Latest Technologic and Surgical Developments in Using InterStim™ Therapy for Sacral Neuromodulation: Impact on Treatment Success and Safety

Pathways and parameters of sacral neuromodulation in rats

The stimulation paradigm for sacral neuromodulation has remained largely unchanged since its inception. We sought to determine, in rats, whether stimulation-induced increases in bladder capacity correlated with the proportion of sensory pudendal (PudS) neurons at each stimulated location (L6, S1). If supported, this finding could guide the choice of stimulation side (left/right) and level (S2, S3, S4) in humans. Unexpectedly, we observed that acute stimulation at clinically relevant (low) amplitudes [1-1.5 × motor threshold (Tm)], did not increase bladder capacity, regardless of stimulus location (L6 or S1). More importantly for the ability to test our hypothesis, there was little anatomic variation, and S1 infrequently contributed nerve fibers to the PudS nerve. During mapping studies we noticed that large increases in PudS nerve activation occurred at amplitudes exceeding 2Tm. Thus, additional cystometric studies were conducted, this time with stimulation of the L6-S1 trunk, to examine further the relationship between stimulation amplitude and cystometric parameters. Stimulation at 1Tm to 6Tm evoked increases in bladder capacity and decreases in voiding efficiency that mirrored those produced by PudS nerve stimulation. Many animal studies involving electrical stimulation of nerves of the lower urinary tract use stimulation amplitudes that exceed those used clinically (∼1Tm). Our results confirm that high amplitudes generate immediate changes in cystometric parameters; however, the relationship to low-amplitude chronic stimulation in humans remains unclear. Additional studies are needed to understand changes that occur with chronic stimulation, how these changes relate to therapeutic outcomes, and the contribution of specific nerve fibers to these changes.NEW & NOTEWORTHY Acute low-amplitude electrical stimulation of sacral nerve (sacral neuromodulation) did not increase bladder capacity in anesthetized CD, obese-prone, or obese-resistant rats. Increasing stimulation amplitude correlated with increases in bladder capacity and pudendal sensory nerve recruitment. It is unclear how the high-amplitude acute stimulation that is commonly used in animal experiments to generate immediate effects compares mechanistically to the chronic low-amplitude stimulation used clinically.

Retrospective study of sacral neuromodulator implantations in a French hospital center: Lifespan and hospital costs assessment

PURPOSE

Sacral nerve neuromodulation (SNM) is a safe and effective therapy for the management of fecal and/or urinary incontinence. The generators InterStim™ and InterStim™ II (Medtronic™) are non-rechargeable active implantable medical devices with a limited lifespan. The aims of this study were to assess the generators' median lifespan for all indications and the long-term hospital costs of the therapy.

METHODS

This was a retrospective monocentric study that included 215 patients aged over 18 years who were treated by SNM for fecal incontinence and/or urinary incontinence. Lifespan was considered as the amount of time between definitive implantation and observed battery depletion by the surgeon and was assessed by the Kaplan-Meier method. Costs were assessed according to the activity-based pricing of the French public health care system.

RESULTS

The median observed lifetime of stimulators implanted in our center was 7.29 years and 5.9 years for InterStim™ and InterStim™ II, respectively. The difference observed between the two generations was statistically significant. The modelling of primary implantation and renewal costs allowed us to observe that the decrease in the lifetime of Interstim™ II is associated with an increase in hospital costs over time. The retrospective study design is one limitation and we did not take into consideration stimulation's settings.

CONCLUSIONS

The InterStim™ II lifespan is shorter than the first-generation device. This is associated with an increase of the long-term hospital costs. Additional information about the new neuromodulator will be required to choose the most appropriate IPG for the patient while optimizing the costs.

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.

Long-term cost-effectiveness analysis of sacral neuromodulation in the treatment of severe faecal incontinence

AIM

The aim of this study was to evaluate the long-term cost-effectiveness of sacral neuromodulation in the treatment of severe faecal incontinence as compared with symptomatic management.

METHODS

In the public health field, a micro-costing evaluation method was conducted from the perspectives of the health system and the society. The incremental cost-effectiveness ratio was used as a decision index, and we considered various scenarios to evaluate the impact of the cost of symptomatic management and percutaneous nerve evaluation success rate in its calculation. Clinical data were retrieved from a consecutive cohort of 93 patients with severe faecal incontinence undergoing sacral neuromodulation after a failure of conservative (pharmacological and biofeedback) and/or surgical (sphincteroplasty) first-line treatments were considered.

RESULTS

The long-term incremental cost-effectiveness ratio comparing sacral neuromodulation versus symptomatic management was 14347€/QALY and 28523€/QALY from the societal and health service provider's perspectives, respectively. If the definitive pulse generator implant success rate was 100%, incremental cost-effectiveness would correspond to 6831€/QALY and 16761€/QALY, respectively.

CONCLUSIONS

Sacral neuromodulation may be considered a cost-effective technique in the long-term treatment of severe faecal incontinence from the societal and health care sector perspectives. Improving patient selection and determining the predictive outcome factors for successful sacral neuromodulation in the treatment of faecal incontinence would improve cost-effectiveness.

Longitudinal urinary microbiome characteristics in women with urgency urinary incontinence undergoing sacral neuromodulation

INTRODUCTION AND HYPOTHESIS

The objective was to evaluate the stability of the urinary microbiome communities in women undergoing sacral neuromodulation (SNM) for urgency urinary incontinence (UUI). We hypothesized that clinical response to SNM therapy would be associated with changes in the urinary microbiome.

METHODS

Women completed the Overactive Bladder Questionnaire Short-Form, the International Consultation on Incontinence Questionnaire Short Form, and the Female Sexual Function Index at baseline and 3 months post-SNM implantation. Transurethral urinary specimens were obtained for microbiome analysis at baseline and 3 months postoperatively. The V4 region of the 16S rRNA gene (515F-806R) was amplified with region-specific primers, and Amplicon Sequence Variants (ASVs) were identified with a closed-reference approach of taxonomic classification. Alpha-diversity was calculated using the phylogenetic (i.e., Faith's phylogenetic diversity) and nonphylogenetic metrics (i.e., Shannon diversity, and Pielou's evenness) using the QIIME2 plugin. Longitudinal paired volatility analysis was performed using the DEICODE and Gemelli plugin to account for host specificity across both time and space.

