title: 2D versus 3D fluoroscopy-based navigation in posterior pelvic fixation: review of the literature on current technology.
abstract: OBJECTIVE
  Percutaneous sacroiliac (SI) fixation of unstable posterior pelvic ring injuries is a widely accepted procedure. The complex sacral anatomy with narrow osseous corridors for SI screw placement makes this procedure technically challenging. Techniques are constantly evolving as a result of better understanding of the posterior pelvic anatomy. Recently developed tools include fluoroscopy-based computer-assisted navigation, which can be two-dimensional (2D) or three-dimensional (3D). Our goal is to determine the relevant technical considerations and clinical outcomes associated with these modalities by reviewing the published research. We hypothesize that 3D fluoroscopy-based navigation is safer and superior to its 2D predecessor with respect to lower radiation dose and more accurate SI screw placement.
  
  
  METHODS
  We searched four medical databases to identify English-language studies of 2D and 3D fluoroscopy-based navigation from January 1990 through August 2015. We included articles reporting imaging techniques and outcomes of closed posterior pelvic ring fixation with percutaneous SI screw fixation. Injuries included in the study were sacral fractures (52 patients), sacroiliac fractures (88 patients), lateral compression fractures (20 patients), and anteroposterior compression type pelvic fractures (8 patients). We excluded articles on open reduction of posterior pelvic ring injuries and solely anatomic studies. We then reviewed these studies for technical considerations and outcomes associated with these technologies.
  
  
  RESULTS
  Six studies were included in our analysis. Results of these studies indicate that 3D fluoroscopy-based navigation is associated with a lower radiation dose and lower rate of screw malpositioning compared with 2D fluoroscopy-based systems.
  
  
  CONCLUSIONS
  It may be advantageous to combine modern imaging modalities such as 3D fluoroscopy with computer-assisted navigation for percutaneous screw fixation in the posterior pelvis.
authors: Department of Orthopaedic Surgery, The Johns Hopkins Hospital, Baltimore, MD, 21231, USA.
authors: Savyasachi C
authors: SC
authors: Thakkar
authors: Department of Orthopaedic Surgery, The Johns Hopkins Hospital, Baltimore, MD, 21231, USA.
authors: Rashmi S
authors: RS
authors: Thakkar
authors: Department of Orthopaedic Surgery, The Johns Hopkins Hospital, Baltimore, MD, 21231, USA.
authors: Norachart
authors: N
authors: Sirisreetreerux
authors: Department of Radiology and Imaging, Hospital for Special Surgery, New York, NY, 10021, USA.
authors: John A
authors: JA
authors: Carrino
authors: Department of Orthopaedic Surgery, The Johns Hopkins Hospital, Baltimore, MD, 21231, USA.
authors: Babar
authors: B
authors: Shafiq
authors: Department of Orthopaedic Surgery, The Johns Hopkins Hospital, Baltimore, MD, 21231, USA. ehasenb1@jhmi.edu.|Department of Orthopaedic Surgery, The Johns Hopkins Bayview Medical Center, 4940 Eastern Avenue, Baltimore, MD, 21224-2780, USA. ehasenb1@jhmi.edu.
authors: Erik A
authors: EA
authors: Hasenboehler
mesh_terms: D001863:Bone Screws; D005471:Fluoroscopy / Q000379:methods*; D005593:Fracture Fixation, Internal / Q000379:methods*; D050723:Fractures, Bone / Q000000981:diagnostic imaging / Q000601:surgery*; D050815:Fractures, Compression / Q000000981:diagnostic imaging / Q000601:surgery*; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods*; D010384:Pelvic Bones / Q000000981:diagnostic imaging / Q000293:injuries / Q000601:surgery*; D012447:Sacrum / Q000000981:diagnostic imaging / Q000293:injuries / Q000601:surgery*; D016103:Spinal Fractures / Q000000981:diagnostic imaging / Q000601:surgery*; D025321:Surgery, Computer-Assisted / Q000379:methods
keywords: 2D fluoroscopy-based navigation; 3D fluoroscopy-based navigation; Computed tomography; Pelvic ring injuries; Sacroiliac screw fixation