All About Nerves

‘Blame it on the nerves’. Whether it be scaling that 55ft climb or scoring that last goal during shootouts, you will always hear people blaming it on the nerves. But what if it actually were the nerves?

Nerve damage is a scary word and not something anyone wants to hear. Unfortunately you may encounter an injury to your nerves at some point in your life. So what happens then?

There are three types of nerve injuries. In health care, we graded them based on the severity:

Grade I – Neurapraxia

• Mildest form of nerve injury
• Nerve continuity is still present
• Functional loss is temporary

Grade II – Axonotmesis

• Axons are interrupted
• External structures are intact
• Recovery eventually takes place

Grade III – Neurotmesis

• Most severe
• Nerve is very damaged
• There will be a degree of permanent impairment and functional loss

So what actually happens when the nerve is damaged? Something called Wallerian Degeneration occurs. Think of it as pruning flowers. Stimulated by the actual injury, the inflammation process begins with dead material being removed by your body’s immune system. Swelling, redness, and pain are all normal sensations during this period. The parts below the injury are pruned/die off so that the nerve above the injury can regenerate and grow back. During this re-growth period, you will experience sensation loss or changes as well as possible changes in functional use of the area. Then comes a maturation process. Here, the nerve coverings (myelin sheath) have to grow to cover the nerve and the actual nerve has to regrow in width. Often times you will regain your sensation before motor / functional capacity.

This process takes months or even years, so it’s very important to keep those muscles supplied by the nerve as healthy as possible.

Ideally, the nerves re-grow 1mm/day; 1 in/ month; 1 foot/yr, however it does vary and these numbers are influenced by a variety of factors. These factors include the severity and nature (cut, crush, tear, etc) of the injury, condition of the surrounding tissues, duration of the degeneration, and gap length between top and bottom portions of the nerve.

What can you do in the meantime? You can work closely with your physiotherapist and occupational therapist! As mentioned earlier, it is very important to keep the muscles and soft tissues surrounding the injured nerve as healthy as possible. Why? It’s important to keep these structures ready on stand by so that as soon as the nerve is ready to start working you can begin functional training. If the nerve is ready to start firing, but your muscles are too weak to carry out the function, then recovery will just take a lot longer.

With your physical therapist, you will be doing strength training, range of motion exercises, and proprioceptive training (fancy way of saying ‘knowing where your limbs are in space’). If there is no active/voluntary movement available, then you will be working with the therapist doing a lot of assisted and passive motions to keep the structures flexible and activated.

A lot of training will also center on learning new strategies to manage your day – to – day living. Depending on your injury, it might not be focused on going back to your pre – injured state. Treatment would be, in large part, getting you back to doing activities you were doing before whether it be using old methods or learning some new ones.

Because a large part of your rehab relies heavily on the regeneration of the nerve, you should not expect your recovery to be the same as other injuries. It will take time, patience, and a dose of positive attitude (not to mention compliance with your treatment regime!).

References:

• Burnett M.G., & Zager, E.R., (2004) Pathophysiology of peripheral nerve injury: A brief review. Neurosurg Focus, 15(5), 1-7.
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• Foot Drop. (2014) Washington University in St.Louis School of Medicine. Retrieved January 12, 2015 from http://nerve.wustl.edu/nd_transfers_foot.php?np=nerve_disorders.