RESULTS

Nineteen women who underwent SNM and provided both baseline and 3-month urine samples were included in this analysis. Women reported improvement in objective (number of UUI episodes) and subjective (symptom severity and health-related quality of life) measures. Ninety percent of the bacteria were classified as Bacteroidetes, Firmicutes, Proteobacteria, and Actinobacteria. No significant differences were observed in each subject's beta-diversity at 3 months compared with their baseline microbiome.

CONCLUSIONS

Our descriptive pilot study of a cohort of women who had achieved objective and subjective improvements in UUI following SNM therapy demonstrates that the urinary microbiome remains relatively stable, despite variability amongst the cohort.

Sacral Neuromodulation for Neurogenic Lower Urinary Tract Dysfunction

BACKGROUND: Neurogenic lower urinary tract dysfunction (NLUTD) is a highly prevalent and disabling condition; nevertheless, standard treatments often remain unsatisfactory. Sacral neuromodulation (SNM) is a well-established therapy for non-NLUTD, but there is a lack of randomized controlled trials to show benefit in patients with NLUTD. METHODS: For this sham-controlled, double-blind, multicenter trial, patients with refractory NLUTD (and intended SNM) were recruited at four Swiss SNM referral centers. After lead placement into the sacral foramina S3 (rarely, S4), all participants underwent SNM testing. If successful (≥50% improvement in key bladder diary variables), the neurostimulator was implanted for permanent stimulation. For 2 months, neuromodulation was optimized using subsensory stimulation with individually adjusted parameters. Thereafter, the neurostimulator remained on or was switched off (1:1 random allocation to group SNM ON or SNM OFF, respectively) for 2 months, followed by a neurourologic reevaluation. The primary outcome was success, as defined above, of SNM compared with baseline. RESULTS: Of 124 patients undergoing SNM testing, 65 (52%) had successfully improved lower urinary tract function. Of these, 60 patients (median age, 49.5 years; 43 women) were randomly assigned to the intervention. After 2 months of intervention, the SNM ON group demonstrated a success rate of 76%. In the SNM OFF group, 42% of patients showed sustained SNM effects despite their neurostimulator being switched off during the last 2 months (odds ratio, 4.35; 95% confidence interval, 1.43 to 13.21; P=0.009). During the entire study period, there were 11 adverse events (6 dropouts; no dropouts during the intervention phase). CONCLUSIONS: SNM effectively corrected refractory NLUTD in the short term in well-selected neurologic patients. (Funded by the Swiss National Science Foundation, Vontobel–Stiftung, Gottfried und Julia Bangerter–Rhyner Stiftung, Dr. Urs Mühlebach, and the Swiss Continence Foundation; ClinicalTrials.gov number, NCT02165774.)

Neuromodulation for Management of Chronic Pelvic Pain: A Comprehensive Review

INTRODUCTION

Chronic pelvic pain (CPP) is a symptom that derives from a complex group of heterogeneous pathologies of the pelvic organs. The aim of this study was to review the available evidence on efficacy of neuromodulatory modalities including sacral neuromodulation, dorsal root ganglion stimulation, dorsal column neuromodulation, and pudendal nerve stimulation.

METHODS

This narrative review focuses on updated information on neuromodulation for management of chronic pelvic pain. In 2022, we searched English-language studies on neuromodulation, pelvic pain, and chronic pain in a comprehensive search. We searched the following databases: PubMed, Medline, SciHub, Cochrane Database of Systematic Reviews, and Google Scholar. We used the following combinations of keywords: neuromodulation, pelvic pain, chronic pain, chronic pelvic pain, pelvic pain treatment. We tried to include as many recent manuscripts as possible (within the last 3 years) but also included papers older than 3 years if they were particularly relevant to our topic. We also attempted to search for, use, and cite primary manuscripts whenever possible.

RESULTS

CPP is a challenging entity to treat because of diagnostic inconsistencies and limited evidence for therapeutic modalities. Our review found evidence suggestive of benefit for all modalities reviewed but the data was of overall low quality with numerous limitations. The literature highlights a lack of randomized controlled trials for neuromodulatory therapies but suggests a growing role for such techniques in treating refractory chronic pelvic pain syndrome (CPPS).

CONCLUSIONS

This review explores the available evidence on efficacy of neuromodulatory modalities for CPPS and contextualizes the results with information about the type of neuromodulation, lead location and waveform, pain outcomes and assessment timepoints, and reported adverse effects.

Statewide Success of Staged Sacral Neuromodulation for the Treatment of Urinary Complaints in California (2005-2011)

PURPOSE

Sacral neuromodulation (SNS) is approved by the Food and Drug Administration as a third-line treatment for refractory overactive bladder, idiopathic urinary retention, and fecal incontinence. Prior to implantation of an implantable pulse generator, all patients undergo a trial phase to ensure symptom improvement. The published success rates of progression from the test phase to permanent implant vary widely (range, 24% to >90%). We sought to characterize success rates using a statewide registry.

METHODS

Using nonpublic data, we identified SNS procedures using the California Office of Statewide Planning and Development ambulatory surgery database from 2005 to 2011. A successful trial was defined as receiving a stage 2 generator implantation after trial lead placement. Multivariable logistic regression was performed to identify factors associated with staged success.

RESULTS

During the study period, 1396 patients underwent a staged SNS procedure, with 962 (69%) subsequently undergoing generator placement. Successful trial rates were 72% for overactive bladder wet, 69% for urgency/frequency, 68% for interstitial cystitis, 67% for neurogenic bladder, and 57% for urinary retention. On multivariate logistic regression, only male sex (odds ratio, 0.51) and urinary retention [odds ratio, 0.54) were significantly associated with lower odds of success, whereas age, race/ethnicity, medical insurance, and placement at an academic or high-volume institution had no association.

CONCLUSIONS

The "real world" success rates for staged SNS implantation in California are less than those observed by some academic centers of excellence but better than previously reported for Medicare beneficiaries. Successful trial rates for interstitial cystitis and neurogenic voiding dysfunction are similar to refractory overactive bladder.

