/day (95% CI: -4.7 to -1.2) for 80% of sensory threshold group, and -3.6 UI episodes/day (95% CI: -5.2 to -1.9) for the sensory threshold group. In each randomized group, improvements were observed in health-related QoL, its subscales, and symptom interference. Subjects across all three randomization groups reported on the PGI-I that their bladder condition was better at 12 weeks compared to before they were treated with InterStim therapy.

CONCLUSION

These findings provide insights into possible advancements in the postimplantation phase of therapy with potential for improved patient comfort and increased device longevity.

Sacral neuromodulation: troubleshooting needle placement

INTRODUCTION AND HYPOTHESIS

The objective was to develop an instructional video that utilizes fluoroscopic images and anatomical landmarks to increase the surgeon's ability to troubleshoot optimal placement of the foramen needle and lead during a stage I sacral neuromodulation (SNM) procedure.

METHODS

Eight different examples of suboptimal foramen needle placement with subsequent corrections during a SNM procedure were performed and recorded on a fresh female cadaver.

RESULTS

Fluoroscopic images were obtained during the procedure, and illustrations of the posterior aspect of the sacrum highlighting the S3 foramina and nerve are shown for anatomical comparison.

CONCLUSIONS

This video demonstrates how to efficiently identify and correct suboptimal foramen needle placement in order to obtain optimal lead placement during an SNM procedure. Understanding the relationship between the bony landmarks on fluoroscopy and the S3 nerve and foramen are important in order to understand how to correct a suboptimal foramen needle and thus achieve optimal lead placement.

The role of pulse width manipulation compared to program changes alone for unsatisfactory sacral neuromodulation therapy: A retrospective matched-cohort analysis

AIM

Pulse width (PW) influences neuromodulation by its impact on nerve fiber recruitment. A paucity of data regarding the manipulation of PW in sacral neuromodulation (SNM) exists. This study describes the clinical features and outcomes of PW manipulation for unsatisfactory SNM therapy.

METHODS

A retrospective, single-institution review was performed of reprogrammed SNM patients between 2010 and 2019. Two cohorts were created: those with PW changes ± program changes and age-matched controls with program changes alone. Patients lacking follow-up and non-InterStim II models were excluded.

RESULTS

Out of 710 SNM interrogations, 147 (20.7%) had PW changes and 80 met inclusion criteria. Most PW changes were shortened (61/80, 76.3%). Clinical features did not differ between cohorts except by indication for reprogramming. The most common indication for PW change was painful stimulation (34/80, 43%), whereas in controls it was suboptimal efficacy (76/80, 95%). Clinical success was stratified by indication. There was a higher improvement in efficacy in the PW cohort (61%, 17/28 vs. 36%, 27/76, p = .02). PW manipulation successfully relieved painful stimulation in 50% (17/34 vs. 0/3, p = .23), which was more likely with a shortened compared to extended PW (14/15, 93.3% vs. 0/6, 0%, p < .01). PW resulted in improvement in localization of the stimulus in 94% (17/18 vs. 0/1, p = .10). The subsequent lead revision or explant was significantly higher in the PW cohort (43% vs. 25%, p = .03).

CONCLUSION

PW manipulation may aid the salvage of unsatisfactory SNM therapy. These findings represent an initial assessment of the role of PW in SNM, particularly regarding the efficacy and painful stimuli. The further prospective investigation is warranted.

Sacral neuromodulation: sacral anatomy and optimal lead placement

INTRODUCTION AND HYPOSTHESIS

To develop an instructional video that correlates cadaveric anatomy with fluoroscopic images to assist in conceptualization of optimal placement of the foramen needle and lead to complete an efficient and successful sacral neuromodulation (SNM) procedure.

METHODS

A SNM procedure was performed and recorded on a fresh female cadaver. Fluoroscopic images were obtained during the procedure to highlight the bony relationships to the S3 foramen and nerve. Dissection of the anterior and posterior sacrum was completed to highlight the tract of the S3 nerve. Techniques to increase the likelihood of optimal foramen needle and thus lead placement were highlighted.

