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

A prospective feasibility study to differentiate sacral neuromodulation lead electrode configurations using motor and sensory thresholds and locations of sensation

BACKGROUND

Accurate positioning and programming of sacral neuromodulation (SNM) relies upon the use of several intraoperative and postoperative stimulation measurements. While the clinical utility of these acute measurements including pelvic floor motor thresholds (PFMT), toe/leg motor thresholds (TMT), and sensory thresholds (ST), are widely accepted, their usefulness in quantitative research remains unclear. The purpose of this prospective study was to test these measurements and gauge their utility in future research.

METHODS

Eight participants received Axonics SNM, 6 Medtronic Interstim II, and 2 Medtronic Micro SNM. PFMT was measured after implantation. ST and the location of sensation (LOS) were measured immediately postoperatively (PO), at pre-release from the surgery center (PR), and during a follow-up clinic visit (FU). Thresholds were compared across contact and time using linear mixed-effects models.

RESULTS

Significant differences in PFMT were found across electrode configurations, with stimulation through proximal contacts exhibiting lower PFMT than distal configurations. ST displayed no significant differences across electrodes and showed minimal changes over time. LOS exhibited substantial variability across patients and periods.

CONCLUSIONS

Results suggest that PFMT were able to differentiate differences across electrode configurations that may be useful for future quantitative research. The lack of differences in ST and LOS across electrode configurations was interesting given the focus on these measurements clinically. Future testing is to confirm these limitations.

Sacral Neuromodulation Reprogramming Rates: Understanding Office-Based Requirement

IMPORTANCE

Sacral neuromodulation (SNM) is a procedure with the advantage of reprogramming for discomfort or inadequate symptom control.

OBJECTIVES

The aims of this study were to investigate the rates of office-based SNM programming in a large multisite cohort and to examine differences based on implantation indication.

STUDY DESIGN

The TriNetX database was utilized for retrospective cohort comparison using International Classification of Diseases, Tenth Revision, and Current Procedural Terminology (CPT) codes. Cohort selection included female adults with a diagnosis of urinary retention, urgency urinary incontinence, and/or fecal incontinence (FI) at time of implantation. The primary outcome was the rate of SNM reprogramming CPT per individual from 6 weeks to 5 years postimplantation. Secondary outcomes included demographic comparisons, incidence, and survival curves for patients with SNM reprogramming identified with CPT codes. Further comparisons were completed between implantation diagnoses of grouped urinary (urgency and retention) versus fecal indications.

RESULTS

A total of 9,501 patients meet inclusion criteria with a mean of age 62.1 ± 14.9 years (range, 18-90). Office-based SNM reprogramming was identified in 31.5%. The probability of never having reprogramming at 5 years was 52.5%. The mean number of reprogramming sessions was 2.5 ± 2.1. Approximately half (48%) of the patients with FI also had a diagnosis of urgency urinary incontinence, and approximately 25% had urinary retention. The probability of never having reprogramming was 55% and higher in patients with a fecal incontinence indication than those with only urinary indications at 50%, P < 0.001.

CONCLUSIONS

Office-based SNM reprogramming occurs in 31.5% of patients with implants, and rates are likely underreported. Patients with any FI diagnosis have a higher risk of requiring reprogramming.

Acute Cortical Brain Neuroexcitation Can Be Detected With Sacral Neuromodulation

INTRODUCTION

Functional near infrared spectroscopy (fNIRS) is a noninvasive technique for measuring cortical brain neuroexcitation.

OBJECTIVE

The objective of this study was to determine if fNIRS could detect differences in prefrontal cortex (PFC) neuroexcitation due to acute ON/OFF changes in sacral neuromodulation (SNM) during natural bladder filling.

STUDY DESIGN

Female participants who had an SNM device implanted for ≥6 months underwent a 2-fill natural hydration protocol in this cross-sectional study. Continuous oxygenated hemoglobin (O2Hb) concentration was recorded using an fNIRS headcap as a measure of neuroexcitation. Sacral neuromodulation devices were acutely changed from ON to OFF and OFF to ON in 3-minute cycles. One-minute segments of fNIRS signals before and after acute modulation were selected and linear fitting was used to output slope. Two-minute control periods at a similar level of bladder sensation were used for comparison.

RESULTS

Twelve women completed the study and median time from SNM implant was 13 (6, 42) months. In the left and middle PFC regions, there was a significant alteration of fNIRS slope (∆O2Hb/time) from baseline to postactivation (OFF to ON) compared to control periods. The first deactivation (ON to OFF) showed continuation of the prior fNIRS slope. The control segments showed stability of averaged O2Hb signals regardless of sensation in all brain regions.

