[Chronic sacral bilateral neuromodulation. Using a minimal invasive implantation technique in patients with disorders of bladder function]

Abstract

The implantable neuromodulation system described by Tanagho and Schmidt enables unilateral sacral nerve stimulation. Reports have been made on sacral neuromodulation failures of up to 50% in patients undergoing this procedure. We chose the bilateral electrode implantation and a minimal invasive laminectomy to ensure a more effective modulation and better placement and fixation of the electrodes. After successful assessment using a peripheral nerve evaluation test, 20 patients (14 with detrusor instability, 6 with hypocontractile detrusor) underwent minimally invasive laminectomy and bilateral electrode placement. In the patients with detrusor instability, the incontinence episodes were reduced from 7.2 to 1 per day and the bladder capacity improved from 198 to 352 ml. In patients with hypocontractile detrusor, the initial residual urine level of 450 ml dropped to 108 ml. Maximum detrusor pressure during micturition rose from 12 cmH2O initially to 34 cmH2O. The average follow up period was 17.5 months. There was no sign of deterioration in the modulation effect in any of the patients. Bilateral electrode implantation and the new sacral approach allow optimal neuromodulation in patients with bladder dysfunction. Laminectomy enables optimum electrode placement and fixation with minimal trauma.