title: Linear bearing device as a solution for optical navigation of fine needle procedures.
abstract: BACKGROUND
  Optical navigation of needles < 1 mm diameter remains a challenging task. Bending of these tools is the limiting factor.
  
  
  OBJECTIVE
  To use a conventional optical navigation system for interventional fine needle procedures.
  
  
  METHODS
  A novel custom-made device was constructed to guide the needle in the direction of the planned trajectory. Accuracy of this device was analyzed with two setups (A = ballistic gelatin; B = used pork meat). For both setups, a Plexiglas cube with integrated Plexiglas reference arrays was used. Metal targets of 1 mm diameter were placed in the center. Images were acquired using a 3D fluoroscope connected to a conventional optical navigation system. After trajectory planning, ten navigated injections were performed freehand and with the linear bearing device for each setup. A 3D scan was performed to measure the distance between contrast medium and metal target after each injection.
  
  
  RESULTS
  Freehand navigation with a needle of 0.9 mm in diameter was not accurate with either setup (Setup A: mean 33.4 mm; range, 3-63 mm; Setup B: mean 40.1 mm; range, 12-75 mm). Linear bearing navigation was significant more precisely (Setup A: mean 0.7 mm; range, 0-0.75 mm; Setup B: mean 0.29 mm, range 0-1.3 mm) than freehand navigation.
  
  
  CONCLUSIONS
  The linear bearing device reduced all bending. Optical fine needle navigation was accomplished with precision comparable to electromagnetic navigation. This device may provide useful for minimally-invasive clinical applications. Follow-up studies should compare electromagnetic and optical navigation systems in the same setup.
authors.affiliation: Trauma Department, Hannover Medical School, Hannover, Germany. Stueber.Volker@mhhannover.de
authors.forename: Volker
authors.initials: V
authors.lastname: Stüber
authors.forename: Eduardo M
authors.initials: EM
authors.lastname: Suero
authors.forename: Tobias
authors.initials: T
authors.lastname: H U Fner
authors.forename: Martin
authors.initials: M
authors.lastname: Wiewiorski
authors.forename: Christian
authors.initials: C
authors.lastname: Krettek
authors.forename: Musa
authors.initials: M
authors.lastname: Citak
mesh_terms: D005471:Fluoroscopy; D006801:Humans; D009339:Needles; D025321:Surgery, Computer-Assisted / Q000295:instrumentation* / Q000379:methods; D014057:Tomography, X-Ray Computed