Animal models of sacral neuromodulation for detrusor overactivity.

The recent increase in the use of sacral neuromodulation (SN) for the treatment of detrusor overactivity has coincided with improved knowledge of micturition physiology and technological advances in nerve stimulation. Efficacy of SN treatment and patient satisfaction should continue to progress. Nevertheless, the exact mechanism of the action of this technique remains uncertain. Numerous theories have been proposed to explain the mechanism of action, including stimulation of efferents, or direct effect on the muscle, stimulation of the afferents, induction of spinal plasticity, and modifications of cortical activation. In experimental conditions, to evaluate the effects of electrical stimulation, animal models are generally focused on bladder inflammation or spinalization which both induce detrusor overactivity. Recently, experimental autoimmune encephalomyelitis in rats has proven useful to study bladder dysfunction characterized as both detrursor overactivity or acontractile detrursor. The present article reviews experimental approaches for SN for treatment of detrusor overactivity and provides explanations for the potential acting mechanisms. (c) 2008 Wiley-Liss, Inc.