Preclinical assessment of potential interactions between botulinum toxin and neuromodulation for bladder micturition reflex

Management of Idiopathic Overactive Bladder Syndrome: What Is the Optimal Strategy After Failure of Conservative Treatment?

CONTEXT

A considerable number of patients affected by the overactive bladder syndrome (OAB) do not respond to pharmacotherapy and bladder training due to unsatisfactory response or intolerability.

OBJECTIVE

To review the available literature assessing therapeutic effect of the available third-line treatment modalities for OAB.

EVIDENCE ACQUISITION

PubMed, Medline, and Cochrane databases were searched for all studies comparing outcomes of the available third-line treatment modalities for OAB.

EVIDENCE SYNTHESIS

Several minimally invasive surgical procedures are available for patients with refractory OAB. These therapies include intravesical botulinum toxin type A, posterior tibial nerve stimulation, and sacral neuromodulation.

CONCLUSIONS

None of the mentioned therapeutic modalities shows strong superiority over another. If the results of one therapy are not satisfactory, switching to another third-line treatment can be attempted. The treatment algorithm is dependent on several factors, including age, comorbidity, patient preference, surgical expertise, and financial concerns. All these factors should be taken into consideration before initiation of treatment.

PATIENT SUMMARY

In the management of drug-resistant overactive bladder syndrome, the different minimally invasive treatments that are available are equal. If the results of one therapy are not satisfactory, switching to another treatment can be attempted. The treatment algorithm is dependent on several factors, including age, comorbidity, patient preference, surgical expertise, and financial concerns.

Comparison of Bladder Inhibitory Effects of Patterned Spinal Nerve Stimulation With Conventional Neuromodulation in the Rat

OBJECTIVES

The present study compared the effectiveness of patterned frequency of spinal nerve stimulation (SNS) with continuous, fixed-frequency nerve stimulation in an animal model of the bladder reflex contraction (BRC).

MATERIALS AND METHODS

In anesthetized female rats, wire electrodes were placed under each of the L6 spinal nerve to produce bilateral SNS. A cannula was placed into the bladder via the urethra, and the urethra was ligated to ensure an isovolumetric bladder.

RESULTS

Using motor threshold intensity, continuous stimulation at fixed frequencies of 4 Hz (n = 5) and 10 Hz (n = 7) decreased the frequency of BRC of 71 ± 24% (mean, SEM) and 85 ± 18% of controls, respectively (vs. no stimulation, n = 10, p < 0.05, two-way analysis of variance [ANOVA]). Fixed-frequency stimulation at 0.01, 0.1, 1, 40, and 100 Hz, did not demonstrate a trend change on BRC. When stimulation frequency is delivered with a 4-6 pulse/burst pattern every 1-100 sec, neuromodulation has demonstrated a trend toward effectiveness, with a four-pulse 40 Hz burst stimulation per second showing the most difference, reducing the BRC frequency of 74 ± 8% of control (n = 8, p < 0.05, two-way ANOVA). However, it is not more effective than continuous neuromodulation at a fixed frequency of 4 Hz or 10 Hz at BRC inhibition.

CONCLUSIONS

Burst stimulations may inhibit bladder contractions; however, they are not more effective than continuous neuromodulation. Without further knowledge regarding mechanisms and potential benefit of burst stimulation on bladder control in patients with neuropathological conditions, applications should utilize continuous fixed 10 Hz stimulation for maximal clinical outcomes.