Conventional vs High-Frequency Spinal Cord Stimulation for Chronic Pain
Although spinal cord stimulation effectively alleviates chronic axial back pain in 50% to 70% of cases, it is accompanied by adverse effects.
In a preliminary study published in Neuromodulation, high-frequency spinal cord stimulation was found to be more effective in treating chronic pain than conventional stimulation.
Although spinal cord stimulation (SCS) effectively alleviates chronic axial back pain in 50% to 70% of cases, it is accompanied by adverse effects (eg, frequent paresthesias). In the current pilot study, investigators sought to examine whether these issues could be resolved by alternating conventional stimulation (≤100 Hz) with high-frequency or "shuffle" stimulation (10,000 Hz).
Twelve patients with chronic pain were implanted with a SCS device before surgery and enrolled in the study if they achieved >50% pain relief with SCS after surgery.
All study participants were continued on conventional stimulation for 4 weeks after surgery, after which they were randomly assigned to continue receiving conventional stimulation for an additional 4 weeks (n=6) or were switched to shuffle stimulation for the same period (n=6). After a 1-week washout period, the groups were alternated again for another 4 weeks.
Pain was assessed with the numeric rating scale (NRS). NRS scores were reduced from baseline to 13 weeks for the whole cohort (average NRS, 6.7±1.8 and 5.0±1.5, respectively; P =.005). NRS scores were reduced in patients who had received shuffle vs conventional stimulation (4.0±1.6 vs 5.8±2.3, respectively; P =.024).
In the final week of the study, average pain scores showed an improvement in patients who had received shuffle stimulation, although this did not reach significance (P =.096). When asked posttreatment which stimulation method they preferred, 7 patients indicated shuffle, 4 indicated conventional stimulation, and 1 had no preference.
The investigators note that "the use of conventional stimulation immediately following device implantation and during the washout periods may have altered the effect size and perception of shuffle stimulation," thus presenting a study limitation.
"[G]iven that the more standard improvement in pain reduction (>50% pain relief in the SCS trial) was not observed in this pilot study, further investigation with larger sample sizes is necessary," concluded the study authors.
Kumar V, Prusik J, Lin Y, Hwang R, Feustel P, Pilitsis JG. Efficacy of alternating conventional stimulation and high frequency stimulation in improving spinal cord stimulation outcomes: a pilot study [published online February 5, 2018]. Neuromodulation. doi: 10.1111/ner.12755