Interventional neuroradiology in hemifacial spasm. Diagnostic and therapeutic implications

There have never been functional studies in the diagnosis of hemifacial spasm caused by neurovascular compression. We used neurointerventional techniques to conduct a functional investigation of the artery responsible for hemifacial spasm in seven patients. A microcatheter was inserted into the various arteries of the posterior circulation under systemic heparinization, and its effect on the spasm was evaluated clinically and electromyographically. In six patients who underwent microvascular decompression surgery, the vessels compressing the root exit zone of the facial nerve were surgically determined, and compared with the result of the procedure. The catheter was inserted into twelve arteries. The spasms were stopped immediately and completely by the insertion of the catheter into seven arteries. Six of them were surgically proven to compress the root exit zone of the facial nerve. The spasm was changed in frequency or in type by the insertion into two arteries. These arteries were also compressing the root exit zone. One artery was located at a more peripheral part of it and the other was running over another artery compressing the root exit zone. The spasms were not affected at all by the insertion into three arteries. These arteries were not observed in the operative field and had no contact with the nerve. Superselective angiograms showedpositional qnd configurational changes of the arteries. There was no arterial spasm and tight catheterization leading to stasis of contrast material within the arteries. There were no complications related to the procedures. Functional relationship between the artery and the spasms was established in all the patients, and one patient refused surgery because the frequency of the spasm was reduced by the procedure. The result of this study may suggest that a functional investigation of hemifacial spasm is feasible and seems useful for selecting good candidates for microvascular decompression surgery.