Hemifacial spasm as a feature of Chiari malformation: case report.

BACKGROUND AND IMPORTANCE: Hemifacial spasm has rarely been described as one of the presenting features of Chiari I malformation. We present a case in which we found an association between the two in the absence of a basilar impression. CLINICAL PRESENTATION: A case of a 39-year-old man who presented with a disabling hemifacial spasm and was found to have Chiari I malformation as the possible cause is described. A foramen magnum decompression successfully relieved the hemifacial spasm. The patient remains symptom free at 20 months after the operation. CONCLUSION: Neurosurgeons may want to consider foramen magnum decompression as first-line surgical treatment for hemifacial spasm when it coexists with Chiari I malformation. Chiari I malformation should be considered one of the rare causes of hemifacial spasm.