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

One-stage implant in sacral neuromodulation for faecal incontinence - short-term outcome from a prospective study

AIM

Sacral neuromodulation (SNM) is approved for the treatment of faecal incontinence (FI) in a two-stage technique. With standardized implantation, approximately 90% of patients undergo successful Stage I operation and proceed to a permanent implant (Stage II). The aim of this work was to explore the feasibility of SNM as a one-stage procedure and report the 24-week efficacy.

METHOD

This study included patients diagnosed with idiopathic FI or FI due to an external anal sphincter defect ≤160° and one or more episodes of FI per week despite maximal conservative therapy. Patients were offered a one-stage procedure if a motor response of the external anal sphincter was achieved in three or more poles with at least one at ≤1.5 mA at lead placement. Patients were followed for 24 weeks. Their evaluation included the Wexner/St Mark's Incontinence Score, Faecal Incontinence Quality of Life score (FIQoL), a visual analogue scale (VAS) for assessing patient satisfaction and a bowel habit diary.

RESULTS

Seventy-three patients with a median age of 60 years (interquartile range 50-69 years) completed this prospective study. Episodes of FI were significantly reduced at the 24-week follow-up, from 13 (8-23) at baseline to 2 (0-5) (p-value = 0002). A ≥50% reduction in the number of FI episodes was achieved in 92% of participants. The Wexner score improved significantly from 16 (14-17) at baseline to 9 (5-13) (p-value < 0.001), and the St Mark's score improved significantly from 18 (16-20) to 11 (7-16) (p-value < 0.001). All domains in the FIQoL score and VAS for patient satisfaction improved significantly following the one-stage procedure.

CONCLUSION

A one-stage implantation procedure is feasible in selected patients with FI, significantly improving continence, quality of life and patient satisfaction after 24 weeks of follow-up.

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.

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.

Infection Rate of a Prolonged Sacral Neuromodulation Test: A Large Retrospective Study

OBJECTIVES

It is estimated that 3.8% to 12.5% of patients develop a device infection during the two to four weeks of the sacral neuromodulation (SNM) test, leading to removal of the entire system. It is possible to prolong the test phase up to the clinician's decision, particularly when benefits are unclear. The aim of our study is to assess the device infection rate in a prolonged SNM test.

MATERIALS AND METHODS

We retrospectively enrolled patients who performed a prolonged SNM test (at least eight weeks) in the last five years (2017-2021). All procedures were performed using a standardized technique and the same prophylactic antibiotic protocol. In case of a clinical suspicion of infection, all components were explanted. Patient information (age at implantation, medical history of diabetes, metabolic syndrome, immunologic diseases, or chronic immunosuppressive therapy), surgical data (operative time, intraoperative complications), and infection data (timing of onset, symptoms reported, wound culture results) were recorded.

RESULTS

We enrolled 232 patients who underwent a prolonged SNM test (mean duration 65.5 days). A local infection that led to the removal of the entire system occurred in six patients (2.6%). The gluteal pocket was always involved, and in two cases, infection was also extended to the exit point of the extension wire. No significant correlations with clinical data were found. Infection occurred beyond four weeks in two cases, between three and four weeks in three cases, and within two weeks in one case. Intraoperative wound culture was performed in five of six patients, and Staphylococcus aureus (S aureus) was isolated in four cases. One culture test gave negative bacterial growth results.

CONCLUSIONS

The infection rate of a prolonged eight-week SNM test is low and does not differ from that reported in the literature for a two-to-four-week SNM test. S aureus remains the most frequent bacterium involved.

Assessing the effectiveness of antimicrobial pouch use for infection prevention in sacral neuromodulation

INTRODUCTION AND HYPOTHESIS

Sacral neuromodulation (SNM) is a commonly performed procedure for various conditions. Infection rates range as high as 10% and often require operative explantation with resultant increased cost and morbidity. Pouches impregnated with antibiotic have been utilized in cardiovascular procedures with decreasing infectious complications. TYRX is an antibiotic pouch utilizing minocycline and rifampin manufactured by Medtronic. The objective of this study is to investigate the utility of antimicrobial pouches for patients undergoing SNM.

METHODS

We retrospectively analyzed our patients undergoing SNM using an antimicrobial pouch and compared them with a historic cohort. Additional variables of interest included post-operative infection, diagnosis of diabetes, weight, and revision case or virgin implant.

RESULTS

A total of 170 cases were identified, ranging from March 2017 to November 2022. Overall infection rate was 2.9% with 0 in the antimicrobial pouch cohort (0%) versus 5 in the historic cohort (5.5%; p = 0.04). Groups were similar in terms of body habitus. The group receiving an antimicrobial pouch was noted to be older with a higher percentage of female patients. 85 patients received an antimicrobial pouch and 85 did not. Of the infections, 4 occurred in revision cases (6.9%) and 1 in a virgin implant (0.9%; p = 0.03). No difference was noted in infection rate with regard to a diagnosis of diabetes or body habitus.

CONCLUSION

The use of antimicrobial pouches in SNM is associated with a decreased rate of infectious complications. Revision cases displayed a higher rate of infectious complications.

