title: Deep Brain Stimulation of the Dentato-Rubro-Thalamic Tract: Outcomes of Direct Targeting for Tremor.
abstract: OBJECTIVE
  Targeting the dentato-rubro-thalamic tract (DRTt) has been suggested to be efficacious in deep brain stimulation (DBS) for tremor suppression, both in case reports and post-hoc analyses. This prospective observational study sought to analyze outcomes after directly targeting the DRTt in tremor patients.
  
  
  METHODS
  20 consecutively enrolled intention tremor patients obtained pre-operative MRI with diffusion tensor (dTi) sequences. Mean baseline tremor amplitude based on The Essential Tremor Rating Assessment Scale was recorded. The DRTt was drawn for each individual on StealthViz software (Medtronic) using the dentate nucleus as the seed region and the ipsilateral pre-central gyrus as the end region and then directly targeted during surgery. Intraoperative testing confirmed successful tremor control. Post-operative analysis of electrode position relative to the DRTt was performed, as was post-operative assessment of tremor improvement.
  
  
  RESULTS
  The mean age of patients was 66.8 years; mean duration of tremor was 16 years. Mean voltage for the L electrode = 3.4 V; R = 2.6 V. Mean distance from the center of the active electrode contact to the DRTt was 0.9 mm on the L, and 0.8 mm on the R. Improvement in arm tremor amplitude from baseline after DBS was significant (P < 0.001).
  
  
  CONCLUSIONS
  Direct targeting of the DRTt in DBS is an effective strategy for tremor suppression. Accounting for hardware, software, and model limitations, depiction of the DRTt allows for placement of electrode contacts directly within the fiber tract for modulation despite any anatomical variation, which reproducibly resulted in good tremor control.
authors.affiliation: Department of Neurosurgery, Mischer Neuroscience Institute, McGovern Medical School, University of Texas - Houston Health Science Center, Houston, TX, USA.
authors.forename: Albert J
authors.initials: AJ
authors.lastname: Fenoy
authors.affiliation: Department of Neurology, Movement Disorders and Neurodegenerative Disease Program, McGovern Medical School, University of Texas - Houston Health Science Center, Houston, TX, USA.
authors.forename: Mya C
authors.initials: MC
authors.lastname: Schiess
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002529:Cerebellar Nuclei / Q000000981:diagnostic imaging* / Q000601:surgery; D046690:Deep Brain Stimulation / Q000379:methods*; D056324:Diffusion Tensor Imaging / Q000379:methods; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009434:Neural Pathways / Q000000981:diagnostic imaging / Q000601:surgery; D011446:Prospective Studies; D012012:Red Nucleus / Q000000981:diagnostic imaging* / Q000601:surgery; D013788:Thalamus / Q000000981:diagnostic imaging* / Q000601:surgery; D016896:Treatment Outcome; D014202:Tremor / Q000000981:diagnostic imaging* / Q000601:surgery
keywords: Dentato-rubro-thalamic tract; dTi; deep brain stimulation; essential tremor; tractography