Sacral Nerve Stimulation in Parkinson's Disease Patients With Overactive Bladder Symptoms

Variations and Asymmetry in Sacral Ventral Rami Contributions to the Bladder

Background/Objectives: We have demonstrated in human cadavers and canines that nerve transfer to bladder vesical nerve branches is technically feasible for bladder reinnervation after nerve injury. We further clarify here that sacral (S) ventral rami contribute to these vesical branches in 36 pelvic sides (in 22 human cadavers). Methods: Gross post-mortem visualization and open anterior abdominal approaches were used, as was micro-CT of sacral nerve bundles, for further confirmation when needed. Results: Considerable between and within-subject variation was observed. Sacral (S) ventral rami contributions to vesical nerves were observed as shared contributions from several rami or, in a few cases, from single rami: S2 alone (6%), S3 alone (6%), S2 and S3 (28%), S3 and S4 (28%), S2-S4, 14%, L5 in combination with S1-S4 (6%), S1 and S2 (6%), and S3-S5 (3%). The most common contributor to these shared or single rami contributions was from the S3 ventral ramus, which contributed 100% of the time on the left side and 79% on the right side. Side-to-side asymmetry was observed in 10 of 14 cadavers examined bilaterally (71%). Conclusions: This characterization of the anatomical variation in sacral ventral rami contributions to the bladder will ultimately aid in developing therapeutics for patients with bladder dysfunction.

Third-line therapy for overactive bladder in the elderly: Nuances and considerations

INTRODUCTION

Overactive bladder (OAB) disproportionally affects older adults in both incidence and severity. OAB pharmacotherapy is often problematic in the elderly due to polypharmacy, adverse side effect profiles and contraindications in the setting of multiple comorbidities, and concerns regarding the risk of incident dementia with anticholinergic use. The burden of OAB in older patients coupled with concerns surrounding pharmacotherapy options should motivate optimization of nonpharmacologic therapies in this population. At the same time, several aspects of aging may impact treatment efficacy and decision-making. This narrative review critically summarizes current evidence regarding third-line OAB therapy use in the elderly and discusses nuances and treatment considerations specific to the population.

METHODS

We performed an extensive, nonsystematic evidence assessment of available literature via PubMed on onabotulinumtoxinA (BTX-A), sacral neuromodulation, and percutaneous tibial nerve stimulation (PTNS) for OAB, with a focus on study in elderly and frail populations.

RESULTS

While limited, available studies show all three third-line therapies are efficacious in older populations and there is no data to support one option over another. BTX-A likely has a higher risk of urinary tract infection and retention in older compared to younger populations, especially in the frail elderly. PTNS incurs the lowest risk, although adherence is poor, largely due to logistical burdens.

CONCLUSION

Advanced age and frailty should not preclude third-line therapy for refractory OAB, as available data support their efficacy and safety in these populations. Ultimately, treatment choices should be individualized and involve shared decision-making.

Neuromodulation for lower urinary tract symptoms in special populations

AIMS

Discuss the efficacy, safety, and future directions of neuromodulation in special populations of patients with neurological conditions.

METHODS

A literature review was done to find meta-analyses, review articles, studies, and case reports of the use of neuromodulation, either sacral neuromodulation or percutaneous tibial nerve stimulation, in patients with various neurological conditions of interest.

RESULTS

Sacral neuromodulation (SNM) and posterior tibial nerve stimulation (PTNS) appear to be safe and effective in special neurological populations of patients with multiple sclerosis (MS), Parkinson's disease (PD), and spinal cord injury (SCI). The majority of publications are smaller retrospective case series. Outcomes appear similar to those seen in nonneurogenic patients but also partly depend on disability progression. Magnetic resonance imaging (MRI) compatibility has helped to improve eligibility for SNM in these special populations.

CONCLUSIONS

In a small number of studies, SNM and PTNS appear to be safe and effective in special neurological populations of patients with MS, PD, and SCI. MRI compatibility has helped to improve eligibility for SNM in these special populations. Studies looking at SNM are limited by a small number of subjects, lack of prospective trials, and selection bias. Larger, randomized studies with long-term follow up are needed to better predict response to SNM and PTNS in these populations.

