Endoscope-Assisted Microvascular Decompression for the Management of Hemifacial Spasm Caused by Vertebrobasilar Dolichoectasia.

Objective: Vertebrobasilar dolichoectasia (VBD) is a rare cause of hemifacial spasm. The ectatic vessel hinders microscopic visualization of the root exit zone. The aim of this study was to evaluate the benefit of endoscopic visualization during microvascular decompression (MVD) in managing this type of neurovascular compression.
Methods: Retrospective evaluation of patients with VBD treated by endoscope-assisted MVD for hemifacial spasm between 2007 and 2016 was performed. A prospectively maintained database of all patients treated by MVD for hemifacial spasm was screened for vascular compression. Magnetic resonance imaging was evaluated to detect patients who had VBD according to defined criteria. The value of endoscopic inspection to detect offending vessels was analyzed, and clinical outcome was evaluated.
Results: VBD was detected in 11 of 290 patients (incidence 3.8%). In these patients, 12 MVD procedures were performed. The endoscope was useful in identifying the offending vessels and adjacent perforators without any brain retraction in all patients. At last clinical follow-up, all patients had almost complete to complete resolution of clinical symptoms. The interposing technique alone was effective with excellent results in 8 patients. Three patients required an additional transposition-fixation technique to achieve sufficient decompression.
Conclusions: VBD is a rare cause of hemifacial spasm. Because of the large diameter of the offending vessel, MVD is technically more demanding. Endoscopic inspection with a 45° endoscope enables accurate visualization of the root exit zone, offending vessels, and perforating arteries. Furthermore, accurate placement of the Teflon pledgets can be confirmed leading to a favorable outcome.
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