Longitudinal imaging correlates of stereotactic radiosurgery for refractory trigeminal neuralgia: A case report of rapid pain relief with 18-month follow-up.

Stereotactic radiosurgery (SRS) is a well-established treatment for refractory trigeminal neuralgia (TGN), but longitudinal imaging data correlating radiological changes with clinical outcomes remain limited. We present a 79-year-old male with idiopathic TGN involving the right V2 trigeminal nerve distribution, refractory to pharmacotherapy and prior trigeminal ganglion balloon compression. Using an advanced plate-based SRS system, a precision dose of 90.0 Gy was delivered to the trigeminal nerve root entry zone (REZ). The patient reported complete pain relief within 3 days, sustained through 18-month follow-up, with mild sensory changes (paresthesia, numbness) considered an acceptable trade-off for pain freedom. Serial MRI follow-up at 4, 6, 12, and 18 months demonstrated dynamic post-SRS inflammatory changes at the REZ-initial enhancement peaking at 6-12 months followed by resolution at 18 months-providing rare radiological insights into treatment response. This case reinforces SRS as an effective option for refractory TGN, particularly in elderly patients, while highlighting the prognostic value of longitudinal imaging to bridge gaps in understanding post-procedural radiological evolution.