CONCLUSIONS

This video demonstrates how achieving optimal foramen needle placement within the S3 foramen is key to optimal lead placement. Understanding the relationship of the bony landmarks on fluoroscopy to the S3 nerve and foramen, seen in the cadaveric dissections, are important in understanding how to achieve optimal lead placement. This optimization should lead to decreased operating room time, maximization of programming options, and decreased amplitude requirements.

Two-year safety and efficacy outcomes for the treatment of overactive bladder using a long-lived rechargeable sacral neuromodulation system

AIMS

Sacral neuromodulation (SNM) therapy for overactive bladder (OAB) has proven long-term safety and efficacy. Historically, the only commercially available SNM device was nonrechargeable requiring replacement surgery due to battery depletion. The Axonics System is the first rechargeable SNM device and is qualified to last a minimum of 15 years in the body. The study objective was to evaluate the safety and efficacy of this rechargeable SNM system. This study reports 2-year outcomes.

METHODS

A total of 51 subjects were implanted with the Axonics System in a single nonstaged procedure. Subjects had OAB, confirmed on a 3-day voiding diary (≥8 voids/day and/or ≥2 incontinence episodes over 72 hours). Test Responders were defined as subjects that were responders at 1 month postimplant. The efficacy analysis included therapy responder rates, change in the quality of life, and subject satisfaction reported in Test Responders (n = 30) and all implanted subjects (n = 37) that completed the follow-up visits. Adverse events (AEs) are reported in all implanted subjects.

RESULTS

At 2 years, 90% of the Test Responders continued to respond to the therapy based on voiding diary criteria. Satisfaction with therapy was reported by 93% of subjects and 86% found their charging experience acceptable. Of the urinary incontinence Test Responders, 88% continued to be responders at 2 years, and 28% were completely dry. There were no unanticipated (AEs) or serious device-related AEs.

CONCLUSIONS

The Axonics System® provides sustained clinically meaningful improvements in OAB subjects at 2 years. There were no serious device-related AEs. Subjects reported continued satisfaction with their therapy.

New Implantable Tibial Nerve Stimulation Devices: Review of Published Clinical Results in Comparison to Established Neuromodulation Devices

Purpose

The purpose of this review is to offer an update for medical providers practicing general urology and urogynecology in evolving and new promising technologies for neuromodulation in patients with OAB.

Patients and Methods

A focused literature search for the years 2015 through 2019 was conducted on PubMed/Medline for the terms: “new techniques” AND “neuromodulation” AND “tibial nerve stimulation” AND “overactive bladder”. We limited our search to publications in English, for the last five years and with patient follow-up of at least 3 months.

Results

Clinical success, safety based on adverse events, and quality of life improvement criteria were evaluated and compared to sacral nerve stimulation (SNS) devices and older, non-implantable percutaneous tibial nerve stimulation (PTNS) treatment devices. Considering the limited number of participants with up to 6 months follow-up data currently available, overall the clinical response rates suggest that the new implantable devices stimulating the tibial nerve have a promising clinical outlook, are less invasive upon implantation than SNS, less expensive, and less of a burden on patients compared to the older non-implantable PTNS devices.

Conclusion

Practicing urologists should be aware of this new treatment option when counseling their patients regarding treatment for OAB.

First-in-human implantation of a mid-field powered neurostimulator at the sacral nerve: Results from an acute study

INTRODUCTION

Commercially approved implantable systems for sacral neuromodulation require the implantation of a multipolar lead subcutaneously connected to an implantable pulse generator (IPG). Eliminating the need for an IPG would eliminate the need for tunneling of the lead, reduce procedure time, infection risk, and the need for IPG replacement. The objective was to demonstrate the feasibility of implanting the AHLeveeS System in the S3 Foramen to stimulate the S3 sacral nerve.