CONCLUSIONS

This study indicates that fNIRS may be a useful tool to assess acute changes in neuroexcitation of the PFC in response to SNM device activation in female patients with overactive bladder. The results suggest that SNM may acutely affect the PFC during bladder filling.

Is Our Limited Understanding of the Effects of Nerve Stimulation Resulting in Poor Outcomes and the Need for Better "Rescue Programming" in SNM and PTNS, and Lost Opportunities for New Sites of Stimulation? ICI-RS 2024

AIMS

Sacral neuromodulation (SNM) and percutaneous tibial nerve stimulation (PTNS) are strongly recommended by international guidelines bodies for complex lower urinary tract dysfunctions. However, treatment failure and the need for rescue programming still represent a significant need for long-term follow-up. This review aimed to describe current strategies and future directions in patients undergoing such therapies.

MATERIALS AND METHODS

This is a consensus report of a Think Tank discussed at the Annual Meeting of the International Consultation on Incontinence - Research Society (ICI-RS), June 6-8, 2024 (Bristol, UK): "Is our limited understanding of the effects of nerve stimulation resulting in poor outcomes and the need for better 'rescue programming' in SNM and PTNS, and lost opportunities for new sites of stimulation?"

RESULTS

Rescue programming is important from two different perspectives: to improve patient outcomes and to enhance device longevity (for implantable devices). Standard SNM parameters have remained unchanged since its inception for the treatment of OAB, nonobstructive urinary retention, and voiding dysfunction. SNM rescue programming includes intermittent stimulation (cycling on), increased frequency and changes in pulse width (PW). The effect of PW setting on SNM outcomes remains unclear. Monopolar configurations stimulate more motor nerve fibers at lower stimulation voltage; hence, this could be an option in patients who failed bipolar stimulation in the long term. Unfortunately, there is little evidence for rescue programming for PTNS. However, the development of implantable devices for intermittent stimulation of the tibial nerve may increase long-term adherence to therapy and increase interest in alternative programming. There has been recent promising neurostimulation targeting the pudendal nerve (PNS), especially in BPS/IC. More recently, preliminary data addressed the benefits of high-frequency bilateral pudendal nerve block for DESD and adaptive PNS on both urgency and stress UI in women.

CONCLUSION

The exploration of rescue programming and new stimulation sites remains underutilized, and there are opportunities that could potentially expand the therapeutic applications of nerve stimulation. By broadening the range of target sites, clinicians may be able to tailor treatments according to individual patient needs and underlying conditions, thereby improving overall outcomes. However, further studies are still needed to increase the level of evidence, potentially allowing for an individualized treatment both in patients who are candidates for electrostimulation and in those who have already received surgical implants but seek a better outcome.

Differential effects of low- and high-frequency sacral neuromodulation on urinary symptoms: high-frequency improves Qmax, low-frequency enhances bladder capacity

OBJECTIVE

To compare the efficacy, safety, and patient satisfaction between low- and high-frequency sacral neuromodulation (SNM) in patients undergoing SNM.

METHODS

This retrospective study included 263 patients treated between January 2016 and December 2022 at PLA General Hospital of Southern Theater Command. Patients received either low-frequency (≤ 16 Hz) or high-frequency (> 16 Hz) SNM. Urodynamic outcomes, quality of life, adverse events, and patient satisfaction were assessed pre- and post-treatment.

RESULTS

Of the cohort, 128 patients received low-frequency and 135 received high-frequency stimulation. Post-treatment, the high-frequency group showed a significant improvement in maximum urinary flow rate (Qmax) and detrusor contractility compared to the low-frequency group. In contrast, the low-frequency group exhibited greater increases in maximum bladder capacity. Both groups demonstrated significant reductions in urination difficulty and waiting times, with the high-frequency group achieving more pronounced improvements. Quality of life scores and adverse event rates were similar across both groups. High patient satisfaction was noted in both groups, with no significant difference in overall satisfaction rates (P = 0.404). Correlation analysis indicated significant relationships between stimulation frequency and various urodynamic parameters, with higher frequencies generally associated with better urodynamic outcomes.

CONCLUSION

Both low- and high-frequency SNM improve urinary symptoms and quality of life, with high-frequency showing better urodynamic outcomes in Qmax and detrusor contractility, while low-frequency enhances bladder capacity. Both treatments are safe and highly satisfactory to patients.

