Treatment for Hemifacial Spasm Associated with a Dissecting Vertebral Artery Aneurysm Requiring Microvascular Decompression in Addition to Endovascular Trapping: A Case Report with Literature Review

Background The treatment protocol for hemifacial spasm (HFS) associated with dissecting vertebral artery aneurysm (DVAA) has not been established. Case Description A-42-year-old man with left HFS underwent endovascular trapping for a DVAA that was identified on brain imaging. Although the dissecting segment was treated successfully, the HFS persisted for 3 months, and subsequently microvascular decompression (MVD) was needed. The posteroinferior cerebellar artery (PICA) was found to be interposed between the root exit zone of the facial nerve and DVAA during surgery. After pulling out the PICA, the HFS ceased immediately. Conclusion HFS associated with DVAA should be considered carefully before formulating a treatment strategy. Moreover, the cause of pulsatile compression may not be visible on brain imaging, and MVD surgery may be indicated in such cases.