The Gamma Knife Dose Rate Does Not Affect Outcomes Of Trigeminal Neuralgia Radiosurgery

Yoshio Arai, MD1, Dade Lunsford2, Douglas Kondziolka, MSc, MD3, John C. Flickinger, MD4, Ajay Niranjan, MCh3

1Department of Radiation Oncology, University of Pittsburgh School of Medicine 2University of Pittsburgh School of Medicine, Pittsburgh, United States. 3Department of Neurological Surgery, University of Pittsburgh 4Department of Radiation Oncology, University of Pittsburgh

Keywords: trigeminal neuralgia, dose, pain, outcome, radiosurgery

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     To determine whether the Leksell Gamma Knife dose rate affects the outcome of trigeminal neuralgia (TN) stereotactic radiosurgery (SRS).
     We studied 165 patients (female =103, male= 63) who had medically intractable TN. We used the U unit (80 Gy maximum dose, 4 mm collimator) between 1994 and 2005. 
     The Gamma knife output factor was determined as 0.8 and the dose rate (DR) varied from 1.21 Gy/minute to 3.74 Gy/minute (median= 2.0555 Gy/minute). Treatment time ranged from 26.73 – 95.11 minutes.
     Pain relief (BNI scores of I-IIIa) occurred in 72.3 % of patients in the LDRG compare to 80.7% of HDRG patients (p= 0.200). Median duration of pain relief control (better or equal to BNI  IIIa) was 52 months for LDRG and was 50 months for HDRG patients (p=0.403). Deafferentation symptoms (paresthesias) occurred 16.9% of LDRG and 14,5 % of HDRG patients (p=0.669), New or worsened trigeminal sensory loss occurred in14.5 % of LDRG and 19.3 % HDRG patients ( p=0.407).
     This is a retrospective study.
     In this study a varying Leksell Gamma Knife Dose rate of 1.21 Gy to 3.74 Gy/minute did not affect pain relief.
     Nor did the dos rate affect treatment related side effects in the management of TN.


Project Roles:

Y. Arai (), D. Lunsford (), D. Kondziolka (), J. Flickinger (), A. Niranjan ()