SPARC Bladder Mapping and Training Study

Overview

The investigators propose to determine the electrode configurations that promote functional gains in the storage and voiding phases of lower urinary tract function as a result of activation of spinal circuits with spinal cord epidural stimulation in humans with spinal cord injury. The innovative approach and novel application of the Medtronic Specify 5-6-5 (16-electrode array) epidural device will allow the investigators to determine, with this early feasibility study, specific parameters of spinal cord epidural stimulation and approaches for bladder training needed for lower urinary tract function which will lay the groundwork for expedient translation of this promising technology to larger numbers of individuals with spinal cord injury who currently have limited treatment options. The current proposed study will increase the understanding of human lumbosacral spinal networks and guide the use of innovative therapeutic strategies that would be immediately available to not only improve the motor output during standing and walking but also ameliorate bladder dysfunction and thus improve quality of life in individuals after spinal cord injury.

Deficits in urologic function after spinal cord injury impact quality of life and consistently ranks as a top priority issue in the spinal cord injury population. Bladder dysfunction may manifest as detrusor hyperreflexia (bladder contractions at low volumes, causing incontinence and smooth muscle hypertrophy), detrusor-sphincter dyssynergia (uncoordinated bladder and external urethral sphincter contractions, causing inefficient emptying and smooth muscle hypertrophy), decreased compliance (unable to store urine under appropriately low pressures) and loss of continence, requiring lifelong management, maintenance, and health care visits. Current therapeutic approaches aim to manage both the storage and voiding phases of bladder function and include intermittent catheterization, pharmacologic and surgical interventions. While most of these strategies are necessary for urological maintenance post-injury they oftentimes are associated with side effects and therefore remain inadequate. Therapies addressing recovery of function are still needed. The use of spinal cord epidural stimulation is a promising alternative approach to addressing the primary phases of bladder dysfunction. Additionally, the effects of spinal cord epidural stimulation on bladder alone is not known as its use has been directed towards the locomotor system. Thus, the overall objective of this study is to perform functional mapping in order to identify the spinal cord epidural stimulation configurations (anode/cathode selection, amplitude, frequency and pulse width) at the lumbosacral level that can promote neural control of bladder storage (capacity) and bladder emptying (voiding efficiency) after spinal cord injury.