Long-term efficacy and safety of sacral neuromodulation for diarrhoea-predominant and mixed irritable bowel syndrome

BACKGROUND

Irritable bowel syndrome (IBS) is a very common condition worldwide. Treatment options for severe IBS are few. Sacral neuromodulation (SNM) for patients with IBS has been shown to reduce symptoms and improve quality of life in the medium term. This study aimed to evaluate the long-term effectiveness and safety of SNM in diarrhoea-predominant and mixed IBS.

METHODS

A prospective cohort of patients with IBS treated with SNM were evaluated 1, 3, 5, and 10 years after implantation. The primary end-point was a change in the Gastrointestinal Symptom Rating Scale-Irritable Bowel Syndrome version questionnaire (GSRS-IBS) from baseline to 10-year follow-up (FU). Secondary end-points were change in the GSRS-IBS score from baseline to 5-year FU and change in the Irritable Bowel Syndrome-Impact Scale questionnaire (IBS-IS) from baseline to 5- and 10-year FU. Adverse events following SNM were observed.

RESULTS

Of 36 patients treated with SNM, 23 were eligible for 5-year FU and 13 for 10-year FU. The GSRS-IBS score was significantly reduced at both 5-year (p < 0.0001) and 10-year (p = 0.0007) FU. The IBS-IS score was also significantly improved at both 5 years (p < 0.0001) and 10 years (p = 0.0002). Fifty-six adverse events were registered. Five patients were explanted because of adverse events.

CONCLUSION

SNM seems to offer an effective and safe treatment option for highly selected patients with diarrhoea-predominant and mixed IBS.

CLINICAL TRIAL REGISTRATION

The present study has not been registered. The latest founding study was registered at ClinicalTrials.gov, NCT01948973.

Sacral and Implantable Tibial Neuromodulation for the Management of Overactive Bladder: A Systematic Review and Meta-analysis

INTRODUCTION

Implantable tibial neuromodulation (iTNM) systems have recently become commercially available in the US, and offer a new method of neurostimulation for the treatment of overactive bladder (OAB). In the absence of head-to-head studies, the aim of this meta-analysis was to indirectly compare the efficacy and safety of sacral neuromodulation (SNM) and implantable tibial neuromodulation (iTNM) for the treatment of OAB.

METHODS

A comprehensive search was performed using terms for OAB and neuromodulation. Primary efficacy measures included a ≥ 50% reduction in urgency urinary incontinence (UUI) episodes, urinary frequency, and/or OAB symptoms. Primary safety measures included the rate of device-related adverse events (AEs).

RESULTS

A total of 20 studies met selection criteria, encompassing 1416 patients treated with SNM and 350 patients treated with iTNM. No comparative or placebo-controlled studies for SNM and iTNM were identified, and therefore the analysis was completed using single-arm results. Weighted averages showed that the UUI responder rate was similar for both SNM and iTNM (71.8% and 71.3%, respectively). Similarly, weighted averages of OAB responder rates were 73.9% for SNM and 79.4% for iTNM. Similar rates of device-related AEs were also observed.

CONCLUSIONS

This meta-analysis found similar efficacy and safety of SNM and iTNM for the treatment of OAB and UUI, including UUI and OAB symptom response rates, reduction in UUI episodes, significant improvements in quality-of-life (QoL), and low rates of procedure and device-related adverse events. Notably, this comparable efficacy was seen without the use of a trial phase of neuromodulation in the iTNM studies versus SNM studies.

Effects of robotic therapy associated with noninvasive brain stimulation on motor function in individuals with incomplete spinal cord injury: A systematic review of randomized controlled trials

CONTEXT

Motor deficits are among the most common consequences of incomplete spinal cord injury (SCI). These impairments can affect patients' levels of functioning and quality of life. Combined robotic therapy and non-invasive brain stimulation (NIBS) have been used to improve motor impairments in patients with corticospinal tract lesions.

OBJECTIVES

To examine the effects of combined robotic therapy and NIBS on motor function post incomplete SCI.

METHODS

PubMed, SCOPUS, MEDLINE, PEDro, Web of Science, REHABDATA, CINAHL, and EMBASE were searched from inception until July 2023. The Physiotherapy Evidence Database (PEDro) scale was employed to evaluate the selected studies quality.