MATERIALS AND METHODS

A first-in-human, prospective, single center, nonrandomized, acute feasibility clinical investigation at the Maastricht University Medical Center+. Patients with refractory overactive bladder underwent acute implantation of the AHLeveeS neurostimulator before the InterStim procedure. Outcome measurements included motor responses, procedural time and a scoring of the difficulty of the implant and explant procedure. Retrospectively, qualitative responses to the stimulation protocol were assessed by video motion analyses. Only descriptive statistics were used.

RESULTS

During the stimulation a motor response to stimulation was seen in four of the five subjects. In all implantations the AHLeveeS was correctly placed. The median time for complete procedure was 24 minutes. The implant and explant procedures were successfully performed and no device or procedure related adverse events occurred.

CONCLUSIONS

The results from this acute first-in-human study demonstrate the feasibility of implantation and acute stimulation of the sacral nerve with this mid-field powered system. Future clinical studies will focus on safety and efficacy of a chronically implanted device.

Sacral neuromodulation for female pelvic floor disorders

Objective: To systematically review available studies on the effectiveness and safety of sacral neuromodulation (SNM) in women with various pelvic floor disorders not responding to more conservative treatment, as SNM is indicated in such women.

Methods: Data source: We did a systematic review through the PubMed and the Cochrane Library according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement from 1998 to 2018 in English using the keywords ‘Sacral Neuromodulation’ and ‘Sacral Nerve Stimulation’.

Study selection: Randomised controlled trials and prospective studies were selected, with a minimum sample size of 20 patients and ≥6 months of follow-up.

Results: We identified 19 articles. A ≥50% reduction in symptoms qualifies the patient for a permanent implant. Several advances have been introduced into SNM to decrease the invasiveness of the procedure, including a smaller implantable pulse generator battery (improved comfort) and better localisation of the lead wire (improved outcome). The literature reports success for overactive bladder (OAB) to range between 56% and 68% (up to 80%). We report a 5-year therapeutic success rate of 67%. In our previous studies, 38% of our patients with urge urinary incontinence achieved complete continence at 60-months follow-up, with a therapeutic response rate of 57%. Effectiveness in patients with urinary retention and faecal incontinence are about 70% and 85%, respectively. Effectiveness in interstitial cystitis/bladder pain syndrome appears to be lower compared with OAB.

Conclusion: SNM is a safe and effective therapy for women with various pelvic floor disorders.

Abbreviations: BONT: botulinum toxin; FDA: USA Food and Drug Administration; FS: Fowler’s syndrome; FI: faecal incontinence; IC/BPS: interstitial cystitis/bladder pain syndrome; ICIQ-OABqol: International Consultation on Incontinence Modular Questionnaire-Overactive Bladder Symptoms Quality of Life; INS: implantable neurostimulator; OAB: overactive bladder; PET: positron emission tomography; PNE: peripheral nerve evaluation; PRISMA: Preferred Reporting Items for Systematic Reviews and Meta-Analyses; PTNM: posterior tibial nerve modulation; PVR: post-void residual urine; QoL: quality of life; RCT: randomised controlled trial; SNM: sacral neuromodulation; (U)UI: (urgency) urinary incontinence

Remotely programmed sacral neuromodulation for the treatment of patients with refractory overactive bladder: a prospective randomized controlled trial evaluating the safety and efficacy of a novel sacral neuromodulation device

PURPOSE

The efficacy and safety of a novel remotely programmed BetterStim sacral neuromodulation (SNM) system was evaluated in patients with refractory overactive bladder (OAB) in a prospective, controlled, multicenter trial.

METHODS

A total of 84 patients referred for SNM therapy from October 2015 to January 2018 were studied. Of the patients who qualified for implantation, 37 and 33 were randomly assigned to treatment and control groups, respectively. Patients in the treatment group underwent stimulation upon implantation, while stimulation was delayed in the control group for 3 months. Follow-up visits, consisting of voiding diary outcome, questionnaires regarding overactive bladder symptom score (OABSS) and quality of life were conducted at 1, 3, and 6-month post-implantation.

