"Based on a 5-year, prospective, multicenter trial evaluating the long-term safety and efficacy of sacral nerve neuromodulation in patients with refractory urge incontinence, van Kerrebroeck and coworkers13 reported on 152 patients in 17 centers worldwide undergoing implantation. Ninety-six had urge incontinence, 25 had urgency-frequency, and 31 had retention.
Voiding diaries were collected annually for 5 years. At 5 years after implantation, 68% of patients with urge incontinence, 56% with urgency-frequency, and 71% with retention continued to have successful outcomes based on 50% or greater improvement from baseline."
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2672997/For me, a 50% improvement isn't even close to something I'd call success. If I wet myself 10 times a day, and you get it down to 1 time a day, it's still not success to me. I'd still need diapers.