title: Evaluation of 2D and 3D navigation for iliosacral screw fixation.
abstract: OBJECTIVE
  Image guidance is essential in some orthopedic surgical procedures, especially iliosacral screw fixation. Currently, there is no consensus regarding the best image guidance technique. An ex-vivo study was performed to compare conventional, 2-dimensional (2D), and 3D imaging techniques and determine the optimal image guidance technique for pelvic surgery.
  
  
  METHODS
  Plastic (n = 9) and donated cadaver pelvises (n = 8) were evaluated in the laboratory. The pelvises were positioned on radiolucent operation tables in a prone position. Transiliosacral screws were inserted without or with 2D- and 3D-navigational support. A digital mobile X-ray unit with flat-panel fluoroscopy and navigation software was used to measure precision, radiation exposure, and time requirements.
  
  
  RESULTS
  2D-navigation resulted in 40% incorrect screw positioning for the cadavers, 6% for the plastic phantoms, and 21% overall. The highest accuracy was accomplished with 3D-navigation (plastic: 100%; cadavers: 83%; p < 0.05). The dose-area product showed that both 2D- and 3D-navigation required increased exposure compared to the conventional technique (p < 0.01). For both plastic and cadaver specimens, navigated techniques required significantly longer times for screw insertion than the conventional technique (p < 0.01).
  
  
  CONCLUSIONS
  3D image guidance for transiliosacral screw fixation enabled more accurate screw placement in S1 and S2 vertebrae. However, radiation exposure in 3D-navigation was excessive; thus, we recommend avoiding 3D-navigation in young patients. A primary advantage of 3D-navigation was that the operating team could leave the room during the scan; thus, it reduced their radiation exposure. Moreover, the time required for screw insertion with 3D-navigation was similar to that required in the conventional technique; thus, 3D-navigation is recommended for older patients.
authors.affiliation: Department of Trauma, Reconstructive and Plastic Surgery, University of Leipzig, Liebigstrasse 20, 04103, Leipzig, Germany. daniel.behrendt@medizin.uni-leipzig.de
authors.forename: Daniel
authors.initials: D
authors.lastname: Behrendt
authors.forename: Maria
authors.initials: M
authors.lastname: Mütze
authors.forename: Hanno
authors.initials: H
authors.lastname: Steinke
authors.forename: Martin
authors.initials: M
authors.lastname: Koestler
authors.forename: Christoph
authors.initials: C
authors.lastname: Josten
authors.forename: Jörg
authors.initials: J
authors.lastname: Böhme
mesh_terms: D000368:Aged; D001863:Bone Screws; D002102:Cadaver; D003936:Diagnosis, Computer-Assisted / Q000379:methods; D005471:Fluoroscopy; D005593:Fracture Fixation, Internal / Q000295:instrumentation* / Q000379:methods; D050723:Fractures, Bone / Q000000981:diagnostic imaging* / Q000601:surgery; D006801:Humans; D007085:Ilium / Q000000981:diagnostic imaging* / Q000293:injuries / Q000601:surgery; D007090:Image Interpretation, Computer-Assisted; D021621:Imaging, Three-Dimensional; D008875:Middle Aged; D008953:Models, Anatomic; D010384:Pelvic Bones / Q000293:injuries / Q000601:surgery; D019047:Phantoms, Imaging; D011786:Quality Control; D012447:Sacrum / Q000000981:diagnostic imaging* / Q000293:injuries / Q000601:surgery; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods