A second subtype, causalgia, is a chronic pain condition that can develop after injury or trauma to a peripheral nerve. The pain is regional (not in a specific nerve territory or dermatome) and usually has a distal predominance of abnormal sensory, motor, sudomotor, vasomotor edema, and/or trophic findings. CRPS type I (CRPS‐I) is a syndrome characterized by a continuous (spontaneous and/or evoked) pain that is seemingly disproportionate in time or degree to the usual course of pain after trauma or other lesion. This pooled analysis evaluates a substantial patient population with complex regional pain syndrome (CRPS). We conducted a pooled analysis of published, prospective studies to identify differences in effectiveness of DRG stimulation by pain etiology or location and to investigate the generalizability and reproducibility of individual studies that followed patients for at least 12 months. A recent study with laser‐evoked potentials has shown that DRG stimulation might even result in restorative processes by normalizing pain signal transfer from the periphery to supra‐spinal levels 21. Therefore, lower stimulation amplitudes are required with DRG stimulation compared with SCS, resulting in less postural variation. The cerebrospinal fluid layer surrounding the DRG has much lower volume than the one that surrounds the spinal cord. In the last decade, the DRG has become a focus for electrical stimulation with the potential advantage of better target control. In addition, to our knowledge, all in vitro and in vivo animal studies have shown that DRG stimulation has positive effects on pain‐related outcomes without causing any inflammation or DRG tissue damage and may actually be anti‐inflammatory 16, 17.Ĭonventional spinal cord stimulation (SCS, which applies electrical stimulation to the dorsal column) can result in sub‐optimal effectiveness for treating different chronic pain etiologies 18, 19, 20. The end result of electrical stimulation on the DRG neurons is to stabilize and decrease hyperexcitability 15. A review by Krames summarized various other mechanisms of action of DRG stimulation that have been hypothesized over the years, such as modification of growth factor release, reversal of cytokine release and genetic changes, downregulation of irregular ion channels, and restoration of normal ion flux 15. Koopmeiners et al were the first to establish that low‐frequency electrical stimulation increases Ca 2+ influx into DRG neurons, decreases the frequency of multiple action potentials, and significantly reduces conduction velocity 14. Because of this, the DRG might be an attractive target for electrical stimulation. The DRG houses the cell bodies of sensory neurons and is an active participant in the development of certain forms of chronic pain 8, 9, 10, 11, 12, 13. The dorsal root ganglion (DRG) is located at both sides of the spinal cord on the distal end of the dorsal root in the lateral epidural space. Spinal nerves, formed from afferent sensory axons (the dorsal root) and motor efferent axons (the ventral root), emerge from the intervertebral neural foramina between adjacent vertebral segments 7. Nociplastic pain is a relatively new term the International Association for the Study of Pain describes it as “altered nociception despite no clear evidence of actual or threatened tissue damage causing the activation of peripheral nociceptors or evidence for disease or lesion of the somatosensory system causing the pain” 6. Nociceptive pain arises from harmful stimuli to non‐neural tissue and is due to the activation of nociceptors 6. Neuropathic pain is caused by a lesion or disease of the somatosensory system. Chronic pain has a wide range of etiologies that can be neuropathic, nociceptive, or nociplastic in nature 5, 6. Post‐surgical complications and trauma (25%) and spine problems (20%) are responsible for almost half the incidence of chronic pain 4. It is often a debilitating condition that substantially diminishes quality of life. Chronic pain affects approximately 20–30% of the population in the United States and Europe 2, 3. Chronic pain is defined as pain persisting past normal healing time, lasting or recurring for more than six months 1.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |