[Microvascular decompression for hemifacial spasm: experience of 215 cases]

To investigate the relationship between pre-operational etiological diagnosis of medically intractable hemifacial spasm (HFS) and patterns of offending vessels and the curative effect of microvascular decompression (MVD).

Two hundred and fifteen patients with medically intractable HFS underwent MVD under general anesthesia. Pre-operative MRI examination was made for all cases to exclude space occupying lesion and magnetic imaging tomographic angiography (MRTA) was conducted for 145 cases of them instead of routine MRI.

Routine MRI failed to provide information about offending vessels except for ruling out mass lesions whereas MRTA revealed the offending vessels with a positive rate of 82.8%, thus helping make correct diagnosis and operation decision. Follow-up of more than two years showed that the surgical intervention achieved a high relief rate of 91.2% without major complication, and with a low recurrence rate of only 3.5% after averaging more than two years' follow-up.

Pre-operative MRTA can replace conventional MRI as a best approach for pre-operational etiological diagnosis of facial spasm. It helps perceive the offending vessels before operation. Skilled microsurgical technique along with correct recognition and mobilization of offending vessels are a must to assure MVD a high efficacious and low risk treatment of choice for HFS patients.