Perspectives on the urological care in Parkinson's disease patients

Parkinson's disease (PD) is recognized as the most common neurodegenerative disorder after Alzheimer's disease. Lower urinary tract symptoms are common in patients with PD, either storage symptoms (overactive bladder symptoms or OAB) or voiding symptoms. The most important diagnostic clues for urinary disturbances are provided by the patient's medical history. Urodynamic evaluation allows the determination of the underlying bladder disorder and may help in the treatment selection. Pharmacologic interventions especially anticholinergic medications are the first-line option for treating OAB in patients with PD. However, it is important to balance the therapeutic benefits of these drugs with their potential adverse effects. Intra-detrusor Botulinum toxin injections, electrical stimulation were also used to treat OAB in those patients with variable efficacy. Mirabegron is a β3-agonist that can also be used for OAB with superior tolerability to anticholinergics. Desmopressin is effective for the management of nocturnal polyuria which has been reported to be common in PD. Deep brain stimulation (DBS) surgery is effective in improving urinary functions in PD patients. Sexual dysfunction is also common in PD. Phosphodiesterase type 5 inhibitors are first-line therapies for PD-associated erectile dysfunction (ED). Treatment with apomorphine sublingually is another therapeutic option for PD patients with ED. Pathologic hypersexuality has occasionally been reported in patients with PD, linked to dopaminergic agonists. The first step of treatment of hypersexuality consists of reducing the dose of dopaminergic medication. This review summarizes the epidemiology, pathogenesis, risk factors, genetic, clinical manifestations, diagnostic test, and management of PD. Lastly, the urologic outcomes and therapies are reviewed.

Is sacral neuromodulation effective in patients with Parkinson's disease? A retrospective review

INTRODUCTION AND OBJECTIVE

Parkinson's disease (PD) is the second-most common degenerative neurologic disease worldwide. Overactive bladder (OAB) is prevalent in this population but can be challenging to treat. Sacral neuromodulation (SNM) is an attractive option but remains understudied. We have utilized SNM in PD patients and herein describe our outcomes.

METHODS

We performed a retrospective chart review of PD patients who underwent peripheral nerve evaluation (PNE) or Stage 1 SNM from 2000 to 2020. The primary outcome was progression to a permanent implant. The impact of PD stage and preprocedural urodynamic (UDS) parameters on test-phase outcome were investigated. Long-term efficacy was assessed using Wilcoxon matched-pairs test looking at a change in urinary symptoms (frequency, nocturia, incontinence episodes, and pad use) documented at follow-up visits and further need for treatment.

RESULTS

Thirty-four patients underwent test phase SNM (7 PNE and 27 Stage 1). Median follow-up was 11 (interquartile range 5.8-29.8) months. Indications included refractory OAB (30/34) and nonobstructive urinary retention (4/34). Overall, 82% (28/34) of patients proceeded to a permanent implant. 71% (5/7) of PNEs were successful. Test-phase success did not differ based on PD disease severity or UDS parameters. In patients with OAB/urgency incontinence who progressed to the permanent implant, there was a statistically significant improvement in their urinary symptoms from baseline. Most (68%) patients were able to discontinue OAB medications post-implant. The overall lead revision rate was 14% (4/28) and 3 devices required removal.

CONCLUSIONS

SNM is an efficacious treatment option for PD patients with a high percentage of patients having improvement in their urinary symptoms.

Neuromodulation for Storage Lower Urinary Tract Symptoms in Parkinson Disease: A Systematic Review

BACKGROUND

Bladder symptoms are common in Parkinson disease (PD), affecting quality of life. Medications commonly used such as antimuscarinics can cause frequently intolerable side effects, and therefore, new, better tolerated approaches are needed. Neuromodulation techniques have an established role in urologic disorders; these techniques include tibial nerve stimulation (TNS) and sacral neuromodulation (SNM), which are localized therapies lacking the side effects associated with medication.

OBJECTIVES

This study aimed to undertake a systematic review of the literature reporting the use of neuromodulation techniques for the treatment of bladder symptoms in PD and related conditions.

MATERIALS AND METHODS

A systematic search of data bases was conducted including MEDLINE, CENTRAL, and Web of Science. Studies were required to present specific outcomes for individuals with PD for neuromodulation interventions.

RESULTS

Ten primary studies were identified concerning detailed outcomes of neuromodulation on bladder symptoms in PD, including seven for TNS, one for SNM, and one using transcranial magnetic stimulation (TMS). Two further mixed cohort studies documented minimal data on individuals with PD. All studies demonstrated benefit in a range of outcome measures following neuromodulation. Two randomized sham-controlled studies were carried out using TNS, with one clearly demonstrating superiority over sham, although difficulties with achieving believable yet ineffective sham treatment are highlighted. Further studies reported limited, uncontrolled outcomes of SNM in patients with PD, demonstrating benefit.

CONCLUSIONS

Evidence from case series suggests benefit from TNS in PD, with limited literature on SNM or TMS. Placebo effect from neuromodulation is a concern, and only limited controlled data exist. Future well-designed and sham-controlled studies need to be completed to provide definitive data on the benefit of neuromodulation in PD. Definitively proving the utility of a neuromodulation modality will allow better treatment of bladder symptoms without the need for pharmacologic measures that cause side effects.