Hemifacial spasm or HFS is a neurological

Neurology

Neurology is a medical specialty dealing with disorders of the nervous system. Specifically, it deals with the diagnosis and treatment of all categories of disease involving the central, peripheral, and autonomic nervous systems, including their coverings, blood vessels, and all effector tissue,...

 disorder in which blood vessels constrict the seventh cranial nerve

Cranial nerves

Cranial nerves are nerves that emerge directly from the brain, in contrast to spinal nerves, which emerge from segments of the spinal cord. In humans, there are traditionally twelve pairs of cranial nerves...

 and cause varying degrees of facial

Facial nerve

The facial nerve is the seventh of twelve paired cranial nerves. It emerges from the brainstem between the pons and the medulla, and controls the muscles of facial expression, and functions in the conveyance of taste sensations from the anterior two-thirds of the tongue and oral cavity...

 spasm, typically originating around the eye

Human eye

The human eye is an organ which reacts to light for several purposes. As a conscious sense organ, the eye allows vision. Rod and cone cells in the retina allow conscious light perception and vision including color differentiation and the perception of depth...

 of the afflicted side of the face. Severe forms of HFS will contort an entire side of the face.

Treatment

Botulinum toxin or botox injections is typically the primary treatment modality.

Surgical treatment is a more permanent solution. Surgery for this particular type of disorder is called microvascular decompression

Microvascular decompression

Microvascular decompression , also known as the Jannetta procedure, is a neurosurgical procedure used to treat trigeminal neuralgia, a pain syndrome characterized by severe episodes of intense facial pain and hemifacial spasm.-History:...

. Entering through a small aperture cut behind the ear of the affected side, Teflon strips are placed between constricting blood vessels and the nerve, relieving pressure and freeing the nerve. A titanium

Titanium

Titanium is a chemical element with the symbol Ti and atomic number 22. It has a low density and is a strong, lustrous, corrosion-resistant transition metal with a silver color....

 plate then replaces the bone removed from the skull.

Risks of surgery

Hearing

Hearing (sense)

Hearing is the ability to perceive sound by detecting vibrations through an organ such as the ear. It is one of the traditional five senses...

 loss is the most common of side-effects, though remaining comparatively minimal (~2.5%). The hearing nerve (the eighth cranial nerve, vestibulocochlear

Vestibulocochlear nerve

The vestibulocochlear nerve is the eighth of twelve cranial nerves, and is responsible for transmitting sound and equilibrium information from the inner ear to the brain...

) is next to the seventh cranial nerve and damage can lead to either permanent loss of hearing in one side or diminished hearing.

As a result of relieving pressure on the nerve, weakness along one side of the face is also a possibility.

External links

• Centre for Cranial Nerve Disorders.
• Hemifacial Spasm Association support site.