Background and Aims:
Results from a recent randomized controlled trial (RCT) demonstrated that equivalent pain relief was achieved using a range of frequencies from 1 to 10 kHz spinal cord stimulation (SCS) with appropriate neural dosing (Thomson SJ. et al. Neuromodulation. 2018). The WHISPER RCT evaluated the safety and clinical effectiveness of sub-perception SCS at ≤1.2 kHz in subjects previously implanted with an SCS system for treatment of chronic, neuropathic pain.

Methods:
WHISPER is a prospective, multicenter RCT with a crossover design sponsored by Boston Scientific (ClinicalTrials.gov:NCT02314000). Subjects previously implanted with SCS and a baseline overall pain score ≥6 (with SCS off) at study start were enrolled. Eligible subjects were randomized to either receive sub-perception or supra-perception for a period of 90 days and then crossed over to receive vice versa.  At the completion of crossover, outcomes related to overall pain, satisfaction and preference were collected.

Results
The primary endpoint, based on overall pain responder rate (≥ 50% improvement from Baseline) with no increase in medications, was achieved in a pre-specified cohort of 70 randomized subjects (interim analysis) who were previously implanted ~4 years with mean disability score (Oswestry Disability Index) of 69.4. For those subjects using sub-perception SCS, significant pain relief was sustained (p < 0.001) at 1 year. Post-hoc analysis demonstrated that multiple options provide superior outcomes when subjects could choose the most effective option.

Conclusions:
The WHISPER study demonstrates that sub-perception SCS at ≤1.2 kHz is safe and effective. Waveform options provided superior outcomes when subjects could choose the most effective therapy.

WHISPER RCT: AN UPDATED POST-HOC EVALUATION OF SUB-PERCEPTION SCS AT &#8804;1.2 KHZ IN PREVIOUSLY-IMPLANTED SUBJECTS

WHISPER RCT: AN UPDATED POST-HOC EVALUATION OF SUB-PERCEPTION SCS AT ≤1.2 KHZ IN PREVIOUSLY-IMPLANTED SUBJECTS