Urodynamic responses to sacral stimulation in the chronic spinal dog

Abstract

AbstractRecent reports have shown that electrical stimulation of the bladder wall or sacral nerves can be effective for bladder management in the spinal‐cord‐injured (SCI) patient. However, unacceptable bladder pressures and urethral resistances have been reported in many of these patients following such stimulation procedures. These problems were evaluated in this study using epidural electrodes in the sacral canal of the chronic spinal male dog. We found that bladder reflex activity is important for sacral stimulation to induce effective voiding. Voiding in response to stimulation was poor during the first week following spinal injury but improved during the next 2 weeks. A significant increase in bladder pressure in response to stimulation occurred during this period, but urethral resistance remained unchanged. Urethral resistance, the ratio of bladder pressure to voiding rate, was lower for poststimulus voiding than for voiding during continuous stimulation. Bladder compliance, measured via cystometry, was improved in one spinal dog during a period of sacral stimulation. However, an adverse trend toward increased bladder thickness was seen on postmortem examination. Overall, this minimally invasive method was encouraging and may be efficacious for bladder control in some SCI patients.