Sacral neuromodulation for refractory urge incontinence is less effective following spinal surgery

Patients with neurogenic disorders and voiding dysfunction have been reported to respond poorly to sacral neuromodulation. We report on our experience in treating voiding symptoms with sacral neuromodulation after spinal surgery. The medical charts of patients evaluated for sacral neuromodulation from 2000-2008 were retrospectively reviewed. Indications, need for explantation, and clinical success (>50% symptom improvement) were recorded. The cohort of patients who had undergone prior spinal surgery was compared to patients with no history of spinal surgery or neurological disease. Thirty-two patients with a history of spinal surgery and 136 with no history of neurologic disease underwent sacral neuromodulation testing. Twenty men and women (62.5%) from the spinal surgery group ultimately underwent permanent implantation. Seventeen of the 32 patients were diagnosed with urge incontinence, of whom 52.9% reported a successful outcome at a mean of 2.3 years of follow-up, compared to an 80.3% success rate in patients with no history of spinal surgery (p=0.018). Sixteen of 32 carried a diagnosis of urgency/frequency with 62.5% success at last follow-up, compared 73.9% (p=0.35) of those without a history of spinal surgery or neurological disease. Thirteen of 32 patients diagnosed with urinary retention experienced a 61.5% long-term success rate, compared with 63.6% for those without spinal surgery and urinary retention. Six of 20 (30.0%) in the spinal surgery group were explanted at a mean time of 2.9 years, compared with 27 of 102 (26.5%) of the non-neurologic patients. Clinical success can be achieved using sacral neuromodulation in patients with voiding dysfunction and a history of spinal surgery; however, those with urge incontinence are less likely to report significant improvement.