2025 Proffered Presentations
S097: RESULTS OF GAMMA KNIFE RADIOSURGERY FOR TUMOR RELATED TRIGEMINAL NEURALGIA
Prabu Raj Andiperumal Raj; Nishanth Sadhashiva; NIMHANS
Introduction: Trigeminal neuralgia (TN) can occur secondary to tumors in the cerebellopontine (CP) angle due to the indentation of a lesion on the trigeminal nerve. Vestibular schwannomas (VS), meningiomas, and other lesions can cause TN. Stereotactic radiosurgery (SRS) has emerged as a feasible treatment option in such cases but has shown heterogeneous clinical results. In this study, we report our experience and results in treating such tumors with Gamma Knife radiosurgery (GKRS).
Methods: We retrospectively reviewed all patients who underwent GKRS at our institute for TN secondary to tumors in the CP angle. Pain outcomes were evaluated using the Barrow Neurological Institute (BNI) pain score. We collected patient demographics, lesion characteristics, pain characteristics, segments, side, severity, and BNI scores before the procedure and at the latest follow-up.
Results: Between 2007 and 2017, 121 patients with TN secondary to tumors in the CP angle underwent GKRS at our institute. Thirty-two patients had less than 24 months of follow-up, and three patients died due to unrelated causes and were excluded. Thus, 86 patients were included for outcome analysis. The mean age was 47 years (± 11.4 years), with the majority being female (66.1%). The median duration of pain before the procedure was 19.9 months (range 1-170 months).
The most common diagnoses were vestibular schwannoma, followed by trigeminal schwannoma. Significant pain relief among patients with pain scores greater than IIIB occurred around 11 months post-treatment. Among those who experienced initial pain relief, 22.1% had a recurrence of pain. Recurrence developed on average 28 months (± 24 months) after treatment. Eight patients (9.3%) with prior significant pain never experienced any pain relief.
Most patients achieved pain relief within 24 months, after which the chances of pain relief significantly decreased. Recurrence of pain after initial relief can occur even after 10 years (120 months). The tumor control rate was 97.6% at the latest follow-up. Unfavourable outcomes were observed in 24 patients (27.9%). Post-GKRS facial numbness was noted in 7 patients (8.1%).
Conclusion: Gamma Knife radiosurgery (GKRS) is a feasible treatment modality for various tumors causing trigeminal neuralgia. GKRS can provide long-term pain relief for a significant number of patients. Failure to achieve pain relief after 24 months should prompt surgeons to consider alternative treatments, such as surgical decompression.