Pulsed radiofrequency in peripheral posttraumatic neuropathic pain: A double blind sham controlled randomized clinical trial
Scandinavian Journal of Pain, 07/11/2012

Akural E et al. – Pulsed radiofrequency treatment (PRF) was well tolerated, but this study failed to show efficacy of PRF over sham treatment for peripheral posttraumatic neuropathic pain (NP).

• 45 patients with peripheral posttraumatic NP in their upper or lower limb were randomly assigned to receive PRF or sham treatment to the injured peripheral nerve(s) causing peripheral posttraumatic NP.
• Only patients whose pain intensity was at least 5 on numerical rating scale (NRS) 0–10 and who had suffered from their NP for at least 6months were included.
• All patients had dynamic mechanical allodynia or pinprick hyperalgesia in their painful area.
• They had achieved temporary pain relief of at least 50% with a local nerve block performed at a previous visit.
• The primary efficacy variable was the difference in 3–day mean pain intensity score from the baseline to 3months.
• Other variables included response defined as ≥30% reduction in mean pain intensity at 3months compared to baseline, Neuropathic Pain Scale (NPS) results, health related quality of life (SF–36) and adverse effects.
• The skin was anesthetized with 1% lidocaine.
• A radiofrequency needle was introduced through the skin, and then guided to a SMK cannula (52, 100 or 144mm depending on the target nerve) with 4 or 5mm active tip (SMK–C5–4, SMK–C10–5, SMK–C15–5, Radionics, Burlington, MA, USA).
• The nerve was located accurately by stimulating at 50Hz (threshold <0.5V).
• Sham treatment or PRF was applied for 120s 1–4 times at each treatment point (Radionics, Burlington, MA, USA).
• The total treatment time was up to 8min.
• Both patients and clinicians were blinded during the whole treatment and follow–up period.

• Forty–three patients were included in the analyses.
• There was no statistically significant difference between PRF and sham treatment for the primary outcome efficacy variable.
• Seven patients (3 in PRF group and 4 in sham treatment group) achieved ≥30% pain relief (difference between groups was not significant).
• There was no statistically significant difference in the NPS or any dimension of SF–36 between the treatments.
• Eighteen patients reported adverse effects.
• They were mild and did not necessitate any treatment.
• Transient pain was reported by 17 patients, local irritation by 5 patients and local inflammation by 1 patient.
• There was no significant difference between the groups in the presence of adverse effects.