title: A role of diffusion tensor imaging fiber tracking in deep brain stimulation surgery: DBS of the dentato-rubro-thalamic tract (drt) for the treatment of therapy-refractory tremor.
abstract: BACKGROUND
  Deep brain stimulation (DBS) can alleviate tremor of various origins. A number of regions are targeted. In recent work our group was able to show the involvement of the dentato-rubro-thalamic tract (drt) in tremor control with fiber tracking techniques. Here we report for the first time the successful use of magnetic resonance tractography in combination with traditional landmark-based targeting techniques to perform the implantation of a bilateral DBS system in a patient with dystonic head tremor.
  
  
  METHODS
  We report on a 37-year-old female with long-standing pure head tremor from myoclonus dystonia. She was identified as a candidate for thalamic DBS. The use of head fixation in a stereotactic frame would blur target symptoms (head tremor) during surgery and was therefore avoided. Her dentate-rubro-thalamic tracts were visualized with preoperative diffusion tensor imaging (DTI) and tractography, and then directly targeted stereotactically with DBS electrodes.
  
  
  RESULTS
  Three months after implantation, tremor control was excellent (>90%). A close evaluation of the active electrode contact positions revealed clear involvement of the drt.
  
  
  CONCLUSIONS
  This is the first time that direct visualization of fiber tracts has been employed for direct targeting and successful movement disorder tremor surgery. In the reported case, additional knowledge about the position of the drt, which previously has been shown to be a structure for modulation to achieve tremor control, led to a successful implantation of a DBS system, although there was a lack of intra-operatively testable tremor symptoms. In concordance with studies in optogenetic neuromodulation, fiber tracts are the emerging target structures for DBS. The routine integration of DTI tractography into surgical planning might be a leading path into the future of DBS surgery and will add to our understanding of the pathophysiology of movement disorders. Larger study populations will have to prove these concepts in future research.
authors.affiliation: Division of Stereotaxy and MR-based Operative Techniques/Department of Neurosurgery, University of Bonn, Sigmund Freud Straße 25, 53105 Bonn, Germany. volker.coenen@ukb.uni-bonn.de
authors.forename: Volker A
authors.initials: VA
authors.lastname: Coenen
authors.forename: Niels
authors.initials: N
authors.lastname: Allert
authors.forename: Burkhard
authors.initials: B
authors.lastname: Mädler
mesh_terms: D000328:Adult; D002529:Cerebellar Nuclei / Q000503:physiopathology / Q000601:surgery*; D046690:Deep Brain Stimulation / Q000379:methods*; D056324:Diffusion Tensor Imaging / Q000379:methods*; D004525:Efferent Pathways / Q000502:physiology / Q000601:surgery; D005116:Extrapyramidal Tracts / Q000503:physiopathology / Q000601:surgery; D005260:Female; D006801:Humans; D038361:Neuronavigation / Q000379:methods; D013787:Thalamic Nuclei / Q000503:physiopathology / Q000601:surgery*; D016896:Treatment Outcome; D014202:Tremor / Q000503:physiopathology / Q000601:surgery*