title: Outcome of gamma knife thalamotomy in patients with an intractable tremor.
abstract: OBJECTIVE
  Tremor is a common movement disorder that interferes with daily living. Since the medication for tremor has some limitations, surgical intervention is needed in many patients. In certain patients who cannot undergo aggressive surgical intervention, Gamma Knife thalamotomy (GKT) is a safe and effective alternative.
  
  
  METHODS
  From June 2012 to August 2013, 7 patients with an intractable tremor underwent GKT. Four of these 7 patients had medical comorbidities, and 3 patients refused to undergo traditional surgery. Each patient was evaluated with the modified Fahn-Tolosa-Marin tremor rating scale (TRS) along with analysis of handwriting samples. All of the patients underwent GKT with a maximal dose of 130 Gy to the left ventralis intermedius (VIM) nucleus of the thalamus. Follow-up brain MRI was performed after 3 to 8 months of GKT, and evaluation with the TRS was also performed.
  
  
  RESULTS
  Six patients showed objective improvement in the TRS score. Excluding one patient who demonstrated tremor progression, there was 28.9% improvement in the TRS score. However, five patients showed subjective improvement in their symptoms. On comparing the TRS scores between follow-up periods of more and less than 4 months, the follow-up TRS score at more than 4 months of GKT was significantly improved compared to that at less than 4 months of GKT. Follow-up MRI showed radiosurgical changes in 5 patients.
  
  
  CONCLUSIONS
  GKT with a maximal dose of 130 Gy to the VIM is a safe procedure that can replace other surgical procedures.
authors: Department of Neurosurgery, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors: Kyung Rae
authors: KR
authors: Cho
authors: Department of Neurosurgery, Konyang University Hospital, College of Medicine, Konyang University, Daejeon, Korea.
authors: Hong Rye
authors: HR
authors: Kim
authors: Department of Neurosurgery, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors: Yong Seok
authors: YS
authors: Im
authors: Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors: Jinyoung
authors: J
authors: Youn
authors: Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors: Jin Whan
authors: JW
authors: Cho
authors: Department of Neurosurgery, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors: Jung-Il
authors: JI
authors: Lee
keywords: Gamma Knife; Thalamotomy; Tremor; Ventralis intermedius