Gamma Knife Radiosurgery For Trigeminal Neuralgia: A Review Of 450 Consecutive CasesVerheul HB1, PEJ Hanssens1, ST Lie1, S Leenstra1, H. Piersma1, GN Beute11Gamma Knife center Tilburg, Tilburg, Netherlands Keywords: trigeminal neuralgia, gamma knife, pain, radiosurgery, outcome
Radiosurgery is becoming more and more the first treatment modality for trigeminal neuralgia (TN).
In the present study we present the treatment results of a large cohort of patients treated for TN using Gamma Knife® radiosurgery.
Between 2002 and 2009, a total of 380 patients were treated. 70 patients were re-treated. The treatment parameters were highly consistent.
80 Gray was delivered using a 4 mm collimator shot that was placed on the root entry zone, with the 40% isodose line touching the brainstem. For re-treatments 80 Gray was given on an anterior location on the cisternal trigeminal nerve, also in a highly consistent manner. The outcome on pain was evaluated using the Barrow Neurological Institute (BNI) pain scale. Kaplan-Meier curves for pain relief were made for all patients and for different subgroups, with pain scores 4 or 5 as endpoints.
Short term (3 month) success rate was 92%, slowly decreasing over the first 2 years and leveling off at longer time intervals. The long term (5 year) success rate was 70 % for typical idiopathic TN. Different subgroups (multiple sclerosis, atypical pain, re-treatment, prior treatment with other modality) were found to have a significant worse outcome in terms of pain relief. The adverse effects were scored according to the BNI numbness score. Overall, 55 % of patients experienced some form of numbness, which developed slowly over time. 12 % found this to be somewhat bothersome, 2 % very bothersome. In patients that were previously treated with another surgical modality Gamma Knife treatment showed an additive effect on the numbness.
This is a retrospective study.
This study contains a large population with a long follow up after GKRS for TN, enabling a robust statistical analysis of pain relief, adverse effects and various prognostic factors.
MS, prior treatment and atypical pain showed worse outcomes. Project Roles:
V. HB (), P. Hanssens (), S. Lie (), S. Leenstra (), H. Piersma (), G. Beute ()