This project has two OVERALL GOALS: 1) to apply Functional Electrical Stimulation (FES) techniques for bladder voiding and incontinence management after Spinal Cord injury (SCI), 2) to use new monitoring capabilities of implantable neuroprosthetics for continuous recording of lower urinary tract functions. These goals are particularly relevant to the SCI patient where control over voiding functions such as emptying and continence are lost. Moreover, current treatments such as intermittent catheterization, continuous catheterization or external catheterization are not always effective and can have significant, even life-threatening, side effects such as autonomic dysreflexia, urinary tract infections and upper urinary tract problems. Our two HYPOTHESES are 1) a multichannel implantable stimulator can be used to stimulate the bladder for voiding and the pelvic floor/pudendal nerve for inhibiting the bladder and preventing incontinence, 2) the monitoring and display capabilities of the implanted device can be used to show bladder volume and pressure using impedance monitoring techniques as well as urethral resistance using pelvic floor EMG techniques. Our abbreviated SPECIFIC OBJECTIVES are: 1) to demonstrate in both upper- and lower-motor-neuron SCI cats that direct bladder stimulation can be effective for daily bladder emptying; 2) to demonstrate the upper-motor-neuron lesioned cats that pelvic floor/pudendal nerve stimulation can be used to inhibit the bladder and prevent incontinence and in lower-motor-neuron lesioned cats that stimulation of the pelvic floor/pudendal nerve can be used to increase urethral resistance for incontinence prevention; 3) to demonstrate the implanted device's monitoring capabilities for showing urethral resistance and bladder volume and pressure; 4) to determine if daily direct bladder wall stimulation results in bladder wall hypertrophy; 5) to demonstrate that electrode corrosion is not a significant problem with implantable 316LVM suture type electrodes. We are PROPOSING chronic studies in both upper- and lower-motor-neuron lesioned male cats to further evaluate an implantable stimulator for micturition control and monitoring. In this two year study, two groups of five cats each will be used. The upper-motor-neuron lesioned cats will have a lesion at T-1 and the lower motor lesioned cats will have the lesion at S1-3. Cats will be cared for and studied for 3 weeks following an initial surgery for instrumentation and for 5 month following a second survival surgery. Complete urodynamic recording facilities are available at our Center as well as fluoroscopy for a thorough evaluation of the effects of stimulation on the lower urinary tract. Studies to evaluate the implantable device and bladder wall hypertrophy will be conducted. Finally, the potential corrosion problem of the implantable suture electrodes will be evaluated within the two years. If the hypotheses to be tested in the proposed study are accepted, a clinical study will be designed for SCI patients.
| Walter, J S; Wheeler, J S; Cai, W et al. (1999) Evaluation of a suture electrode for direct bladder stimulation in a lower motor neuron lesioned animal model. IEEE Trans Rehabil Eng 7:159-66 |
