Hemifacial spasm

Hemifacial spasm or HFS is a neurological disorder in which blood vessels constrict the seventh cranial nerve and cause varying degrees of facial spasming, typically originating around the eye of the afflicted side of the face. Because the nerve directs muscular activities in a particular region, interference will create involuntary contractions. Severe forms of HFS will contort an entire side of the face.

Treatment
Botulin toxin or botox injections, now familiar through cosmetic purposes, are a measure which can be taken to temporarily alleviate spasming. However, should a person later elect to undergo surgery, botox injections could affect the outcome.

Surgical treatment is a more permanent solution. Surgery for this particular type of disorder is called microvascular decompression or MVD. 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 plate then replaces the bone removed from the skull.

Risks of surgery
Hearing loss is the most common of side-effects, though remaining comparatively minimal (~2.5%). The highly fragile hearing nerve (the eighth cranial nerve, vestibulocochlear) is situated 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, termed Bell's palsy.

Stroke, heart attack, or death constitute other possible mishaps; most, however, are related to the nature of surgery in general rather than the delicacy of this particular surgical treatment.