When a nerve is severed or injured, it will attempt to regenerate itself. However, in some cases, the nerve does not have a clear target to regenerate toward, such as in limb amputations or certain procedures. With no goal in sight, the regeneration process can result in a neuroma, a disorganized mass of nerve tissue that can cause debilitating pain.1 Amputees, in particular, experience two broad categories of pain. PLP, or phantom limb pain, comes from the part of the limb that has been removed.2 RLP, residual limb pain, originates in the remaining part of the limb.3 A surgical procedure known as targeted muscle reinnervation (TMR) shows promise for the management of both PLP and RLP, as well as the prevention of neuroma formation.
TMR was initially developed in the early 2000s with the goal of improving prosthesis control. Modern prosthetic extremities rely on myoelectric signals (electric signals from the muscle). To improve the movement of a prosthesis, “increased myoelectric signals are required to operate multiple joints more intuitively.”4 TMR reroutes severed or injured nerves to new muscle targets, providing the nerve ending with a muscle to enervate.5 This encourages the nerve to regenerate in an organized fashion rather than resulting in the jumbled mass of a neuroma. For the purpose of increasing signals for prosthetics to recognize, the procedure actually generates two myoelectric signals where there was only one before.6 Early in the application of this procedure, it was found that TMR reduced post-amputation pain as well, which led researchers to theorize that giving the previously damaged nerve something to do reduced the chance of neuroma formation, which was found to be true.7 Now, TMR is performed to decrease the pain of amputees as well as to improve a person’s ability to control certain types of prosthetics.
TMR is not limited to reducing pain in limb amputations. In fact, “the procedure can be used anywhere a painful neuroma can develop.”8 TMR has been used to treat post-mastectomy pain syndrome, a chronic pain condition that can develop after breast removal surgery. TMR has also had promising results in lessening pain for chronic abdominal wall pain caused by neuromas in certain nerves. It is also possible for TMR to relieve pain from neuromas formed after hand surgery, such as digital amputation, and even after headache surgery.9 While TMR is not a guaranteed fix for pain in any of these cases, it is a promising technique that has reduced pain for many people, improving their quality of life.
Thanks for reading,
Ashby
References
1. “Procedure Enables Some Nerves to Regenerate.” RWJ Barnabas Health. https://www.rwjbh.org/rwj-university-hospital-new-brunswick/treatment-care/plastic-and-reconstructive-surgery/targeted-muscle-reinnervation-tmr-/
2. “Managing Phantom Pain.” Amputee Coalition. https://www.amputee-coalition.org/limb-loss-resource-center/resources-for-pain-management/managing-phantom-pain/
3. “Management of Residual Limb Pain.” Amputee Coalition. https://www.amputee-coalition.org/limb-loss-resource-center/resources-for-pain-management/management-of-residual-limb-pain/
4. Brittany N. Corder, Michael S. Lebhar, Peter Arnold, Laura S. Humphries. “Targeted Muscle Reinnervation: A Brief History of a Promising Procedure for Effective Management of Amputation Pain.” Wounds 35, no. 12 (2023): E433-E438. doi: 10.25270/wnds/23079 5. “Procedure Enables.”
6. Corder, “Targeted Muscle Reinnervation.”
7. Corder, “Targeted Muscle Reinnervation.”
8. Corder, “Targeted Muscle Reinnervation.”
9. Corder, “Targeted Muscle Reinnervation.”
Photo by Polina Tankilevitch: https://www.pexels.com/photo/a-men-and-woman-with-prosthetic-arms-5708618/
Comments