RESULTS

Of 557 studies, five randomized trials (n = 122), with 25% of participants being females, were included in this review. The PEDro scores ranged from eight to nine, with a median score of nine. There were variations in treatment protocols and outcome measures, resulting in heterogeneous findings. The findings showed revealed evidence for the impacts of combined robotic therapy and NIBS on motor function in individuals with incomplete SCI.

CONCLUSIONS

Combined robotic training and NIBS may be safe for individuals with incomplete SCI. The existing evidence concerning its effects on motor outcomes in individuals with SCI is limited. Further experimental studies are needed to understand the effects of combined robotic training and NIBS on motor impairments in SCI populations.

A Prospective Feasibility Study to Differentiate Sacral Neuromodulation Lead Electrode Configurations Using Motor and Sensory Thresholds and Locations of Sensation

Background

Accurate positioning and effective programming of sacral neuromodulation (SNM) relies upon the use of several acute stimulation measurements. While the clinical utility of these acute measurements including pelvic floor motor thresholds (PFMT), toe/leg motor thresholds (TMT), and sensory thresholds (ST), are widely accepted, their usefulness in quantitative research remains unclear. The purpose of this prospective study was to test these measurements and gauge their utility in future research.

Methods

Eight participants received Axonics SNM, 6 Medtronic Interstim II, and 2 Medtronic Micro SNM. PFMT was measured after implantation. ST and the location of sensation (LOS) were measured immediately postoperatively (PO), at pre-release from the surgery center (PR), and during a follow-up clinic visit (FU). Thresholds were compared across contact and time using linear mixed-effects models.

Results

Significant differences in PFMT were found across electrode configurations, with stimulation through proximal contacts exhibiting lower PFMT than distal configurations. ST displayed no significant differences across electrodes and showed minimal changes over time. LOS exhibited substantial variability across patients and periods.

Conclusions

Results suggest that PFMT were able to differentiate differences across electrode configurations that may be useful for future quantitative research. The lack of differences in ST and LOS across electrode configurations was interesting given the focus on these measurements clinically. Future testing is to confirm these limitations.

[Invasive neurostimulation in neuro-urology: state of the art]

Modulation or stimulation of the nerves supplying the lower urinary tract is a possible treatment option for dysfunction of the lower urinary tract, pelvic floor and rectum if conservative or minimally invasive treatment approaches fail. This overview shows the possibilities and limitations of sacral neuromodulation, sacral deafferentation with sacral anterior root stimulation and conus deafferentation.Sacral neuromodulation (SNM) is a procedure for the treatment of refractory pelvic floor dysfunction of various origins (idiopathic, neurogenic or post-operative), such as overactive bladder, non-obstructive retention and faecal incontinence. A particular advantage of SNM is the possibility of prior test stimulation with a high prognostic value. The procedure is minimally invasive, reversible and associated with relatively low morbidity rates.Following the introduction of MRI-compatible SNM systems, there has been renewed interest in the treatment of neurogenic bladder dysfunction. A recent meta-analysis reports similar success rates as in the idiopathic patient population.Sacral deafferentation with implantation of a sacral anterior root stimulator (SARS/SDAF) is an excellent therapeutic option for patients with spinal cord injury, which can significantly improve the quality of life of those affected and, in addition to treating neurogenic lower urinary tract dysfunction, can also have a positive effect on neurogenic bowel dysfunction, neurogenic sexual dysfunction or autonomic dysreflexia. If conservative or minimally invasive treatment fails, it is crucial for the success of this procedure to consider SDAF/SARS at an early stage in order to avoid irreversible organic damage.Conus deafferentation (KDAF) is a less invasive surgical treatment option for patients with spinal cord injury for whom sacral deafferentation would be indicated but who would not benefit from the simultaneous implantation of a sacral anterior root stimulator. In principle, these patients also have the option of being subsequently treated with an extradural implant and thus utilising the advantages of anterior root stimulation. Indications for KDAF are autonomic dysreflexia, therapy-refractory detrusor overactivity, recurrent urinary tract infections, urinary incontinence and spasticity triggered by detrusor overactivity. With KDAF, we have a safe and efficient procedure with great potential for improving the spectrum of paraplegiological and neuro-urological treatment.

Can we improve techniques and patients' selection for nerve stimulation suitable for lower urinary tract dysfunctions? ICI-RS 2023

AIMS

Lower urinary tract dysfunctions (LUTD) are very common and, importantly, affect patients' quality of life (QoL). LUTD can range from urinary retention to urgency incontinence and includes a variety of symptoms. Nerve stimulation (NS) is an accepted widespread treatment with documented success for LUTD and is used widely. The aim of this review is to report the results of the discussion about how to improve the outcomes of NS for LUTD treatment.

