Prolonged percutaneous SNM testing does not cause infection-related explanation


Correspondence: Karl-Dietrich Sievert, Department of Urology, Eberhard Karls University Tuebingen, Hoppe-Seyler-Str. 3, 72076 Tuebingen, Germany.



What's known on the subject? and What does the study add?

  • Sacral neuromodulation (SNM) is an effective treatment option of different pelvic-related dysfunctions. SNM evaluation by either temporary or permanent electrodes is generally accepted. Extended testing with temporary electrodes has been reported on before but less is known about infection-related risks during prolonged evaluation with definitive electrodes.
  • The present findings show that prolonged testing (mean = 52.3 days) with permanent electrodes does not increase infection-associated explantation rates, although bacterial colonization was found in more than one-third of the patients. Prolonged SNM evaluation under everyday conditions might improve long-term success.


  • To evaluate the impact of prolonged stage 1 testing on bacterial electrode colonization, infection and treatment success.

Materials and Methods

  • In all, 21 patients who underwent sacral neuromodulation (SNM) for periods ≥1 month were prospectively evaluated; nine patients had overactive bladder syndrome (OAB), 10 had urinary retention, two had faecal incontinence (FI), and 13 had diabetes and overweight/obesity.
  • After stage 1 testing electrode extension leads were microbiologically analysed to assess bacterial colonization.
  • The primary measurements were pre- and post-SNM treatment comparisons based on patient-agreed criteria using an increased 70% minimum improvement rate; secondary measurements were bacterial colonization and impact of infection.


  • The mean stage 1 evaluation period was 52.3 days; 16 patients (76%) progressed to stage 2, and five patients were explanted due to inadequate improvement (<70%).
  • There was bacterial colonization in 42.9% of patients and 38.2% of extension leads.
  • Stage 2 patients showed no infection or wound-healing disorders at a mean follow-up of 33.9 months.
  • The success rate for stage 2 implantation treatment was 94%.


  • There are few studies in the literature evaluating SNM testing periods vs the risk of clinically relevant implant infection rates. The present study shows that prolonged testing could potentially enhance treatment efficacy without infection-related explantations of the chronic implant, despite the identification of bacteria.
  • SNM-implanted patients with diabetes mellitus or obesity should be followed closely.
  • Clinicians might consider using prolonged testing under everyday conditions.
  • Prolonged SNM stage 1 testing is a very effective minimally invasive treatment option to evaluate pelvic-related dysfunction.