Neuromodulation

Sacral neuromodulation (SNM) has been available in the United States for more than 20 years and is a guideline-recommended therapy by both the American Urological Association and the American Society of Colon and Rectal Surgeons, with proven long-term success for urinary urgency incontinence, urinary urgency frequency, nonobstructive urinary retention, and fecal incontinence. Initially the therapy involved a more invasive surgical approach that included a large cut down over the sacrum. This article reviews recent advancements in SNM therapy including updates in best practices for implant technique, technological innovations, and the new clinical literature relevant to contemporary practice.

[Sacral neuromodulation as treatment of non-neurological vesical emptying disorders]

GOAL

The goal was to evaluate the results of sacral neuromodulation (SNM) in non-neurological vesical emptying disorders.

PATIENTS AND METHODS

From February 2010 to October 2017, 28 patients presenting voiding symptoms or a non-obstructive chronic urine retention without neurological cause have been operated for an SNM (test phase). The test was positive in case of decreased number of proper intermittent self-catheterization (SC) or post-voiding residual urine (PVR) of at least 50 %. A 100 % positive result meant the return to a spontaneous voiding without SC with a non-significative PVR (<100ml).

RESULTS

The median follow-up was of 53.2±21.2 months. Twenty-four (85.7%) tests were positive, from which twenty-two (78.6%) were 100% positive. 16 (84.2%) out of 19 patients with SC had spontaneous voiding without PVR. The number of daily SC decreased from 4.6±1.5 to 0.4±1.2 in post-operative (P<0.001). The PVR was of 287.1±170.4ml vs. 30.4±48.6ml in post-operative (P<0.001). Fourteen patients (58.3%) underwent at least one chirurgical revision or a removal of material ; mainly for loss of efficiency, end of battery, electrode migration and pain on material. At the end of the follow-up, 70.8% of the responding patients had their device still efficient.

CONCLUSION

Results showed that SNM appears to be an efficient treatment of non-neurological emptying vesical troubles. Nevertheless, the re-operation rate was still significant.

LEVEL OF EVIDENCE

3.

Axonics® system for treatment of overactive bladder syndrome and urinary urgency incontinence

Introduction: Overactive bladder and urge urinary incontinence affect millions of women and men and results in billions of dollars in health-care expenses. First- and second-line therapy includes behavioral modifications and/or pharmacotherapies however, many patients' symptoms remain or progress on these treatments. There has been concern regarding the detrimental side effects of the most widely prescribed medications for these bladder symptom management.Areas covered: As a result, there has been increased interest in continuous sacral neuromodulation, an FDA approved therapy for refractory urinary urgency and urge urinary incontinence. In this article, we specifically review current research on the efficacy and patient/provider satisfaction and safety profile of the Axonics® System. In addition, we address the current state of sacral neuromodulation and potential future direction and applicability.Expert opinion: The Axonics® system is a safe effective device for the treatment of overactive bladder and urinary urge incontinence. Additionally, it affords patient's the convenience of a rechargeable, compact, MRI safe system. It should be noted that the rechargeable system, while allowing for approximately 15 years of battery and lead life, may have its challenges in terms of charge burden. Furthermore, this system is easily adapted for experienced implanters of sacral neuromodulating devices.

Sacral Neuromodulation in Patients With Neurogenic Lower Urinary Tract Dysfunction: A Multicenter Retrospective Study From China

OBJECTIVES

This retrospective study aimed to determine the effectiveness of sacral neuromodulation (SNM) on neurogenic lower urinary tract dysfunction (NLUTD) and analyze the predictive factors.

MATERIALS AND METHODS

From January 2012 to January 2020, 152 subjects with NLUTD from four medical centers in China received SNM test stimulation. Subjects were assessed via bladder diaries, postvoid residual volumes (PRVs) and neurogenic bowel dysfunction (NBD) scores before and during the testing period. Patients who showed a minimum 50% improvement in symptoms through the SNM test phase were eligible for permanent SNM implantation.

RESULTS

The pooled success rate for chronic urinary retention was 31.0% (40/129), which was significantly lower (p < 0.05) than the rates for frequency-urgency (64.8%, 59/91), urinary incontinence (65.2%, 30/46), and NBD score (61.7%, 82/133). The results of the risk factor analysis showed that the urinary storage symptom was a statistically significant positive predictor (p = 0.001).

CONCLUSIONS

In conclusion, SNM is an effective and reliable method for treating NLUTD, especially in patients with urinary storage symptoms. Although not all of the symptoms in every patient can be resolve, SNM still might be a superior choice together with other treatment procedures.

Application of ultrasound during electrode implantation for sacral neuromodulation in patients with neurogenic bladder secondary to spinal cord disease: a retrospective study

PURPOSE

To compare the use of intraoperative ultrasound with X-ray fluoroscopy during sacral neuromodulation lead electrode placement in patients with neurogenic bladder secondary to spinal cord disease.

METHODS

We reviewed the medical records of 52 patients who underwent sacral neuromodulation (SNM) lead electrode implantation under fluoroscopy or ultrasound guidance from July 2016 to July 2019. The operating time, number of electrode contacts with stimulus responses, minimum voltage that causes a stimulus response, and rate of standard lead electrode placement were used to assess the differences between the two methods. All patients were evaluated by recording bladder diaries, postvoid residual volumes before and during the testing period. Permanent SNM implantation is acceptable if symptoms improve by at least 50%.

RESULTS

The operating time decreased from 87.1 ± 25.19 min in the X-ray group to 68.2 ± 25.20 min (p < 0.05) in the ultrasound group. The number of electrode contacts with stimulus responses, rate of standard lead electrode placement, and implantable pulse generator (IPG) placement rate were not significantly different between the two groups (p > 0.05). There was no radiation exposure during the operation in the ultrasound group. No incisional infections, hematomas, or other critical complications were reported in either groups.

CONCLUSION

Ultrasound can be applied to safely place lead electrode for sacral neuromodulation and leads to no radiation exposure to the patient, surgeon, and operating room staff and a shortened operating time while maintaining the same efficacy as X-ray.

