title: An evaluation of image-guided technologies in the placement of percutaneous iliosacral screws.
abstract: METHODS
  A surgical simulation study in human cadaver spine specimens was conducted to evaluate the accuracy of 3 different surgical navigation systems compared to standard fluoroscopy in the percutaneous placement of iliosacral screws.
  
  
  OBJECTIVE
  To compare the accuracy of percutaneous iliosacral screw placement using standard fluoroscopy, computer-assisted fluoroscopic image guidance, Iso-C3D image guidance (Medtronic Surgical Navigation Technologies, Louisville, CO), and electromagnetic fluoroscopic image guidance.
  
  
  BACKGROUND
  Conventional percutaneous sacroiliac screw placement has a malposition rate as high as 15%, as reported in the English-speaking literature (Hinsche et al [Clin Orthop Relat Res 2002;395:135-44] and Templeman et al [Clin Orthop Relat Res 1996;329:194-8]). Iso-C3D and computer-assisted image guidance technologies have been proposed to increase this accuracy rate.
  
  
  METHODS
  Two iliosacral screws were placed bilaterally (4 screws) in each of 4 cadavers using standard fluoroscopy, computer-assisted fluoroscopic image guidance, Iso-C3D image guidance, and electromagnetic fluoroscopic image guidance. Screw positions were analyzed by computerized tomography after instrumentation and assigned a score based on deviation from ideal screw position.
  
  
  RESULTS
  The StealthStation with FluoroNav (Medtronic Surgical Navigation Technologies) appeared to provide the highest accuracy of all guidance techniques. This result was more accurate than standard fluoroscopy.
  
  
  CONCLUSIONS
  Computer-assisted fluoroscopy based image navigation appears to be more accurate than standard fluoroscopy in placing these screws. However, errors may occur with all techniques. Further refinement in registration procedures may highly improve the accuracy of percutaneous screw placement in a variety of spinopelvic procedures.
authors.affiliation: Department of Orthopaedic Surgery, Thomas Jefferson University, Philadelphia, PA 19107, USA.
authors.forename: Harvey E
authors.initials: HE
authors.lastname: Smith
authors.forename: Philip S
authors.initials: PS
authors.lastname: Yuan
authors.forename: Rick
authors.initials: R
authors.lastname: Sasso
authors.forename: Steven
authors.initials: S
authors.lastname: Papadopolous
authors.forename: Alexander R
authors.initials: AR
authors.lastname: Vaccaro
mesh_terms: D000368:Aged; D001863:Bone Screws; D017587:Diskectomy, Percutaneous / Q000295:instrumentation / Q000379:methods / Q000592:standards; D005471:Fluoroscopy / Q000295:instrumentation / Q000379:methods / Q000592:standards; D006801:Humans; D007085:Ilium / Q000000981:diagnostic imaging* / Q000601:surgery; D008875:Middle Aged; D012447:Sacrum / Q000000981:diagnostic imaging* / Q000601:surgery; D025321:Surgery, Computer-Assisted / Q000295:instrumentation / Q000379:methods / Q000592:standards*; D014057:Tomography, X-Ray Computed / Q000379:methods