title: Three-dimensional rotational X-ray navigation for needle guidance in percutaneous vertebroplasty: an accuracy study.
abstract: METHODS
  The position of a needle tip displayed on a navigation system after transpedicular introduction into a vertebral body is compared with the real position of the needle tip when using a direct navigation coupling between a three-dimensional rotational X-ray (3DRX) system and a navigation system.
  
  
  OBJECTIVE
  To assess whether the needle tip position displayed by the navigation system corresponds to the real needle position and to quantitatively determine needle navigation accuracy in a clinically relevant setting.
  
  
  BACKGROUND
  Image-guided navigation has reportedly increased the accuracy and safety of pedicle screw insertion and decreased complication rates. In former studies, the result of image-guided navigation was mainly compared qualitatively with the result of conventional fluoroscopy-guided procedures. Previously, a direct navigation coupling between a 3DRX system and a standard navigation system was introduced that bypasses the need for explicit patient-to-image registration necessary for image-guided orthopedic surgery. In a phantom experiment, the reported accuracy of navigation with the coupling to a 3DRX system was approximately 1 mm. However, in a clinical setting, additional errors can be introduced.
  
  
  METHODS
  Twenty-three needles were placed transpedicularly into vertebral bodies of embalmed human trunks using 3DRX-guided navigation. The navigated needle tip positions were compared with the real needle tip positions manually extracted from 3DRX volumes acquired after completion of the introduction.
  
  
  RESULTS
  The average distance between the navigated needle tip and the real position of the needle tip extracted from a postprocedure 3DRX volume was 2.5 +/- 1.5 mm.
  
  
  CONCLUSIONS
  Accuracy of 3DRX-guided navigation is 2.5 +/- 1.5 mm in a clinically relevant setting, which is less than the accuracy determined in phantom experiments.
authors.affiliation: Image Sciences Institute, University Medical Center, Utrecht, The Netherlands. everine@isi.uu.nl
authors.forename: Everine B
authors.initials: EB
authors.lastname: van de Kraats
authors.forename: Theo
authors.initials: T
authors.lastname: van Walsum
authors.forename: Jorrit-Jan
authors.initials: JJ
authors.lastname: Verlaan
authors.forename: Maurits H J
authors.initials: MH
authors.lastname: Voormolen
authors.forename: Willem P Th M
authors.initials: WP
authors.lastname: Mali
authors.forename: Wiro J
authors.initials: WJ
authors.lastname: Niessen
mesh_terms: D000369:Aged, 80 and over; D001707:Biopsy, Needle / Q000295:instrumentation / Q000379:methods*; D002102:Cadaver; D004867:Equipment Design; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional; D008297:Male; D011859:Radiography; D012399:Rotation; D013131:Spine / Q000000981:diagnostic imaging* / Q000473:pathology*; D025321:Surgery, Computer-Assisted / Q000592:standards*