Millions of individuals have partial or full loss of bladder control. This large population cohort is due to the wide variety of etiologies, from neurological disorders like spinal cord injury and multiple sclerosis to non- neurological deficits like diabetes, pregnancy complications and the effects of aging. Typical medications and interventions like diapers and catheters provide limited benefit or are not well received. Neurostimulators have been developed to drive bladder nerves, however they do not provide fully effective bladder control. We propose an alternate neuroprosthetic approach that interfaces directly with the bladder, towards full closed- loop control. Through this proposal we will develop a stretchable electrode grid that will be placed directly on the bladder exterior surface. Previous research with electrodes on the bladder wall failed due to lead migration and current spread. We will use a novel substrate with stretchable stimulation contacts that maintains a tight fit to the bladder and uses current steering to optimize bladder recruitment, for effective micturition. Integrated within the electrode grid will be strain gauges that will detect the bladder state. In te ultimate implementation, this electrode grid will be wirelessly powered with an external or implanted power source and processing unit, which will also drive pudendal nerve branch stimulation for continence. The objective of this proposal is to develop the stretchable electrode grid, including determining an ideal size and layout for the stimulating electrodes and number and arrangement of the strain gauges to effectively detect bladder stretch. Across several design generations, wired prototypes will first be evaluated in ex vivo preparations followed by acute in vivo experiments. Finally, two four-week in vivo implants will be performed to evaluate the semi-chronic bladder response to the electrode grid. At the end of this proposed study we will have a robust electrode grid that can be scaled up for eventual human use and will have developed system specifications for an optimal wireless control system. Future studies will include implementation of and in vivo testing of a wireless electronics module on the electrode grid and integration of an external control module with pudendal nerve stimulator. Collaboration with clinicians will lead to development of a minimally invasive implant procedure and versatile algorithms for closed-loop control.
Millions of Americans are affected by bladder dysfunction, which has a profound impact upon quality of life and the healthcare system. In this project we will develop a novel direct-bladder interface that will observe and drive bladder activity.
