Phantom pain or a neuroma after amputation: telling them apart

If you have had an amputation and you still hurt, the first question is where the pain comes from. Pain that seems to be in the foot that is no longer there is one thing. Pain at the end of the limb, especially a sharp, electric spot that flares when it’s touched or when the prosthesis presses, is another. They need different thinking, and they can exist side by side.

The two kinds of pain

Phantom limb pain feels as though it comes from the missing limb. It is different from phantom sensation, where you can feel the missing part without pain, and from residual limb pain, which is felt in the part that remains.^[1] Phantom limb pain involves changes in how the brain and spinal cord process signals, along with activity in the injured nerve endings and psychological factors. Because several mechanisms are at work, treatment often needs more than one approach.^[1,7]

A residual limb neuroma is a knot of nerve fibers at the end of a nerve that was cut. Each cut nerve tries to regrow, and without a target, the fibers tangle. A neuroma can be very painful, may prevent prosthesis use, and can reduce quality of life.^[2]

How common each one is

• A pooled analysis of studies from 1980 to 2019 estimated that 64% of people with an amputation reported phantom limb pain, with wide variation between studies. Risk was higher with long-lasting pain before the operation, with higher-level amputations, and with pain in the residual limb.^[3]
• A meta-analysis found residual limb pain in 59% and symptomatic neuroma in 15% of people after lower-extremity amputation.^[2] Another meta-analysis of 1,329 lower-limb amputees reported symptomatic neuromas in 19% overall, and 30% in studies with at least three years of follow-up, compared with 3% in studies with shorter follow-up. That suggests some neuromas take years to become symptomatic.^[4]

Clues that separate them

These are guides, not rules, and your clinician will sort them out with an examination:

• A tender spot at the end of the limb that reproduces a sharp, shocking or burning pain when tapped or pressed suggests a neuroma.
• Pain when the prosthesis presses on one area also points to a neuroma, and the socket can add to the pressure.
• Pain that seems to be in the foot or toes that are no longer there, with no tender spot, fits phantom limb pain.
• Both can be present. A neuroma can add to phantom pain.

An evaluation includes an examination of the residual limb, with attention to tender spots that shoot or tingle, the prosthesis fit and the skin, along with your medicines, sleep, mood and daily activity. Ultrasound or MRI can help show a neuroma, and a small anesthetic injection near the suspected nerve can help confirm the source. These tests are arranged with another specialist. Your prosthetist is an important partner.

What treatment can look like

• For phantom limb pain: medicines, brain and nerve stimulation, mirror therapy and rehabilitation have all been studied, and the strength of evidence differs among them. A network meta-analysis of 12 randomized trials found morphine linked to a higher rate of side effects, and repetitive transcranial magnetic stimulation gave the largest improvement, with moderate-quality evidence from a small number of trials. A review of placebo-controlled trials found the evidence for mirror therapy too weak to conclude that it works.^[8]
• For a neuroma: prosthetic adjustments, desensitization, medicines and injections come first. When they don’t help enough, surgery targets the nerve directly.
• Surgery that gives the nerve somewhere to go. In a randomized trial of 28 people with chronic pain after amputation, targeted muscle reinnervation improved phantom limb pain compared with removing the neuroma and burying the nerve in muscle, and residual limb pain trended toward improvement.^[5] A pooled analysis of 17 studies of targeted muscle reinnervation and regenerative peripheral nerve interface surgery found phantom limb pain improved in 45% to 80% of patients, although most studies were small. Complication rates ranged from 13% to 31%, most often slow wound healing.^[6] See targeted muscle reinnervation and regenerative peripheral nerve interface.

Timing may matter. In a comparison of 105 limbs, a symptomatic neuroma recurred in 19% of limbs that had delayed targeted muscle reinnervation, compared with 1% of limbs that had it at the time of amputation.^[9] If you are facing an amputation, it is worth asking your surgical team how the cut nerves will be managed.

What to do

Tell your care team about the pain early. It is real, and there are options. For more, see phantom limb pain, residual limb neuroma pain and pain after leg amputation.

When to see a specialist

Consider an evaluation if you have pain in an amputated limb that is not controlled, is affecting sleep or walking, or is accompanied by a tender, shocking spot in the residual limb.