Spasmodic torticollis due to neurovascular compression of the spinal accessory nerve by the anteroinferior cerebellar artery: Case report

OBJECTIVE AND IMPORTANCE: Spasmodic torticollis is a neuromuscular disorder characterized by uncontrollable clonic and intermittently tonic spasm of t he neck muscles. We report a case of spasmodic torticollis attributable to neurovascular compression of the right XIth cranial nerve by the right ante roinferior cerebellar artery (AICA). CLINICAL PRESENTATION: A 72-year-old man with a 2-year history of right spa smodic torticollis underwent magnetic resonance imaging, which demonstrated compression of the right XIth cranial nerve by an abnormal descending loop of the right AICA. INTERVENTION: The patient underwent microvascular decompression surgery. Du ring surgery, it was confirmed that an abnormal loop of the right AICA was compressing the right accessory nerve. Compression was released by the inte rposition of muscle between the artery and the nerve. CONCLUSION: The patient's postoperative course was uneventful, and his symp toms were fully relieved at the 2-year follow-up examination. This is the f irst reported case of spasmodic torticollis attributable to compression by the AICA; usually, the blood vessels involved are the vertebral artery and the posteroinferior cerebellar artery.