Direct Bladder Contraction by Single and Multi-Electrode Stimulation

Detrusor sphincter dyssynergia (DSD) is characterized by the uncoordinated activity between contraction of the detrusor and relaxation of the external urinary sphincter, affecting 70%-84% of individuals with spinal cord injury (SCI). Current treatments include catheterization, medication, sphincterotomy, and neuromodulation. Here we divided the bladder in quarters and used point (0.78 mm2) electrical stimulation at 0.5, 1.0 and 2 mA to map those that evoked maximal contraction (9.88 mm2), as determined by vascular fiduciary markers before and after stimulation. A multi-electrode array was then used to reduce the electrodes size (2000μm2) which evoked a more efficient bladder contraction (16.51 mm2) and at a lower threshold (0.15 mA). The relative change of bladder size evoked by single electrodes was -7.3 %, whereas that evoked by the multichannel electrode was 12.9% (p = 0.007). This result defines the optimal targets sites and parameters that can be used to improve the neuromodulation treatment of DSD.