Restoration of Bladder Function in Spinal Cord Injury

This is a proof of concept study of the effects on the urinary bladder and sphincter of high frequency stimuli applied to sacral efferent nerves. The effects on the bladder of low frequency stimuli applied to sacral afferent nerves will also be studied. It is also part of an academic collaboration between Oxford and Stanford University. The results will not be sold to Stanford but will be shared to enhance the development of therapies for patients with spinal cord injury. There is no intention to commercialise the findings at this stage nor to use the data for CE-marking.

Participants will be patients with clinically complete spinal cord injury who already have a commercially available implanted Finetech Brindley bladder stimulator with electrodes on the sacral nerves or roots, controlled by an external transmitter whose frequency can be adjusted by the investigator. This study will explore modified stimulation parameters and will deliver the stimulation pattern with a modified/experimental external stimulation control unit. The motivation for exploring these parameters is to see if clinical efficacy might be improved for future systems.

Primary outcome: Measurement of the effects of high and low frequency stimulation of the sacral efferent nerves on Bladder Pressure, rectal pressure, Detrusor pressure, Sphincter pressure, volume voided, post-void residual volume, voiding flow rate

Secondary measures: Effects of low frequency stimulation on bladder pressure, bladder capacity and reflex incontinence

The exploration of these novel stimulation parameters will require modification of the existing CE-marked system. The modifications will be limited to the external stimulation control unit, and will not compromise either the implantable system or its capability to continue normal operation with the existing CE-marked external control unit. The modified external stimulation control unit will be referred to as the "research stimulation controller." The use environment for the research stimulation controller will be a controlled hospital/laboratory setting, under clinical supervision. Outside of the clinic, the CE-marked system will be used to ensure normal therapy is provided to the subject. Access to the research stimulation controller will be controlled by the PI to prevent inadvertent misuse.