RESULTS

Compared with the control group, subjects in the treatment group exhibited statistically significant improvement in OAB symptoms at 3 months. The overall success rate was achieved in 72% of the treatment group, compared with 12% of the control group at 3 months. At 6 months, there were no significant differences in key voiding diary variables between the two groups. Further, this study demonstrated sustained improvement in urinary symptom interference in OAB patients. In addition, nearly all patients expressed great satisfaction with the remote-programming methods. No serious adverse events occurred, and device-related adverse events rate was 12.86%.

CONCLUSION

This clinical study demonstrates subjective and objective success of the BetterStim SNM system. Importantly, our data suggest that remote programming can be safely used as a viable option for the conventional programming with a high degree of patient satisfaction.

Abdominal Versus Standard Placement of the Sacral Nerve Stimulator Implantable Pulse Generator

OBJECTIVES

To determine patient factors prompting anterior abdominal wall placement of the sacral nerve stimulator implantable pulse generator and investigate revision and infection rates for buttock (standard) and abdominal placement.

METHODS

We retrospectively reviewed records of consecutive sacral nerve stimulation procedures by a single surgeon from 2012 to 2017 at a single institution.

RESULTS

75 patients underwent sacral nerve stimulation--60 with standard and 15 with abdominally placed implantable pulse generators. The mean age and body mass index of the standard group was higher than that of the abdominal group and the majority was female. A greater proportion of patients in the abdominal group had a neurological diagnosis and was wheelchair-dependent. Overall, a total of 20 patients underwent 38 revision surgeries. The indications for revision surgery were pain, loss of efficacy, or lead migration. The standard group accounted for more revisions than the abdominal group (34vs 4 cases, P = .048), with no revisions due to pain in the abdominal group. The infection rate (2% vs 13%, P = .10), average time from implantation to revision, and operative duration were not statistically different between groups.

CONCLUSION

In a subset of patients who were wheelchair-dependent or lacked gluteal fat, placement of the implantable pulse generator in the anterior abdominal wall resulted in no revisions due to pain. Operative duration and infection rates were similar between abdominal and standard placement. Abdominal placement with extended length leads could be considered as a primary or revision option in these select patients.

Cost–effectiveness of overactive bladder treatments: from the US payer perspective

Aim: To assess the cost–effectiveness of onabotulinumtoxinA (onabotA), implantable sacral nerve stimulation devices, percutaneous tibial nerve stimulation, anticholinergic medications and mirabegron compared with best supportive care (BSC) for management of refractory overactive bladder (OAB). Methods: A Markov model was developed to compare the cost–effectiveness of treatment options with BSC over a 10-year time horizon. Resource utilization, discontinuation rates and costs were derived from unpublished and published sources. Quality-adjusted life-years (QALYs) and incremental cost–effectiveness ratios were reported. Results: Treatment with onabotA 100U produced the largest gain in QALYs (7.179) and lowest estimated incremental cost–effectiveness ratio ($32,680/QALY) of all assessed treatments compared with BSC. Conclusion: Compared with BSC, onabotA 100U was the most cost-effective treatment option for patients with refractory OAB.

Outcomes of treatment of faecal incontinence with sacral nerve stimulation - a Finnish multicentre study

AIM

The aim of this multicentre study is to report the results of sacral nerve stimulation (SNS) treatment for faecal incontinence (FI) in Finland and determine factors that could influence SNS treatment outcomes.

METHOD

This is a national multicentre study, involving all patients tested for SNS implantation in Finland from 1999 to 2017. Data were collected retrospectively from electronic patient archives and analysed for possible effects on treatment outcome.

RESULTS

Of the 432 patients with FI tested for SNS, 365 were women. Three hundred and thirteen (72.5%) of the tested patients advanced to permanent implantation of a stimulator. A successful final treatment outcome, with subjective alleviation of FI, was reported by 59.3% of the patients at the end of follow-up (mean 2.4 years, range 8 days to 13.3 years). Patients with obstetric sphincter injury and idiopathic FI had more permanent stimulator implantations than patients with iatrogenic injury (P = 0.012). Male patients had significantly worse test phase outcomes than female patients (P < 0.001). Age did not influence treatment outcome (P = 0.446) CONCLUSION: Subjective final success of SNS treatment for FI was achieved in 59.3% of patients at a mean of 2.4 years. Gender and the aetiology of FI influenced the test phase and final treatment outcome of SNS treatment.