The Effect of Sacral Neuromodulation in Ambulatory Spina Bifida Patients with Neurogenic Bladder and Bowel Dysfunction

OBJECTIVE

To assess the effect of sacral neuromodulation (SNM) in ambulatory spina bifida patients with neurogenic bladder and bowel dysfunction.

MATERIALS AND METHODS

We retrospectively reviewed the records of 29 ambulatory spina bifida patients with neurogenic bladder and bowel dysfunction who underwent SNM testing from July 2012 to January 2020. Clinical data and video-urodynamic parameters were collected and compared using the t-test and the chi-square test. The potential risk factors were considered by logistic regression analysis. P < .05 was considered significant.

RESULTS

In the test phase, 21 patients (72.4%) achieved successful improvement of at least 1 symptom. The success rate for chronic urinary retention (26.09%) was significantly lower (P <.05) than that for urgency-frequency syndrome (58.82%) and urinary incontinence (56.25%). The mean neurogenic bowel dysfunction score decreased from 13.3±6.29 to 6.9±5.09 (P <.0001). The urodynamic evaluation showed a significant improvement in the mean maximum cystometric capacity, compliance, and maximum detrusor pressure (P <.05). Implantation was performed in 16 cases (55.17%). The analysis of the risk factors showed that chronic urinary retention was a statistically significant variable (P <.05). No complications were reported in the test phase. The average follow-up time was 41.19±33.06 months. Two patients changed to intermittent catheterization, and 2 patients changed to augmentation cystoplasty.

CONCLUSION

SNM is effective for neurogenic bladder and bowel dysfunction in patients with ambulatory spina bifida, especially in those without chronic urinary retention. And SNM can also significantly improve the urodynamic parameters of these patients during the storage period.

Effect of sacral neuromodulation on bowel dysfunction in patients with neurogenic bladder

AIM

The aim of this retrospective study was to evaluate the clinical effect of sacral neuromodulation (SNM) on bowel dysfunction in patients with neurogenic bladder using the neurogenic bowel dysfunction (NBD) score.

METHOD

Between July 2012 and July 2019, 41 patients with both neurogenic bladder and bowel dysfunction underwent permanent SNM implantation. The NBD score was used to evaluate the bowel symptoms before the testing phase and at follow-up. The first follow-up was at the time of discharge after permanent implantation. The second follow-up was conducted by telephone after discharge.

RESULTS

The mean NBD score before the testing phase was 11.0 ± 5.83, whilst it significantly decreased to 5.2 ± 5.32 (n = 41, P < 0.05) at the first follow-up (32 ± 3.9 days). Before the testing phase, there were 9 patients with very minor NBD, 10 with minor NBD, 13 with moderate NBD and 9 with severe NBD. At the first follow-up, there were 26 patients with very minor NBD, 7 with minor NBD, 4 with moderate NBD and 4 with severe NBD (P < 0.05). Twenty-six patients were interviewed in the long-term follow-up (34 ± 30.9 months). The NBD score in these 26 patients was 5.6 ± 5.18, which was not significantly different from the NBD score (5.5 ± 5.33) at the first follow-up (n = 26, P > 0.05).

CONCLUSION

SNM facilitates a significant reduction in NBD score in patients with neurogenic bladder and bowel dysfunction. The improvement in NBD symptoms can also be used as a future indicator to determine the clinical efficacy of permanent SNM implantation in the treatment of neurogenic bladder.

Early sacral neuromodulation ameliorates urinary bladder function and structure in complete spinal cord injury minipigs

Aims

To determine the effects of early sacral neuromodulation (SNM) and pudendal neuromodulation (PNM) on lower urinary tract (LUT) function, minipigs with complete spinal cord injury (cSCI) were analyzed. SNM and PNM have been proposed as therapeutic approaches to improve bladder function, for example after cSCI. However, further evidence on efficacy is required before these methods can become clinical practice.

Methods

Eleven adults, female Göttingen minipigs with cSCI at vertebral level T11‐T12 were included: SNM (n = 4), PNM (n = 4), and SCI control (SCIC: n = 3). Tissue from six healthy minipigs was used for structural comparisons. Stimulation was started 1 week after cSCI. Awake urodynamics was performed on a weekly basis. After 16 weeks follow‐up, samples from the urinary bladder were taken for analyses.

Results

SNM improved bladder function with better capacities and lower detrusor pressures at voiding and avoided the emergence of detrusor sphincter dyssynergia (DSD). PNM and untreated SCI minipigs had less favorable outcomes with either DSD or constant urinary retention. Structural results revealed SCI‐typical fibrotic alterations in all cSCI minipigs. However, SNM showed a better‐balanced distribution of smooth muscle to connective tissue with a trend towards the reduced progression of bladder wall scarring.

Conclusion

Early SNM led to an avoidance of the emergence of DSD showing a more physiological bladder function during a 4 month follow‐up period after cSCI. This study might pave the way for the clinical continuation of early SNM for the treatment of neurogenic LUT dysfunction after SCI.

Neuromodulation - a therapeutic option for refractory overactive bladder. A recent literature review

Overactive bladder (OAB) affects approximately 17% of the population. The treatment of this clinical condition is challenging, especially when conservative therapy is not effective. There are limited options for the treatment of recurrent OAB. Neuromodulation has taken a significant place in the therapy of recalcitrant lower urinary tract dysfunctions over the past 20 years. The aim of this study was to review the literature evaluating the different forms of neuromodulation in various urological clinical conditions and to show the future prospects of this treatment method. Further studies are necessary to determine the effectiveness of neuromodulation and to identify the prognostic factors of therapeutic success. This could be helpful in the selection of patients who will be most likely to respond positively to the treatment.

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

Sacral neuromodulation treating chronic pelvic pain: a meta-analysis and systematic review of the literature

INTRODUCTION AND HYPOTHESIS

Sacral neuromodulation (SNM) is gaining popularity as a treatment option for chronic pelvic pain (CPP). Our hypothesis is that SNM is effective in improving CPP.

METHODS

A systematic search was conducted through September 2018. Peer-reviewed studies using pre- and postpain intensity scores were selected. The primary outcome was pain improvement on a 10-point visual analog scale (VAS) (adjusted or de novo) in patients with CPP. Secondary outcomes included comparing SNM approaches and etiologies and evaluating lower urinary tract symptoms (LUTS).

