Niranjan Singh, MD, DM
Petersen EA, Stauss TG, Scowcroft JA, et al. Effect of High-frequency (10-kHz) Spinal Cord Stimulation in Patients With Painful Diabetic Neuropathy: A Randomized Clinical Trial. JAMA Neurol
. 2021;78(6):687-698. doi:10.1001/jamaneurol.2021.0538
Nevro's SENZA-PDN study, a randomized controlled trail (RCT) of spinal cord stimulation (SCS) treatment conducted for painful diabetic polyneuropathy (PDN), compares 10 kHz SCS plus conventional medical management (CMM) to CMM alone in 216 patients at 18 centers in the United States (US). Important inclusion criteria included failure of symptomatic treatment for 12 months and having tried Lyrica®
or gabapentin + 1 other class of analgesic with average pain of more than 5 out of 10. The device was implanted between T8-T10 to stimulate the dorsal root ganglia. The primary endpoint of the study is a composite endpoint that includes the difference in proportion of treatment responders without deterioration of neurological deficits at 3-month follow-up. Study participants continue to be followed up to 24 months. The SENZA-PDN RCT 6-month data show sustained effectiveness of 10 kHz SCS versus CMM and demonstrated the following benefits: At 6 months, 85% of participants in the 10 kHz SCS study arm reported pain relief >50% versus 5% in the CMM control arm (p < 0.001). At 6 months, average pain relief in the 10 kHz SCS treatment arm was 76% (% reduction of visual analog scale (VAS) from baseline) vs 2% in the control arm. Only 2 of 90 permanent SCS devices were explanted at 6 months for a 2.2% explant rate (both explants were due to infection). At 6 months, 92% of patients were either "satisfied" or "very satisfied" with 10 kHz SCS therapy compared to 91% of CMM patients who were either "dissatisfied" or "very dissatisfied" with treatment. At 6 months, sleep disturbance due to pain in the 10 kHz SCS group was remarkably diminished.
On average in the US, there are 140,000 to 200,000 patients with PND each year who have failed conventional treatment. Adherence to commonly prescribed gabapentin and pregabalin is around 40% at 6 months, while Cymbalta is around 50%. SCS with low frequency stimulation has been studied earlier, with 40-60 stimulation hertz in a small group of patients. A previous study has shown that 10kHZ stimulation is superior to low frequency stimulation.
In this study, 216 patients were randomized in a multicenter study. Initial results are encouraging, treatment groups were well matched, and the study provides level 1 evidence supporting the addition of high-frequency SCS to CMM for patients with PDN refractory to medical management. Wound complication were 5.6%. They also noted improvement in sensation.
The study’s limitation is lack of blinding. The finding of neurological improvement should be interpreted in context with the limitations of the study. More data is needed.