Painful Diabetic Neuropathy-Spinal Cord Stimulation, Peripheral Nerve Stimulation, Transcutaneous Electrical Nerve Stimulation, and Scrambler Therapy: A Narrative Review

Background: First-line medications for the treatment of painful diabetic neuropathy (PDN) are associated with a substantial rate of discontinuation due to adverse effects or insufficient efficacy. Neuromodulation techniques have been used for PDN, but a comprehensive review of the literature that incorporates several distinct device categories has yet to be undertaken. Objectives: We aimed to summarize the evidence regarding 4 major types of neuromodulation devices for the treatment of PDN. We focused on spinal cord stimulators (SCS), peripheral nerve stimulators (PNS), transcutaneous electrical nerve stimulators (TENS), and scrambler therapy devices (ST) because they are often used for refractory neuropathic pain. Study Design: Narrative Review. Methods: A comprehensive and reproducible literature search was performed using PubMed with no search restrictions applied. The available Medical Subject Headings were used. Inclusion criteria included prospective studies, retrospective studies, case series, and case reports indexed from database inception to the search date (September 14, 2021). Results: Seventeen studies met inclusion criteria, 10 of which were regarding SCS. Only 3 of the 10 were randomized controlled trials. We found no studies assessing contemporary PNS. Four studies assessed TENS, but the devices varied widely in voltages and waveforms. Two case reports described ST. Limitations: Potential selection bias due to the nature of a narrative review, although a reproducible search strategy was utilized. Several neuromodulation modalities have minimal published evidence available. Conclusions: The evidence for neuromodulation devices for the treatment of PDN mostly comprises open-label prospective trials or case reports. SCS has the most volume of evidence for efficacy. Studies regarding TENS show mixed results, possibly due to numerous device varieties. PNS and ST may hold promise based on their proposed mechanisms of action, but prospective controlled trials are needed.