Neuromodulation in urology, state of the art

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.

Electroacupuncture for urinary retention after stroke: A systematic review and meta-analysis of randomized controlled trials

BACKGROUND AND PURPOSE

Electroacupuncture (EA) is one of the non-pharmacological therapies in traditional Chinese medicine to treat urinary retention. The objective of this meta-analysis is to assess the efficacy of electroacupuncture in the treatment of urinary retention after stroke.

METHODS

Overall, seven electronic databases were searched until December 31, 2023, and randomized control trials about EA for urinary retention after stroke were reviewed. Two reviewers independently screened the literature, extracted the data, and assessed the risk of bias for included studies. The meta-analysis was conducted by RevMan 5.4 and Stata/MP 17.0 software.

RESULTS

Eleven studies with a total of 856 participants were included in this meta-analysis. EA treatment yielded an improved reduction in the post-void residual (PVR) (mean difference [MD]: 37.85, 95 % confidence interval [CI]: 55.09 to -20.61 p < 0.0001) and the weight of diaper pads (MD: 38.87, 95 % CI: 42.68 to -335.06). Further analysis indicated that EA improved the effectiveness ratio (risk ratio [RR]: 1.36, 95 % CI: 1.20 to 1.53, p < 0.00001), the function of the bladder (MD: 0.45, 95 % CI: 0.61 to -0.30), and the quality of life (MD: 1.15, 95 %: CI: 2.10 to -0.20) in comparison to normal treatment and simple acupuncture.

CONCLUSION

EA may be an effective way and reasonable modality to incorporate into the multiple prevention and therapy for urinary retention after stroke. The wide application of EA could be associated with the improvement of bladder and life quality and decline in the PVR for patients after stroke with urinary retention.

Current position of neuromodulation for bladder pain syndrome/interstitial cystitis

PURPOSE OF REVIEW

Despite established effectiveness in overactive bladder and nonobstructive retention, neuromodulation's application in interstitial cystitis/bladder pain syndrome (IC/BPS) remains a topic of ongoing research. The purpose of this article is to review recent developments in neuromodulation as treatment of IC/BPS offering guidance for healthcare practitioners dealing with IC/BPS cases.

RECENT FINDINGS

Recent research underlines the promising role of sacral, tibial and pudendal neuromodulation in management of IC/BPS symptoms. Studies reveal encouraging outcomes, particularly in alleviating urgency and frequency symptoms. However, while urgency and frequency symptoms tend to improve, comprehensive pain relief remains a challenge. Percutaneous tibial nerve stimulation (PTNS) and transcutaneous tibial nerve stimulation (TTNS) stand out due to their minimal invasive nature. Existing literature points to the need for larger prospective studies with extended follow-up periods to validate the efficacy and sustainability of neuromodulation.

SUMMARY

Neuromodulation is a promising treatment modality for refractory IC/BPS. Due to the minimal invasive nature, they should be tried before rigorous surgery. However, the limited quantity of available data and the variability in pain relief outcomes necessitate cautious interpretation. The review emphasizes the need for further research.

Sacral neuromodulation in the management of non-obstructive urinary retention: Test phase and predictive factors

AIM

The aim of this study is to evaluate the success of the test phase of sacral neuromodulation in management of chronic non-obstructive urinary retention and the factors predictive of good response.

MATERIALS AND METHODS

This is a retrospective study carried out on a cohort of patients followed up in a tertiary University Hospital in France. Fifty-two patients with chronic non-obstructive urinary retention were included in this study. These patients were seen over the past 20 years, from the year 2000 to 2020. The initial evaluation of patients included a summary of medical and surgical history, age, BMI, history of pelvic floor disorders, initial voiding pattern, physical examination, voiding diary, initial uroflowmetry and a urodynamic study. Postoperative follow-up and analysis of complications were also carried out.

RESULTS

A total of 52 patients were included in this study, 13 males and 39 females. Out of these patients, 17 patients (32.7%) with a median age of 47.3 years±18.1 benefited from definitive implantation of the sacral neuromodulation. The univariate analysis showed that age was the only significant variable in this study and the optimal age threshold was<58.5 years.

CONCLUSION

SNM is a therapy with significant clinical benefits and low morbidity for patients with chronic non-obstructive urinary retention. The results obtained need to be confirmed with a prospective study with a larger number of patients.

