Subsequent to the publication of the guideline by Gormley et al (reference 10 in article) several studies have reported continued BTX efficacy and improved quality of life while maintaining the same median inter-injection intervals beyond 2-year followup.1-3 Causes for therapy discontinuation are most accurately reported in prospective studies. Thus, as referenced in the comment, the 3.5-year followup in the study by Nitti et al showed that 5.7% of discontinuations were due to lack of efficacy and the highest rate, 12%, was due to trial burden.4 For the 22 BTX participants who did not complete the study protocol a sensitivity analysis showed that assuming maximum BTX costs for all would raise 2-year BTX costs to almost $13,000, compared to 2-year SNM costs of $35,680 (supplementary Appendix C, https://www.jurology.com).
The ROSETTA study accommodated for advancements in lead technology and minimal stimulation thresholds during lead placement were incorporated in the study design, a novel concept for an InterStim® study. Thus, optimal lead placement was assessed by the high clinical responder rate (84%), low revision and removal rates (3% and 8.6%) and 2-year sustained efficacy (reference 14 in article).
Threshold analysis evaluated the impact of single stage vs 2-stage SNM implantation and length of SNM technology life. It showed that a single stage implantation technique would reduce SNM costs by 15% compared to 2-stage, but importantly this did not include implantation and explantation costs for the trial’s nonresponders. In addition, the assumption of rechargeable SNM technology would result in similar costs for SNM and BTX by 39 years for 2-stage and by 25 years for single stage implantation.
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