Background: Percutaneous electrical nerve stimulation (PENS) is an electrical neuromodulation technique that has shown its therapeutic potential in various chronic pain conditions over the past few years, but well-blinded controlled studies are lacking.
Patients and methods: A randomized double-blind sham-controlled crossover trial on 31 patients with chronic pain with surface hyperalgesia to investigate the efficacy of PENS.
Results: For the active PENS therapies, the median numerical rating scale (NRS) for pain changed from 7.5 (standard deviation [SD] ± 1) (range 6-10) before therapy to 0.5 (range 0-8.5) after therapy (Z = -4.206, P < 0.0005 [two-tailed]). The mean pain pressure threshold (PPT) measured with the von Frey aesthesiometer changed from 202 gm (SD ± 137 gm) (range 55-800 gm) before therapy to 626 gm (SD ± 228 gm) (range 45-800 gm) after therapy (Z = -4.373, P < 0.0005 [two-tailed]). There was a statistically significant difference between the changes in NRS for the active (3.9 [±3.2][0-8]) compared with the sham (0.1 [±0.4][0-1.5]) therapies, U = 40, Z = -3.484, P < 0.0001 (two-tailed). There was a statistically significant difference between the changes in PPT for the active (310 gm [±267 gm][0-670 gm]) compared with the sham (8 gm [±4 gm][0-15 gm]) therapies, U = 48.5, Z = -2.699, P = 0.007 (two-tailed).
Conclusion: PENS therapy appears to be effective in providing short-term pain relief in chronic pain conditions. Studies, involving larger sample sizes and longer follow-up are recommended.
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