Surgical management for overactive bladder

Effects of sacral neuromodulation on isolated urinary bladder function in a rat model of spinal cord injury

INTRODUCTION

Sacral neuromodulation has been considered as an effective treatment option for various types of chronic voiding dysfunction, but the mechanism of action has not been well understood. The aim of this study was to evaluate the effect of chronic sacral neuromodulation on isolated bladder functions in a rat model of spinal cord injury.

MATERIALS AND METHODS

Female Sprague-Dawley rats (250-300 g; N = 20) were assigned to four groups as follows: 1) control group (N = 6); 2) spinal cord transection group (SCT; N = 5); 3) spinal cord transection + sacral neuromodulation group (SCT + SNM; N = 5); 4) sham (spinal cord transection + electrode wire implantation without sacral neuromodulation; N = 4). The rats in the SCT, SCT + SNM, and sham groups were anesthetized with ketamine (60 mg/kg, i.p.) and xylazine (7 mg/kg, i.p.). The spinal cord was completely transected at T8-T9 level in SCT and SCT + SNM groups. Electrode wires were implanted into S3 dorsal foramina in both sham and SNM groups, but only the SNM group was subjected to electrical stimulation for four hours a day for three weeks. Twenty-one days later, the rats were sacrificed via anesthetic overdose, and isolated longitudinal bladder strip preparations were placed in organ baths for the investigation of their isometric responses to pharmacological agents.

RESULTS

In isometric contraction experiments, SCT was found to increase the contraction responses of the bladder strips to muscarinic stimulation, and SNM could not prevent this increase. In isometric relaxation experiments, SCT caused a decrease in β-adrenergic relaxation responses, and SNM augmented the bladder's β-adrenergic relaxation responses. Nitric oxide did not affect the relaxation responses.

CONCLUSION

In our rat model of SCT, SNM seemed to alter adrenergic receptor function in the urinary bladder. Further studies are required to clarify the mechanism of these alterations at the level of bladder receptors following sacral neuromodulation.

Intradetrusor injection of botulinum toxin for the management of refractory overactive bladder syndrome: an update

Overactive bladder (OAB) is a common syndrome that has a negative impact on daily activities and quality of life. The first-line treatment to manage this condition includes behavioral modifications, physical treatment, and oral pharmacotherapy with antimuscarinics. Botulinum toxin has emerged as an alternative and second-line treatment option for patients with OAB who are refractory to first-line treatment modalities when injected into the detrusor muscle. Although its application in the management of OAB remains off label, studies have shown its efficacy both subjectively and objectively. It is considered as a minimally invasive and reversible alternative. Adequate dosage of the toxin, number of injection sites, and reinjection rates are yet to be determined. This review attempts to provide an update on the current position of botulinum toxin in managing refractory OAB addressing contemporary data on the mechanism of action, technique, safety, complications, and clinical results.

Sacral neuromodulation and refractory overactive bladder: an emerging tool for an old problem

Overactive bladder (OAB) syndrome negatively affects the daily life of many people. Conservative treatments, such as antimuscarinics, do not always lead to sufficient improvement of the complaints and are often associated with considerable side effects resulting in treatment failure. In the case of failure or intolerable side effects, sacral neuromodulation (SNM) and botulinum toxin intravesical injections are minimally invasive and reversible alternatives. Currently, both SNM and botulinum toxin injection have FDA approval for use in OAB patients. This mini-review attempts to provide an update on SNM as a second-line management of adults with refractory OAB, based on the available clinical evidence concerning the efficacy and safety.

Pelvic electrical neuromodulation for the treatment of overactive bladder symptoms

Overactive bladder syndrome negatively affects the daily life of many people. First-line conservative treatments, such as antimuscarinics, do not always lead to sufficient improvement of the complaints and/or are often associated with disabling adverse effects leading to treatment failure. Electrical stimulation of the sacral nerves has emerged as an alternative and attractive treatment for refractory cases of bladder overactivity. Few theories attempted to explain its mechanism of action which remains elusive. It involves percutaneous posterior tibial nerve stimulation and more commonly sacral neuromodulation. For the latter, temporary sacral nerve stimulation is the first step. If the test stimulation is successful, a permanent device is implanted. The procedure is safe and reversible. It carries a durable success rate. The technique should be combined with careful followup and attentive adjustments of the stimulation parameters in order to optimize the clinical outcomes. This paper provides a review on the indications, possible mechanisms of action, surgical aspects and possible complications, and safety issues of this technique. The efficacy of the technique is also addressed.

A noninvasive evaluation of autonomic nervous system dysfunction in women with an overactive bladder

OBJECTIVE

To verify the hypothesis that a connection exists between overactive bladder (OAB) syndrome and a bladder-specific dysfunction of the autonomic nervous system (ANS).

METHOD

An electrocardiogram recorded heartbeat cycles from the onset of urinary urgency to 5 minutes after voiding in 33 women with an overactive bladder and 176 controls. Power spectral density (PSD) analysis allowed to quantify heart rate variability (HRV), which is in relation to ANS function. Three-dimensional spectrograms and multiscale entropy graphs were used to display HRV values.

RESULTS

The differences between patients and controls were all significant in the time and frequency domains of HRV (P<0.05), which suggests disturbances in bladder-specific ANS activity in women with OAB.

CONCLUSION

By quantifying HRV data, PSD analysis provides a simple, noninvasive method of assessing disturbances in ANS activity and monitoring treatment in women with OAB. It can also be used to evaluate other neuronal conditions.