RESULTS

Fourteen of 2175 studies, evaluating 210 patients, were eligible for further analysis. The overall VAS pain score improvement was significant [weighted mean difference (WMD) -4.34, 95% confidence interval (CI) = -5.22, to-3.64, p < 0.0001)]. Regarding SNM approach, both standard and caudal approaches had significant reduction in pain scores: WMD -4.32, CI 95% = -5.32, to -3.31 (p < 0.001) for the standard approach, compared with WMD -4.63, 95% CI = -6.57 to -2.69 (P < 0.001), for the caudal approach (p = 0.75). While significant improvement in pain was observed both in patients with and without interstitial cystitis/bladder pain syndrome (IC/BPS), the observed improvement was lower in patients with (WMD -4.13, CI 95% -5.36 to -2.90 versus without (WMD -5.72, CI 95% = -6.18, to-5.27) IC/BPS (p = 0.02). SNM was effective in treating voiding symptoms (frequency, urgency, nocturia) associated with IC/BPS (all p < 0.01).

CONCLUSIONS

SNM is an effective therapy for CPP in both IC/BSP and non-IC/BSP patients, with better results in non-IC/BSP patients. Outcomes of the antegrade caudal approach were comparable with the standard retrograde approach.

Results of Sacral Neuromodulation Therapy for Urinary Voiding Dysfunction: Five-Year Experience of a Retrospective, Multicenter Study in China

PURPOSE

This five-year, retrospective, multicenter study evaluated the long-term safety and efficiency of sacral neuromodulation (SNM) in Chinese patients with urinary voiding dysfunction.

PATIENTS AND METHODS

This is a Chinese national, multicenter, retrospective study that included 247 patients (51.2% female) who received an implantable pulse generator (IPG) (InterStim, Medtronic, Minneapolis, MN, USA) between 2012 and 2016. Success was considered if the initial ≥50% improvement in any of primary voiding diary variables persisted compared with baseline. The results were further stratified by identifying patients who showed >50% improvement and those although showed <50% improvement but still wanted to receive IPG; these data were collected and analyzed for general improvement.

RESULTS

Following test stimulation, 187 patients (43%) declined implantation and 247 (57%) underwent implantation using InterStim®. Among 247 patients, 34 (13.7%) had overactive bladder (OAB), 59 (23.8%) had interstitial cystitis/bladder pain syndrome (IC/BPS), 47 (19%) had idiopathic urinary retention (IUR), and 107 (44.1%) had neurogenic bladder (NB). IPG efficiency rate for OAB, interstitial cystitis/bladder pain syndrome, idiopathic urinary retention, and neurogenic bladder were 42.5, 72.4, 51.6, and 58.8%, respectively. The mean duration of follow-up was 20.1 ± 12.8 months.

CONCLUSIONS

SNM appears effective in the long term, with a total IPG implantation rate of approximately 57% (ranging between 42.5 and 72.4% depending on indication). Interstitial cystitis/bladder pain syndrome appear to be the best indication for stage I testing. Chinese neurogenic bladder patients are most inclined to choose SNM. SNM is relatively safe, with low postoperation adverse events of 16.1% and reoperation rate of 3.2% during the follow-up period.

Application of an individualized and reassemblable 3D printing navigation template for accurate puncture during sacral neuromodulation

OBJECTIVE

To evaluate the feasibility and safety of an individualized and reassemblable three-dimensional (3D) printing navigation template for making accurate punctures during sacral neuromodulation (SNM).

METHODS

From July 2016 to July 2017, 24 patients undergoing SNM were enrolled. Conventional X-ray guidance was used in the control group, which included 14 patients, while the 3D printing template was used in the experimental group, which included 10 patients. The number of punctures, the average puncture time, the exposure to X-ray, the adjustment time during the operation and the testing of the SNM device, the infection and haemorrhage rate, and the implantable pulse generator (IPG) implantation rates were compared between the two groups.

RESULTS

In total, 24 patients successfully underwent stage I. When comparing the control group and the experimental group, the number of punctures were 9.6 ± 7.7 and 1.5 ± 0.7, respectively; the average puncture times were 35.4 ± 14.6 and 4.1 ± 2.2 min, respectively; and the X-ray exposure levels were 8.37 ± 4.83 mAs and 2.34 ± 0.54 mAs, respectively. No postoperative complications were reported in either group. The IPG implantation rates were not different between the two groups.

CONCLUSION

The 3D printing template for SNM can help us to perform accurate and quick punctures into the target sacral foramina, reduce X-ray exposure, and shorten the operation time. For patients with obesity, sacral variation, sacral bone fractures or losses and for patients who are unable to tolerate the prone position during operation, use of the 3D printing template is recommended.

Lumbosacral spinal cord epidural stimulation improves voiding function after human spinal cord injury

Deficits in urologic function after spinal cord injury (SCI) manifest both as a failure to store and empty, greatly impacting daily life. While current management strategies are necessary for urological maintenance, they oftentimes are associated with life-long side effects. Our objective was to investigate the efficacy of spinal cord epidural stimulation (scES) as a promising therapy to improve bladder control after SCI. A bladder mapping study was undertaken for sixteen sessions over the course of four months in an individual with chronic, motor complete SCI. Varying combinations of stimulating cathode electrodes were initially tested during filling cystometry resulting in the identification of an effective configuration for reflexive bladder emptying at the caudal end of the electrode array. Subsequent systematic testing of different frequencies at a fixed stimulus intensity and pulse width yielded lowest post-void residual volumes at 30 Hz. These stimulation parameters were then tested in four additional research participants and found to also improve reflexive voiding efficiency. Taken together with SCI studies on step, stand, voluntary motor control and cardiovascular regulation, these findings further corroborate that scES has an all-encompassing potential to increase the central state of excitability, allowing for the control of multiple body functions, including the urological system.

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.

Clinical utility of neurostimulation devices in the treatment of overactive bladder: current perspectives

Objectives

This review describes the evidence from established and experimental therapies that use electrical nerve stimulation to treat lower urinary tract dysfunction.

