Bacterial colonization of stimulation electrode wires in patients undergoing temporary sacral nerve stimulation

Microbial colonization of sacral nerve stimulators pseudo-capsule: A single institution experience

PURPOSE

To evaluate the incidence and type of microbial colonization of the pseudo-capsule (PC) that forms around sacral nerve stimulators (SNS) and consequently the significance of surgical excision of this PC at time of SNS revision or removal.

MATERIALS AND METHODS

A cohort of 31 patients who underwent SNS revision or removal from January 2018 to June 2021 were retrospectively reviewed. The baseline demographics, rate and type of PC microbial colonization and development of SNS insertion site infection were reported.

RESULTS

A cohort of 31 patients who underwent "InterStim device (Medtronic)" revision or removal were included. The majority were females (93.5%). The most common indication for SNS insertion was refractory overactive bladder (67.7%). Nine patients (29.0%) underwent SNS revision due to malfunctional device, and 9 patients had SNS removal for the need of MRI procedures. Four patients (12.9%) had positive tissue culture growing Coryneform bacillus (50.0%), Cutibacterium acnes (25.0%) and Pseudomonas aeruginosa (25.0%).

CONCLUSIONS

PC colonization was uncommon at the time of SNS explant. However, more research is needed to better understand the role of PC-positive culture in increasing the risk of SNS device infections if strict adherence to sterile techniques is adopted.

Sonication in Patients With Spinal Cord Stimulation: A New Approach for Infection Diagnostics

INTRODUCTION

Spinal cord stimulation (SCS) offers improvement in pain and function for several chronic pain conditions. There are concerns regarding bacterial colonization of the temporary lead extensions and subsequent infection risk in a two-session implantation procedure. Although there is no standardized evaluation of SCS lead contamination, this study evaluates the infection rate and microbial colonization of SCS lead extensions with sonication, a method that is established in implant-related infection diagnostics.

MATERIALS AND METHODS

This prospective observational study comprised 32 patients with a two-stage SCS implantation procedure. Microbial colonization of the lead extensions was assessed with sonication. The presence of organisms in the subcutaneous tissue was evaluated separately. Surgical-site infections were recorded. Patient demographics and risk factors including diabetes, tobacco use, obesity, trial length, and infection parameters in serum were recorded and analyzed.

RESULTS

The mean age of the patients was 55 years. On average, the trial length was 13 days. In seven cases (21.9%), a microbial lead colonization was found with sonication. In contrast, there was one positive culture (3.1%) from the subcutaneous tissue samples. The C-reactive protein and leukocyte count remained at the preoperative level. One early surgical-site infection (3.1%) occurred. No other late infections occurred six months after surgery.

CONCLUSIONS

There is a discrepancy between the presence of microbial colonization and the occurrence of clinically relevant infections. Although the rate of microbial colonization of the lead extensions is high (21.9%), the surgical-site infection rate remained low (3.1%). Therefore, we can conclude that the two-session procedure is a safe approach that is not associated with a higher incidence of infection. Although the sonication method cannot be used as the sole tool for detecting infections in patients with SCS, it can provide additional value in microbial diagnostics in combination with clinical and laboratory parameters and conventional microbiological methods.

[Functional results and satisfaction in 44 patients after implantation of a NS3-type sacral neurostimulator for refractory idiopathic overactive bladder followed at 43 months, single-center series]

OBJECTIVES

Sacred neuromodulation (SNM) has been used in France since 1997 for the management of non-neurogenic urinary disorders that do not respond to first-line pharmacological treatment. The aim of this study is to analyze the clinical efficacy and satisfaction of patients with refractory idiopathic overactive bladder (OAB) treated with SNM.

METHODS

This single-center retrospective series included 59 patients with refractory OAB of idiopathic origin and eligible for the SNM between January 2010 and December 2017. Demographic data, history of pelvic surgery, complications according to Clavien-Dindo classification, as well as revision and explantation rates were collected. All the patients included underwent a test phase. Therapeutic success for the test phase and definitive implantation was defined by≥50% improvement. Satisfaction was a secondary criteria.

