Is a 50% improvement threshold adequate to justify progression from sacral neuromodulation testing to implant?

Purpose: A ≥50% subjective improvement in urinary symptoms during sacral neuromodulation testing (SNM-I) is currently used as the indication for progression to second-stage implantation (SNM-II). While most patients will have successful SNM-I and proceed to SNM-II, deterioration in efficacy over time has been reported. It remains unclear if the durability of efficacy is related to the initial symptom reduction.