title: Target and trajectory clinical application accuracy in neuronavigation.
abstract: BACKGROUND
  Catheter, needle, and electrode misplacement in navigated neurosurgery can result in ineffective treatment and severe complications.
  
  
  OBJECTIVE
  To assess the Ommaya ventricular catheter localization accuracy both along the planned trajectory and at the target.
  
  
  METHODS
  We measured the localization error along the ventricular catheter and on its tip for 15 consecutive patients who underwent insertion of the Ommaya catheter surgery with a commercial neuronavigation system. The preoperative computed tomography/magnetic resonance images and the planned trajectory were aligned with the postoperative computed tomography images showing the Ommaya catheter. The localization errors along the trajectory and at the target were then computed by comparing the preoperative planned trajectory with the actual postoperative catheter position. The measured localization errors were also compared with the error reported by the navigation system.
  
  
  RESULTS
  The mean localization errors at the target and entry point locations were 5.9 ± 4.3 and 3.3 ± 1.9 mm, respectively. The mean shift and angle between planned and actual trajectories were 1.6 ± 1.9 mm and 3.9 ± 4.7°, respectively. The mean difference between the localization error at the target and entry point was 3.9 ± 3.7 mm. The mean difference between the target localization error and the reported navigation system error was 4.9 ± 4.8 mm.
  
  
  CONCLUSIONS
  The catheter localization errors have significant variations at the target and along the insertion trajectory. Trajectory errors may differ significantly from the errors at the target. Moreover, the single registration error number reported by the navigation system does not appropriately reflect the trajectory and target errors and thus should be used with caution to assess the procedure risk.
authors.affiliation: School of Engineering and Computer Science, The Hebrew University, Jerusalem, Israel.
authors.forename: Reuben R
authors.initials: RR
authors.lastname: Shamir
authors.forename: Leo
authors.initials: L
authors.lastname: Joskowicz
authors.forename: Sergey
authors.initials: S
authors.lastname: Spektor
authors.forename: Yigal
authors.initials: Y
authors.lastname: Shoshan
mesh_terms: D057785:Catheters; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D038361:Neuronavigation / Q000379:methods*; D019635:Neurosurgical Procedures / Q000379:methods*; D012189:Retrospective Studies; D025321:Surgery, Computer-Assisted / Q000379:methods; D014057:Tomography, X-Ray Computed / Q000379:methods