KEY POINTS
- This retrospective analysis included 86 patients with medically refractory trigeminal neuralgia treated between 2017 and 2021 with at least one year of follow-up. 54 received proximal targeting and 32 distal targeting.
- Every patient received 85 Gy in a single fraction. The proximal target was the dorsal root entry zone near the brainstem, whereas the distal target was the retrogasserian segment.
- Any pain improvement was more frequent after distal targeting: 90% versus 74%. However, complete pain freedom showed the opposite pattern, occurring in 46% with proximal versus 31% with distal targeting (p=0.011).
- Among responders, median duration of pain relief was 37 months with proximal versus 24 months with distal targeting, but the difference was not statistically significant (p=0.18).
- Complete discontinuation of trigeminal-neuralgia medication occurred in 39% versus 13% with proximal and distal targeting, respectively. Partial medication reduction was more frequent with distal targeting (75% vs 33%; overall p=0.001).
- No radiation necrosis was observed and no patient required treatment for an adverse radiation effect during follow-up.
- The key limitation is major treatment confounding: Gamma Knife patients were treated proximally, while LINAC patients were treated distally. The study therefore cannot cleanly separate anatomical target effects from platform, planning and institutional-treatment differences.
CLINICAL TAKEAWAY
Both dorsal-root-entry-zone and retrogasserian SRS produced substantial pain relief, but the type of response differed: distal treatment produced more partial responders while proximal treatment produced more complete responses. The finding is hypothesis-generating because target location and treatment platform were inseparable in this cohort.