METHODS

During its 2023 meeting in Bristol, the International Consultation on Incontinence Research Society discussed a literature review, and there was an expert consensus discussion focused on the emerging awareness of NS suitable for LUTD.

RESULTS

The consensus discussed how to improve techniques and patients' selection in NS, and high-priority research questions were identified.

CONCLUSIONS

Technique improvement, device programming, and patient selection are the goals of the current approach to NS. The conditional nerve stimulation with minimally invasive wireless systems and tailored algorithms hold promise for improving NS for LUTD, particularly for patients with neurogenic bladder who represent the new extended population to be treated.

Preliminary analysis of stimulation parameters for sacral neuromodulation in different indications: a multicenter retrospective cohort study from China

BACKGROUND

Sacral neuromodulation (SNM) is an effective approach for treating lower urinary tract dysfunction (LUTD), and stimulation programming is essential for successful treatment. However, research on SNM programming for various indications is limited. Thus, the authors aimed to determine whether there were differences in the stimulation parameters for different SNM indications and the appropriate programming recommendations.

MATERIALS AND METHODS

Clinical data were retrospectively collected from patients with LUTD who underwent SNM and completed internal pulse generator implantation. The parameters with the highest patient satisfaction or the most symptom improvement during the test period were considered optimal and used to set the programming after internal pulse generator implantation.

RESULTS

After screening, 282 patients were enrolled and categorized into four groups based on the following indications: refractory overactive bladder (OAB) ( n =61), neurogenic lower urinary tract dysfunction (nLUTD) ( n =162), interstitial cystitis/painful bladder syndrome (IC/BPS) ( n =24), and idiopathic nonobstructive urinary retention (NOUR) ( n =35). When analyzing the optimal stimulus parameters, disparities in the stimulation amplitude and pulse frequency were noted among the four groups. The stimulation amplitude in the nLUTD group was higher than that in the idiopathic NOUR group ( P =0.013). Differences in pulse frequency were observed between the refractory OAB and nLUTD groups ( P <0.001) and between the refractory OAB and idiopathic NOUR groups ( P =0.001). No differences in the electrode configuration or pulse width settings existed among the four groups.

CONCLUSIONS

The stimulation parameters for SNM varied among the different indications. For the initial programming of stage I, most patients are recommended to start with stimulation amplitudes below 2 V, although patients with nLUTD may benefit from higher amplitudes. A standard pulse width of 210 μs is recommended for all patients. However, for individuals experiencing nLUTD or idiopathic NOUR, the pulse frequency can begin above the standard 14 Hz but not exceed 50 Hz.

[Sacral Neuromodulation for Fecal Incontinence and Constipation: Evidence, Programming and Long-term Management]

BACKGROUND

Over the last two decades, sacral neuromodulation (SNM) has established its role in the treatment of functional pelvic organ-/pelvic floor disorders. Even though the mode of action is not fully understood, SNM has become the preferred surgical treatment of fecal incontinence.

METHODS AND RESULTS

A literature search was carried out on programming sacral neuromodulation and long-term outcomes in treating fecal incontinence and constipation.Sacral neuromodulation was found to be successful in the long term. Over the years, the spectrum of indications has expanded, and now includes patients presenting with anal sphincter lesions. The use of SNM for low anterior resection syndrome (LARS) is currently under clinical investigation. Findings of SNM for constipation are less convincing. In several randomised crossover studies, no success was demonstrated, even though it is possible that subgroups may benefit from the treatment. Currently the application cannot be recommended in general.The pulse generator programming sets the electrode configuration, amplitude, pulse frequency and pulse width. Usually pulse frequency and pulse width follow a default setting (14 Hz, 210 s), while electrode configuration and stimulation amplitude are adjusted individually to the patient need and perception of stimulation.Despite low infection rates and few electrode-/pulse generator dysfunctions, up to 65% of patients require surgical reintervention during long term follow-up - in 50% of cases because of battery depletion, which is an expected event. At least one reprogramming is necessary in about 75% of the patients during the course of the treatment, mostly because of changes in effectiveness, but rarely because of pain. Regular follow-up visits appear to be advisable.

CONCLUSION

Sacral neuromodulation can be considered to be a safe and effective long-term therapy of fecal incontinence. To optimise the therapeutic effect, a structured follow-up regime is advisable.

[Therapeutic value of neuromodulation in women]

BACKGROUND

Neuromodulative treatment for the treatment of overactive bladder has been used in clinical practice since its introduction in the early 1980s.

