Is it effective to raise the irradiation dose from 80 to 85 Gy in gamma knife radiosurgery for trigeminal neuralgia?
OBJECTIVE
In order to assess the effect of raising gamma knife radiosurgery (GKS) doses from 80 to 85 Gy for the treatment of trigeminal neuralgia (TN), the authors analyzed the outcomes of GKS in each group.


METHODS
The authors retrospectively collected follow-up data of 104 GKS procedures conducted for TN. Doses of 80 and 85 Gy were prescribed for 60 and 44 patients, respectively. The target was 2-4 mm anterior to the junction of the trigeminal nerve and pons. Outcomes were quantified based on facial pain levels and classified using the Barrow Neurological Institute scale.


RESULTS
Actuarial rates of a favorable pain control outcome at 1 and 3 years after GKS were 75.0 and 61.2% for 80 Gy and 65.9 and 60.3% for 85 Gy. Post-GKS facial sensory loss developed in 20.6%. There was no statistically significant difference in pain control rate between the two groups. Time to maximal pain relief was shorter in the 85-Gy group. Protracted morbidity before GKS was a favorable prognostic factor of pain control in a multivariate analysis.


CONCLUSIONS
According to our finding that 85 Gy brought more rapid clinical improvement without causing more complications, 85 Gy seems to be preferable to 80 Gy, but prospective randomized trials are mandatory to get a more definite conclusion on the optimal dose for GKS of TN.
Kim
Yong Hwy
YH
Department of Neurosurgery, Seoul National University College of Medicine, Seoul, South Korea.
Kim
Dong Gyu
DG
Kim
Jin Wook
JW
Kim
Young-Hoon
YH
Han
Jung Ho
JH
Chung
Hyun-Tai
HT
Paek
Sun Ha
SH
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D004307:Dose-Response Relationship, Radiation; D005157:Facial Pain / Q000601:surgery*; D005260:Female; D005720:Gamma Rays / Q000627:therapeutic use*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010147:Pain Measurement; D017060:Patient Satisfaction; D011829:Radiation Dosage; D016634:Radiosurgery / Q000295:instrumentation*; D016896:Treatment Outcome; D014277:Trigeminal Neuralgia / Q000601:surgery*