The most common injury is from traction, or stretching. However, the plexus can also be crushed, squashed or cut. This may be from an accident, fragments from a fracture (broken bone) or occasionally from surgery itself.
There are different types of injury that you may hear the doctor discussing. The first is described as a conduction block (sometimes known as a neurapraxia). This is when the signals travelling through the nerve are unable to pass the injured area but the nerve cells have not died back. This is often a problem that resolves without surgery. Sometimes surgery is required to relieve the pressure on the nerve. A good analogy is to think of the nerve as a hose-pipe that has been stepped on and squashed. It can take time for the hose-pipe to open up again and let the water through.
The second type of injury is called a degenerative injury. This is where the nerve, or part of the nerve, has been injured to such an extent that part of it dies and has to regrow. The nerve cells have a great ability to re-grow by themselves and do so at the speed of about 1mm a day. Sometimes surgery is needed to help them re-grow or know which way to grow.
Often the injury is a combination of both conduction block and degenerative injuries.
There is also a serious nerve injury called a nerve root avulsions. This is when the nerve has been torn directly out of the spinal cord. It is not possible to repair this directly however there may be other surgery that we can do improve the function of your arm.