Differentiation of Bilateral Neuromodulation for Bladder Control Using a Preclinical Model

Abstract

Therapy,applies electrical stimulation unilaterally to the sacral spinal nerve(SN, S3) as an established clinical treatment modality forpatients with overactive bladder [1]. Scheepens and colleagues [2]reported that bilateral stimulation was superior to unilateral sacralneuromodulation in only 2 out of 25 patients. Retrospective stud-ies, however, have also suggested that patients receiving bilateralstimulation are more likely to show a significant symptomaticimprovement [3–5]. Preclinical testing is consistent with thisclinical finding. Bilateral stimulation results in a stronger bladderinhibition than unilateral stimulation when tested in cats [6,7] andpigs [8].In the present study we attempt to define and characterizeresponses to several forms of bilateral SN neuromodulation usingend-points related to bladder control. We characterize the effec-tiveness of three stimulation modalities: 1) bilateral stimulationwith phase-matched individual pulses, 2) bilateral stimulationwith phase-mismatched pulses, and 3) unilateral stimulation of asingle SN root sequentially with stimulation of the alternate side.For all testing stimulation was applied at a fixed frequency of10 Hz which has been shown to be optimal for inhibition of blad-der contractions in the rat using both low and high intensity stimu-lation [9].