Repeat Gamma-Knife Radiosurgery for Refractory or Recurrent Trigeminal Neuralgia with Consideration About the Optimal Second Dose.
To investigate adequate radiation doses for repeat Gamma Knife radiosurgery (GKS) for trigeminal neuralgia in our series and meta-analysis.



Fourteen patients treated by ipsilateral repeat GKS for trigeminal neuralgia were included. Median age of patients was 65 years (range, 28-78), the median target dose, 140-180). Patients were followed a median of 10.8 months (range, 1-151) after the second gamma-knife surgery. Brainstem dose analysis and vote-counting meta-analysis of 19 studies were performed.



After the second gamma-knife radiosurgeries, pain was relieved effectively in 12 patients (86%; Barrow Neurological Institute Pain Intensity Score I-III). Post-gamma-knife radiosurgery trigeminal nerve deficits were mild in 5 patients. No serious anesthesia dolorosa was occurred. The second GKS radiation dose ≤ 60 Gy was significantly associated with worse pain control outcome (P = 0.018 in our series, permutation analysis of variance, and P = 0.009 in the meta-analysis, 2-tailed Fisher's exact test). Cumulative dose ≤ 140-150 Gy was significantly associated with poor pain control outcome (P = 0.033 in our series and P = 0.013 in the meta-analysis, 2-tailed Fisher's exact test). A cumulative brainstem edge dose >12 Gy tended to be associated with trigeminal nerve deficit (P = 0.077).



Our study suggests that the second GKS dose is a potentially important factor.
Department of Neurosurgery, Asan Medical Center, Seoul, Korea.
Seong-Cheol
SC
Park
Department of Neurosurgery, Asan Medical Center, Seoul, Korea; Department of Neurosurgery, College of Medicine, University of Ulsan, Seoul, Korea.
Do Hoon
DH
Kwon
Department of Neurosurgery, Asan Medical Center, Seoul, Korea; Department of Neurosurgery, College of Medicine, University of Ulsan, Seoul, Korea.
Do Hee
DH
Lee
Department of Neurosurgery, Asan Medical Center, Seoul, Korea; Department of Neurosurgery, College of Medicine, University of Ulsan, Seoul, Korea. Electronic address: jklee2@icloud.com.
Jung Kyo
JK
Lee
D000328:Adult; D000368:Aged; D001933:Brain Stem; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010147:Pain Measurement; D011829:Radiation Dosage; D016634:Radiosurgery; D012008:Recurrence; D019233:Retreatment; D012189:Retrospective Studies; D016896:Treatment Outcome; D014277:Trigeminal Neuralgia / Q000601:surgery*
Recurrent trigeminal neuralgia; Refractory trigeminal neuralgia; Repeat gamma-knife radiosurgery; Retrogasserian target; Trigeminal neuralgia