Purpose: This 5-year, prospective, multicenter trial evaluated the long-term safety and efficacy of sacral neuromodulation in patients with refractory urge incontinence, urgency frequency and retention.
Materials and methods: A total of 17 centers worldwide enrolled 163 patients (87% female). Following test stimulation 11 patients declined implantation and 152 underwent implantation using InterStim. Of those treated with implantation 96 (63.2%) had urge incontinence, 25 (16.4%) had urgency frequency and 31 (20.4%) had retention. Voiding diaries were collected annually for 5 years. Clinical success was defined as 50% or greater improvement from baseline in primary voiding diary variable(s).
Results: Data for all implanted cases were reported. For patients with urge incontinence mean leaking episodes per day decreased from 9.6 +/- 6.0 to 3.9 +/- 4.0 at 5 years. For patients with urgency frequency mean voids per day decreased from 19.3 +/- 7.0 to 14.8 +/- 7.6, and mean volume voided per void increased from 92.3 +/- 52.8 to 165.2 +/- 147.7 ml. For patients with retention the mean volume per catheterization decreased from 379.9 +/- 183.8 to 109.2 +/- 184.3 ml, and the mean number of catheterizations decreased from 5.3 +/- 2.8 to 1.9 +/- 2.8. All changes were statistically significant (p <0.001). No life threatening or irreversible adverse events occurred. In 102 patients 279 device or therapy related adverse events were observed. At 5 years after implantation 68% of patients with urge incontinence, 56% with urgency frequency and 71% with retention had successful outcomes.
Conclusions: This long-term study demonstrates that InterStim therapy is safe and effective for restoring voiding in appropriately selected cases refractory to other forms of treatment.