Hemifacial Spasms with Unusual Neurovascular Compression Type: Arterial Cisternal Segment Offender

Area of Science:

• Neurosurgery
• Neurology
• Neuroscience

Background:

• Hemifacial spasm (HFS) typically results from neurovascular compression at the facial nerve's root exit zone (REZ).
• Isolated compression of the cisternal segment of the facial nerve is rare and less understood.
• Anterior inferior cerebellar artery (AICA) compression of the cisternal segment can cause typical HFS symptoms.

Purpose of the Study:

• To investigate the clinical features of HFS caused by cisternal segment arterial compression.
• To analyze intraoperative neurophysiological findings in these patients.
• To evaluate the surgical outcomes of microvascular decompression (MVD) for this specific condition.

Main Methods:

• Retrospective analysis of 874 patients undergoing MVD for HFS.
• Identification of 18 patients (2.1%) with isolated cisternal segment compression, primarily by AICA.
• Evaluation of clinical data, compression site, intraoperative monitoring (LSR, BAEPs), and postoperative outcomes.
• Standardized Teflon interposition technique used for all surgical cases.

Main Results:

• 83.3% of patients achieved immediate relief from hemifacial spasm post-surgery.
• Significant improvement was observed in 94.4% of patients at the latest follow-up.
• No severe complications were reported, indicating a safe surgical profile.

Conclusions:

• Cisternal segment arterial compression, though uncommon, is a viable cause of typical HFS.
• Consider this diagnosis when REZ compression is uncertain or intraoperative monitoring is atypical.
• Microvascular decompression with Teflon interposition offers a safe and effective treatment for HFS due to cisternal segment compression.