What is hemifacial spasm?

Hemifacial spasm is a condition characterised by spontaneous and uncontrolled twitching of one side of the face, hence its name.  It is important to appreciate the relative rarity of the condition and also that it is common to experience some spontaneous twitching, particularly around the eye, which is often noticeable when tired.  In contrast to this minor twitching around the eye, hemifacial spasm is characterised by being both more severe and more extensive.  It can develop in a progressive fashion, often starting with twitching around either the eye or the mouth and spreading to involve the entire face.  At its worst, it is both distressingly uncomfortable and socially embarrassing with severe and uncontrollable spasms.

What is the cause of hemifacial spasm?

The cause of hemifacial spasm may be a blood vessel pressing on the facial nerve on its course between the brain and the bone at the base of the skull. The facial nerve then goes on to supply the facial muscles.

What is the treatment for hemifacial spasm?

The treatment of hemifacial spasm can be either with Botox injections to the relevant part of the face or in severe cases, surgery.
Hemifacial spasm is often satisfactorily managed by Botox injections to the involved part of the face.  This is often overseen by other specialties including neurologists and eye specialists.  The disadvantages of Botox injections are that they can over time become less effective and often require repeating at increasing intervals.  There is also the associated facial weakness, which can be a temporary effect of Botox injections. 

If the issues with Botox injections are becoming problematic, you may consider the surgical option for hemifacial spasm, namely that of a microvascular decompression.  Before considering this, you will need to have a fine cut MR scan of your facial nerve to establish whether there is indeed a blood vessel pressing on your facial nerve and thereby causing the hemifacial spasm.  On occasion, no such blood vessel is identified on an MR scan, in which case you would probably not be a candidate for this operation.

If a blood vessel is identified on an MR scan, removal of the blood vessel from the facial nerve may very well cure your hemifacial spasm.  A microvascular decompression is achieved by approaching the facial nerve from an incision behind the ear on the affected side of the head.  A small window of bone is removed from the skull which allows us access to a part of the brain cavity called the cerebellopontine angle.  This is where a variety of nerves emerge from the brain to supply head and neck function including the facial nerve.   The nerve and offending blood vessel are identified and then using microsurgical techniques, the two are separated.   A variety of methods are used to keep the nerve and blood vessel apart including using specially fashioned slings and Teflon cushions.  A microvascular decompression usually entails 3 or 4 days in hospital.  It is a very safe procedure when carried out by an experienced surgeon with complications being very rare.  However, these do include tiny risks of harm to the nerves in the cerebellopontine angle, which can result in facial weakness, deafness, facial numbness and/or double vision.  These complications are very rare indeed. 

The chances of a facial microvascular decompression helping your hemifacial spasm are high.  Up to 50% of people having this operation will have complete relief.  A further significant proportion will have a marked improvement in their spasm, although it may remain to a lesser degree.  A small number of patients may not see any improvement.