RESULTS

Of the 59 patients tested for SNM, 44 patients had a permanent implantation, of which 36 (82%) were women and 8 (12%) were men. The median age of the study was 55 years old. The median follow-up was 43 months [21,2-66,5]. All of the patients had an idiopathic refractory OAB. The median time between test and final implantation was 28 days [18-35]. The success rate for all patients tested was 60% (34/59). In patients implanted, 34 patients (77%) had clinical improvement. Adverse events had to be managed including multiple re-parameterizations (n=13), device revision (n=16), or even device implantation (n=8). The satisfaction rate was 82% (36/44).

CONCLUSION

With a median follow-up of 43 months, this retrospective study on NMS shows the efficacy of second-line SNM for idiopathic OAB. This technique remains minimally invasive but with significant adverse events when informing our patients.

LEVEL OF EVIDENCE

3.

[The use of surgical neuromodulation to treat chronic pelvic pain]

Chronic pelvic pain (CPP) is a pain syndrome that is very difficult to treat. The effectiveness of CPP treatment remains low despite the use of integrated approaches. That is why it is necessary to search for new treatment approaches and methods. Surgical neuromodulation has recently been used increasingly often to treat CPP.

OBJECTIVE

To evaluate the effectiveness of different types of neurostimulation in patients with chronic pelvic pain.

MATERIAL AND METHODS

Thirty-two patients were treated at the N.N. Burdenko National Scientific and Practical Center for Neurosurgery. All the patients were diagnosed with CPP and transferred to the Center because of unsatisfactory results of earlier treatment. The mean duration of pain was 8.6 years (range: 1-31 years). Pain intensity and the neuropathic component of the pain syndrome were assessed using the conventional scales and questionnaires (VAS, LANSS, Pain Detect, and DN4). The levels of anxiety, depression, and catastrophic pain were also assessed. The effect of pain on quality of life was evaluated using the modified Brief Pain Inventory (BPI). All the selected patients underwent trial lead implantation at the first stage. Sacral root stimulation was used in 15 patients (unilateral one in 8 patients and bilateral one in 7 patients); three patients underwent spinal cord stimulation; 14 patients were treated with combined neurostimulation.

RESULTS

In 27 (84.37%) patients, the trial period was regarded as positive and the systems were implanted for chronic neurostimulation. After one year of stimulation, the mean VAS score for pain intensity was 3.53 (compared to 8.61 before the surgery). Regarding quality of life, the most significant effects of treatment were as follows: the number of pain paroxysms was reduced; physical self-maintenance, social life, sleep, and sexual activity were improved; and daily physical activity was increased.

CONCLUSION

. Neurostimulation ensures a stable pain relief and improves quality of life in patients with chronic pelvic pain refractory to conservative treatment.

A randomized double-blinded sham-controlled cross-over trial of tined-lead sacral nerve stimulation testing for chronic constipation

OBJECTIVES

Sacral nerve stimulation (SNS) may provide long-term symptom relief to patients suffering from chronic constipation. Patients are currently selected for SNS using a 2-week peripheral nerve evaluation (PNE) comprising stimulation by temporary leads. However, only 40% of test responders receive long-term benefit from treatment meaning that healthcare costs per successfully treated patient are too high. The primary objective was to assess tined-lead testing to predict benefit from SNS for chronic constipation.

PATIENTS AND METHODS

A randomized double-blind sham-controlled cross-over design evaluated enhanced PNE (ePNE) using tined quadripolar electrode leads over 6 weeks. The design differentiated between patients with discriminate and indiscriminate responses to testing. A score improvement of 25% or more was considered to be a positive response within a stimulation period. The primary outcome was the proportion of patients showing a reduction of at least 0.5 in constipation symptom score at 6 months.

