Sacral Neuromodulation (SNM) is a known therapy for bladder and bowel dysfunctions. It involves a test phase and permanent implantation, with success defined as > 50% improvement in symptoms. Two methods exist for the test phase: the staged procedure in the operating room and Percutaneous Nerve Evaluation (PNE) in the office. We compared the clinical success and maintained long-term results of PNE versus the Staged procedure.

A retrospective cohort study was conducted between March 2017 and June 2022. It included all patients with various lower urinary tract dysfunction who proceeded with the sacral neuromodulation test phase. Patients underwent PNE as initial test phase. Those who had technical difficulties, refused PNE or had electrode migration, underwent staged procedures. The primary outcome is proceeding to stage 2 implantation, secondary outcome include maintaining device efficacy in clinical symptoms, and the need for reprogramming at 6 weeks and later at 6 months. Further correlation analysis between the implantation and other patient demographics. PNE was performed without fluoroscopy and tested for 3 to 5 days. Those who had procedure intolerance, difficulty locating the sacral foramina, had electrode migration or refused PNE underwent staged procedure for  2 weeks.

A total of 155 patients were categorized into 2 groups according to the type of test trial. 69 patients underwent Staged Implants (Group 1) and 86 patients underwent PNE (Group 2). Diagnoses were as follows: Refractory Overactive bladder in 21 patients (30%) and 21 (30%), Urinary retention 40 (57.9%) and 37 (43%), CPPS/ IC 3 (4.3%) and 7 (8%) in Staged and PNE group, respectively. 36 patients (42%) from the staged group and 50 patients (57%) from the PNE group had permanent implants with no significant statistical difference. After 6 weeks of implantation, most of the patients maintained their test trial response >50% while only 2 patients from each group noticed <50% clinical improvement. Most of the patients didn’t need to have a second reprogramming at 6 weeks post-implantation. At 6 months, more patients in group 2 noticed <50% clinical improvement post-implantation ( 8 patients in group 2 in comparison to 2 in group 1), but still didn’t show any statistical significance p-value =0.126, and so the reprogramming in PNE group (group 2) was more in comparison to stage 1 ( group 1) without any statistical significance, p-value =0.172.

This study showed a similar success rate in both groups with no statistical difference and maintained improved symptoms at 6 weeks and 6 months postoperatively. Reprogramming showed no statistical difference between the two groups at 6 weeks and 6 months post-operatively. Overactive Bladder diagnosis, female gender, and history of prior pelvic surgery were positive indicators for a successful test phase, regardless of the type of test being performed.

There was no difference between PNE and staged procedure in conversion to permanent implants and long-term clinical outcomes. We recommend PNE as an initial cost-effective and office-based test phase for sacral neuromodulation in patients with Lower urinary tract dysfunction.

Continence 7S1 (2023) 100933
DOI: 10.1016/j.cont.2023.100933