Duplication of Right Superior Cerebellar Artery Leading to Trigeminal Neuralgia: A Rare Neurovascular Conflict.

Trigeminal neuralgia (TN) is a chronic neuropathic pain condition characterized by brief, intense, and electrical shock-like facial pain. The most common causes of this are due to neurovascular compression of the superior cerebellar artery (SCA). However, as seen in this case report, duplication of the SCA resulting in TN is extremely uncommon. A 63-year-old woman presented with a 1-day history of paroxysmal, shock-like pain on the right side of her face affecting both the ophthalmic (V1) and maxillary (V2) branches of the trigeminal nerve. Each episode of pain would last 1-2 min, occur multiple times each day, and be precipitated by chewing, with resultant ipsilateral tearing. Her past medical history included no trauma, dental disease, or systemic illnesses. Examination of the neurological system revealed all cranial nerves were normal, and there were no facial motor deficits. Magnetic resonance imaging (MRI) of the head-and-neck region with gadolinium enhancement, demonstrated an anomalous duplication of the right SCA where its lower branch compressed and deformed the cisternal portion of the right trigeminal nerve, representing a Grade II neurovascular conflict, with no cerebrospinal fluid visible between the vessel and nerve. Computed tomography scan of the brain demonstrated evidence of chronic ischemic changes and age-related cortical atrophy. Based on the findings from the above diagnostic testing, she was diagnosed with typical TN secondary to neurovascular compression from an anomalous duplicated SCA. She was started on carbamazepine with good symptomatic relief. Duplication of the SCA is a rare anatomical anomaly which may result in symptomatic neurovascular compression of the trigeminal nerve. In cases of suspected neurovascular compression of the trigeminal nerve, high-resolution MRI is necessary to identify these vascular abnormalities and guide the appropriate treatment options.