Neuroprosthetics for SCI Bladder Management: The Argument for Direct Bladder Stimulation

James S Walter

doi:10.4172/2329-9096.1000230

Abstract

Implantable neuroprosthetic systems are an important area of practice and research in urinary care for individuals with spinal cord injury (SCI). These devices need to manage three lower urinary tract conditions: urethral sphincter contractions during bladder contractions, an underactive bladder producing poor voiding responses, and neurogenic detrusor overactivity causing urinary incontinence. Two neuroprosthetic approaches have addressed these conditions: sacral anterior root stimulation (SARS) and direct bladder wall stimulation (DBWS). The SARS approach is commercialized for SCI bladder management as the Brindley-Finetech Bladder Control System and is available in Europe. Limitations of this device include invasive surgery and the need for rhizotomy of sacral dorsal (sensory) nerve roots. The DBWS implants produced daily voiding in many SCI individuals, however, clinical use was discontinued primarily because of technical concerns with stimulators and electrodes as well as some cases of poor voiding responses and side effects. These limitations are reviewed as well as efforts to return DBWS to clinical investigations using Permaloc® Systems (Synapse Biomedical Inc., Oberlin OH). This new neuroprosthetic platform includes mapping and intramuscular electrodes as well as multilead cables and new stimulator devices.

Highlights

For the spinal cord injured (SCI) individual, urinary management has to address three lower urinary tract conditions: first, detrusorsphincter-dyssynergia (DSD) or reflex sphincter contractions caused by bladder contractions that prevent voiding; second, an underactive bladder where spontaneous bladder contractions do not continue long enough or with sufficient pressure to produce effective bladder emptying; and, third, neurogenic detrusor overactivity (NDO, where detrusor is the bladder pressure after subtraction of abdominal pressure) were unwanted events occur spontaneously causing urinary incontinence [1,2,3,4,5,6]
Two neuroprosthetic approaches have been used as alternatives to intermittent catheterization: sacral anterior root stimulation (SARS) and direct bladder wall stimulation (DBWS) [6,7,8,9,10,11,12,13]
Voiding responses with the Brindley-Finetech SARS can vary; for example, we reported that two SCI individuals

Summary

Introduction

The DBWS approach has demonstrated daily voiding in many SCI individuals; clinical studies were discontinued because of concerns with stimulators and electrodes in some patients that limited voiding or caused side effects such as increased urethral resistance or pain [8,9]. Brindley-finetech bladder control system The Brindley-Finetech SARS device uses an implanted stimulator and tripolar cuff electrodes to stimulate the second to fourth anterior sacral nerve roots as well as a dorsal afferent rhizotomy of the same sacral roots [7,8,9,10,11,12,13].

Results

Conclusion