Methods

Clinical studies on established treatments such as percutaneous posterior tibial nerve stimulation (P-PTNS), transcutaneous electrical nerve stimulation (TENS), sacral nerve stimulation (SNS) and sacral anterior root stimulation (SARS) are evaluated. In addition, clinical evidence from experimental therapies such as dorsal genital nerve (DGN) stimulation, pudendal nerve stimulation, magnetic nerve stimulation and ankle implants for tibial nerve stimulation are evaluated.

Results

SNS and P-PTNS have been investigated with high-quality studies that have shown proven efficacy for the treatment for overactive bladder (OAB). SARS has proven evidence-based efficacy in spinal cord patients and increases the quality of life. TENS seems inferior to other OAB treatments such as SNS and P-PTNS but is noninvasive and applicable for ambulant therapy. Results from studies on experimental therapies such as pudendal nerve stimulation seem promising but need larger study cohorts to prove efficacy.

Conclusion

Neurostimulation therapies have proven efficacy for bladder dysfunction in patients who are refractory to other therapies.

Significance

Refinement of neurostimulation therapies is possible. The aim should be to make the treatments less invasive, more durable and more effective for the treatment of lower urinary tract dysfunction.

Using the Native Afferent Nervous System to Sense Bladder Fullness: State of the Art

The regulation of micturition involves complex neurophysiologic pathways, and its understanding has grown immensely over the past decade. Alternative approaches and applied technologies in the treatment of bladder dysfunction have minimized the complications that result from neurogenic bladder. The use of natural bladder mechanoreceptors and electroneneurographic (ENG) signal recordings from afferent nerves to chronically monitor bladder volume is a promising concept, but the technology to accomplish this has proven to be a great biomedical engineering challenge. The focus of this paper will be to describe the current state of ENG signal recording as a method to detect bladder fullness.

Effects of Appropriate Prolonged Sacral Neuromodulation Testing in Improving Implantation Rate of a Permanent Implantable Pulse Generator in Patients with Refractory Lower Urinary Tract Dysfunctions in Mainland China

Background:

Sacral neuromodulation (SNM) has become an effective method for treating lower urinary tract voiding dysfunction during the past 20 years. Because of the expensive cost, the number of implantable pulse generator (IPG) implantations per year in China is far lower than that in Western developed countries since 2012. This study was to summarize the effects of the appropriate prolonged SNM testing time in improving the implantation rate of a permanent IPG in patients with refractory lower urinary tract symptoms (LUTS) in mainland China.

Methods:

From January 2013 to June 2016, 51 patients with refractory LUTS received SNM therapy. In this study, we compared the conversion rate 2 weeks after the Stage I test and final actual conversion rate. We also observed the complications (such as pain, infection, and electrode displacement) and effectiveness. We tried to improve an appropriate prolonged test time which was favorable for improving the SNM conversion rate while ensuring safety and effectiveness.

Results:

Among 51 patients receiving SNM therapy, 19 patients (mean age 45.0 ± 16.9 years) had poor Stage I test results, and on an average, the electrode was removed 27.4 ± 9.6 days after the surgery. In one patient, the electrode was removed within 2 weeks; when the remaining 18 patients were questioned 2 weeks after testing, none of the patients wanted to terminate the test, and all the 18 patients desired to prolong the testing time to further observe the treatment effect. The remaining 32 patients (mean age 46.7 ± 15.3 years) received Stage II permanent implantation at 19.6 ± 10.4 days after the surgery. The overall Stage I–II conversion was 62.7% (32/51) in this study. Within 2 weeks after the surgery, only eight patients received Stage II permanent implantation, and the conversion rate was only 15.7% (8/51), which was much lower than the overall conversion rate of 62.7%. Nearly 84.4% (27/32) of the patients received Stage II implantation within 4 weeks. None of the patients had incision infections. In one patient, the entire system was removed 1 month after Stage II implantation due to pain in the implantation site.

Conclusions:

Appropriate extension of the Stage I testing time of an SNM-barbed electrode could significantly improve the Stage II permanent implantation rate in Chinese refractory LUTS patients; there were no wound infections, and the postoperative complication rate was low. This study recommended that Stage I period of SNM therapy should be 4 weeks according to safety and successful conversion rate.

Sacral Neuromodulation: Foray into Chronic Pelvic Pain in End Stage Endometriosis

Excision of all endometriotic lesions is the method of choice in the treatment of severe endometriosis resistant to medical therapy. The infiltrating nature of the disease as well as extensive surgery may, however, cause chronic pain that cannot be relieved by either surgery or hormonal treatment. As a pilot treatment, we tested the effect of sacral neuromodulation (SNM) for four endometriosis patients suffering chronic pelvic pain and pelvic organ dysfunction after radical surgical treatment. Three out of four patients reported improvement in their symptoms during the neuromodulation testing period and a permanent pulse generator was installed. After 2.5 years, all three patients report better quality of life and want to continue with SNM.

Long-term outcome of sacral neuromodulation in patients with idiopathic nonobstructive urinary retention: Single-center experience

OBJECTIVE

The objective of this study was to determine the safety and efficacy of sacral neuromodulation (SNM) in patients with idiopathic nonobstructive urinary retention.

MATERIALS AND METHODS

We retrospectively reviewed the files of patients who underwent staged neuromodulation for idiopathic nonobstructive urinary retention from 2004 to 2016 at our hospital. Patients who had a 50% improvement in symptoms after 1 week of stage 1 procedure were qualified for permanent device implantation. Patient data were assessed on efficacy and need for intermittent self-catheterization, complications, and operative revision rates.

RESULTS

Twenty-seven female patients who underwent SNM therapy were analyzed. The mean age of the patients was 32.5 ± 10.8 years. The mean duration of urinary retention was 3.2 ± 1.7 years. All patients were doing intermittent self-catheterization, but few were able to void <100 ml. Twenty-four (88.8%) of the 27 patients demonstrated a >50% improvement in symptoms and underwent permanent device placement. At a median follow-up of 5.7 ± 3.2 years, 20 (83.3%) of the 24 patients demonstrated sustained improvement rates of >50%. Seventeen (70.83%) of 24 patients could void spontaneously with a mean residual urine of 28.1 ± 24.4 ml (P < 0.001). Three (12.5%) were voiding with significant mean decreasing number of catheterizations from 5.6 ± 2.4 to 1.4 ± 2.1 (P < 0.001). Four (16.6%) had their device explanted. Ten (41.6%) of the 24 patients underwent surgical revision. Most of the adverse events were managed by device reprograming.

