Troubleshooting Sacral Neuromodulation Issues

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.

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 with the InterStim System for Overactive Bladder: 3-Year Results from the French Prospective, Multicenter, Observational SOUNDS Study

BACKGROUND

SOUNDS strengthens the evidence basis of sacral neuromodulation (SNM) for overactive bladder (OAB) through real-world data.

OBJECTIVE

To analyze diary-based effectiveness, quality of life (QoL), disease severity, symptom bother, and safety data for SNM with the InterStim system up to 3 yr after implantation.

DESIGN, SETTING, AND PARTICIPANTS

Twenty-five representative French sites enrolled 291 patients with OAB followed according to the local standard of care. Overall, 229 patients received a de novo or replacement InterStim implant and had four follow-up visits, two within the first yr and annually thereafter. A total of 190 patients completed the fourth follow-up visit after a mean of 33.7 ± 3.7 mo.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

The effectiveness outcomes measured were changes in daily voids and leaks and the therapy responder rates. Other outcomes included validated QoL data (Ditrovie and EuroQol 5-dimension 5-level questionnaires), disease severity (Urinary Symptom Profile [USP]), symptom bother rated using a numeric rating scale (NRS), and safety data. Follow-up data were compared to baseline results using the Wilcoxon signed-rank test.

RESULTS AND LIMITATIONS

Average daily voids and leaks were significantly reduced at all time points up to 3 yr after implantation (p < 0.05) except for voids at 21 mo in the group receiving a replacement device. The therapeutic response for urinary urge incontinence at the fourth follow-up was 72% for the de novo group and 86% for the replacement group. Disease-specific QoL (Ditrovie), OAB-specific symptom severity (USP domain 2), and NRS-rated disease bother were significantly improved at all visits (p < 0.001). Device- or procedure-related adverse events occurred in 49% of patients, with 68% of the events classified as minor (Clavien-Dindo grade I or II). Surgical revisions were performed in 33% of patients, including permanent removal in 13%, over a mean exposure time of 44.4 ± 15.3 mo.

CONCLUSIONS

This study confirms the safety and effectiveness of SNM for OAB and improvements in QoL and disease bother in real life.

PATIENT SUMMARY

Our study in French patients with overactive bladder showed that disease symptoms and bother were significantly reduced and quality of life was significantly improved over a study duration of approximately 3 yr after implantation of a device to stimulate nerves that control the bladder. This trial is registered at ClinicalTrials.gov as NCT02186041.

Progress in research of sacral nerve stimulation

Sacral nerve stimulation (SNS) is well-known as a minimally invasive treatment. Originally, it was mainly used to treat urinary system diseases such as urge urinary incontinence. Gradually, it is used to treat digestive system diseases such as fecal incontinence and chronic constipation. SNS is a method in which electrical pulse signals are sent out through pulse generators to stimulate the sacral nerve directly or indirectly, thus modulating the nerve reflex of the bladder, urethra, anus, colon, and rectum and improving abnormal nerve regulation to achieve the therapeutic effect. The regulation of the sacral nerve is often carried out by inserting electrodes into the sacral spinal canal S_2-4 (mostly S₃), and the symptoms are improved by complex regulation of spinal reflex and supraspinal reflex. However, the exact mechanism is still unclear. Many studies have shown that SNS plays a key role in the treatment of many diseases of the urinary system and digestive system. This paper reviews the progress in the research of SNS.

The Impact of Sacral Neuromodulation on Sexual Dysfunction

Background/Aims

Sacral neuromodulation (SNM) is a well-established treatment in several urinary and bowel dysfunctions, nevertheless its role on sexual dysfunction remains unclear. We evaluate the impact of SNM on sexual function and its association with age at SNM, functional diagnosis and post-void residual urine (PVR) before SNM.

Methods

Patients who had SNM were retrospectively analyzed. Sexual function was assessed before and after treatment with the International Index of Erectile Function (IIEF-5) for men and the Female Sexual Function Index (FSFI) for women. IIEF-5 and FSFI were also associated with age at SNM, functional diagnosis, and PVR.

Results

Fifteen females and 9 males, with a median age of 41 years (26-72 years), median follow-up 20.7 months (2-53 months) were enrolled. IIEF-5 improved in 4 patients (p = 0.06), and FSFI total score in 5 (p = 0.2). There was significant association between functional diagnosis and FSFI total score (p = 0.05), and FSFI specific domains of arousal (p = 0.03), lubrication (p = 0.04), and satisfaction (p = 0.03), with significant improvement showed in patients with detrusor overactivity with impaired contractility.

Conclusion

Although gains observed in IIEF-5 and FSFI were modest, our preliminary results show that SNM may have favorable impact on sexual function.

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%.

CT evaluation of acupuncture needles inserted into sacral foramina

OBJECTIVE

To use CT scanning to evaluate the precision with which acupuncture needles can be inserted into sacral foramina to establish sacral nerve modulation by electroacupuncture.

METHODS

The subjects were five adult women (mean age 71.6 years). These five cases were divided into two groups. In the first three subjects (group A) the intention was to insert acupuncture needles in the S3 and S4 foramina; in the remaining two subjects (group B) the intention was to insert acupuncture needles in the S2 and S3 foramina.

RESULTS

CT scanning showed that in subject 1 of group A, the acupuncture needle intended for insertion in S3 was actually in the S4 foramen, and the acupuncture needle intended for insertion in S4 was actually distal to the sacral body. In subjects 2 and 3, the acupuncture needles were inserted accurately in the S3 and S4 foramina. In the three subjects who had acupuncture needles inserted in the S4 foramen, the tip of the acupuncture needle was an average distance of 6.0 mm from the rectum. The acupuncture needles inserted in subjects 4 and 5 of group B were inserted accurately into the S2 and S3 foramina.

CONCLUSIONS

Inserting acupuncture needles into the sacral foramina of S2 and S3 at an angle of about 60° has the potential to be used for sacral nerve modulation by repeated electroacupuncture stimulation. Needling may be less accurate in subjects with higher body mass index. Because of the potential risk of perforating the rectum with the needle, this technique must be used by specialists only.

TRIAL REGISTRATION NUMBER

2013-026.