title: External Noninvasive Peripheral Nerve Stimulation Treatment of Neuropathic Pain: A Prospective Audit.
abstract: BACKGROUND
  Peripheral nerve stimulation (PNS) is a neuromodulation technique in which electrical current is applied to the peripheral nerves to ameliorate chronic pain through preferential activation of myelinated fibres, inducing long-term depression of synaptic efficacy. External noninvasive peripheral nerve stimulation (EN-PNS) is a novel and simple form of PNS that involves stimulation via an external nerve-mapping probe that is placed on the skin and connected to a power source.
  
  
  OBJECTIVE
  We aimed to assess the clinical utility of EN-PNS in patients with refractory neuropathic pains referred to a tertiary pain treatment center.
  
  
  METHODS
  We undertook a prospective audit of EN-PNS. Patients with a diagnosis of either complex regional pain syndrome or neuropathic pain after peripheral nerve injury who met inclusion criteria were included. Participants completed three stages of the audit: stage 1, six weekly outpatient treatment sessions; stage 2, six-week equipment home loan; stage 3, six weeks of no EN-PNS treatment. The primary outcome was the average post-treatment instantaneous pain intensity during the last week in stage 2 compared with baseline (11-point numerical rating scale).
  
  
  RESULTS
  EN-PNS provided significant short-term pain relief (n = 20 patients, average reduction of 2.8 numerical rating scale points, 95% CI 1.6-4.0, p < 0.001, intention-to-treat analysis). Eight patients (40%) improved in several outcome parameters ("responders"), including quality of life and function.
  
  
  CONCLUSIONS
  In this first prospective report on the use of EN-PNS in neuropathic pain, this technology provided significant clinical benefit for some patients. Controlled studies are required to confirm our results and the place of EN-PNS in future neuromodulation treatment algorithms. Given the refractory nature of these conditions, these results are encouraging.
authors.affiliation: Pain Management Department, Walton Centre NHS Trust, Liverpool, UK.
authors.forename: Selina
authors.initials: S
authors.lastname: Johnson
authors.affiliation: Pain Management Department, Walton Centre NHS Trust, Liverpool, UK.
authors.forename: Helen
authors.initials: H
authors.lastname: Ayling
authors.affiliation: Pain Management Department, Walton Centre NHS Trust, Liverpool, UK.
authors.forename: Manohar
authors.initials: M
authors.lastname: Sharma
authors.affiliation: Pain Management Department, Walton Centre NHS Trust, Liverpool, UK.|University of Liverpool, Liverpool, UK.
authors.forename: Andreas
authors.initials: A
authors.lastname: Goebel
mesh_terms: D020918:Complex Regional Pain Syndromes / Q000523:psychology* / Q000628:therapy*; D004599:Electric Stimulation Therapy / Q000379:methods*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D009437:Neuralgia / Q000523:psychology* / Q000628:therapy*; D010147:Pain Measurement; D011446:Prospective Studies; D016896:Treatment Outcome
keywords: Chronic pain; complex regional pain syndrome; neuropathic pain; peripheral nerve stimulation