CONCLUSION

SNM is a highly effective and safe procedure in this subset of the female population with idiopathic refractory nonobstructive urinary retention.

Sacral neuromodulation in overactive bladder: a review and current perspectives

Overactive bladder (OAB) symptoms of urgency, frequency, and urge incontinence currently affect a substantial portion of the population, especially as age increases. Sacral neuromodulation has become a popular option for refractory OAB symptoms over the past 2 decades. Studies have demonstrated that it is an effective treatment for OAB and urge incontinence as indicated by decreased number of voids, increased bladder capacity, and fewer leakage events. In addition, the effects have proved to be durable to multiple years following implantation. These benefits come at the expense of a high rate of adverse events, although with comparable long-term cost-effectiveness to botulinum toxin A. We aimed to review the literature that demonstrates that sacral neuromodulation continues to be an efficacious treatment for refractory OAB wet and dry patients, with continuously expanding indications.

Pathophysiology, Clinical Importance, and Management of Neurogenic Lower Urinary Tract Dysfunction Caused by Suprasacral Spinal Cord Injury

Management of persistent lower urinary tract dysfunction resulting from severe thoracolumbar spinal cord injury can be challenging. Severe suprasacral spinal cord injury releases the spinal cord segmental micturition reflex from supraspinal modulation and increases nerve growth factor concentration in the bladder wall, lumbosacral spinal cord, and dorsal root ganglion, which subsequently activates hypermechanosensitive C-fiber bladder wall afferents. Hyperexcitability of bladder afferents and detrusor overactivity can cause urine leaking during the storage phase. During urine voiding, the loss of supraspinal control that normally coordinates detrusor contraction with sphincter relaxation can lead to spinal cord segmental reflex-mediated simultaneous detrusor and sphincter contractions or detrusor-sphincter dyssynergia, resulting in inefficient urine voiding and high residual volume. These disease-associated changes can impact on the quality of life and life expectancy of spinal-injured animals. Here, we discuss the pathophysiology and management considerations of lower urinary tract dysfunction as the result of severe, acute, suprasacral spinal cord injury. In addition, drawing from experimental, preclinical, and clinical medicine, we introduce some treatment options for neurogenic lower urinary tract dysfunction that are designed to: (1) prevent urine leakage arising because of detrusor overactivity during bladder filling, (2) preserve upper urinary tract integrity and function by reducing intravesical pressure and subsequent vesicoureteral reflux, and (3) prevent urinary tract and systemic complications by treating and preventing urinary tract infections.

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

INTRODUCTION

The InSite trial is a prospective, multicenter study of sacral neuromodulation (SNM) therapy with the InterStim® System in subjects with overactive bladder (OAB). One of the primary aims of the study is to report on long-term safety of the tined lead. This analysis provides detailed descriptions of device-related adverse events (AEs) and surgical interventions to 12 months.

METHODS

Analysis included those subjects who completed test stimulation with a tined lead, received a full implant, and reported device-related AEs out to 12 months. A Clinical Events Committee (CEC) adjudicated AEs to 12 months.

RESULTS

Device-related AEs occurred in 30% (82/272) of subjects, with only one considered serious. Fifty-six percent of the device-related AEs occurred between implant and 3 months. The most frequent device-related AEs were undesirable change in stimulation (12%, 32/272); implant site pain (7%, 20/272); and implant site infection (3%, 9/272). Of the 26 events of implant site pain, 13 required surgical intervention, with only two resulting in explant. Ten subjects experienced 13 events of a surgical site infection (including an additional cellulitis), five of which resolved with antibiotics and eight required explantation. The overall surgical intervention rate was 13% with the most common reasons being pain at the surgical site (4%), lack/loss of efficacy (4%), and infection (3%).

CONCLUSIONS

Although a 30% AE rate was reported, most AEs were minor and were resolved without surgical intervention. Surgical intervention was required in 13% of subjects, with the majority being revision or replacement. Neurourol. Urodynam. 36:1136-1139, 2017. © 2016 Wiley Periodicals, Inc.

Disparities in the Use of Sacral Neuromodulation among Medicare Beneficiaries

PURPOSE

Sacral neuromodulation with the InterStim® has been done to treat urinary and bowel control. There are limited data in the literature on use trends of sacral neuromodulation. We explored disparities in use among Medicare beneficiaries.

MATERIALS AND METHODS

We queried a 5% national random sample of Medicare claims for 2001, 2004, 2007 and 2010. All patients with an ICD-9 diagnosis code representing a potential urological indication for sacral neuromodulation were included. Patients who underwent device implantation were identified using CPT-4 codes. Statistical analysis was done with the chi-square and Fisher tests, and multivariate logistic regression using software.

RESULTS

A total of 2,322,060 patients were identified with a diagnosis that could potentially be treated with sacral neuromodulation. During the 10-year study period the percent of these patients who ultimately underwent implantation increased from 0.03% to 0.91% (p <0.0001) for a total of 13,360 (0.58%). On logistic regression analysis women (OR 3.85, p <0.0001) and patients younger than 65 years (OR 1.00 vs 0.29 to 0.39, p <0.0001) were more likely to be treated. Minority patients (OR 0.38, p <0.0001) and those living in the western United States (OR 0.52, p <0.0001) were less likely to receive treatment.

CONCLUSIONS

Sacral neuromodulation use significantly increased among Medicare beneficiaries in a 10-year period. Patients were more likely to be treated with sacral neuromodulation if they were female, white, younger (younger than 65 years) and living outside the western United States.

The technique of sacral nerve modulation

AIM

The aim of this review was to summarize current knowledge and recommendations regarding the technique of implantation of the electrode in performing sacroneuromodulation (SNM) and the available information on programming parameters and implantation algorithms.