Risk factors for explantation due to infection after sacral neuromodulation: a multicenter retrospective case-control study

BACKGROUND

Sacral neuromodulation is an effective therapy for overactive bladder, urinary retention, and fecal incontinence. Infection after sacral neurostimulation is costly and burdensome. Determining optimal perioperative management strategies to reduce the risk of infection is important to reduce this burden.

OBJECTIVE

We sought to identify risk factors associated with sacral neurostimulator infection requiring explantation, to estimate the incidence of infection requiring explantation, and identify associated microbial pathogens.

STUDY DESIGN

This is a multicenter retrospective case-control study of sacral neuromodulation procedures completed from Jan. 1, 2004, through Dec. 31, 2014. We identified all sacral neuromodulation implantable pulse generator implants as well as explants due to infection at 8 participating institutions. Cases were patients who required implantable pulse generator explantation for infection during the review period. Cases were included if age ≥18 years old, follow-up data were available ≥30 days after implantable pulse generator implant, and the implant was performed at the institution performing the explant. Two controls were matched to each case. These controls were the patients who had an implantable pulse generator implanted by the same surgeon immediately preceding and immediately following the identified case who met inclusion criteria. Controls were included if age ≥18 years old, no infection after implantable pulse generator implant, follow-up data were available ≥180 days after implant, and no explant for any reason <180 days from implant. Controls may have had an explant for reasons other than infection at >180 days after implant. Fisher exact test (for categorical variables) and Student t test (for continuous variables) were used to test the strength of the association between infection and patient and surgery characteristics. Significant variables were then considered in a multivariable logistic regression model to determine risk factors independently associated with infection.

RESULTS

Over a 10-year period at 8 academic institutions, 1930 sacral neuromodulator implants were performed by 17 surgeons. In all, 38 cases requiring device explant for infection and 72 corresponding controls were identified. The incidence of infection requiring explant was 1.97%. Hematoma formation (13% cases, 0% controls; P = .004) and pocket depth of ≥3 cm (21% cases, 0% controls; P = .031) were independently associated with an increased risk of infection requiring explant. On multivariable regression analysis controlling for significant variables, both hematoma formation (P = .006) and pocket depth ≥3 cm (P = .020, odds ratio 3.26; 95% confidence interval, 1.20-8.89) remained significantly associated with infection requiring explant. Of the 38 cases requiring explant, 32 had cultures collected and 24 had positive cultures. All 5 cases with a hematoma had a positive culture (100%). Of the 4 cases with a pocket depth ≥3 cm, 2 had positive cultures, 1 had negative cultures, and 1 had a missing culture result. The most common organism identified was methicillin-resistant Staphylococcus aureus (38%).

CONCLUSION

Infection after sacral neuromodulation requiring device explant is low. The most common infectious pathogen identified was methicillin-resistant S aureus. Demographic and health characteristics did not predict risk of explant due to infection, however, having a postoperative hematoma or a deep pocket ≥3 cm significantly increased the risk of explant due to infection. These findings highlight the importance of meticulous hemostasis as well as ensuring the pocket depth is <3 cm at the time of device implant.

Efficacy and satisfaction with transcutaneous electrostimulation of the posterior tibial nerve in overactive bladder syndrome

Objective:

Overactive bladder is a disease with a high prevalence. The management is difficult, because different demographic, social or economic aspects converge. Our objective was to evaluate the efficacy and satisfaction in patients with overactive bladder treated with transcutaneous electrostimulation of the posterior tibial nerve.

