Background: Hemifacial spasm (HFS) has an impact on physical, social, mental, and occupational perspectives of patients. Botulinum toxin injection is an effective, non-invasive therapeutic procedure; however, the injection cannot get rid of cause of the disease. Microvascular decompression (MVD) is the only treatment which can eliminate the etiology of HFS.
Objective: MVD surgery aims to relieve symptoms of HFS by decompression of the facial nerve.
Material and Method: The authors reviewed medical literatures regarding pathophysiology, clinical presentation, diagnosis, and treatment of HFS which emphasizes in MVD surgery.
Results: The main pathophysiology is focal demyelination of the compressed facial nerve at the root exit zone. The other
Babinski sign (the Babinski-2 sign) is commonly found in HFS with high specificity and reliability for the diagnosis.
Neurovascular conflict can be obviously visualized in high resolution T2-weighted MRI of the brain and constructive
interference in steady stage (CISS) sequence. Conventionally, MVD is performed by microscopic decompression of the facial
nerve from offending vessel. Teflon felt pledget is interposed between the nerve and vessel. Neuroendoscopy is useful in
visualization of the structures which cannot be seen by microscopic MVD.
Conclusion: MVD is an effective surgery which can treat the cause of HFS. Even though operative complications are
uncommon, the complications, particularly hearing impairment and facial paresis should be minimized.

Keywords: Hemifacial spasm, Microvascular decompression, Neurovascular conflict, Facial nerve, Offending vessel