Craniofacial Muscles

294 J. Park et al.
evident eyelid squeezing (Tozlovanu et al. 2001 ) . The eyelids appear relaxed, and
the eyebrows are often raised as a result of prominent use of the frontalis to elevate
the upper eyelid (Krack and Marion 1994 ) . In contrast, the spasms in BEB usually
involve all the subparts of the orbicularis oculi muscles, causing characteristic lowering
of the eyebrows.
Injections of paralytic agents into the preseptal orbicularis oculi only are generally
unsuccessful in treating apraxia (Lepore et al. 1995 ) . Injection of 4–5 units of
botulinum toxin A into several sites around the pretarsal orbicularis oculi muscle
has been shown to elicit an improvement in eyelid opening, with the sites of most
effectiveness being between the preseptal and pretarsal portions of the orbicularis
oculi (Vissenberg et al. 1993 ; Forget et al. 2002 ) . On average, symptoms improve
for 2 months, with retreatment necessary after this time period to maintain improved
eyelid control. Limited myectomy with complete removal of the pretarsal orbicularis
and a frontalis sling operation should be considered for patients who are visually
disabled by the apraxia.
16.2.4.3 Meige Syndrome
Meige syndrome consists of blepharospasm plus oromandibular dystonia, characterized
by dystonic movements of the lower face, jaw, and neck. The most frequent
presenting complaint is blepharospasm, although it is not always present. The full
syndrome can take years to develop. It is estimated that as many as 50% of patients
with blepharospasm may have Meige syndrome (Bradley et al. 2003 ; Defazio
et al. 2001 ) . Eyelid involvement may predate or follow midfacial, oral, mandibular,
or pharyngeal involvement which includes facial grimacing, frowning, fl aring of the
nostrils, yawning, retraction and forced opening of the mouth, contractions of the
soft palate and fl oor of the mouth, pursing and tightening of the lips, jaw clenching,
tongue protrusion, head titubation, tensing of the platysma, torticollis, and spastic
dystonia.
Its earliest symptom is usually “action dystonia” with involuntary dystonic
movements appearing only when the involved muscles are used, such as in talking
or chewing. Typically one action may precipitate the dystonia; at the beginning
other actions may not be involved at all. As the disorder worsens, more and more
actions are affected, and the spasms become more intense. Eating, swallowing, and
speaking all may become impaired. Forced jaw closure may damage the lips, gums,
tongue, and teeth. Temporomandibular joint pain may occur, along with recurrent
jaw dislocation.
16.2.4.4 Eyelid Myokymia (Ocular or Orbicularis Myokymia)
Eyelid myokymia is a relatively common condition, and is a localized form of facial
myokymia characterized by benign episodes of continuous fi brillary twitching or
quivering of one or more fi bers or fascicles of the orbicularis oculi muscle lasting