Outcome Predictors After Gamma Knife Radiosurgery for Recurrent Trigeminal Neuralgia

BACKGROUND: Trigeminal neuralgia (TN) that recurs after surgery can be difficult to manage. OBJECTIVE: To define management outcomes in patients who underwent gamma knife stereotactic radiosurgery (GKSR) after failing 1 or more previous surgical procedures. METHODS: We retrospectively reviewed outcomes after GKSR in 193 patients with TN after failed surgery. The median patient age was 70 years (range, 26-93 years). Seventy-five patients had a single operation (microvascular decompression, n = 40; glycerol rhizotomy, n = 24; radiofrequency rhizotomy, n = 11). One hundred eighteen patients underwent multiple operations before GKSR. Patients were evaluated up to 14 years after GKSR. RESULTS: After GKSR, 85% of patients achieved pain relief or improvement (Barrow Neurological Institute grade I-IIIb). Pain recurrence was observed in 73 of 168 patients 6 to 144 months after GKSR (median, 6 years). Factors associated with better long-term pain relief included no relief from the surgical procedure preceding GKSR, pain in a single branch, typical TN, and a single previous failed surgical procedure. Eighteen patients (9.3%) developed new or increased trigeminal sensory dysfunction, and 1 developed deafferentation pain. Patients who developed sensory loss after GKSR had better long-term pain control (Barrow Neurological Institute grade I-IIIb: 86% at 5 years). CONCLUSION: GKSR proved to be safe and moderately effective in the management of TN that recurs after surgery. Development of sensory loss may predict better long-term pain control. The best candidates for GKSR were patients with recurrence after a single failed previous operation and those with typical TN in a single trigeminal nerve distribution.