Predictors of Outcome After Radiosurgery for Trigeminal Neuralgia

Hussein Al-Ahmadi, MD1, Gelareh Zadeh, MD1, Norman Laperriere1, Shobhan Vachhrajani, MD1, Fred Gentili, MD1, Nora Mazloom1, Mojgan Hodaie, MD1

1Toronto, Canada

Keywords: trigeminal neuralgia, outcome, radiosurgery, pain, gamma knife

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     Gamma knife radiosurgery is an established treatment for trigeminal neuralgia.
     With the availability of other treatment modalities, understanding the predictors of good response will provide guidance in patient selection.
     A hundred and forty five patients were treated. Sixteen patients had trigeminal neuralgia secondary to multiple sclerosis. At last follow up, 48 patients (33%) were pain free with no medications, and 48 patients (33%) were pain free maintained on medications. Twenty-eight patients (19%) had pain after the treatment but had significant reduction in their pain severity. Twenty-one patients (15%) did not have any significant pain reduction.
     We conducted a retrospective review of patients treated with Gamma Knife for trigeminal neuralgia at our institution from 2005 to 2009. Patients were treated with maximum dose of 80 grays targeting the cisternal segment of the trigeminal nerve.
     Among the patients with trigeminal neuralgia secondary to multiple sclerosis, 50% became pain free (with or without medications). Forty-four patients (30%) developed facial numbness. Recurrence occurred in 51 patients (35%). Mean follow up period was 24 months (range 6-56 months). Post-treatment numbness predicted good treatment response (OR 2.720, CI 1.193-6.200, p= 0.0173). Higher integrated dose was a predictor of poor pain response to radiosurgery (OR 0.729, CI 0.566-0.940, p= 0.0146). Restricting the integrated dose to below 5.3 mJ was associated with good pain outcome.
     This is a retrospective study.
     Radiosurgery is an effective treatment modality for trigeminal neuralgia.
     Post treatment numbness is associated with good treatment response and higher integrated dose predicts poor pain outcome.


Project Roles:

H. Al-Ahmadi (), G. Zadeh (), N. Laperriere (), S. Vachhrajani (), F. Gentili (), N. Mazloom (), M. Hodaie ()