Degrees of facial nerve injury

The speed at which the facial nerve recovers will vary according to the type of nerve injury.  Injury to the facial nerve can be caused by many different things.  For example:

• Infections
• Viruses
• Trauma
• Surgery
• Tumours

All these conditions cause swelling on or around the facial nerve.  Swelling causes pressure on the nerve and it can become compressed or pinched depending on the degree of swelling and how long the pressure persists.

There are three different kinds of facial nerve injury:

1. 1. First-degree injury – this occurs when the facial nerve is concussed or bruised, and the nerve recovers fairly quickly within approximately 4 – 6 weeks or earlier if the concussion/bruising is very mild.  People with first-degree nerve injury are most likely to make a full recovery and are unlikely to develop involuntary or unwanted movements (synkinesis).  Link to synkinesis page
   2. Second-degree injury – this is where the facial nerve is more severely compressed.  The outer cover or layer of the nerve remains intact but the nerve fibres inside are damaged. When this happens, the nerve cannot receive nutrients or oxygen and so it starts to shrink and wither.  As the swelling subsides it slowly starts to repair itself at the rate of one millimetre per day which is why it takes longer to recover (12 – 16 weeks).  When the nerve does recover facial movements are not so easy to control.  An unavoidable symptom of slow nerve recovery is synkinesis and people with second-degree nerve injury will inevitably develop synkinesis.

• 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.

Photo by Noah Buscher on Unsplash