Sacral Neuromodulation: Determining Predictors of Success

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.

Our 11-Year Experience With Percutaneous Tibial Nerve Stimulation in Men and Women for the Treatment of Interstitial Cystitis/Bladder Pain Syndrome

OBJECTIVE

To evaluate the effect of percutaneous tibial nerve stimulation (PTNS) in interstitial cystitis/bladder pain syndrome (IC/BPS).

METHODS

Retrospective chart review was completed for patients with at least 10 weekly treatments of PTNS from January 2010 to October 2021. PTNS success was defined as conversion to PTNS maintenance therapy following 12weeks of PTNS induction therapy. Data were analyzed using GraphPad.

RESULTS

Over the 11-year study period, 27 out of 34 patients (mean age 52.9 ± 16.8years; 25 females, 9 males) completed 12weeks of PTNS induction therapy, and 48.1% (13/27) successfully converted to PTNS maintenance therapy. Following 12weeks of PTNS induction therapy, significant improvements were noted in the urgency severity scale (range 0-4: 2.9 ± 1.2 before vs 1.1 ± 1.1 after PTNS, P = .001) and nocturnal urinary frequency (number of voids: 3.3 ± 1.9 before vs 2.2 ± 1.6 after PTNS, P = .041); and nonsignificant improvements were noted in daytime void frequency (hours: 1.5 ± 0.7 before vs 2.0 ± 0.9 after PTNS, P = .090) and the pain domain of the interstitial cystitis symptoms index (question 4, range 0-4: 2.5 ± 1.4 before vs 1.3 ± 1.8 after PTNS, P = .082).

CONCLUSION

Our sample size is among the largest sample of PTNS in IC/BPS from a single center. While PTNS achieved nonsignificant improvements in pain and daytime void frequency, significant improvements were observed in urinary urgency and nocturia. PTNS appears to be a plausible option in the multimodal approach to managing IC/BPS.

[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.

Bullseye Technique to Optimize S3 Foramen Access: Applying a Trusted Endourology Technique to Pelvic Medicine

BACKGROUND

Sacral neuromodulation (SNM) is an advanced therapy that stimulates sacral spinal nerves to modulate bladder or bowel dysfunction and is approved for the treatment of overactive bladder, fecal incontinence, and non-obstructive urinary retention. Prior to implantation, a successful trial period must be performed via percutaneous nerve evaluation (PNE) or a staged trial to assess treatment efficacy. Ideal lead placement in the S3 foramen is imperative to produce an adequate response and successful outcome. Traditional lead placement with fluoroscopic guidance utilizes the anteroposterior (AP) and lateral views. In this abstract we describe an additional modification which may aid lead placement.

OBJECTIVE

This video demonstrates the bullseye technique to obtain S3 foramen access for optimal lead placement in SNM.

METHODS/MATERIAL

Begin the procedure by placing the patient in the prone position. The medial edges of the S3 foramen are marked bilaterally in the AP view followed by a horizontal marking at the level of S3. The pelvis is imaged with live fluoroscopy starting at 0 degrees and then rotating the C-arm to 30 degrees. This rotation allows the "opening up" of the S3 foramen from an ellipsoid to an oval. The surgeon grasps the needle with a Kelly clamp, placing it at the level of the skin approximately 2 cm cephalad from the horizontal marking. Live fluoroscopy is performed to align the needle with the image intensifier to form the bullseye. Once the correct angle is identified, the needle is advanced. The procedure is repeated on the contralateral foramen.

RESULTS

The bullseye technique allows quick and predictable access into S3. It can potentially decrease operating time, minimize needle entries in PNE, and allows the surgeon to access S3 while maintaining proper medial orientation.

CONCLUSION

The bullseye technique can assist surgeons in obtaining optimal access in SNM and can quickly be integrated into current practices.

Implementation of sacral neuromodulation for urinary indications. A Danish prospective study during the initial 15 months of a new service in a tertiary referral hospital

OBJECTIVE

Sacral neuromodulation (SNM) is a well-established treatment modality for idiopathic overactive bladder and urgency incontinence, idiopathic fecal incontinence and non-obstructive urinary retention. This study describes the start-up phase of establishing the SNM service. Primary objective: To investigate the patient-reported outcome measures of SNM on lower urinary tract dysfunction symptoms. Secondary objectives: To investigate bowel function, sexual satisfaction and to monitor SNM safety.

