Sacral nerve stimulation for pain relief in interstitial cystitis

Neuromodulation for Management of Chronic Pelvic Pain: A Comprehensive Review

INTRODUCTION

Chronic pelvic pain (CPP) is a symptom that derives from a complex group of heterogeneous pathologies of the pelvic organs. The aim of this study was to review the available evidence on efficacy of neuromodulatory modalities including sacral neuromodulation, dorsal root ganglion stimulation, dorsal column neuromodulation, and pudendal nerve stimulation.

METHODS

This narrative review focuses on updated information on neuromodulation for management of chronic pelvic pain. In 2022, we searched English-language studies on neuromodulation, pelvic pain, and chronic pain in a comprehensive search. We searched the following databases: PubMed, Medline, SciHub, Cochrane Database of Systematic Reviews, and Google Scholar. We used the following combinations of keywords: neuromodulation, pelvic pain, chronic pain, chronic pelvic pain, pelvic pain treatment. We tried to include as many recent manuscripts as possible (within the last 3 years) but also included papers older than 3 years if they were particularly relevant to our topic. We also attempted to search for, use, and cite primary manuscripts whenever possible.

RESULTS

CPP is a challenging entity to treat because of diagnostic inconsistencies and limited evidence for therapeutic modalities. Our review found evidence suggestive of benefit for all modalities reviewed but the data was of overall low quality with numerous limitations. The literature highlights a lack of randomized controlled trials for neuromodulatory therapies but suggests a growing role for such techniques in treating refractory chronic pelvic pain syndrome (CPPS).

CONCLUSIONS

This review explores the available evidence on efficacy of neuromodulatory modalities for CPPS and contextualizes the results with information about the type of neuromodulation, lead location and waveform, pain outcomes and assessment timepoints, and reported adverse effects.

A protocol of systematic review and meta-analysis of neuromuscular electrical stimulation for interstitial cystitis

BACKGROUND

This study will examine the effectiveness and safety of neuromuscular electrical stimulation (NMES) for the treatment of patients with interstitial cystitis (IC).

METHODS

We will retrieve the following electronic databases from their commencements to the March 1, 2020 to discover all related potential studies: MEDLINE, EMBASE, Cochrane Library, Web of Science, Cumulative Index to Nursing and Allied Health Literature (CINAHL), China National Knowledge Infrastructure, Chinese Biomedical Literature Database, Chinese Scientific Journal Database, and WANFANG Database. Randomized controlled trials related to the NMES for the treatment of patients with IC will be included, regardless publication status and language. Literature selection, data collection, and study quality assessment will be independently performed by 2 authors. The extracted data will be expressed as risk ratio and 95% confidence intervals for dichotomous data, and mean difference or standard mean difference and 95% confidence intervals for continuous data. RevMan V.5.3 software will be employed for statistical analysis.

RESULTS

This study will summarize current high quality randomized controlled trials to appraise the effectiveness and safety of NMES for the treatment of patients with IC.

CONCLUSION

The findings of this study will provide helpful evidence to determine whether NMES is an effective treatment for patients with IC or not.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42020170495.

Electrical Stimulation and Motor Recovery

In recent years, several investigators have successfully regenerated axons in animal spinal cords without locomotor recovery. One explanation is that the animals were not trained to use the regenerated connections. Intensive locomotor training improves walking recovery after spinal cord injury (SCI) in people, and >90% of people with incomplete SCI recover walking with training. Although the optimal timing, duration, intensity, and type of locomotor training are still controversial, many investigators have reported beneficial effects of training on locomotor function. The mechanisms by which training improves recovery are not clear, but an attractive theory is available. In 1949, Donald Hebb proposed a famous rule that has been paraphrased as “neurons that fire together, wire together.” This rule provided a theoretical basis for a widely accepted theory that homosynaptic and heterosynaptic activity facilitate synaptic formation and consolidation. In addition, the lumbar spinal cord has a locomotor center, called the central pattern generator (CPG), which can be activated nonspecifically with electrical stimulation or neurotransmitters to produce walking. The CPG is an obvious target to reconnect after SCI. Stimulating motor cortex, spinal cord, or peripheral nerves can modulate lumbar spinal cord excitability. Motor cortex stimulation causes long-term changes in spinal reflexes and synapses, increases sprouting of the corticospinal tract, and restores skilled forelimb function in rats. Long used to treat chronic pain, motor cortex stimuli modify lumbar spinal network excitability and improve lower extremity motor scores in humans. Similarly, epidural spinal cord stimulation has long been used to treat pain and spasticity. Subthreshold epidural stimulation reduces the threshold for locomotor activity. In 2011, Harkema et al. reported lumbosacral epidural stimulation restores motor control in chronic motor complete patients. Peripheral nerve or functional electrical stimulation (FES) has long been used to activate sacral nerves to treat bladder and pelvic dysfunction and to augment motor function. In theory, FES should facilitate synaptic formation and motor recovery after regenerative therapies. Upcoming clinical trials provide unique opportunities to test the theory.

