Physiology of Peripheral Nerve Injuries

     When one thinks of nerve damage in the body, our minds may first go to internal causes such as diabetes or autoimmune diseases such as rheumatoid arthritis. In fact, I would probably agree with this train of thought, especially as someone who is more aware of the internal processes of the body than the common person. That is until I was called to the hospital one day last summer to pick up my sister who had cut her finger while opening a package. Initially the doctors did not think that there was any serious damage in the finger, and sent her on her way with a bit of surgical glue to close the wound. A few days later, however, she began to loose feeling in her finger, which of course began to raise some flags. She finally went to see an orthopedic surgeon, who identified that she had in fact completely severed the nerve in her hand and would need to go into surgery as soon as possible to attempt to repair the nerve.

     This type of peripheral nerve injury (PNI) by laceration makes up about 30% of all PNIs (Burnett and Zager, 2004). When an injury to the nerve takes place, there is a degenerative process that takes place, and the damaged nerve endings will retract due to the elastic endoneurium (Burnett and Zager, 2004). Inflammation then occurs, leading to swelling and the formation of scar tissue(Burnett and Zager, 2004). If this is not treated shortly after the injury, there can be detrimental affects to the nerve, including nerve death, this is what happened in the case of my sister. Due to the fact that the ER doctors did not initially detect any issue with the nerve and she was sent home, this allowed for the degradation to occur to the nerve causing it to die. As I mentioned, she was able to get a surgery performed to try and resolve the issue, but they had to use a cadaver nerve to replace the damaged nerve in her finger. There were a few months of treatment and occupational therapy required, but now she is able to fully use her finger again with fully neurological function.

Burnett, M. G., & Zager, E. L. (2004). Pathophysiology of peripheral nerve injury: A brief review. Neurosurgical Focus, 16(5), 1–7. https://doi.org/10.3171/foc.2004.16.5.2