MATERIALS AND METHODS

Twenty-two patients with refractory idiopathic and neurogenic lower urinary tract dysfunction were offered a two-stage test-phase procedure and SNM device implantation. On completing the study, the patients rated their satisfaction with the treatment using a five-point Likert scale and a bother score of urinary, bowel and sexual symptoms on a scale of 1-10 (the worst). Their complications were assessed.

RESULTS

Nineteen patients (86%) were responders during the test phase and had the pulse generator implanted. Seventeen patients were very satisfied/satisfied. A statistically significant change in urinary symptoms bother score was observed in the idiopathic and neurogenic patients, a reduction from 10 to 4 (p = .0057) and 10 to 3 (p = .014), respectively. Eleven patients (58%) had symptoms from two or three pelvic compartments. Nine patients (47%) had complications. All but one event was resolved.

CONCLUSIONS

SNM is safe in this heterogeneous group of patients with refractory lower urinary tract dysfunction of various etiologies. A substantial improvement was observed in the pelvic organ dysfunction, demanding a multidisciplinary approach. More studies are required to standardize the evaluation of the subjective and objective outcomes of SNM.

Unsuccessful Progression of Sacral Neuromodulation From the Evaluation to the Implantation Stage: A Single-Center Experience

Introduction

Over the years, sacral neuromodulation (SNM) has become an established and effective treatment for chronic urinary system retention and incontinence. The process of SNM is performed in two stages, the first is an evaluation phase and the second an implant phase. This study aimed to assess the rate of failure of progression from the evaluation to the implantation stage and the factors predicting the outcome of this commonplace procedure.

Materials and methods

This retrospective cross-sectional study took place at King Abdulaziz Medical City (KAMC), Riyadh, Saudi Arabia. All the patients who underwent SNM implantation from January 1, 2016 to January 1, 2021 were included. Patients younger than 14 years and patients who had the SNM implantation in a different hospital and were only followed-up at KAMC were excluded. Patient-related information were extracted from the BESTCare system. Frequency and percentage were used for the categorical variables, and the mean, median, and standard deviation to display the continuous variables. Chi-square test and Mann-Whitney U test were used to test for the association of the categorical variables.

Results

Among 28 patients, 46.4% (n=13) failed to progress from the evaluation phase to the implantation phase. Gender, age, having a co-morbidity, and SNM indication were not significant factors for predicting the outcome of the SNM evaluation phase.

Conclusion

The observed failure rate was marginally higher than the ones detected in other studies. Although no significant association was detected between evaluation stage failure and the assigned predictors, the results need to be interpreted with caution due to the small population size. Larger multicenter studies need to be done in order to investigate the link between patient characteristics and the efficacy of SNM. Establishing a concrete evidence would further refine the targeted patient population and indications for SNM.

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

Objectives

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

Materials and Methods

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

Results

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

Conclusions

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

Predictive Factors in Sacral Neuromodulation: A Systematic Review

INTRODUCTION

Sacral neuromodulation (SNM) is an effective treatment in patients with overactive bladder syndrome or nonobstructive urinary retention when conservative treatment fails. Several factors that could impact outcome with SNM have been studied. This systematic review investigated these predictive factors and their relevance for clinical practice.

METHODS

Systematic review according to the PRISMA guidelines was conducted. This review is registered in the PROSPERO register (CRD42015016256).

RESULTS

Seventy-eight studies (of which 11 abstracts) were included. Females, younger patients, and a tined lead procedure tend to be predictive in successful SNM outcome. Factors that did not influence SNM outcome were prior back surgery, surgery for stress urinary incontinence, affective symptoms, and duration of complaints. Reduced detrusor contractility is associated with a lower success rate. The level of evidence of most studies (graded according to the Centre for Evidence-Based Medicine) was 3b.

CONCLUSION

Even though this systematic review investigated predictive factors (gender, age, type of procedure, type of lead, and detrusor contractility), no general consensus on predictive factors could be made. Most studies are small, retrospective, and involve a heterogeneous population. Therefore, prospective research in larger specific patient groups remains necessary to find predictors of SNM outcome.