Efficacy of sacral neuromodulation in treating chronic pain related to painful bladder syndrome/interstitial cystitis in adults

OBJECTIVE

The objective of this review is to evaluate the efficacy and safety of sacral neuromodulation in treating chronic pelvic pain related to Painful bladder syndrome/Interstitial-cystitis.

DESIGN

The databases searched were MEDLINE and EMBASE [1950- Nov 2011]. Additional searches were performed on the Cochrane Database of Systematic reviews (CDSR), Scopus, CINAHL, BIOSIS, The Cochrane controlled trials register, the science citation index, TRIP DATABASE.

RESULTS

Overall 70.8% or 170/244 patients were successful at the trial stage. The only randomized controlled trial reported a decrease in Visual analogue pain scores of 49% (7.9 to 4.0) for sacral nerve stimulation [SNS] and 29%(4.5 to 3.2) for pudendal nerve stimulation [PNS] at 6 months follow up. Nine observational studies reported a decrease in pain scores/decrease in pain medications at long term follow up following permanent sacral neuromodulation. One study showed an 80% improvement in Global response assessment score.

CONCLUSION

The results from the randomised controlled trial and case series/case reports demonstrate a reduction of pain symptoms of Painful bladder syndrome following sacral neuromodulation.

Interstitial cystitis: diagnosis and management

Interstitial cystitis/painful bladder syndrome is a chronic condition that causes debilitating bladder pain which can be associated with urgency, frequency and nocturia. Its cause is not clear and it is still a disease diagnosed by exclusion. Oral or intravesical therapies are the main stay of treatment whilst surgical procedures are reserved for refractory cases. This condition usually warrants a multidisciplinary approach for optimum outcome. This article gives an overview of the changes in definition, aetiopathogenesis and available treatments.

Advances in the role of sacral nerve neuromodulation in lower urinary tract symptoms

Sacral neuromodulation has been developed to treat chronic lower urinary tract symptoms, resistant to classical conservative therapy. The suspected mechanisms of action include afferent stimulation of the central nervous system and modulation of activity at the level of the brain. Typical neuromodulation is indicated both in overactivity and in underactivity of the lower urinary tract. In the majority of patients, a unilateral electrode in a sacral foramen and connected to a pulse generator is sufficient to achieve significant clinical results also on long term. In recent years, other urological indications have been explored.

Sacral nerve stimulation for neuromodulation of the lower urinary tract

Patients with symptoms of overactive bladder syndrome or non-obstructive urinary retention, refractory to conservative therapy, can nowadays be treated minimally invasively with sacral nerve stimulation (SNS). The use of electric currents to treat urological pathology has a long history but SNS therapy only received FDA approval in 1997. The mechanisms of action are still not known so there are different theories explaining the modulation effect. Recent studies have shown a central modulation effect. Predictive factors which can help to identify the perfect candidates are not known. Over the years the technique of SNS has become less invasive and because of two stage implantation test results have proven to be more reliable. The clinical results for this therapy have proven to be safe and effective and with the technical improvements over the years the re-operation and complication rates have decreased significantly. The clinical results have led to expanding indications because of positive effects in other symptoms. In the field of urology this has resulted in the use of SNS therapy for interstitial cystitis, neurogenic lower urinary dysfunction, and pediatric voiding dysfunction. In the field of gastro-intestinal pathology, SNS therapy is used to treat faecal incontinence and constipation.

Frequency, urgency, and pelvic pain: Treating the pelvic floor versus the epithelium

For years the bladder epithelium has been the focus for diagnosing and treating the frequency, urgency, and pelvic pain of interstitial cystitis. However, many patients have not found symptom relief with these therapies. Pelvic floor dysfunction is often present in these patients, yet it is often untreated. Pelvic floor dysfunction may be related to abuse, past surgeries, or other causes. It is important to look outside of the bladder and explore other causes and treatments for this condition. Pelvic floor therapies should be a first line of treatment for those women with chronic pelvic pain related to pelvic floor dysfunction.

