Recent Treatment Results Of Gamma Knife Radiosurgery For Trigeminal Neuralgia

Chisa Hashizume1, Yoshimasa Mori2, Tatsuya Kobayashi1, Takahiko Tsugawa3

1Nagoya Kyoritsu Hospital, Nagoya, Japan 2Aichi, Japan 3Nagoya, Japan

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

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       Gamma Knife radiosurgery (GKS) has been reported as one of effective treatment options for essential trigeminal neuralgia.   This study is aimed to evaluate the recent treatment results of GKS for trigeminal neuralgia.   Model-C Gamma Knife can place an isocenter at the target by 0.1 mm all in three dimensions.  
     In addition, recent advancement of magnetic resonance imaging (MRI) visualizes the nerve structures more clearly and enables us to target at the affecting trigeminal nerve more accurately.
     We treated 39 patients with trigeminal neuralgia by GKS from 2004, installation of model C Gamma Knife, through 2009.   The treatment results were evaluated with a mean follow-up period of 25.5 months (range, 7 to 57 months) in 34 patients (age, 48 to 89 years).   All patients had undergone comprehensive trials of medication, such as carbamazepine previously.   Prior open surgical procedure had been done including microvascular decompression in 7 patients.  
     GKS was performed using a 4 mm-collimator beams targeting at the nerve root 2 to 3 mm distal from the root entry zone of ipsilateral trigeminal nerve with the maximum dose of 80Gy (otherwise, 70Gy in 1 patient and 85Gy in 2)
     Complete pain relief was achieved in 24 patients (71%) and significant improvement of pain was obtained in 8 (24%). The success rate of pain relief was 94%.   Pain relief occurred after latent interval of one day to 15 months (median 8 weeks).   Delayed relapse of pain occurred only in one patient and retreatment of GKS was done and pain relief was attained again.  Complications after radiosurgery occurred only in a form of mild or minimal hypesthesia or dysesthesia in 9 patients (26.5%).
     This is a retrospective study.
     Longer follow-up time is necessary to further evaluate effectiveness and safety of GKS for trigeminal neuralgia.
     Our excellent recent results of GKS for trigeminal neuralgia was encouraging.


Project Roles:

C. Hashizume (), Y. Mori (), T. Kobayashi (), T. Tsugawa ()