RESULTS

A total of 45 patients were randomized, of whom 29 (64.4%) were test-phase responders. Of these, 27 were implanted providing permanent SNS. During ePNE, seven (18%) were discriminate responders, 22 (56%) were indiscriminate responders and 10 (26%) were nonresponders. Six patients were withdrawn during the test phase because of infection or noncompliance. At 6 months, there was no significant difference in primary outcome between discriminate and indiscriminate responders (60 vs. 57%, P=0.76). The study was terminated prematurely because of a persistent infection rate of 10 (22%) during ePNE of which nine (20%) were severe.

CONCLUSION

ePNE is a poor predictor of treatment response at 6 months. This suggests a strong and persistent placebo response during both SNS PNE and treatment. An extended 6-week PNE poses a high risk of infection.

Sacral Nerve Stimulation for Fecal Incontinence: How Long Should the Test Phase Be?

BACKGROUND

Decision-making for pulse generator implantation for sacral nerve stimulation in the management of fecal incontinence is based on the results of a test phase. Its duration is still a matter of debate.

OBJECTIVE

The purpose of this study was to determine whether an early positive response during the test phase could predict implantation of a permanent sacral nerve pulse generator.

DESIGN

This was a short-term observational cohort study. A positive response was defined as a >50% decrease of fecal leaks compared with baseline. A multivariate logistic regression was computed to predict pulse generator implantation after the first week of the test phase.

SETTINGS

The study was conducted in 3 national referral centers.

PATIENTS

From January 2006 to December 2012, 144 patients with fecal incontinence enrolled in a prospectively maintained database completed a 2- to 3-week bowel diary, at baseline and during test phase.

MAIN OUTCOME MEASURES

The primary outcome was the clinical decision to implant a pulse generator. The primary predictor was a calculated score including the number of leak episodes, bowel movements, and urgencies and the time to defer defecation expressed in minutes during the first screening test week.

RESULTS

After the first, second and third week of the test phase, 81 (56%) of 144, 96 (67%) of 144, and 93 (70%) of 131 patients had a positive test. A permanent pulse generator was implanted in 114. Time to defer defecation increased during the 3 weeks of screening. Urgencies were unchanged. The computed score was predictive of a permanent pulse generator implantation (Se = 72.6% (95% CI, 59.8-83.1); Sp = 100% (95% CI, 78.2-100); c-index = 0.86 (95% CI, 0.78-0.94)).

LIMITATIONS

No cost analysis or projection based on our proposal to reduce the test phase has been made.

CONCLUSIONS

Permanent pulse generator implantation can be safely proposed early (1-week screening) to fast responders. Nonetheless, permanent implantation may be decided as well in patients exhibiting a delayed response. Whether a rapid response to sacral nerve stimulation could be predictive of a long-term response remains to be determined. See Video Abstract at http://links.lww.com/DCR/A452.

Sacral Neuromodulation Implant Infection: Risk Factors and Prevention

Device infection is one of the most common complications of sacral nerve stimulator placement and occurs in approximately 3-10% of cases. Infection is a serious complication, as it often requires complete explantation of the device. Not much is known regarding risk factors for and methods of preventing infection in sacral nerve stimulation. Multiple risk factors have been linked to device infection including prolonged percutaneous testing and choice of preoperative antibiotic. Methods of infection prevention have also been studied recently, including antibiotic-impregnated collage and type of skin preparation. This review will discuss the recent literature identifying risk factors and means of preventing infection in sacral nerve stimulation. Finally, we will outline a protocol we have enacted at our institution which has resulted in an incidence of infection of 1.6%.

Infection Rates of Electrical Leads Used for Percutaneous Neurostimulation of the Peripheral Nervous System

BACKGROUND

Percutaneous neurostimulation of the peripheral nervous system involves the insertion of a wire "lead" through an introducing needle to target a nerve/plexus or a motor point within a muscle. Electrical current may then be passed from an external generator through the skin via the lead for various therapeutic goals, including providing analgesia. With extended use of percutaneous leads sometimes greater than a month, infection is a concern. It was hypothesized that the infection rate of leads with a coiled design is lower than for leads with a noncoiled cylindrical design.

