To evaluate the outcomes of sacral neuromodulation (SNM) using the InterStim II system in patients with neurogenic lower urinary tract dysfunction (NLUTD), including both detrusor overactivity (DO) and detrusor underactivity (DU), in terms of subjective improvement, validated questionnaire scores (NBSS), post-void residual (PVR) volume, and frequency of clean intermittent catheterization (CIC).

This retrospective single center study included 50 patients treated with SNM between 2018 and 2024, with a minimum follow-up of one year. The implantation includes test phase and permanent implant. Among them, 26 (52%) had a diagnosis of neurogenic lower urinary tract dysfunction (NLUTD) secondary to conditions such as multiple sclerosis (n= 3), spinal cord injury (n=4), iatrogenic pelvic nerve lesions (n=3), or cauda equina syndrome (n=3), stroke (n=2), Spina Bifida (n=2),  Parkinson’s disease (n=1). Subjective improvement, NBSS (Neurogenic Bladder Symptom Score) total score, post-void residual (PVR) volume, and the number of daily clean intermittent catheterizations (CICs) were assessed before and after SNM therapy. Therapeutic success was defined as a subjective improvement of at least 50% in urinary symptoms and quality of life and improvement in NBSS questionnaire.

Therapeutic success was achieved in 18 of 26 NLUTD patients (69.2%). Mean subjective improvement among responders with DO was 66.2%, and in patients with DU it was 57.9% (p = 0.377).
NBSS total scores significantly improved in both subgroups:
DU group: from 32.6 to 20.7 (p = 0.016)
DO group: from 51.5 to 35.25 (p < 0.001)
In DU patients, the median PVR volume significantly decreased from 300 ml to 150 ml (p = 0.0057), and the median number of daily CICs dropped from 5 to 2.5 (p = 0.0206).

Sacral neuromodulation appears to be an effective treatment for NLUTD in both subtypes, significantly improving symptom burden and quality of life. While subjective improvement was slightly higher in patients with DO, the difference between groups was not statistically significant. In DU patients, SNM contributed to a significant reduction in PVR and CIC frequency.

This is the first large Polish study evaluating SNM in NLUTD. Our results confirm that SNM is a highly effective therapy for selected patients with neurogenic bladder dysfunction, consistent with outcomes from major international centers.