Gamma Knife Surgery for Essential Trigeminal Neuralgia: Advantages in New Treatment Strategy with Robotized Micro-Radiosurgery

摘要

Gamma Knife surgery (GKS) is a minimally invasive treatment for brain diseases, and is currently used for functional disorders. Moreover, a revised version of Gamma Knife system, ‘Model C-APS (automatic positioning system)’ started to be installed in Japan since 2001. This latest model enables us to adjust coordinates by every 0.1 mm, and treat the patient automatically. We have completed a retrospective study of 222 patients suffering from essential trigeminal neuralgia treated with GKS in which the target was localized at the retro-gasserian portion of the nerve (We have treated 179 patients with essential trigeminal neuralgia by ‘Model C-APS’). Among the patients, 147 were followed up more than 12 months, and we evaluated a cause-and-effect relationship between the technical development and the clinical results. We categorized patients into three groups based on the term mentioned as follows: first are the patients treated by Model B without completed fusion images in between 1999 and 2001, second are the patients treated by Model B with completed fusion images in 2002, and third are those treated by model C-APS with completed fusion images since 2003. Clinical result, initial pain free was observed in 62.9% (first group), 85.7% (second group), 98.1% (third group), complete recurrence was observed in 12, 8.3, 1.9% for each groups, and postoperative complication was observed in 22.2, 28.6, and 23.6% respectively. We believe that precise dose planning, so-called ‘Robotized Micro Radiosurgery’, is the key to have a successful GKS.