METHODS

The literature was retrospectively reviewed for clinical studies of percutaneous neurostimulation of the peripheral nervous system of greater than 2 days that included explicit information on adverse events. The primary endpoint was the number of infections per 1,000 indwelling days.

RESULTS

Forty-three studies were identified that met inclusion criteria involving coiled (n = 21) and noncoiled (n = 25) leads (3 studies involved both). The risk of infection with noncoiled leads was estimated to be 25 times greater than with coiled leads (95% confidence interval [CI] 2 to 407, P = 0.006). The infection rates were estimated to be 0.03 (95% CI 0.01 to 0.13) infections per 1,000 indwelling days for coiled leads and 0.83 (95% CI 0.16 to 4.33) infections per 1,000 indwelling days for noncoiled leads (P = 0.006).

CONCLUSIONS

Percutaneous leads used for neurostimulation of the peripheral nervous system have a much lower risk of infection with a coiled design compared with noncoiled leads: approximately 1 infection for every 30,000 vs. 1,200 indwelling days, respectively.

Sacral nerve stimulation for faecal incontinence and constipation: a European consensus statement

AIM

In Europe during the last decade sacral nerve stimulation (SNS) or sacral neuromodulation (SNM) has been used to treat faecal incontinence (FI) and constipation. Despite this, there is little consensus on baseline investigations, patient selection and operative technique. A modified Delphi process was conducted to seek consensus on the current practice of SNS/SNM for FI and constipation.

METHOD

A systematic literature search of SNS for FI and constipation was conducted using PubMed. A set of questions derived from the search and expert opinion were answered on-line on two occasions by an international panel of specialists from Europe. A 1-day face-to-face meeting of the experts finalized the discussion.

RESULTS

Three hundred and ninety-three articles were identified from the literature search, of which 147 fulfilled the inclusion criteria. Twenty-two specialists in FI and constipation from Europe participated. Agreement was achieved on 43 (86%) of 50 domains including the set-up of service, patient selection, baseline investigations, operative technique and programming of the device. The median of agreement was 95% (35-100%).

CONCLUSION

Consensus was achieved on the majority of domains of SNS/SNM for FI and constipation. This should serve as a benchmark for safe and quality practice of SNS/SNM in Europe.

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.

Sacral neuromodulation for bowel dysfunction: a consensus statement from the Italian group

BACKGROUND

Representatives from the Italian centers experienced in sacral neuromodulation (SNM) for the treatment of bowel dysfunction met in order to define the current clinical practice in Italy and to produce a consensus statement regarding indications for this therapy and patient management.

METHODS

Fifty Italian colonproctologists were asked to complete a questionnaire concerning their clinical practice in SNM (290 questions, grouped within 4 broad areas). Physicians expressed their opinion by completing the questionnaire, assigning to each statement their level of agreement according to the 5-point Likert scale; the data were analyzed by attributing to each expert's answers a weight proportional to the degree of experience. During a meeting held 2 months later, the critical aspects of the therapy were re-examined and discussions held with the goal of reaching an agreement on controversial topics. The available literature was reviewed.

RESULTS

Patient selection criteria, etiology, diagnostic investigations, test procedures and implantation, follow-up and evaluation of results have been reviewed. The aim was to achieve an algorithm for patient management, showing the place of SNM in the treatment of bowel dysfunction. The approach in case of treatment failure was also discussed.

CONCLUSIONS

Analysis of the data collected reveals substantial consensus at the national level concerning all the main points with regard to the therapy. The recommendations expressed in this article can be considered as national guidelines and taken into account by the principal international implantation centers.

Postoperative issues of sacral nerve stimulation for fecal incontinence and constipation: a systematic literature review and treatment guideline

BACKGROUND

There is a lack of knowledge on the incidence and management of suboptimal therapeutic effect and the complications associated with sacral nerve stimulation for fecal incontinence and constipation.

