Predictors of Longterm Sacral Nerve Stimulation Failures Kevin M Zeeck MD1, Morgan Schubbe BS1, Robert C O’Connor MD1, Anjishnu Banerjee PhD2, and Michael L Guralnick MD1 Department of Urology1, Division of Biostatistics2 Medical College of Wisconsin, Milwaukee Wisconsin, USA Introduction Sacral nerve stimulation is an accepted treatment option for refractory over active bladder (OAB) and nonobstructive urinary retention (UR). Over time, some patients have return of symptoms despite a functioning SNS implant with reported failure rates of 29% in OAB patients1 and 14% in UR patients.2 Our objective is to identify predictors for which patients have symptomatic failure despite a functioning SNS implant. Methods This is an IRB-approved retrospective chart review of patients who underwent SNS for the management of refractory voiding dysfunction. Data collected included: primary indication for SNS (over active bladder (OAB) and urinary retention (UR)), presence of mixed urinary incontinence (MUI), hypersensate bladder (HB), and detrusor overactivity (DO) on urodynamics, as well as demographic variables including age, sex, diabetes, prior pelvic/incontinence surgery, and neurogenic disorder/spine surgery. Patients who had successful test stimulation and implant were analyzed. We then compared patients who had ongoing symptom improvement (long term success) to those who failed (failure of SNS was defined as return of symptoms despite a functioning system) using cox regression analysis. Results 140 patients analyzed, mean follow up time of 46 months 89/140 (64%) had ongoing symptom improvement 51/140 (36%) had loss of efficacy over time despite a functioning implant (mean 42.8 months {range 2-109}) SNS Efficacy Durability   Success (N=89) Failure (N=51) Univariate Analysis (P-Value) Age 50.1 48.3 0.51 Female 88% 87% 0.92 Depression or Anxiety 55% 45% 0.26 OAB 81% 82% 0.83 UR 19% 20% 0.94 MUI 30% 27% SUI Surgery 18% 14% Urge Incontinence 51% 0.50 Smoking 44% 47% 0.71 Diabetes 21% 0.43 Interstitial Cystitis 9% 15% 0.61 Prior Hysterectomy 40% 33% 0.40 Prolapse Surgery 12% 10% 0.64 Neurological History 16% 0.11 Spinal Disease 31% 0.12 Underwent Revisions 42% 53% 0.97 Revisions in first year 0.29 Hypersensate Bladder 36% 0.35 Detrusor Overactivity 34% 49% 0.06 All Patients UR Patients OAB Patients   Multivariate Analysis (P-Value) Hazard Ratio Female 0.21 0.51 (0.2 – 1.5) Depression or Anxiety 0.07 1.75 (0.95 – 3.26) OAB 0.01 0.30 (0.1 – 0.75) Prior Hysterectomy 0.02 0.44 (0.22 – 0.87) Neurological History 0.002 2.9 (1.5 – 5.8) Spinal Disease 0.26 1.4 (0.8 – 2.7) Underwent Revisions <0.001 0.49 (0.33 – 0.72) Revisions in First year 2.7 (1.3 – 5.7) Detrusor Overactivity 0.10 0.1 (0.9 – 3.6) On multivariate analysis: Predictors of failure: Underlying neurological conditions and Need for revision in 1st year after implant Conclusions 36% of patients with SNS patients lost efficacy over time. The presence of an underlying neurologic condition and the need for surgical revision within the first year of implant may be associated with an increased risk of long term failure. References White et al. Sacral nerve stimulation for treatment of refractory urinary retention: long-term efficacy and durability. J Urology. 2008. Peeters et al. Long-term follow up of sacral neuromodulation for lower urinary tract dysfunction. British Journal of Urology 2014