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

INTRODUCTION AND HYPOTHESIS

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

CLINICAL TRIAL REGISTRATION

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

[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.

Long-term results of sacral neuromodulation for the treatment of anorectal diseases

INTRODUCTION

Sacral neuromodulation (SNM) aims to improve anorectal function in patients with disorders of anal continence and rectal emptying. The mechanism of action of SNM is not well known, and its indications are still under evaluation. We report the functional results and morbidity of a prospective cohort treated between 2002 and 2019.

RESULTS

A total of 284 patients (of 423 tested) had implantation of a SNM. Five patients (1.8%) were lost to follow-up. Among those who had implantation, the indications for SNM were anal incontinence (n=376), refractory constipation (n=17), anterior resection syndrome (n=13), solitary rectal ulcer syndrome (n=7), and chronic inflammatory bowel disease (IBD) (n=10). The morbidity rate was 2.7% (Dindo-Clavien>2), 33 patients (11%) required explantation for infection (n=5), pain (n=2), inefficacy (n=24) or other reasons (rectal cancer) (n=3). It was necessary to change the stimulator in 68 patients (24%) during the follow-up period. Regarding the group of patients with anal incontinence, functional results showed improvement of the incontinence score in 40% and of quality of life in 25% after a mean follow-up of 55months.

CONCLUSION

SNM constitutes a mini-invasive treatment associated with low morbidity. Its' efficacy in anal incontinence makes it a priority approach. Other indications are still under evaluation; while results are promising, they are highly variable.

Is there a role for sacral neuromodulation in patients with neurogenic lower urinary tract dysfunction?

PURPOSE

To review current literature regarding sacral neuromodulation (SNM) for neurogenic lower urinary tract dysfunction (NLUTD) focused on indications, barriers and latest technological developments.

MATERIAL AND METHODS

A PubMed database search was performed in April 2020, focusing on SNM and various neuro-urological conditions.

RESULTS

SNM has been increasingly indicated for lower urinary tract dysfunction (LUTD) in neuro-urological patients. Most studies are cases series with several methodological limitations and limited follow-up, lacking standardized definition for SNM clinical success. Most series focused on neurogenic overactive bladder in spinal cord injured (incomplete lesions) and multiple sclerosis patients. Barriers for applying this therapy in neurogenic LUTD were mainly related to magnetic resonance imaging incompatibility, size of the implantable pulse generator (IPG), and battery depletion. Newer technological advances have been made to address these limitations and will be widely available in the near future.

CONCLUSIONS

SNM seems a promising therapy for neurogenic LUTD in carefully selected patients with incomplete lesions. Further studies are still needed to define which subgroups of neurological patients benefit the most from this minimally invasive technique.

Evaluation of progression from first to second stage sacral neuromodulation and unplanned device removal

OBJECTIVE

Sacral neuromodulation (SNM) is an advanced treatment option for patients with refractory overactive bladder (OAB) symptoms, urinary retention, and bowel disorders; it is usually performed in 2 separate procedures. This study aims to determine a cohort's progression rate from stage 1 to 2 and predict factors for progression and unplanned device removal or revision.

MATERIAL AND METHODS

A retrospective review was conducted in patients who underwent SNM at a single institution between June 2012 and May 2019. Progression rates from stage 1 to 2, patient characteristics, and indications for unplanned SNM removal or revision were recorded. Chi-square, Mann-Whitney U, and Fisher's exact tests were used for data analysis.

RESULTS

A total of 128 patients underwent SNM for 1 or more of the following diagnoses: OAB (n=103), urinary retention (n=15), neurogenic bladder dysfunction (n=4), fecal incontinence (n=2), and constipation (n=4). The progression rate to stage 2 was 92.2% (118/128). Patients who failed to progress to stage 2 had additional diagnoses other than OAB, such as urinary retention or bowel disorders (p=0.007). Fifteen patients (12.7%) required SNM removal or revision within 4 years of surgery. Among these patients, the body mass index was significantly lower (p=0.036).

CONCLUSION

Most patients (92.2%) progressed to stage 2. Patients with only OAB symptoms had a higher progression rate to stage 2. Single full-stage procedures may be considered in select patients to reduce morbidity, time, and costs.

Needs, priorities, and attitudes of individuals with spinal cord injury toward nerve stimulation devices for bladder and bowel function: a survey

Study Design:

Survey.

Objectives:

To investigate the needs and priorities of people with spinal cord injury for managing neurogenic bladder and bowel function and to determine their willingness to adopt neuromodulation interventions for these functions.

Methods:

Anonymous online survey. It was advertised by word-of-mouth by community influencers and social media, and by advertisement in newsletters of advocacy groups.

Results:

Responses from 370 individuals (27% female, 73% male) were included. Bladder emptying without catheters was the top priority for restoring bladder function, and maintaining fecal continence was the top priority for restoring bowel function. The biggest concerns regarding external stimulation systems were wearing a device with wires connecting to electrodes on the skin and having to don and doff the system daily as needed. The biggest concerns for implanted systems were the chances of experiencing problems with the implant that required a revision surgery or surgical removal of the whole system. Respondents were willing to accept an external (61%) or implanted (41%) device to achieve improved bladder or bowel function.

