Trigeminocerebellar artery as a subsequent offending vessel for recurrent trigeminal neuralgia after initial microvascular decompression: illustrative case

BACKGROUND The most common cause of trigeminal neuralgia (TN) is vascular compression at the root entry zone of the trigeminal nerve, most frequently by the superior cerebellar artery (SCA). Trigeminocerebellar artery (TCA) involvement in TN is rare, and its management with microvascular decompression (MVD) has not been elucidated. OBSERVATIONS The authors report the case of a 64-year-old woman with TN caused by compression from the SCAs who underwent successful MVD with complete symptom resolution. The TCA had been identified intraoperatively; however, it was not considered the offending vessel and was not fully transposed owing to the presence of small perforating branches. Three years later, TN recurred, predominantly in the left V3 distribution. MRI showed that the SCAs were not compressing the trigeminal nerve. Rather, the TCA had adhered to and was compressing the nerve. Revision MVD revealed strong adhesion of the TCA between the sensory and motor roots of the trigeminal nerve. After splitting the roots and transposing the TCA, including sacrificing a small perforating branch, complete symptom relief was achieved without neurological deficits. LESSONS Transposition should be considered when the TCA is identified during MVD for TN, even if it is not the initial apparent offending vessel. https://thejns.org/doi/10.3171/CASE26172