METHOD

All English-language articles published from January 1985 to December 2013 that reported the SNM surgical technique and results were considered for inclusion. Data were considered useful for the present review only if related to: (i) peripheral nerve evaluation; (ii) temporary nerve stimulation; (iii) definitive impulse generator placement; and (iv) parameters programming.

RESULTS

The literature search revealed 193 potentially relevant studies from initial electronic search terms and eligibility criteria, and these studies were evaluated in detail. In total, 41 studies were included in the final analysis. Of the studies reviewed, the majority (n = 37) were prospective or retrospective case series. Only three randomized clinical trials were eligible for inclusion.

CONCLUSION

Although the technique seems to be standardized, several steps still need to be clarified in order to define the best way to perform the procedure and then to maximize the outcome.

Results of a prospective, multicenter study evaluating quality of life, safety, and efficacy of sacral neuromodulation at twelve months in subjects with symptoms of overactive bladder

AIMS

This prospective, multicenter post-approval study evaluated the success rate of sacral neuromodulation (SNM) with the InterStim® System at 12-months. Subjects with bothersome symptoms of overactive bladder (OAB) including urinary urge incontinence (UI) or urgency-frequency (UF), who failed at least one anticholinergic medication and had at least one not tried were included.

METHODS

Subjects with successful test stimulation received an SNM implant. Therapeutic success (≥50% improvement in average leaks/day or voids/day or a return to normal voiding frequency [<8 voids/day]) and quality of life through 12 months were evaluated for implanted subjects.

RESULTS

Of the 340 subjects that went through test stimulation, 272 were implanted with SNM. Of these, 91% were female, mean age was 57, UI subjects had 3.1 ± 2.7 leaks/day, UF subjects had 12.6 ± 4.5 voids/day. The analysis which includes all implanted subjects with diary data at baseline and 12 months showed an OAB therapeutic success rate of 85% at 12 months. UI subjects had a mean reduction of 2.2 ± 2.7 leaks/day; UF subjects had a mean reduction of 5.1 ± 4.1 voids/day (both P < 0.0001). Subjects showed significant improvement from baseline in all measures of ICIQ-OABqol (all P < 0.0001). 80% of subjects reported improved changes in their urinary symptom interference at 12 months. Device-related adverse events occurred in 16% (56/340) of subjects during test stimulation and 30% (82/272) of subjects post-implant.

CONCLUSIONS

This multicenter study shows SNM is safe and effective and results in improved outcomes through 12 months in subjects with OAB symptoms, without requiring failure of all medications.

Surface and boney landmarks for sacral neuromodulation: a cadaveric study

INTRODUCTION AND HYPOTHESIS

Standard external landmarks have been suggested as a guide for in-office percutaneous nerve evaluation (PNE), but validity of these landmarks has not been assessed. Our objective was to determine whether the standard 9 cm from the tip of the coccyx indicates the position of the S3 sacral foramen and whether other boney landmarks and measurements improved positioning.

METHODS

Measurements and distances between external boney landmarks were obtained in 22 embalmed cadavers. Spinal needles were placed 9 cm superior to the coccyx and 2 cm lateral to midline bilaterally. After dissection, internal measurements relating to sacral length, position of S3, and location of the needle in relation to S3 were recorded. Correlations among measured variables were assessed using descriptive statistics.

RESULTS

Mean distance from the tip of coccyx to S3 was 9.26 cm (±0.84), from S3 to midline 2.30 cm (±0.2); from needle to S3 1.25 cm, and needle placement was as likely to be placed above or below S3; and S2-S3 and S3-S4 interforamenal distance 1.48 cm (±0.30) and 1.48 cm (±0.24), respectively. Mean distance from S3 to sacroiliac joint (SIJ) was shorter than S2 to SIJ. All associations between external measurements and length from tip of coccyx to S3 were not significant.

CONCLUSION

A distance 9 cm from the tip of the coccyx is a reasonable starting landmark for in-office blind PNE. However, given the variability in coccyx length, caution should be taken; also, sensory-motor response is necessary to confirm proper placement.

Sacral neuromodulation for neurogenic bladder and bowel dysfunction with multiple symptoms secondary to spinal cord disease

STUDY DESIGN

Retrospective case series.

OBJECTIVES

The primary aim was to assess the clinical effects of sacral neuromodulation (SNM) for neurogenic bladder and/or bowel dysfunction with multiple symptoms secondary to spinal cord disease or injury.

SETTING

Beijing, China.

METHODS

Between 2011 and 2013, 23 patients with multiple bladder and/or bowel problems secondary to spinal cord disease or injury were treated with a preliminary test SNM. If at least 50% clinical improvement occurred, then the patient underwent a permanent SNM procedure. We evaluated the patients using a bladder diary, post-void residual volume measurement and the Wexner questionnaire score for constipation before the test phase, during the test phase and after the permanent SNM.

RESULTS

In the test phase, the rate of improvement in dysuria (29.4%) was significantly lower than urgency frequency (64.7%), urinary incontinence (69.2%) and constipation (75.0%). An implant was performed in 13 (56.5%) patients, including 4 patients who still used intermittent catheterization to exclude urine after permanent SNM because the symptom of dysuria could not be improved significantly and 1 patient who achieved ⩾50% improvement in lower urinary tract dysfunction but not in constipation. During follow-up (17.5±2.0 months), 1 patient (7.7%) failed and 1 patient had bilateral vesicoureteral reflux.

CONCLUSION

Chronic SNM cannot always resolve all the bladder and bowel symptoms secondary to spinal cord disease or injury, but combined with other treatments may help improve multiple symptoms.

Sacral neuromodulation and peripheral nerve stimulation in patients with anal incontinence: an overview of techniques, complications and troubleshooting

Sacral neuromodulation (SNM) therapy has revolutionized the management of many forms of anal incontinence, with an expanded use and a medium-term efficacy of 75% overall. This review discusses the technique of SNM therapy, along with its complications and troubleshooting and a discussion of the early data pertaining to peripheral posterior tibial nerve stimulation in incontinent patients. Future work needs to define the predictive factors for neurostimulatory success, along with the likely mechanisms of action of their therapeutic action.