L6-S1 spinal nerve stimulation reduces micturition frequency in anaesthetized rats with cyclophosphamide-induced cystitis

OBJECTIVE

To further investigate the rationale for using spinal nerve stimulation (SNS) for treating bladder overactivity associated with cystitis in a rat model of cyclophosphamide-induced cystitis, as several studies suggested that symptoms associated with chronic cystitis could be treated using stimulation of sacral spinal nerves, but the mechanisms by which it works are unknown.

MATERIALS AND METHODS

Cystitis was induced by i.p. injection of cyclophosphamide 48 h before the experiments in anaesthetized male rats. Neurograms were taken by placing a recording electrode onto the pelvic nerve and a stimulating electrode on either the L6 or S1 ipsilateral spinal nerves. Two selected intensities were then evaluated for SNS in control and cyclophosphamide-treated rats during cystometry.

RESULTS

Cyclophosphamide resulted in significant bladder overactivity. There was no apparent difference in the neurograms generated in response to SNS of the S1 and L6 spinal nerves, and between cyclophosphamide and control rats. Intensities of 200 microA (Adelta-fibre-specific) and 2 mA (Adelta+ C-fibres) were chosen for SNS. Continuous SNS at 200 microA significantly reduced the frequency of voiding and non-voiding contractions in cyclophosphamide-treated rats. SNS at 2 mA resulted in the abolition of voiding contractions, accompanied by continuous leakage of urine.

CONCLUSION

SNS recruiting only Adelta-fibre produced fewer voiding contractions in cyclophosphamide-treated rats, to a level similar to that from the control rats. These results support the ability of SNS to decrease bladder overactivity in a pathophysiological model of chemical irritation of the bladder.

Is There a Relationship between Chronic Bladder Dysfunction and Somatic Symptoms in other Body Regions? 1. Clinical Observations

OBJECTIVE

Investigation of patients with chronic bladder dysfunction regarding associated general symptoms and complaints in the cervico-facial, upper and lower extremity regions.

PATIENTS AND METHODS

We retrospectively evaluated history, physical and special neurourological examination and urodynamic studies in 213 patients with non-neurogenic bladder dysfunction.

RESULTS

22 patients out of 213 patients with chronic bladder dysfunction reported reproducible associated symptoms involving the temporo-mandibular joint, the distal forearm/hand or feet and headache. There was an obvious clinical connection regarding the severity of bladder dysfunction and associated symptoms and possible relief of both by successful treatment.

CONCLUSION

Symptomatic lower urinary tract dysfunction may accompanied by specific muscular and or sensory disturbances in different areas of the body. These associated pathologies in patients without neurological disease can be explained by functional changes in a complex autonomic peripheral and central nervous network.

Posterior tibial nerve stimulation in patients with intractable interstitial cystitis

OBJECTIVE

To evaluate the efficacy of intermittent percutaneous posterior tibial nerve stimulation (PPTNS) in patients with refractory interstitial cystitis.

PATIENTS AND METHODS

One man and 13 women (mean age 58.3 years) with suprapubic or perineal pain were enrolled in a prospective open study, in which they had 10 weekly sessions of PPTNS. Their mean duration of symptoms was 8.3 years. All patients were previously diagnosed as having interstitial cystitis according to the National Institute of Diabetes and Digestive and Kidney Diseases criteria. The response to the treatment were assessed using voiding diary, visual analogue scale diary for a pain index, and the Interstitial Cystitis Problem Index (ICPI), O'Leary/Sant Interstitial Cystitis Symptom Index (ICSI) and the 36-item short-form health survey (SF-36) quality-of-life questionnaire.

RESULTS

Of the 14 patients, 13 completed the 10 weeks of treatment with no complications; 12 continued treatment for a short period after the study. There were no statistically significant changes in pain scores, voiding frequency and volumes, or in the ICPI, ICSI and SF-36 scores. However, there was an improvement in some patients, with one having complete resolution of the pain.

CONCLUSION

Intermittent PPTNS in patients with refractory interstitial cystitis has no significant clinical effect over 10 weeks of treatment.