Peripheral nervous system origin of phantom limb pain
- PMID: 24769187
- DOI: 10.1016/j.pain.2014.04.018
Peripheral nervous system origin of phantom limb pain
Abstract
Nearly all amputees continue to feel their missing limb as if it still existed, and many experience chronic phantom limb pain (PLP). What is the origin of these sensations? There is currently a broad consensus among investigators that PLP is a top-down phenomenon, triggered by loss of sensory input and caused by maladaptive cortical plasticity. We tested the alternative hypothesis that PLP is primarily a bottom-up process, due not to the loss of input but rather to exaggerated input, generated ectopically in axotomized primary afferent neurons in the dorsal root ganglia (DRGs) that used to innervate the limb. In 31 amputees, the local anesthetic lidocaine was applied intrathecally and/or to the DRG surface (intraforaminal epidural block). This rapidly and reversibly extinguished PLP and also nonpainful phantom limb sensation (npPLS). Control injections were ineffective. For intraforaminal block, the effect was topographically appropriate. The suppression of PLP and npPLS could also be demonstrated using dilute lidocaine concentrations that are sufficient to suppress DRG ectopia but not to block the propagation of impulses generated further distally in the nerve. PLP is driven primarily by activity generated within the DRG. We recommend the DRG as a target for treatment of PLP and perhaps also other types of regional neuropathic pain.
Keywords: DRG; Ectopic firing; Electrogenesis; Intraforaminal; Neuropathic pain; Phantom limb pain.
Copyright © 2014 International Association for the Study of Pain. Published by Elsevier B.V. All rights reserved.
Comment in
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A sore spot: central or peripheral generation of chronic neuropathic spontaneous pain?Pain. 2014 Jul;155(7):1189-1191. doi: 10.1016/j.pain.2014.04.002. Pain. 2014. PMID: 24928202 No abstract available.
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PNS origin of phantom limb sensation and pain: reply to letter to the editor regarding Foell et al., peripheral origin of phantom limb pain: is it all resolved?Pain. 2014 Oct;155(10):2207-2208. doi: 10.1016/j.pain.2014.08.018. Epub 2014 Aug 26. Pain. 2014. PMID: 25168666 No abstract available.
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Peripheral origin of phantom limb pain: is it all resolved?Pain. 2014 Oct;155(10):2205-2206. doi: 10.1016/j.pain.2014.08.028. Epub 2014 Aug 29. Pain. 2014. PMID: 25180014 No abstract available.
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