Automated Neural Dosing for Fast-Acting Subperception Therapy: Sustained Spinal Cord Stimulation Outcomes from a Multicenter Study

INTRODUCTION: Therapy habituation is a barrier to sustained success with spinal cord stimulation (SCS). Fast-acting subperception therapy (FAST) is a low-frequency, subperception waveform that can achieve rapid wash-in pain relief via the surround inhibition mechanism. FAST-Autodose is an automated neural dosing schedule designed to provide effective pain relief while potentially reducing habituation and maintaining therapy within an efficient therapeutic window-thus eliminating the need for manual patient adjustments. We assessed the efficacy of FAST-Autodose and provide preliminary long-term outcomes. METHODS: We conducted a retrospective review of consecutive patients from a multicenter, observational study in the USA who had received SCS and used FAST-Autodose to manage their chronic pain of the low back and/or lower limbs. The numerical rating scale (NRS) evaluated the overall pain intensity until the last follow-up postimplantation. RESULTS: Data were collected from 73 patients who had used FAST-Autodose for 11.9 ± 6.8 months on average. At the last follow-up visit (average 1.8 ± 1.5 years after implantation), the NRS score for overall pain decreased by 5.1 ± 2.8 points, to a mean of 2.1 ± 2.0 (p < 0.0001) and 69% of patients reported minimal pain (NRS ≤ 2/10). In total, 23 patients had been implanted for more than 3.5 years and had used FAST-Autodose for a mean of 17.7 ± 5.9 months; in these patients, the mean NRS pain score decreased by 6.1 ± 2.0 points to 1.6 ± 1.2 points (p < 0.0001). CONCLUSIONS: FAST-Autodose is a novel, automated, subperception paradigm for SCS. In our study, this program delivered significant and sustained pain relief in patients with chronic low back and/or leg pain who had been implanted with SCS for up to 3.6 years. These preliminary results constitute a promising rationale for larger, prospective studies on the long-term efficacy of FAST-Autodose. CLINICAL TRIAL REGISTRATION: Trial registered at clinicaltrials.gov (ID: NCT01550575).