Doses greater than 85 Gy and two isocenters in Gamma Knife surgery for trigeminal neuralgia: updated results.
OBJECTIVE
The purpose of this study was to assess the efficacy of Gamma Knife surgery (GKS) in treating patients with trigeminal neuralgia (TN). Preliminary results of this study were previously reported. The updated results are reported in this paper.


METHODS
Ninety seven patients with TN refractory to medical or surgical management underwent GKS between September 1998 and October 2005. Fifteen patients had multiple sclerosis (MS). The radiation dose was escalated from 70 to 99 Gy. The Barrow Neurological Institute Pain Scale (BNIPS) was used to assess pain before and after GKS. Eighty-four patients were available for evaluation with a mean follow up of 8.9 months. The overall response and complete response rates were 70.2% and 36.9%, respectively. At 12 months, there was a greater improvement in BNIPS scores for patients who were treated with two isocenters compared with those treated with a single isocenter. The mean percentage of pain decrease was 56.26% compared with 11.53% (p < 0.001). Patients treated with two isocenters rather than one and patients receiving greater than 85 Gy compared with lower doses had a longer duration of response. Only nine patients (11%) had mild numbness attributable to the GKS. Five of the nine patients experienced complete resolution of facial numbness on follow up. Patients with MS have a shorter duration of response compared with those without MS (p = 0.35).


CONCLUSIONS
These updated results show that GKS continues to be an effective therapy for TN. It appears there is an enhanced response with doses 85 Gy or more and with two isocenters without increased complications.
Morbidini-Gaffney
Stefania
S
Department of Radiation Oncology, State University of New York Upstate Medical University, Syracuse, New York 13210, USA. smorbidini@yahoo.com
Chung
Chung-Taik
CT
Alpert
Tracy Erin
TE
Newman
Nancy
N
Hahn
Seung Shin
SS
Shah
Hemangini
H
Mitchell
Lisa
L
Bassano
Daniel
D
Darbar
Aneela
A
Bajwa
Saeed Ahmed
SA
Hodge
Charles
C
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015331:Cohort Studies; D004307:Dose-Response Relationship, Radiation; D006801:Humans; D008875:Middle Aged; D009103:Multiple Sclerosis / Q000150:complications; D010146:Pain / Q000209:etiology / Q000473:pathology / Q000517:prevention & control*; D016634:Radiosurgery / Q000379:methods*; D011879:Radiotherapy Dosage; D012189:Retrospective Studies; D016896:Treatment Outcome; D014277:Trigeminal Neuralgia / Q000209:etiology / Q000473:pathology / Q000601:surgery*; D055815:Young Adult