Methods:

This was a prospective and descriptive study of 45 patients with overactive bladder (with or without detrusor overactivity) resistant to pharmacological treatment. Patients received a weekly session for 12 weeks, with a duration of 30 minutes for each of the sessions. There was a screening after 12 sessions, after which if there had been no response, treatment was suspended and maintenance sessions were not continued (six twice-monthly sessions and three monthly sessions). It was considered that the treatment had been effective when it was possible to decrease the number of events, except the maximum voiding volume, the objective of which was to increase. The results were evaluated using a 3-day voiding diary, an overactive bladder short form questionnaire and a satisfaction level questionnaire. Statistical analysis was performed using IBM SPSS Statistics version 19.0. Independent variables with a normal distribution were examined using the t-test. The Wilcoxon signed-rank test was used to compare the averages of the quantitative variables without a normal distribution. Satisfaction was analysed by a binary and ordinal regression analysis, univariate and multivariate. A P value less than 0.05 was considered statistically significant.

Results:

All the parameters of the study improved to a statistically relevant degree: frequency, nocturia, urgency, maximum voided volume, urge urinary incontinence. The overactive bladder short form questionnaire score improved but was not statistically significant.

Conclusions:

The use of transcutaneous electrostimulation of the posterior tibial nerve is a safe, effective and minimally invasive alternative in the treatment of overactive bladder when pharmacological treatment has failed. Patients had a good objective and subjective response in our study.

Level of evidence:

4.

International Continence Society best practice statement for use of sacral neuromodulation

AIMS

Sacral neuromodulation (SNM) is an accepted therapy for a variety of conditions. However, despite over 20 years of experience, it remains a specialized procedure with a number of subtleties. Here we present the recommendations issued from the International Continence Society (ICS) SNM Consensus Panel.

METHODS

Under the auspices of the ICS, eight urologists, three colorectal surgeons and two urogynecologists, covering a wide breadth of geographic and specialty interest representation, met in January 2017 to discuss best practices for neuromodulation. Suggestions for statements were submitted in advance and specific topics were assigned to committee members, who prepared and presented supporting data to the group, at which time each topic was discussed in depth. Best practice statements were formulated based on available data. This document was then circulated to multiple external reviewers after which final edits were made and approved by the group.

RESULTS

The present recommendations, based on the most relevant data available in the literature, as well as expert opinion, address a variety of specific and at times problematic issues associated with SNM. These include the use of SNM for a variety of underlying conditions, need for pre-procedural testing, use of staged versus single-stage procedures, screening for success during the trial phase, ideal anesthesia, device implantation, post-procedural management, trouble-shooting loss of device function, and future directions for research.

CONCLUSIONS

These guidelines undoubtedly constitute a reference document, which will help urologists, gynecologists, and colorectal surgeons optimize their use of SNM for refractory urinary urgency and frequency, UUI, NOR, and FI.

Baseline symptom severity and therapeutic success in a large prospective trial of sacral neuromodulation therapy for overactive bladder patients

INTRODUCTION

The InSite trial is a prospective, multicenter post-approval study of subjects receiving sacral neuromodulation (SNM) therapy with the InterStim^® System. Enrolled subjects had bothersome symptoms of overactive bladder (OAB). The purpose of this analysis was to determine if severity of baseline symptoms had an impact on clinical outcomes.

METHODS

For device implant, therapeutic success was defined as a  ≥50% improvement in average leaks/day, or in voids/day or a return to normal voiding frequency. Groups were dichotomized into less versus more severe based on median number of leaks and voids. Subjects were grouped as less severe <2 leaks/day for UI; <11 voids/day for UF and more severe ≥2 leaks/day for UI;  ≥11 voids/day for UF. Therapeutic success at 12 and 24 months were compared between groups.

RESULTS

Three hundred and forty subjects completed test stimulation and 272 (80%) subjects received a full system implant. On average UI subjects had 1.3 leaks/day in the less severe group and 4.5 leaks/day in the more severe group. UI success rates were not statistically different between severity groups at 12 months or 24 months). At baseline, on average UF subjects had 9.4 voids/day for the less severe group and 15.1 voids/day for the more severe group. UF success rates were not statistically different between severity groups at 12 months or 24 months.

CONCLUSION

Data evaluating efficacy based on symptom severity demonstrates that SNM is effective in treating both less severe and more severely affected groups for both UI and UF at 12 and 24 months.

