A novel mini-invasive approach to the treatment of neuropathic pain: the PENS study

Background: peripheral neuromodulation is often used as chronic neuropathic pain treatment. percutaneous electrical nerve stimulation (pens) is generally utilized with several probes at the same time and repeated treatments. objectives: evaluate the short- and long-term efficacy of a single probe and single shot pens approach. study design: multicenter,prospective,observational study. setting: four italian pain therapy centers. methods: inclusion criteria were age ≥ 18 and ≤ 80 years,presence of severe peripheral neuropathic pain lasting more than 3 months,localized and refractory to pharmacological therapies. patients with infection,coagulopathies,psychiatric disorders,pacemakers,or implantable cardiac defibrillators were excluded. patients: seventy-six patients (47 women,29 men),mean age 62 ± 14 years,affected by neuralgia (21 herpes zoster infection,31 causalgia,24 postoperative pain) were enrolled in the study. intervention: after localization of trigger point and/or allodynic/hyperalgesic area,pens therapy was achieved with a single 21 gauge conductive probe tunneled percutaneously and a neurostimulator device. measurement: numerical rating scale (nrs) and neuropathic pain scale (nps) were assessed at baseline,60 minutes after pens,at one week,after one,3,and 6 months; perceived health outcome was measured with euroqol-5 dimension (eq-5d) questionnaire at baseline and at 6 months. adverse events and patient satisfaction were reported. results: nrs and nps decreased significantly after 60 minutes and the reduction remained constant over time at follow-up. eq-5d increased significantly with respect to the baseline. two nonclinically significant adverse events (one contralateral dysestesia and one self-resolving hematoma) were observed. limitations: small sample size and non-randomized observational study; high prevalence of post-herpetic and occipital neuralgias. conclusion: pens therapy produced significant and long-lasting pain relief in chronic peripheral neuropathic pains of different etiology. the present study confirms the feasibility,safety,and repeatability of this minimally invasive technique. © 2016,american society of interventional pain physicians. all rights reserved.