Tined lead versus percutaneous nerve evaluation for sacral nerve stimulator assessment

Purpose: We compared the outcomes of percutaneous nerve evaluation (PNE) with first-stage tined lead placement (FSTLP) for the testing phase of sacral nerve neuromodulation (SNM), and we assessed the outcomes of these two techniques following implantation of a (second-stage) permanent sacral nerve stimulator (SNS). Methods: Seventy consecutive patients had either PNE (n = 35) or FSTLP (n = 35) evaluation, and conversion to a permanent SNS implant according to response. Primary outcomes were assessed using frequency-volume charts, pad testing, ICIQ/EQ5D questionnaires and global health perception visual analogue scale (VAS). Success was considered if they achieved greater than 50% improvement in their urinary symptoms. Success and failure rates were compared during the test phase and after implantation of the SNS. Results: Mean follow-up for the FSTLP group was 14 months (nine to 20) and for the PNE group was 22 months (eight to 27). Sixteen (46%) of the PNE tests and 20 (57%) of the FSTLP patients were converted to permanent implant. A significant correlation was noted between patients' general health (VAS score) and a successful test phase (r = 0.297, p = 0.013). Eighteen of 19 (95%) of tined lead patients have successful SNS implants, whereas five of 16 (31%) of PNE evaluations failed to convert test efficacy to the permanent SNS implant (p = 0.042). Furthermore, two of PNE-SNS patients were successfully salvaged by the implantation of a second tined lead. Conclusions: FSTLP-SNS has a significantly higher success rate than PNE-SNS in converting the test phase to SNS implantation. This may be due in part to difficulties retaining accurate lead placement with the two-lead (PNE-SNS) approach. These findings have important cost and logistical implications for SNS services.