Factors Affecting Long-Term Pain Control After Gamma Knife Radiosurgery in Secondary Tumor-Related Trigeminal...

Trigeminal neuralgia (TN) can often result from compression of the trigeminal root by various tumors. Although the efficacy of Gamma Knife radiosurgery (GKRS) in treating these tumors is well documented, it remains to be determined if tumor control drives pain relief in tumor-related TN.

We retrospectively analyzed all patients who underwent GKRS for secondary TN at our center, recording preoperative clinical and radiological data, and assessing outcomes regarding Barrow Neurological Institute (BNI) pain scores and tumor volume at follow-up. We then analyzed the factors that predicted pain relief, including long-term tumor control.

The mean age of 156 patients (90 women and 66 men) was 52.2 ± 13.9 years. The most frequent pathology was schwannoma (108 cases, 67.9%), followed by meningioma (48 cases, 29.6%). The mean dose of GKRS administered was 12.08 ± 5.5 Gy. The mean follow-up was 49.7 ± 17.1 months. Four patients (2.5%) were lost to follow-up. At latest follow-up, 59 patients (38.8%) achieved complete pain relief (BNI 1), whereas 72 patients (47.4%) achieved adequate pain relief (BNI 2 and 3). Failure of pain relief occurred in 21 patients (13.8%). Multivariate analysis revealed that patients aged younger than 50 years (odds ratio: 6.95, 95% CI: 2, 22.8, P = .001) and increase in tumor volume at follow-up (odds ratio: 40.38, 95% CI: 5.39, 321.45, P < .001) predicted failure of pain relief.

GKRS is effective among patients with secondary tumor-related TN, with complete pain relief in 38.8% of patients and adequate pain relief in 47.4%. The most frequent complication is facial hypesthesia, affecting 8.3% of patients. Age ≥50 years and decreased or stable tumor volume significantly predict BNI 1-3 pain relief at the latest follow-up. Although pain relief is linked to long-term tumor control, it is not the sole factor at play.