OBJECTIVES

Description and update of the various neuromodulative techniques (tibial nerve stimulation, sacral and pudendal neuromodulation), presentation of their effectiveness and safety, and evaluation of their evidence for clinical practice.

MATERIALS AND METHODS

Literature search in PubMed and Embase, inclusion of studies according to the following criteria: evidence level, timeliness, length of follow-up and number of female patients according to the author's preference.

RESULTS

The efficacy and safety of both percutaneous tibial nerve stimulation (PTNS) and sacral neuromodulation (SNM) has been proven by studies with an evidence level of 1. Long-term data of up to 20 years are available for SNM, while long-term data for PTNS are limited. Permanent implants for tibial nerve stimulation are promising new developments. Pudendal neuromodulation (PNM) is suitable for more complex indications but is surgically more challenging.

CONCLUSIONS

Both PTNS and SNM are suitable for broad application in clinical practice. PTNS can be offered as an alternative to pharmacotherapy, while SNM provides the most convincing clinical data of all neuromodulative therapies.

Data Gap in Sacral Neuromodulation Documentation: Call to Improve Documentation Protocols

Purpose: We quantified patient record documentation of sacral neuromodulation (SNM) threshold testing and programming parameters at our institution to identify opportunities to improve therapy outcomes and future SNM technologies.Methods: A retrospective review was conducted using 127 records from 40 SNM patients. Records were screened for SNM documentation including qualitative and quantitative data. The qualitative covered indirect references to threshold testing and the quantitative included efficacy descriptions and device programming used by the patient. Findings were categorized by visit type: percutaneous nerve evaluation (PNE), stage 1 (S1), permanent lead implantation, stage 2 (S2) permanent impulse generator implantation, device-related follow-up, or surgical removal.Results: Documentation of threshold testing was more complete during initial implant visits (PNE and S1), less complete for S2 visits, and infrequent for follow-up clinical visits. Surgical motor thresholds were most often referred to using only qualitative comments such as “good response” (88%, 100% for PNE, S1) and less commonly included quantitative values (68%, 84%), locations of response (84%, 83%) or specific contacts used for testing (0%). S2 motor thresholds were less well documented with qualitative, quantitative, and anatomical location outcomes at 70%, 48%, and 36% respectively. Surgical notes did not include specific stimulation parameters or contacts used for tests. Postoperative sensory tests were often only qualitative (80%, 67% for PNE, S1) with quantitative values documented much less frequently (39%, 9%) and typically lacked sensory locations or electrode-specific results. For follow-up visits, <10% included quantitative sensory test outcomes. Few records (<7%) included device program settings recommended for therapy delivery and none included therapy-use logs.Conclusions: While evidence suggests contact and parameter-specific programming can improve SNM therapy outcomes, there is a major gap in the documentation of this data. More detailed testing and documentation could improve therapeutic options for parameter titration and provide design inputs for future technologies.

Is sacral nerve modulation reprogramming effective after permanent implantation for faecal incontinence?

AIM

Sacral nerve modulation (SNM) is recommended as a first-line surgical therapy for patients with faecal incontinence (FI). During patient follow-up, it is recommended that stimulation settings be reprogrammed to optimize patient outcomes. The aim of the present study was to evaluate the efficacy of stimulator reprogramming in patients with an implanted SNM device to treat FI.

METHOD

The data from patients who received a permanent SNM implant in a single centre from January 2008 to December 2019 were retrospectively analysed. Symptoms that occurred after implantation, the stimulator settings of the SNM device and changes made at each follow-up visit were noted. The efficacy of reprogramming was determined by assessing patient satisfaction.

RESULTS

Of the 117 patients (male/female 4/113; mean age 59.5 ± 11.8 years) with a SNM implant for FI, 84 (72%) had at least one symptom requiring reprogramming of the stimulator, most often during the first year after implantation (p = 0.05). The most frequently reported symptoms were loss of efficacy (68.5%; p = 1 × 10^-3 ) and pain (20.5%; p = 1 × 10^-3 ). Reprogramming was effective 53% of the time when treating loss of efficacy and 76% of the time when treating pain. When the stimulation parameters were reprogrammed at least four consecutive times to correct a symptom, the reprogramming was less effective in treating the symptom (p = 0.02).

CONCLUSION

Regular follow-up of patients with SNM device implants associated with reprogramming of stimulation parameters to improve the treatment of reported symptoms would optimize the efficacy of SNM.