Major limb amputation affects a large number of people worldwide. Since the beginning of World War II, over 23,000 combat-related major amputations have been documented from United States forces alone. Additionally, many U.S. veterans undergo major amputation post-discharge, with a rate of 6-8/1000 diabetic Veterans requiring lower limb amputations. There have been 1677 major limb amputees in the U.S. forces since 2001 from Operations Iraqi Freedom, Enduring Freedom, and New Dawn. Multiple studies have documented negative quality of life experienced by service members and Veterans who have undergone major limb amputation.
One of the most common conditions following limb amputation is the continued perception of the missing limb, tactile awareness of the missing limb, and a perceived ability to move the missing limb, which are known as phantom limb sensations. The majority of US military personnel who have undergone traumatic limb loss also experience phantom limb pain (PLP), pain that is perceived to be affecting the phantom limb. There is no consensus on potential differences in the frequency or severity of phantom pain between men and women.
Although PLP has been recognized since the mid-16th century, the etiology is still unknown. There are several proposed mechanisms, including learned paralysis, cortical reorganization, and proprioceptive memory. Ramachandran and colleagues proposed the mechanism of learned paralysis, whereby PLP arises because the brain does not receive visual feedback that a motor movement has occurred, thus creating the sensation that the limb is paralyzed. Cortical reorganization theory states that areas near those corresponding to the amputated limb slowly expand into those corresponding to the amputated limb, such that when a sensation is experienced in those recently expanded areas it may be attributed to the amputated limb. This theory has been supported by the correlation of more severe PLP with increased neural plasticity. Proprioceptive memory refers to a theory that the brain remembers sensations associated with specific perceived positions of the phantom lim7. It is also known that peripheral nervous system input contributes to PLP as anesthetizing the dorsal root ganglia eliminates PLP. There have been no previous NATO activities focused on this particular area of neurology and rehabilitation medicine.
The topic area is post-amputation phantom limb pain. The exploratory panel will review experimental evidence on this topic, clinical care treatments and level of evidence to support treatments, and identify gaps in research which may be supported by NATO nations.
A single final report will be issued by the exploratory panel summarizing findings and recommending the next course of action (conference, lecture series, or work group). It is anticipated that the findings will shape the care for post-amputation phantom limb pain within NATO nations and possibly extending to other countries.