Current opinion on the working mechanisms of neuromodulation in the treatment of lower urinary tract dysfunction

Neuromodulation is a successful treatment for patients with refractory lower urinary tract dysfunction. In the recent years, more applications of various types and ways have been developed and put into clinical practice. It is important, therefore, for urologists to know the existing theories on the working mechanisms that explain the effect. Although much research has been devoted to this subject for the past 35 years, the working mechanism is still unknown. This review presents an overview of the different theories and research into the physiological background of neuromodulation during the past 3 decades with emphasis on recent developments.

Specific receptors in the spinal cord have been identified, which are involved in the working mechanism of neuromodulation. The maximal effect of neuromodulation is not directly reached, indicating that neuromodulation induces learning changes (i.e. neural plasticity). The carry-over effect could be caused by negative modulation of excitatory synapses in the central micturition reflex pathway.

Neuromodulation in the treatment of stress incontinence probably induces physiological changes in the sphincter muscles and pelvic floor. In the treatment of overactive bladder syndrome, nonobstructive voiding dysfunction and chronic pelvic pain, the mechanism of action seems to be more complicated. Most likely, it is a combination of the different suggested modes of action, involving the neuroaxis at different levels.