title: Malposition and revision rates of different imaging modalities for percutaneous iliosacral screw fixation following pelvic fractures: a systematic review and meta-analysis.
abstract: BACKGROUND
  Percutaneous iliosacral screw placement following pelvic trauma is associated with high rates of revisions, screw malpositioning, the risk of neurological damage and inefficient stability. The correct entry point and the small target corridor may be difficult to visualize using only an image intensifier. Therefore, 2D and 3D image-based navigation and reconstruction techniques could be helpful tools. The aim of this systematic review and meta-analysis was to evaluate the best available evidence regarding the rate of malpositioning and revisions using different techniques for screw implantation, i.e., conventional, 2D and 3D image-based navigation and reconstruction techniques, CT navigation.
  
  
  METHODS
  A systematic review and meta-analysis were performed using the data available on Ovid Medline. 430 studies published between 1/1948 and 2/2011 were identified by two independent investigators. Inclusion criteria were percutaneous iliosacral screw fixation after traumatic pelvic fractures with included revision rate or positioning of the screw, language of the article English or German. Exclusion criteria were osteoporotic fracture, tumor, reviews, epidemiological studies, biomechanical/cadaveric studies, studies about operative technique. For statistical analysis the random effect model was used.
  
  
  RESULTS
  A total of 51 studies fulfilled the inclusion requirements describing 2,353 percutaneous screw implantations following pelvic trauma in 1,731 patients. The estimated rate of malposition was 0.1 % for 262 screws using CT navigation. This rate was significantly lower (p < 0.0001) than for the conventional technique with malposition rate of 2.6 % (total 1,832 screws). Using 2D and 3D image-based navigation and reconstruction techniques, the malposition rate was 1.3 % (total 445 screws). No significance was observed between the conventional and the 2D and 3D image-based navigation and reconstruction techniques. The rates of revision were not statistically significant with 2.7 % (1,832 implantations) in the conventional group, 1.3 % (445 implantations) in the group of 2D and 3D image-based navigation and reconstruction techniques and 0.8 % (262 implantations) using the CT navigation.
  
  
  CONCLUSIONS
  CT navigation has the lowest rate of screw malposition, but on the other hand it could not be used for all type of fractures where surgical procedures (reduction maneuvers, additional osteosynthetic procedures) are necessary. The 2D and 3D image-based navigation and reconstruction techniques provide encouraging results with slightly lower rate of complications compared to the conventional technique and are additional tools to enhance the precision and decrease the rate of revision.
authors.affiliation: Department of Orthopaedic and Trauma Surgery, University of Freiburg Medical Center, Hugstetter Straße 55, Freiburg, Germany. joern.zwingmann@uniklinik-freiburg.de
authors.forename: Jörn
authors.initials: J
authors.lastname: Zwingmann
authors.forename: Oliver
authors.initials: O
authors.lastname: Hauschild
authors.forename: Gerrit
authors.initials: G
authors.lastname: Bode
authors.forename: Norbert P
authors.initials: NP
authors.lastname: Südkamp
authors.forename: Hagen
authors.initials: H
authors.lastname: Schmal
mesh_terms: D017760:Bone Malalignment / Q000453:epidemiology*; D001863:Bone Screws; D003952:Diagnostic Imaging; D050723:Fractures, Bone / Q000175:diagnosis* / Q000601:surgery*; D006801:Humans; D007085:Ilium / Q000601:surgery; D007091:Image Processing, Computer-Assisted; D016268:Internal Fixators; D010384:Pelvic Bones / Q000293:injuries*; D011183:Postoperative Complications / Q000453:epidemiology*; D012086:Reoperation / Q000706:statistics & numerical data; D012447:Sacrum / Q000601:surgery