Background and Aims:
A recent randomized controlled trial has suggested a putative relationship between Spinal Cord Stimulation (SCS) frequency, pulse-width, and amplitude termed the “neural dose” (Thomson SJ et al. Neuromodulation. 2018). Additionally, initial evaluation of a new algorithm enabling patient-specific customization of stimulation field shape reported effective sub-perception SCS pain relief with reduced device charging (Paz Solis JF et al. NANS 2018). We describe validation of the proposed relationship between stimulation frequency, pulse-width, and amplitude using outcomes in previously-implanted patients utilizing sub-perception SCS (≤1.2kHz) combined with a novel field shaping algorithm. 

Methods:
This observational study of permanently-implanted patients (up to N=30) at 2 sites in Europe retrospectively (chart review) assessed SCS outcomes for chronic pain (NCT01550575). Pain relief scores (NRS) were collected at baseline and follow-up after utilization of an algorithm enabling a patient-specific field shape and titration of stimulation-frequency with individualized adjustment of pulse-width and amplitude. Patient charging burden is also under evaluation.

Results
As reported earlier, the relationship between frequency and pulse-width (as derived from most effective programs) demonstrated that shorter mean pulse-widths (~30-40µs) at 10kHz increased as frequency decreased, ultimately resulting in mean pulse-widths of ~100–110µs at 1kHz (Thomson SJ et al. Neuromodulation. 2018). In this study, a similar trend has been observed as frequency is further decreased. Data collection is ongoing and final results to be presented.

Conclusions:
We postulate that understanding relationships between stimulation parameters will contribute to better understanding of mechanisms-of-action of sub-perception SCS and foster decreased charge burden while maintaining or improving pain relief outcomes

CUSTOMIZATION OF NEURAL DOSE: REAL-WORLD DATA DEMONSTRATING THE RELATIONSHIP BETWEEN FREQUENCY, PULSE-WIDTH AND AMPLITUDE IN ACHIEVING SUB-PERCEPTION SCS PAIN RELIEF