• 13 SECTIONDisorders Eyelid

Hemifacial Spasm

Key Facts

•Involuntary contraction of facial muscles on one side • Generally no underlying disease, but some patients have old ipsilateral facial palsy • Believed to result from pathologic excitability of facial nerve

•In some patients, surgical exploration shows compression of facial nerve at its exit from brainstem by aberrant artery

• this abnormality is generally not visible with brain imaging

•Botulinum toxin injections into affected side of face are usually temporarily effective • For refractory cases, suboccipital craniectomy with placement of Gelfoam between facial nerve and aberrant artery is an option

Clinical Findings

•Involuntary contraction of facial muscles on one side • Upper face, including orbicular oculi, usually most prominently involved • No other pertinent findings unless pre-existing facial palsy causes ipsilateral facial weakness and ipsilateral deviation of mouth (postparetic facial contracture) and abnormal coactivation of facial muscles (facial synkinesis)

Ancillary Testing

•MRI with attention to brainstem—extrinsic and intrinsic brainstem lesions may rarely cause hemifacial spasm

Treatment

•Botulinum toxin injected into affected side of face is usually temporarily effective

• For refractory cases, suboccipital craniectomy with placement of Gelfoam between facial nerve and aberrant artery is an option

Prognosis

•Botulinum toxin injections generally relieve symptoms for 3–4 months

• Craniectomy usually effective, but there is a small risk of stroke or deafness

A B

Fig. 13.5 Patient with left hemifacial spasm. (A) Upper and lower facial muscles are contracted. (B) Botulinum toxin injections are given subcutaneously in the brow, eyelids, and cheek.

C

Fig. 13.5, con’t (C) One day later, the facial muscle contraction has disappeared.

Fig. 13.6 Hemifacial spasm. Axial T2 MRI shows compression of the seventh cranial nerve (black arrows) by a vessel indenting its root entry zone (white arrow) in the caudal pons. (From Rahman EA et al. Am J Ophthalmol 2002; 133:854–856, with permission.)

Spasm Hemifacial