To investigate data from 211 patients who underwent a trial stimulation (percutaneous nerve evaluation [PNE]) to determine the clinical parameters that can enhance the prediction of PNE success. The advantageous effect of sacral neuromodulation depends on the accurate identification of suitable candidates during the preimplantation PNE.

A total of 211 patients (161 women and 50 men), with refractory urge incontinence, urgency-frequency syndrome, and urinary retention, underwent a PNE. Patient data (demographics, medical history, urologic investigations, and diagnosis) were collected. The PNE results were evaluated from a voiding diary and patient history. More than 50% improvement of voiding parameters was considered a successful PNE, and those patients were selected for implantation. Logistic regression analysis was performed. The factors tested for predicting the test result were sex, patient age, diagnosis, previous surgery, neurogenic bladder dysfunction, duration of complaints, and previous treatments.

The PNEs were positive in 85 patients (40.3%) and negative in 105 patients (49.8%). In 18 patients (8.5%), the test electrode had migrated; 3 more patients were not assessable and were also excluded. Missing data on the variable “duration of complaints” reduced the number of patients in the analyses from 190 to 174 patients.

Intervertebral disk prolapse, duration of complaints, neurogenic bladder dysfunction, and urge incontinence were found to be significant predictive factors. However, a PNE remains necessary to evaluate a patient’s chance of implant success objectively.