OBJECTIVE

This study aimed to review current literature on postoperative issues and to propose a treatment algorithm.

DATA SOURCE

PubMed, MEDLINE, and EMBASE were searched using the keywords "sacral nerve stimulation," "sacral neuromodulation," "fecal incontinence," and "constipation" for English-language articles published from January 1980 to August 2010. A further search was conducted on a wider literature using the keywords "complication," "adverse effect," "treatment failure," "equipment failure," "infection," "foreign-body migration," "reoperation," "pain," and "algorithm."

STUDY SELECTION

Four hundred sixty-one titles were identified, and after a title and abstract review, 135 were subjected to full article review; 89 were finally included in this review. Five articles were added by manual search and consensus.

RESULTS

Forty-eight studies were identified as cohort studies reporting on postoperative issues, including 1661 patients who underwent percutaneous nerve evaluation and 1600 patients who proceeded to sacral nerve stimulation therapy. Pooled data showed that the most common problem during percutaneous nerve evaluation was lead displacement (5.3%). The incidence of suboptimal outcome, pain, and infection after implantation was 12.1%, 13.0%, and 3.9%.

LIMITATIONS

There was significant underreporting of untoward events, because 60% of the studies did not report complications during percutaneous nerve evaluation, and suboptimal outcome after implantation was not disclosed in 44% of the studies.

CONCLUSIONS

The incidence of untoward events associated with sacral nerve stimulation appears to be low. However, there is a significant underreporting of the incidence. Using the information from the structured and systematic literature review, we formulated a clinically relevant guideline for reporting and managing postoperative issues. The guideline can provide a framework for clinical practice.

Sacral nerve stimulation for faecal incontinence: patient selection, service provision and operative technique

AIM

Faecal incontinence is estimated to affect between 2 and 3% of Western adult populations. In recent years sacral nerve stimulation has become an important treatment modality, often as the first-line surgical therapy. The aim of this article was to review the current evidence regarding patient selection and surgical technique and to evaluate the logistics of providing a neurostimulation service.

METHOD

A Medline search was performed including the keywords and/or MeSH headings of sacral nerve stimulation, neuromodulation, artificial pacemaker, faecal incontinence, patient selection, predictive factors and anal canal. Further studies were identified by cross-referencing from relevant articles and by appraisal of recent peer-reviewed conference abstracts and proceedings.

RESULTS

Despite the success of sacral nerve stimulation for several pathophysiological causes of incontinence, case selection is of paramount importance. Sacral nerve stimulation should not be offered outside a multidisciplinary pelvic floor unit. Temporary evaluation using diary cards can lead to false positive and negative results. Adherence to a meticulous surgical technique, using low amplitude stimulation to guide lead placement, provides optimal clinical outcome.

CONCLUSION

The short-term outcome of sacral nerve stimulation is dependent on patient factors and operative technique. Despite this, specific preoperative predictive factors of treatment success have yet to be identified.

The influence of sacral nerve stimulation on anorectal dysfunction

AIM

Sacral nerve stimulation (SNS) has become an established option in the management of defaecatory disorders. There are many data on the end-organ effects of SNS, but limited consensus on its mechanism of action. The objective of this review was to determine the effect of sacral nerve stimulation (SNS) on anorectal function.

METHOD

Systematic literature review of the effect of sacral nerve stimulation (SNS) on anorectal function.

RESULTS

There was significant heterogeneity of data pertaining to the effects of SNS on anorectal function, with no consistent change in physiological measures identified. Most data supported a mixed mechanism of action on anal motor and rectal sensory functioning.

CONCLUSION

To date, conflicting data exist on the mechanism of action of SNS as determined by end-organ changes in anorectal physiology. Nevertheless, the data as they stand best support a mixed mechanism of action on anal motor and rectal sensory functions.