The exact cause of phantom pain is unclear, but it appears to originate in the spinal cord and brain. During imaging scans — such as magnetic resonance imaging (MRI) or positron emission tomography (PET) — portions of the brain that had been neurologically connected to the nerves of the amputated limb show activity when the person feels phantom pain.
Many experts believe phantom pain may be at least partially explained as a response to mixed signals from the brain. After an amputation, areas of the spinal cord and brain lose input from the missing limb and adjust to this detachment in unpredictable ways. The result can trigger the body's most basic message that something is not right: pain.
Studies also show that after an amputation the brain may remap that part of the body's sensory circuitry to another part of the body. In other words, because the amputated area is no longer able to receive sensory information, the information is referred elsewhere — from a missing hand to a still-present cheek, for example.
So when the cheek is touched, it's as though the missing hand also is being touched. Because this is yet another version of tangled sensory wires, the result can be pain.
A number of other factors are believed to contribute to phantom pain, including damaged nerve endings, scar tissue at the site of the amputation and the physical memory of pre-amputation pain in the affected area.
Dec. 03, 2014
- Angarita MA, et al. Pathophysiology and treatment of phantom limb pain. Colombian Journal of Anesthesiology. 2014;42:40.
- Vaso A, et al. Peripheral nervous system origin of phantom limb pain. Pain. 2014;155:1384.
- Niraj S, et al. Phantom limb pain and its psychologic management: A critical review. Pain Management Nursing. 2014;15:349.
- Virani A, et al. Phantom limb pain: A nursing perspective. 2014;29:44.
- Cornish P, et al. Successful peripheral neuromodulation for phantom limb pain. Pain Medicine. In press. Accessed Sept. 15, 2014.
- Virtual reality therapies for phantom limb pain. European Journal of Pain. 2014;18:897.
- Kalapatapu V. Lower extremity amputation. http://www.uptodate.com/home. Accessed Sept. 15, 2014.
- Benzon HT, et al. Practical Management of Pain. 5th ed. Philadelphia, Pa.: Mosby Elsevier; 2014. http://www.clinicalkey.com. Accessed Sept. 16, 2014.
- Alviar MJM, et al. Pharmacologic interventions for treating phantom limb pain. Cochrane Database of Systematic Reviews. http://onlinelibrary.wiley.com/doi/10.1002/14651858.CD006380.pub2/abstract. Accessed Sept. 16, 2014.
- Pain: Hope through research. National Institute of Neurological Disorders and Stroke. http://www.ninds.nih.gov/disorders/chronic_pain/detail_chronic_pain.htm. Accessed Sept. 16, 2014.
- Acupuncture: What you need to know. National Center for Complementary and Alternative Medicine. http://nccam.nih.gov/health/acupuncture/introduction. Accessed Sept. 16, 2014.