European experience with bilateral sacral neuromodulation in patients with chronic lower urinary tract dysfunction.

Although there is experimental and clinical evidence that bilateral stimulation of the sacral nerves could lead to summation effects, no significant differences in unilateral versus bilateral neuromodulation could be demonstrated in a comparative trial. In some individuals, however, only bilateral stimulation relieved symptoms. Therefore, if a unilateral percutaneous nerve evaluation test fails, a bilateral test should be considered. Further clinical research with long-term follow-up will allow the identification of which patients could benefit from bilateral stimulation with greater specificity and ameliorate further the long-term results achieved with unilateral SNS.

Sacral rhizotomies and electrical bladder stimulation in spinal cord injury. Part I: Clinical and urodynamic analysis. Dutch Study Group on Sacral Anterior Root Stimulation.

OBJECTIVES: To present the clinical and urodynamic results of the treatment of neurogenic bladder dysfunction in spinal cord injury by sacral rhizotomies and electrical bladder stimulation with the Finetech-Brindley stimulator during a 3-year inclusion and study period. METHODS: 226 patients with spinal cord lesion and urological problems due to hyperreflexia of the bladder were screened for sacral rhizotomies and electrical bladder stimulation. In 52 patients complete posterior sacral root rhizotomies were performed and a Finetech-Brindley sacral anterior root stimulator implanted. All patients were screened and followed with a standard protocol. RESULTS: Complete continence during daytime was achieved in 73% of patients with 6-month follow-up and in 86% at night. Significant increase in bladder capacity and bladder compliance was achieved in all patients. Residual urine was reduced significantly, resulting in a decrease of the incidence of urinary tract infections. CONCLUSIONS: The treatment of neurogenic bladder dysfunction in spinal cord injury by anterior sacral root stimulation with the Finetech-Brindley stimulator in combination with sacral posterior root rhizotomy produces excellent results with limited morbidity.

Selective sacral root stimulation for bladder control: acute experiments in an animal model.

High bladder pressure is a potential side effect of poststimulus voiding, used to date for stimulation-induced bladder emptying in spinal cord injured patients. To prevent this side effect, selective activation of the bladder without activation of the urethral sphincter by selective stimulation of sacral roots was studied in a canine animal model. On-line registration of bladder, urethral and rectal pressure was performed, and EMG of tail muscles and urethral sphincter was recorded. After laminectomy, intradural left and right sacral root S2 were stimulated with a tripolar cuff electrode. A self-made stimulator generating adjustable pulse shapes was used. Using 200 microsec. rectangular pulses, contraction of bladder and urethral sphincter could be elicited. Selective activation of the bladder occurred with pulses of 600 to 800 microsec. due to anodal blocking of the large nerve fibers in the sacral roots. During acute animal experiments we were able to achieve selective activation of the detrusor without simultaneous activation of the external urethral sphincter, and complete, low-pressure voiding occurred.