Facial Nerve Injury: The three types of injury

When you develop facial palsy, it is difficult to know how long your recovery will take because it depends on the type of injury the facial nerve has sustained.  The only situation in which the outcome is known is when the facial nerve has been cut or severed. This usually occurs during an operation near or around the facial nerve. If the nerve is cut it will be unable to recover and surgery is the only option available to restore facial symmetry and function.

There are three different kinds of facial nerve injury:

1. First degree injury – this occurs when the pressure on the facial nerve is mild and brief which means the nerve recovers fairly quickly within approximately 4 – 6 weeks or possibly earlier if the pressure on the facial nerve is very mild. People with this type of nerve injury will make a full recovery and will not develop involuntary or unwanted facial movements known as synkinesis.
2. Second degree injury – this occurs when the facial nerve has been exposed to a greater amount of swelling and compression is prolonged. The outer cover of the nerve remains intact but the nerve fibres inside are damaged and cannot receive essential nutrients and oxygen. Without these vital supplies the nerve starts to shrink and wither. However, as the swelling subsides and the flow of nutrients and oxygen are restored, the facial nerve slowly starts to repair itself at the rate of one millimetre per day. This is why it takes longer to recover and most people with this type of nerve injury start to notice early signs of recovery at approximately 12 – 16 weeks following the onset of their symptoms. When the nerve does recover facial movements are not so easy to control. This is because the recovering nerve is highly excitable and often overworks. An unavoidable symptom of slow nerve recovery is synkinesis (involuntary or unwanted facial movements). People with second degree nerve injury will develop synkinesis, for example, the affected eye closes or winks when you move your mouth.
3. Third degree injury – this is where the facial nerve is very severely damaged, and recovery is much slower and always incomplete. In some cases, the nerve is cut possibly due to trauma or during an operation around the site of the facial nerve. A nerve which has been cut cannot recover by itself and surgical repair is required to restore facial function.