INTRODUCTION AND OBJECTIVE:
The pulse width (PW) parameter in sacral neuromodulation (SNM) is understudied, with no evidence-based guidance available on alternative PW for bladder indications. The aim of this prospective, randomized, single-blinded, 3x3 cross over design study was to estimate the effect of two PW settings (60 ms, 420 ms) compared to the industry standard (210ms) on efficacy, quality of life, and device parameters.
Eligible patients had urge incontinence or urgency-frequency and subjectively satisfied at the time of enrollment. Patients completed a 3-day voiding diary, validated questionnaires, and device interrogations at baseline and after each 4 week period on the three settings. Eighteen subjects completed the study.
Mean age was 68 years, and mean implant duration was 4.4 years. PW variations did not result in a significant difference in regards to overall objective outcomes. In regards to device parameters amplitude and change in battery life were significantly different with alternative PW. (Table 1) A shortened PW required an average higher amplitude (4.10 vs 2.10) while saving battery life (2.35 months). Subjective stimulus sensation such as location, quality, and intensity did not differ between PW. 11 patients chose standard PW after the study, 5 chose extended, and 2 chose shortened. Upon subset analysis for those that chose an alternative PW, change in urinary frequency from enrollment was significantly different, with an average reduction of -2.23 (p=0.015). For those patients who reported doing “much better” or “very much better” on the extended PW, they reported significantly less urinary frequency and nocturia at 5.6 and 0.4, compared to 8.5 and 2.16 (p=0.005, p=<0.001.) For those patients who reported doing “much better” or “very much better” on the shortened PW, they reported significantly less urinary frequency at 5.15 compared to 7.35 (p=0.026).
In this prospective cross over trial overall device effectiveness was unchanged through use of alternative PW, however 39% of patients preferred an alternative PW with measurable change noted. Our findings support prior animal model data that a shorter PW can result in the same efficacy while saving estimated battery life.
Source of Funding:
SUFU Foundation Study of Neuromodulation Research Grant