Originally theorized to be a psychological issue, Phantom Limb Pain (PLP) is now treated as a condition of the central nervous system. The sensations or pains originate in the brain and spinal cord, therefore they feel as real as if the limb was still there. Research over recent decades has yielded many possible causes and treatments for PLP. The most agreed-upon hypothesis in recent years is that multiple mechanisms are responsible for PLP, including peripheral nerve damage, nerve hyperactivity, changes to neurons, and psychological triggers. There are several medicinal and non-medicinal treatments for PLP, including prosthetics.
What Exactly is Phantom Limb Pain?
Phantom pain, or ghost pains, refer to painful sensations experienced in an amputated body part that no longer exists. For example, a person might feel phantom pain in their amputated leg, despite it no longer being there. PLP is diagnosed based on symptoms and circumstances, as there is no medical test used for diagnosis.
In addition to pain, people with amputated limbs can also experience other pain or non-painful sensations. Stump pain, or residual limb pain, is pain at the location where a body part was amputated. Phantom sensations are non-painful sensations in the amputated body part, such as the feeling of touch or pressure, or even the feeling of clothing brushing across the skin.
Causes of Phantom Pain
It’s unclear what exactly causes phantom limb pain, however, imaging scans such as magnetic resonance imaging (MRI) and positron emission tomography (PET) show activity in the parts of the brain neurologically connected to the nerves of the amputated limb. It’s thought that PLP is triggered by the brain sending and receiving mixed signals. The brain sends these incorrect signals because it has lost input from the missing limb and knows that something is not right.
Some other possible causes of PLP are scar tissue at the amputation site, damaged nerve endings, and the physical memory of pain in the limb before amputation.
Risk Factors for Phantom Limb Pain
Image via Flickr by Derek Bridges
Phantom limb pain is not fully understood, however there are risk factors that make it more likely for someone to experience it. PLP is more common:
- In upper-limb amputations.
- Among females.
- In limbs as opposed to other body parts.
- When pain was already present in the limb prior to amputation.
- With emotional triggers, like stress, anxiety, and depression.
Residual limb pain at the site of the amputation can also be a possible cause of PLP, especially if the amputation site didn’t heal well or if abnormal growths have developed on the damaged nerve endings.
Symptoms of Residual Limb Pain
From headaches to stomach cramps, not all pain feels the same to all people. So it’s no surprise that the same goes for phantom limb pain. The following are common descriptions of what phantom limb pain feels like:
- Like an electric shock
- Tingling like “pins and needles”
PLP can range from mild to severe and be constant or intermittent, and the type of pain can vary widely. Often there are two peak times for phantom limb pain, around the one-month mark and one-year mark after the amputation has taken place. However, PLP can occur at any time.
Prevention of PLP
Since some research indicates that people are more likely to experience phantom limb pain if the limb was causing the person pain before the amputation, some doctors try to prevent PLP by prescribing general anesthesia for hours, or even days, to the limb prior to amputation. Placing the limb under general anesthesia can help reduce pain before surgery, after surgery, and possibly also reduce the risk of phantom limb pain by preventing the brain from sending and receiving pain signals in the limb.
Medicinal Phantom Limb Pain Treatments
Finding the right treatment for phantom limb pain is a unique process for everyone. Most doctors will start with medications and noninvasive therapies before suggesting surgery. While there is no specific medication for PLP, there has been success with prescription drugs designed for other nerve pain conditions. Not every medication works for every person, and the success rate varies widely, so you may need to try several different prescription drugs before finding the one that works for you.
The most common medications used to treat PLP are:
- Over-the-counter (OTC) pain relievers
- N-methyl-d-aspartate (NMDA) receptor antagonists
There are also several noninvasive therapies that may help with phantom limb pain, including:
- Acupuncture, which the use of sterilized needles inserted at specific points on the body, has been used for centuries to help chronic pain.
- A mirror box, which is a device containing mirrors that make it look as if the limb is still attached, lets you observe the limb and trick the brain into thinking it’s still there.
- Repetitive transcranial magnetic stimulation (rTMS), where small electrical pulses are sent to a targeted part of the brain, might also be helpful, although it’s not specifically approved for PLP.
- Spinal cord stimulation, where small electrodes send an electrical current to the spinal cord, which can sometimes relieve the pain.
Non-Medicinal Phantom Pain Treatments
The most common and effective non-medical phantom limb pain treatment is with prosthetics. Wearing a prosthetic limb is a type of therapy because the feeling of the prosthesis on the stump of the limb can stimulate the nerve endings and blood flow of the site, interrupting pain signals. Wearing a prosthetic often also includes wearing bandaging and shrinker socks as padding between the remaining limb and the prosthetic, and the feel of these materials sometimes reduces PLP.
While traditional prosthetic limbs are only cosmetic, still relying on the person’s body to move them, another prosthetic option is bionic limbs. This advanced technology uses sensors to connect the remaining limb’s nerves to the brain, which can help decrease or eliminate PLP as well as move the limb easily through robotics.
To learn more about how prosthetics could help you with phantom limb pain, contact us or stop by our Sheck & Siress offices.