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Arachnoid cyst alone causes hemifacial spasm: illustrative case
Ko Ozaki1, Yoshinori Higuchi1, Shigeki Nakano1
11Department of Neurological Surgery, Chiba University Graduate School of Medicine, Chiba, Japan; and.
Journal of Neurosurgery. Case Lessons
|October 28, 2022
Summary
A rare case of hemifacial spasm (HFS) caused by a cerebellopontine angle arachnoid cyst was successfully treated. Surgical removal of the cyst relieved facial nerve hyperactivity, demonstrating the cyst
Area of Science:
- Neurosurgery
- Neurology
Background:
- Hemifacial spasm (HFS) is rarely caused by cerebellopontine angle arachnoid cysts.
- This study presents a case of HFS attributed to an arachnoid cyst without neurovascular compression.
Purpose of the Study:
- To report a rare case of hemifacial spasm caused by an arachnoid cyst.
- To analyze the mechanism of facial nerve hyperactivity in this context.
Main Methods:
- A 40-year-old male with right HFS underwent magnetic resonance imaging, revealing a cerebellopontine angle cystic mass.
- Surgical excision of the cyst and facial nerve decompression were performed via a lateral suboccipital approach.
- Abnormal muscle response (AMR) was monitored during surgery.
Main Results:
- Preoperative imaging showed a cystic mass consistent with an arachnoid cyst.
- Surgical excision resulted in permanent relief of HFS symptoms.
- Dissection of the cyst led to the disappearance of AMR, with no offending arteries identified.
Conclusions:
- The arachnoid cyst itself was the cause of HFS in this case.
- Abnormal muscle response (AMR) monitoring was a useful tool in confirming the diagnosis and surgical success.
- Pulsatile compression by the cyst likely caused facial nerve hyperactivity leading to HFS.
