The peripheral mechanism occurs after nerves are severed at the site of the amputation, causing neuronal and tissue injury. The proximal portion of the nerve then forms neuromas, abnormal sprouting of nerves, which have increased numbers of sodium channels, leading to hyper-excitability and random neural discharges. (Subedi & Grossberg, 2011). Inflammatory mediators and enzymes also sensitize the nociceptors and stimulate A delta and C fibers, nerves that carry the pain signals. A constant influx of these mediators and enzymes cause the nerves to respond to lower levels of these chemicals, leading to an increased number of action potentials and thus an increased sensation of pain (Chapman, 2010). It has been postulated, “repeated stimulation of peripheral nociceptors produced changes in the dorsal horn neurons of the spinal cord... Epidural analgesia/anesthesia might ameliorate phantom limb pain by preventing excessive simulation of the dorsal horn neurons before and immediately after lower-limb amputation” (Ong et al, 2005, p. 603). This may contribute to decreasing the risk for postoperative phantom limb
The peripheral mechanism occurs after nerves are severed at the site of the amputation, causing neuronal and tissue injury. The proximal portion of the nerve then forms neuromas, abnormal sprouting of nerves, which have increased numbers of sodium channels, leading to hyper-excitability and random neural discharges. (Subedi & Grossberg, 2011). Inflammatory mediators and enzymes also sensitize the nociceptors and stimulate A delta and C fibers, nerves that carry the pain signals. A constant influx of these mediators and enzymes cause the nerves to respond to lower levels of these chemicals, leading to an increased number of action potentials and thus an increased sensation of pain (Chapman, 2010). It has been postulated, “repeated stimulation of peripheral nociceptors produced changes in the dorsal horn neurons of the spinal cord... Epidural analgesia/anesthesia might ameliorate phantom limb pain by preventing excessive simulation of the dorsal horn neurons before and immediately after lower-limb amputation” (Ong et al, 2005, p. 603). This may contribute to decreasing the risk for postoperative phantom limb