Conclusions:

Bladder and bowel dysfunction remain important unmet challenges for individuals living with SCI who answered our survey. These individuals are willing to accept some potential risks of nerve stimulation approaches given potential benefits. Additional consumer input is critical for guiding both research and translation to clinical use and personalized medicine.

Neuromodulation in urology, state of the art

Sacral neuromodulation is an approved and validated treatment for overactive bladder syndrome, chronic non-obstructive retention, and chronic pelvic pain. Percutaneous tibial nerve stimulation is a less invasive approach of neuromodulation. We performed a literature research to assess the current evidence available about neuromodulation. Both techniques appear to be effective and safe third-line treatments. The overall success rate ranges from 43% to 85% for sacral neuromodulation and from 40% to 79.5% for percutaneous tibial nerve stimulation. Sacral neuromodulation has a higher incidence of complications in comparison to percutaneous tibial nerve stimulation, due to the more invasive surgical technique and the presence of a permanent implant. The incidence of surgical revision ranges between 9% and 33%. The most frequent complication with sacral neuromodulation is pain at implant site (15%-42%), followed by lead migration (4%-21%), pain at lead site (5.4%-19.1%), leg pain (18%), and infection (5.7%-6.1%). The quality of the studies on sacral neuromodulation and percutaneous tibial nerve stimulation in literature is quite modest, because of the shortage of good randomized clinical trial; most of the studies are prospective observational studies with mid-term follow-up.

Is Sacral Nerve Modulation a Good Option for Fecal Incontinence in Men?

OBJECTIVE

The objective was to assess the efficacy and the safety of sacral nerve modulation (SNM) in men with fecal incontinence (FI) compared with those of SNM in women.

METHOD

Prospectively collected data from patients from seven tertiary colorectal units who underwent an implant procedure between January 2010 and December 2015 were reviewed retrospectively. Outcomes and surgical revision and definitive explantation rates were compared between men and women.

RESULTS

A total of 469 patients (60 men [12.8%]; mean age = 61.4 ± 12.0 years) were included in the study, 352 (78.1%) (31 men [8.8%]) of whom received a permanent implant. The ratio of implanted/tested men was significantly lower than the ratio of implanted/tested women (p = 0.0004). After a mean follow-up of 3.4 ± 1.9 years, the cumulative successful treatment rates tended to be less favorable in men than in women (p = 0.0514): 88.6% (75.6-95.1), 75.9% (60.9-86.4), 63.9% (48.0-77.3), and 43.9% (26.7-62.7) at one, two, three, and five years, respectively, in men; 92.0% (89.1-94.2), 84.2% (80.3-87.4), 76.8% (72.3-80.7), and 63.6% (57.5-69.3) at one, two, three, and five years, respectively, in women. The revision rate for infection and the definitive explantation rate for infection were higher in men than in women (p = 0.0001 and p = 0.0024, respectively).

CONCLUSION

Both short- and long-term success rates of SNM for FI were lower in men than in women. The revision and definitive explantation for long-term infection rates were significantly higher in men.

[Sacral neuromodulation in under- and overactive detrusor-quo vadis? : Principles and developments]

BACKGROUND

Sacral neuromodulation (SNM) has been used in the treatment of refractory overactive bladder syndrome, nonobstructive urinary retention and faecal incontinence for almost 40 years now. It is not to be confused with the sacral anterior root stimulation which is exclusively used for bladder dysfunction due to spinal paraplegia.

MECHANISM OF ACTION

The principles of SNM are yet to be fully understood. Nevertheless, there is proof of modulating the activity of several micturition-associated, afferent neurons in the spine, brainstem and cerebrum. Thus, premature detrusor contractions are suppressed, the desire to void is delayed and detrusor-sphincter coordination improves.

TECHNIQUES OF IMPLANTATION AND STIMULATION

Motor reactions are an important indicator of correct electrode placement. The implantation procedure consists of two stages with an initial trial phase to determine the best possible treatment response through an external generator before implanting the whole stimulating device. Yearly check-up examinations are recommended; wireless adjustments allow for long-lasting symptom reduction.

INDICATION AND OUTCOME

Success rates in the treatment of the refractory overactive bladder syndrome and the non-obstructive urinary retention lie above 70% and can still be perceived as sufficient after 5 years of ongoing SNM therapy. There is also profound evidence of SNM being an effective option for patients with faecal incontinence or chronic obstipation.

CONTRAINDICATIONS AND RISKS

Children, pregnant women and patients in need of frequent MRI examinations are usually not eligible for SNM therapy. Infection of the implant, technical failure (including lead displacement and battery depletion) and pain in the implantation site are important adverse effects which might require surgical revision.

CONCLUSIONS

The indications for SNM in the German health care system can be expected to be expanded upon the chronic pelvic pain syndrome, erectile dysfunction and additional gastrointestinal conditions. Technical progress will continue to improve the risk-benefit ratio of SNM.