Association Between Stimulation Parameters and Loss of Efficacy of Selective Sacral Nerve Root Stimulation

Treatment of the infected sacral nerve stimulator: A scoping review

BACKGROUND

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

AIMS

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Efficacy and Safety of Sacral Neuromodulation by Converting Constant Frequency Stimulation Into Variable Frequency Stimulation in Patients With Detrusor Overactivity and Impaired Contractility: A Single-Center Prospective Study

OBJECTIVES

In patients with detrusor overactivity with impaired contractility (DOIC), it is difficult to relieve abnormal lower urinary tract symptoms during both storage and voiding using sacral neuromodulation (SNM) with constant frequency stimulation (CFS). We sought to evaluate the efficacy and safety of SNM using variable frequency stimulation (VFS) in patients with DOIC by comparing it with outcomes of SNM with CFS.

MATERIALS AND METHODS

Between September 2020 and May 2021, we prospectively enrolled 20 patients with DOIC, confirmed on urodynamic examination, and administered SNM with VFS. The patients were followed up and required to maintain voiding diaries and record scale scores of overactive bladder symptoms, psychology and quality of life, uroflowmetry, ultrasonic postvoid residual urine, and adverse events at baseline and during the CFS and VFS phases.

RESULTS

The average testing phase was 26.3 ± 4.1 days. Compared with baseline values, overactive bladder symptom, psychologic health questionnaire, and quality of life scores, in addition to voiding frequency, urgency incontinence frequency, daily catheterization volume of voiding diary, and ultrasonic postvoid residual (PVR) decreased significantly during both the CFS and VFS phases (p < 0.05). The average voided volume, functional bladder capacity, and maximum urine flow rate significantly increased during the CFS and VFS phases (p < 0.05). In the VFS phase, voiding frequency, urgency incontinence frequency, daily catheterization volume of voiding diary, and ultrasonic PVR further decreased (p < 0.05), whereas functional bladder capacity, maximum urine flow rate, quality of life score, overactive bladder symptom score, and psychologic health questionnaire score further improved compared with results obtained in the CFS phase (p < 0.05). In the VFS phase, the success rate of further improvement of symptoms was 85.0%, and no new complications were noted.

CONCLUSIONS

SNM that converts CFS into VFS may be an effective treatment option for patients with DOIC, exhibiting no increase in adverse events.

[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.

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.

What uro-gynecologists should know about sacral neuromodulation (SNM) for the treatment of refractory overactive bladder

PURPOSE

To inform uro-gynecologists about the current standards and latest developments of sacral neuromodulation (SNM) in women with overactive bladder (OAB).

METHODS

Literature search in the PubMed database for articles published between 1988 and 2019 on SNM for OAB in women.

RESULTS

In total, 361 articles were identified and 51 articles retrieved for the review. SNM shows an objective success rate of 70-80%, OAB cure rate of 17-47% and a subjective satisfaction rate of 80-90%. These benefits have to be weighed against an adverse event rate of approx. 40%. SNM is significantly more successful than switching to another antimuscarinic after failed antimuscarinic drug therapy. Efficacy of SNM is slightly lower compared to bladder wall injections with 200 U botulinum toxin in the first months but efficacy of both treatments appears to be similar after 24 months. MRI examinations of patients with a sacral neurostimulator should only be performed after radiologist consultation. Sacral neurostimulators in patients with another pacemaker system should only be implanted after interdisciplinary consultation. The sacral neuromodulator should be turned off during pregnancy and delivery. SNM for OAB in patients with concomitant female sexual dysfunction or fecal incontinence seems to be beneficial.

CONCLUSIONS

SNM is a successful and recommended second-line treatment of OAB. Sacral neurostimulators should preferably be implanted in SNM-centers because complications and the frequency of revisions are significantly reduced with increasing experience of the surgeon.