Unfortunately, pain is more common than not, and is a long-term issue following amputation. It’s important to differentiate residual limb pain from phantom limb pain and phantom limb sensation. Periodic episodes of pain are common following amputation. Residual limb pain is located on the residual limb itself while phantom limb pain is located in the phantom foot or hand. Phantom limb sensation is not painful and is the feeling that the absent limb is still intact.
Amount of pain is relative. A pain scale of 0-10 was formed to assess the relative amount of pain of the individual. This is especially useful to monitor effectiveness of pain medication and dosages. Medication can be different for treating residual limb pain compared to phantom limb pain. It’s important to work closely with your doctor to monitor medication effectiveness and to try alternatives to medication whenever possible in order to reduce reliance and to avoid undesirable side effects. A pain journal may help you and your healthcare providers understand pain levels and correlation to medication, prosthetic wear, and other factors.
Residual Limb Pain
Following surgery, it’s only natural that the body’s response to this trauma would be a pain response. Pain is often associated with swelling, so basic principles of RICE (rest, ice, compression, elevation) apply. A sudden increase in pain and swelling during healing could be a sign of infection and immediate attention by a doctor is needed.
After the residual limb is healed and the first prosthesis is provided, hopefully all is going well. However, in this stage of rehabilitation, a moderate level of pain is expected, especially along the suture line. If pain is intolerable, it’s a sign you may be overdoing it and that you need to reduce wear time of your prosthesis or the amount of weight you are bearing on the prosthetic side. It could also mean that you need modifications done to your socket, especially if the pain is located in a specific area. The tolerances for error in a prosthetic socket are very small and small changes can make pain disappear or worsen. It’s important to really understand volume management, carry socks with you, and to adjust sock ply as soon as you start feeling discomfort. If the painful area of the residual limb does not respond to sock ply changes or changes to the socket itself by your prosthetist, you might just need some time out of socket or you may need other treatment.
Pain while not wearing the prosthesis and not related to overdoing it is best treated by a physical therapist, physician, or surgeon. For hyper-sensitivity, a trained therapist can show you techniques for desensitization. This involves rubbing materials varying from very soft to very rough on the residual limb as tolerated. The idea is that over-stimulation leads to desensitization. Scar massage is also important and helps loosen this tissue, preventing adhesion to the bone. Alternative pain treatments such as acupuncture, dry needling, ultrasound, massage, and tens units, can be even more effective than medication for some people.
Long-term pain conditions may be attributed to underlying anatomy and are generally best addressed with injections or surgery. Bone spurs, bursitis, invaginated scar formation, and neuromas are examples of complications that should first be addressed prosthetically, but may necessitate surgical intervention. Neuroma pain is one of the more common long-term complications following amputation surgery. Neuromas are nerve bundles that form after the nerve has been cut. Neuromas that become problematic can be identified with a Tinel test, which involves tapping on the area where the neuroma is believed to be located. A positive test creates shooting pain when someone taps the area of the neuroma. Traditional methods during amputation surgery have been to cut the nerve far back under a muscle belly so that the neuroma is not as problematic. The problem with neuroma resection is that they just grow back. A promising technique for both primary amputation and revision surgery involves plugging the nerve into a muscle so that the neuroma doesn’t form. For more information about this technique, check out this research study: http://www.ncbi.nlm.nih.gov/pubmed/24562875
Phantom Limb Pain
Even though these pains are “phantom”, they are very much real and are not well understood. Phantom limb pain is fairly common and can be debilitating. It’s logical that sensation and sometimes pain would occur following amputation surgery because many of the neural pathways are still established and partially in place. Most people who have phantom limb pain say that it comes and goes. It can happen more during times of stress or when the weather is changing.
Recent research has located the occurrence at the dorsal root ganglion of the spinal cord. http://www.haaretz.com/israel-news/science/1.595726 This evidence refutes the belief that the phantoms occur solely in the brain. Recent reports of an interventional radiology technique which involves freezing the nerves in the residual limb show promise in reducing phantom limb pain. http://medicalxpress.com/news/2016-04-minimally-invasive-treatment-phantom-limb.html
One of the most effective and least intrusive therapeutic treatments involves mirror therapy. During this treatment, for example, a person with a single leg amputation, would place a long length mirror between the legs. The patient is then told to move the sound side foot and leg into a position which alleviates pain of the phantom foot. So if the phantom foot felt like it was in a cramped position, the person would move the sound side and would persceive the mirror image as the phantom foot. This alleviates pain because the visual system recognizes the mirror image of the sound side foot and perceives it as the phantom foot moving around and overrides the tactile system.
Deep breathing and meditation has also been said to help reduce duration and intensity of phantom limb pain. Many of the same therapy options that work with residual limb pain also work with phantom limb pain. Although no drug exists to treat PLP specifically, drugs designed to treat other conditions, such as antidepressants and anticonvulsants, can be prescribed as determine appropriate by your physician.
Phantom Limb Sensation
Phantom limb sensation is normal and can be helpful when it’s time to start using a prosthesis with regard to proprioception (feeling of where the phantom limb is in space). Caution must be taken with phantom limb sensation, especially in the beginning, as there is an increased risk of falls when a person senses the leg and thinks the leg is there when it’s not. A helpful tip is to park your wheelchair or a chair right beside your bed to serve as a reminder until you get a better sense of your new normal.
Pain is an unfortunate consequence that is common immediately after amputation and for some people even long-term. Understanding differences in the type of pain (residual limb pain/phantom limb pain) and the cause of pain (mechanical/non-mechanical) can influence treatment modality. Keeping a pain journal and knowing the treatment options is also helpful when talking with your healthcare team about your specific problem.
By Zach Harvey, CPO