LEVEL OF EVIDENCE: 4

Data Gap in Sacral Neuromodulation Documentation: Call to Improve Documentation Protocols

Purpose: We quantified patient record documentation of sacral neuromodulation (SNM) threshold testing and programming parameters at our institution to identify opportunities to improve therapy outcomes and future SNM technologies.Methods: A retrospective review was conducted using 127 records from 40 SNM patients. Records were screened for SNM documentation including qualitative and quantitative data. The qualitative covered indirect references to threshold testing and the quantitative included efficacy descriptions and device programming used by the patient. Findings were categorized by visit type: percutaneous nerve evaluation (PNE), stage 1 (S1), permanent lead implantation, stage 2 (S2) permanent impulse generator implantation, device-related follow-up, or surgical removal.Results: Documentation of threshold testing was more complete during initial implant visits (PNE and S1), less complete for S2 visits, and infrequent for follow-up clinical visits. Surgical motor thresholds were most often referred to using only qualitative comments such as “good response” (88%, 100% for PNE, S1) and less commonly included quantitative values (68%, 84%), locations of response (84%, 83%) or specific contacts used for testing (0%). S2 motor thresholds were less well documented with qualitative, quantitative, and anatomical location outcomes at 70%, 48%, and 36% respectively. Surgical notes did not include specific stimulation parameters or contacts used for tests. Postoperative sensory tests were often only qualitative (80%, 67% for PNE, S1) with quantitative values documented much less frequently (39%, 9%) and typically lacked sensory locations or electrode-specific results. For follow-up visits, <10% included quantitative sensory test outcomes. Few records (<7%) included device program settings recommended for therapy delivery and none included therapy-use logs.Conclusions: While evidence suggests contact and parameter-specific programming can improve SNM therapy outcomes, there is a major gap in the documentation of this data. More detailed testing and documentation could improve therapeutic options for parameter titration and provide design inputs for future technologies.

Parametric Assessment of Spinal Cord Stimulation on Bladder Pain-Like Responses in Rats

OBJECTIVES

Spinal cord stimulation (SCS) for the treatment of pelvic visceral pains has been understudied and underused. The goal of the current study was to examine multiple stimulation parameters of SCS to determine optimal settings for the inhibition of responses to urinary bladder distension (UBD) in animal models of bladder pain as a guide for human studies.

MATERIALS AND METHODS

Adult, female isoflurane/urethane-anesthetized rats underwent a T13/L1 mini-laminectomy sufficient to implant an SCS paddle lead for neuromodulation. Silver wire electrodes were inserted into the external oblique musculature. A 22-gauge angiocatheter was placed transurethrally into the bladder and used to deliver phasic, air UBDs at pressures of 10 to 60 mm Hg and visceromotor (abdominal contractile) electromyographic responses to UBD measured in the presence and absence of SCS. Electromyographic activity was quantified using standard differential amplification and rectification. Parameter settings for SCS included both conventional (10, 50, 100 Hz) and high frequency (1,000, 5,000, and 10,000 Hz) biphasic square wave pulses with 50 to 200 μs durations. To create states of hypersensitivity, pretreatment of adult rats included an intravesical zymosan infusion 24 hours before testing with and without a preceding episode of neonatal bladder inflammation.

RESULTS

Low frequency (10, 50, and 100 Hz) 200 μs biphasic pulses at submotor thresholds demonstrated inhibition of visceromotor responses (VMRs) to UBD in rats made hypersensitive to UBD by a protocol that included neonatal cystitis. Onset of inhibitory effects occurred within 20 minutes of beginning SCS. Otherwise, SCS at all other parameters studied and in other tested rat models produced either no significant effect or augmentation of VMRs.

CONCLUSIONS

Demonstration of inhibitory effects of SCS in a clinically relevant model of bladder pain suggests the potential utility of this therapy in patients with painful bladder disorders.

Bilateral electrical pudendal nerve stimulation as additional therapy for lower urinary tract dysfunction when stage II sacral neuromodulator fails: a case report

Background

Sacral neuromodulation (SNM) has become an effective therapy for patients with lower urinary tract dysfunction (LUTD) who do not respond to conservative treatment. However, an effective treatment strategy for patients who fail SNM has not yet been identified. An option for LUTD is needed when the clinical response to the SNM diminishes.

