Case report: Percutaneous electrical neural field stimulation in two cases of sympathetically-mediated pain [version 1; referees: 1 approved, 2 approved with reservations]

Background: Fibromyalgia and complex regional pain syndrome (CRPS) are both chronic pain syndromes with pathophysiologic mechanisms related to autonomic nervous system dysregulation and central sensitization. Both syndromes are considered difficult to treat with conventional pain therapies. Case presentations: Here we describe a female veteran with fibromyalgia and a male veteran with CRPS, both of whom failed multiple pharmacologic, physical and psychological therapies for pain, but responded to percutaneous electrical neural field stimulation (PENFS) targeted at the auricular branches of the cranial nerves. Discussion: While PENFS applied to the body has been previously described for treatment of localized pain, PENFS effects on cranial nerve branches of the ear is not well-known, particularly when used for regional and full-body pain syndromes such as those described here. PENFS of the ear is a minimally-invasive, non-pharmacologic therapy that could lead to improved quality of life and decreased reliance on medication. However, further research is needed to guide clinical application, particularly in complex pain patients.