A novel leadless, miniature implantable Tibial Nerve Neuromodulation System for the management of overactive bladder complaints

BACKGROUND

Overactive bladder is a chronic condition affecting lower urinary tract function that has a significant negative impact on QoL.

OBJECTIVE

Evaluation of the BlueWind implantable tibial nerve system performance and safety in refractory OAB.

DESIGN, SETTING, AND PARTICIPANTS INTERVENTION

A 6-month multi-center prospective intervention study.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Objective assessment was done by voiding diary parameters including voids/day, volume voided/day, urgency assessment, leaking episodes/day, pads used/day, leak severity, and clinical success defined as a ≥50% reduction in the number of leaks/day or number of voids/day or number of episodes with degree of urgency >2 or a return to <8 voids/day on a 3 Day diary. Subjective assessment was based on OAB-q including HRQL and symptom severity score. Safety was evaluated by adverse event (AE) analysis.

RESULTS AND LIMITATIONS

Thirty-four of the 36 implanted subjects completed the study. One subject withdrew voluntarily and one developed inflammation necessitating removal of the system. In the remaining subjects, 71% experienced clinical success at 6 months. Leaks/day, leak severity, and pad changes/day decreased significantly over time with 27.6% of urge incontinence subjects that became "dry." Voids/day, degree of urgency, volume/void, pads changed improved significantly. All quality of life aspects (concern, coping, sleep, and social) improved as well as symptom severity scores measured by the OAB-q. Adverse events included: implant site pain (13.9%), suspected infection (22.2%), and procedural wound complications (8.3%).

CONCLUSIONS

The BlueWind implantable tibial nerve stimulator is a safe, minimally invasive system that affords OAB patients significant improvements.

PATIENT SUMMARY

The performance and safety of the BlueWind RENOVA™ implantable tibial nerve neuromodulator for OAB was tested. Our preliminary results demonstrate that the system has a low risk safety profile and may be considered an effective treatment option for OAB management.

Five-Year Followup Results of a Prospective, Multicenter Study of Patients with Overactive Bladder Treated with Sacral Neuromodulation

PURPOSE

We evaluated the therapeutic success rate, changes in quality of life and safety of sacral neuromodulation 5 years after InterStim™ implantation. Included in study were subjects with bothersome symptoms of overactive bladder, including urinary urge incontinence and/or urgency-frequency, in whom at least 1 anticholinergic medication failed and 1 medication had not been tried.

MATERIALS AND METHODS

Therapeutic success was defined as a urinary urge incontinence or urgency-frequency response of 50% or greater improvement in average leaks or voids per day, or return to normal voiding, defined as fewer than 8 voids per day. Quality of life was evaluated by ICIQ-OABqol (International Consultation on Incontinence Modular Questionnaire). Safety was evaluated through adverse events.

RESULTS

Of the 340 subjects who completed the test stimulation 272 had an implant, of whom 91% were female. Mean age was 57 years. At baseline 202 subjects with urinary urge incontinence had a mean ± SD of 3.1 ± 2.7 leaks per day and 189 with urgency-frequency had a mean of 12.6 ± 4.5 voids per day. The 5-year therapeutic success rate was 67% (95% CI 60-74) using modified completers analysis and 82% (95% CI 76-88) using completers analysis. Subjects with urinary urge incontinence had a mean reduction from baseline of 2.0 ± 2.2 leaks per day and subjects with urgency-frequency had a mean reduction of 5.4 ± 4.3 voids per day (each completers analysis p <0.0001). Subjects showed improvement in all ICIQ-OABqol measures (p <0.0001). The most common device related adverse events were an undesirable change in stimulation in 60 of the 272 subjects (22%), implant site pain in 40 (15%) and therapeutic product ineffectiveness in 36 (13%).

CONCLUSIONS

This multicenter study shows that sacral neuromodulation had sustained efficacy and quality of life improvements, and an acceptable safety profile through 5 years in subjects with overactive bladder.