Phantom Limb Pain

Phantom Limb Pain 

    One phenomenon that many people have familiarity with the name of is phantom limb pain. In vague terms, phantom limb pain is a pain in an area where there was once a limb that may have been amputated. This could be as a result of a traumatic event, or a simple medical necessity. Either way, phantom limb pain is a result of "the nerve endings at the site of the amputation [continuing] to send pain signals to the brain that make the brain think that the limb is still there" (Poinior et al.). This type of pain can be different for everyone and can be excruciating to barely noticeable. With these different types of pain thresholds, there have been multiple methods of treating this type of pain. 

    One method of treating phantom limb pain, proposed by Dumanian et al. is Targeted Muscle Reinnervation. In this procedure, "the terminal neuroma is removed and the newly freshened nerve is coapted to a newly divided nearby motor nerve. The fascicles, primed to regenerate, grow down the motor nerve to enter and re-innervate the newly denervated muscle" (Dumanian et al. 239). This way of treatment allows for the fascicles to be channeled towards nerve receptor targets, basically creating a nerve circuit. This redirects the nerve impulses that would be causing the phantom limb pain back into the body, thus relieving the pain. The overall results from the study showed that the phantom limb pain was improved, but not completely eliminated for most patients. Furthermore, TMR provided more promising results than a conventional neurectomy. The researchers concluded that TMR can only partially reverse the nerve pain, but not completely eliminate phantom limb pain in amputees. There will need to be further research to specify how far TMR can go as far as nerve reinnervation. 

    Another developing method for treating phantom limb pain is being designed by the company Ripple LLC. Ripple is working on developing a neural stimulation system with funding from the NIH HEAL initiative. This device is "designed to electrically stimulate the nerves that remain in the limb to decrease phantom limb pain for people who have had an amputation. When paired with a prosthesis, or artificial limb, Ripple's sophisticated device will enable users to sense the prosthesis as though it is a part of their body" (NIH). This device is still working through testing before planning through a clinical trial where it will be implanted in people with below-the-knee amputations. The stimulator should convey the message where the nerve was cut during the amputation, which makes the limb feel like it has not been amputated. The goal of the stimulator is to eliminate phantom limb pain and mimic the feeling of the limb that was once there.

    Both of these methods to reduce phantom limb pain, it shows how there is an abundance of people with this issue and the need for treatments. There are continually developing research methods to improve phantom limb pain, but the main focus is on the nerves that were cut during the initial amputation. In both the TMR and the neural stimulation system, the focus is to try and create a pathway that rewires the nerves at the end of the amputated limb. This is going to be a continually growing base of research until an effective treatment regimen can be completed. 

Works Cited

Dumanian, Gregory A., et al. “Targeted Muscle Reinnervation Treats Neuroma and Phantom Pain in Major Limb Amputees.” Annals of Surgery, vol. 270, no. 2, 2019, pp. 238–246., https://doi.org/10.1097/sla.0000000000003088.

“Next-Gen Device Could Relieve Phantom Limb Pain.” National Institutes of Health, U.S. Department of Health and Human Services, https://heal.nih.gov/news/stories/phantom-limb-pain.

Poinior, Anne., et al. “Phantom Limb Pain and Chronic Pain.” Phantom Limb Pain and Chronic Pain | Michigan Medicine, https://www.uofmhealth.org/health-library/ty6877.