title: Kirschner wire placement in scaphoid bones using intraoperative CT-guided stereotaxy.
abstract: BACKGROUND
  Minimally invasive ostesynthesis of scaphoid fractures may reduce the risk of fracture non-union and shorten the duration of illness. The aim of this study was to analyze the technical feasibility and targeting accuracy of computed tomography (CT) - guided stereotactic Kirschner (K)-wire positioning in the scaphoid.
  
  
  METHODS
  Nineteen Formalin preserved cadaveric upper extremities (10 right, 9 left) were fixed in 90 degree dorsal extension for percutaneous access from palmar. An ideal central position of the K-wire was planned on the computer adapted from intraoperative CT data. A 3D navigation system and stereotactic targeting device were used for K-wire placement. Target positioning errors were evaluated by fusion of the control CT with the K-wire in place with the planning CT.
  
  
  RESULTS
  The procedure allowed for an easy and rigid wrist fixation. K-wire placement showed mean ± SD lateral targeting errors of 0.9 ± 0.5 mm at the scaphoid bone entry and 1.2 ± 0.7 mm at the K-wire tip. The mean angular error was 1.3° ± 1.1° . Total duration of the intervention ranged between 19 and 23 min.
  
  
  CONCLUSIONS
  CT-guided stereotactic K-wire placement in scaphoid bones is highly accurate. The technique may guide minimally invasive screw-osteosynthesis of scaphoid fractures.
authors.affiliation: Section of Microinvasive Therapy, Department of Radiology, Innsbruck Medical University, Innsbruck, Austria.
authors.forename: Christian
authors.initials: C
authors.lastname: Niederwanger
authors.forename: Gerlig
authors.initials: G
authors.lastname: Widmann
authors.forename: Martin
authors.initials: M
authors.lastname: Knoflach
authors.forename: Peter
authors.initials: P
authors.lastname: Schullian
authors.forename: Romed
authors.initials: R
authors.lastname: Hoermann
authors.forename: Reto
authors.initials: R
authors.lastname: Bale
mesh_terms: D001864:Bone Wires; D002102:Cadaver; D005240:Feasibility Studies; D005593:Fracture Fixation, Internal / Q000379:methods*; D050723:Fractures, Bone / Q000601:surgery; D006801:Humans; D021621:Imaging, Three-Dimensional; D019060:Minimally Invasive Surgical Procedures / Q000379:methods*; D021361:Scaphoid Bone / Q000293:injuries / Q000601:surgery*; D013238:Stereotaxic Techniques; D025321:Surgery, Computer-Assisted; D014057:Tomography, X-Ray Computed; D014954:Wrist Injuries / Q000601:surgery