Case presentation

A 51-year-old Chinese man presented to an outpatient clinic complaining of difficulty in urination for > 3 years. The patient also complained of urinary frequency and urgency, accompanied by perineal discomfort. He was diagnosed with LUTD based on his symptoms and previous examinations. The patient underwent sacral neuromodulation with a permanent implantable pulse generator (IPG) (provided free of charge by Chengnuo Medical Technology Co., Ltd.; General Stim, Hangzhou, China) in the left buttock, as he participated in the company’s clinical trial to test the long-term effects of IPG. He reported loss of efficacy of the device 3 months after the implantation. We performed bilateral electrical pudendal nerve stimulation (EPNS) therapy for him. After 2 weeks of treatment, he began to report smooth voiding within 2 h after EPNS, and a moderate improvement in urinary frequency, urgency, and perineal discomfort. After 4 weeks of EPNS, the patient reported > 50% improvement in his urination, evaluated with the short form of the International Consultation on Incontinence Questionnaire for Male Lower Urinary Tract Symptoms. He reported smooth voiding, moderate improvements in urinary frequency and urgency, and the disappearance of the perineal discomfort. He also reported improved sleep and erections. The patient was discharged after 8 weeks of EPNS treatment.

Conclusion

EPNS could be an option as an additional therapy for patients with LUTD who have failed SNM.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12894-021-00808-5.

Does age alone negatively predict the outcome of sacral neuromodulation? A single-centre retrospective observational study

BACKGROUND

For patients over the age of 70 years, sacral neuromodulation (SNM) is often not considered a potential therapeutic option. We therefore report on our results from performing SNM in elderly patients ≥70 years.

METHODS

Between 01/09 and 12/18, a total of 95 patients with refractory overactive bladder (OAB) or chronic non-obstructive urinary retention underwent SNM testing at our department. In the overall sample, 20 patients were aged 70 years or older (21%, group B), and 75 patients were under 70 years old (79%, group A). The mean follow-up period was 50.2 ± 36.2 months. Pre-, peri- and postoperative parameters were compared between the two groups. Statistical analysis was carried out with SPSS 25.0 (p < 0.05).

RESULTS

The mean patient age was 53 ± 16 (17-76) years. The indications for SNM testing were OAB and retention in 51 and 49% of patients, respectively. A total of 56 patients (59%) [8 patients (40%) in group B, 48 patients (64%) in group A] had more than 50% improvement in the context of the test (stage 1), such that a permanent neuromodulator (stage 2) was implanted. A total of 14 patients, all under 70 years old except for one older female, needed to undergo revision due to defects or infection. Overall, the success rate was 58.3% for OAB and 59.6% for urinary retention. The success rates and complications in our patient group were independent of age and geriatric assessment.

CONCLUSION

SNM can also be successfully implemented in older patients.

Medications used to treat bladder disorders may alter effects of neuromodulation

AIMS

Neuromodulation (nerve stimulation) can produce analgesia. One form, bilateral pudendal nerve stimulation (bPNS), suppresses responses to urinary bladder distension (UBD) in hypersensitive rats. Drugs can modify this effect (eg, benzodiazepines, but not opioids, suppress bPNS effects). Prior to a clinical trial of bPNS effects on bladder pain, we felt it was prudent to survey the effects of medications commonly used in patients with bladder disorders.

METHODS

Bladder hypersensitivity was produced by neonatal bladder inflammation in rat pups coupled with a second inflammatory insult as an adult. Antimuscarinic (oxybutynin), β₃ -adrenoceptor agonist (mirabegron, CL316243), α₁ -adrenoceptor antagonist (tamsulosin), antidepressant (amitriptyline), muscle relaxing (baclofen), and sedative (propofol) agents were administered and effects of bPNS on responses to UBD assessed. bPNS consisted of bilateral biphasic electrical stimulation of the mixed motor/sensory component of the pudendal nerves. Visceromotor responses (VMRs; abdominal muscle contractile responses) were used as nociceptive endpoints.

RESULTS

Many of these drugs directly inhibited the VMRs to UBD, but only mirabegron, at the doses employed, significantly reduced inhibitory effects of bPNS. In the presence of the other drugs, bPNS continued to produce statistically significant inhibition of VMRs to UBD.

CONCLUSIONS

This study suggests that concurrent therapy with drugs used to treat bladder disorders could affect assessment of the effects of bPNS on bladder hypersensitivity. This study gives guidance to clinical trials using bPNS for the treatment of painful bladder syndromes and suggests potential clinical use of some of these medications in the treatment of these same disorders.