There are over 2 million Americans living with an amputation. Nearly all patients who have had an amputation will experience phantom sensation, described as any sensation of the missing limb.
Phantom pain is the presence of pain in the missing limb. Phantom sensation/pain can occur after any body part is removed, and has been described after breast, tooth and eye removal.
Approximately 60 percent to 80 percent of amputees have painful sensation in the missing limb following amputation. Generally, the pain will start within weeks after amputation; however, there are cases where pain onset is years later.
Fortunately, only 5 percent to 10 percent of phantom pain cases are considered severe. The pain of phantom limb is usually intermittent and most often described as shooting, pricking or burning. Phantom pain is primarily located in the most distal part of the amputated extremity; this is thought to be due to the larger representation of these areas in the brain sensory cortex.
There is a strong correlation between level of pain pre-amputation and the incidence of phantom limb pain. It is recommended to treat pain aggressively prior to surgical amputation to decrease the incidence and severity of phantom pain. The mechanisms responsible for phantom pain are not completely understood, and thought to be a combination of peripheral and central nervous system factors.
It is important to differentiate phantom pain from stump pain. Stump pain is pain located only in the stump, whereas phantom pain is referred to pain coming from the missing limb. Stump pain is common immediately post-amputation and can be chronic as well. There is a strong correlation between stump pain and development of phantom pain.
Phantom limb pain can be quite difficult to treat. The pain is primarily neuropathic in nature, and the mainstay of management is medications. Medications that have been proven to be helpful with neuropathic pain include tricyclic antidepressants (amitriptyline) and sodium channel blockers (gabapentin). Opiates should also be tried in refractory cases. Other treatment modalities such as massage, manipulation, TENS, acupuncture, spinal cord stimulation, ultrasound and hypnosis have been used to effectively treat phantom pain.
Mirror therapy is an interesting treatment where a long mirror is used to “trick” the brain into thinking the missing limb is still there to facilitate therapy. Surgery is not recommended except in the case of obvious pathology involving the stump.
There is increasing evidence showing the importance of preemptively treating pain prior to amputation. Amputees with more severe phantom pain more often suffered intense pain prior to amputation.
This is consistent with the finding that traumatic, sudden amputations are less likely to experience phantom pain compared to amputations secondary to chronic vascular disease in which patients have experienced pain for years prior to surgery.
Quite often the location and nature of phantom pain replicates the pain experienced prior to amputation. In addition, use of epidural analgesia for the surgical amputation has been shown to decrease the likelihood of phantom pain.
Phantom limb pain can be disabling for many patients who are already suffering after the loss of an extremity. Fortunately, there are many modalities that have shown promising results in relieving this discomfort. Prevention via maximizing pain control prior to surgery and using epidural/regional anesthesia are critical to decreasing the likelihood a patient will develop phantom limb pain.
