V1-dominant Recurrence of Trigeminal Neuralgia after Gamma Knife Radiosurgery for V2–V3 Pain in a Patient with Persistent Vertebral Artery Compression: A Case Report

Gamma knife radiosurgery is an established minimally-invasive treatment for trigeminal neuralgia, but recurrence remains a concern, and the trigeminal division involved at relapse is rarely documented. A 63-year-old man developed recurrent trigeminal neuralgia 3 years after gamma knife radiosurgery for left V2–V3 pain, presenting this time with isolated V1 involvement. Magnetic resonance imaging revealed persistent, severe neurovascular compression of the left trigeminal root by a tortuous left vertebral artery with marked nerve flattening. Microvascular decompression achieved immediate and complete pain relief, and postoperative imaging confirmed full decompression. This case illustrates a V1-dominant recurrence pattern after gamma knife radiosurgery in the setting of persistent, deforming neurovascular compression by a tortuous vertebral artery. Although division-specific radiosurgical effects could not be confirmed, the complete resolution of pain after microvascular decompression supports the clinical importance of reassessing persistent mechanical compression when recurrent pain appears in a different trigeminal division.