title: A novel electromagnetic navigation tool for acetabular surgery.
abstract: BACKGROUND
  Acetabular fracture surgery is demanding and screw placement along narrow bony corridors remains challenging. It necessitates x-ray radiation for fluoroscopically assisted screw insertion. The purpose of this cadaver study was to evaluate the feasibility, accuracy and operation time of a novel electromagnetic navigation system for screw insertion along predefined acetabular corridors.
  
  
  METHODS
  A controlled laboratory study with a total of 24 electromagnetically navigated screw insertions was performed on 8 cadaveric acetabula. 3 peri-acetabular bony corridors (QSS, Quadrilateral Surface Screw; IAS, Infra-Acetabular Screw; PCS, Posterior Column Screw) were defined and screws were placed in a defined order without fluoroscopy. Operation time was documented. Postoperative CT scans were performed to analyse accuracy of screw placement.
  
  
  RESULTS
  Mean cadaver age was 70.4 ± 11.7. Successful screw placement was accomplished in 22 out of 24 (91.7%) cases. The overall mean time for all 3 acetabular screws was 576.6 ± 75.9s. All 3 complications occurred during the placement of the IAS due to an impassable narrow bony corridor. QSS mean length was 50 ± 5mm, IAS mean length was 85 ± 10mm and PCS mean length was 120 ± 5mm.
  
  
  CONCLUSIONS
  In this cadaver study the novel electromagnetic navigation system was feasible to allow accurate screw placement without fluoroscopy in defined narrow peri-acetabular bony corridors.
authors.affiliation: Department of Trauma, Hand and Reconstructive Surgery, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246 Hamburg, Germany. Electronic address: wlehmann@uke.uni-hamburg.de.
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Lehmann
authors.affiliation: Department of Trauma, Hand and Reconstructive Surgery, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246 Hamburg, Germany.
authors.forename: Johannes M
authors.initials: JM
authors.lastname: Rueger
authors.affiliation: Department of Trauma, Hand and Reconstructive Surgery, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246 Hamburg, Germany.
authors.forename: Jakob
authors.initials: J
authors.lastname: Nuechtern
authors.affiliation: Department of Trauma, Hand and Reconstructive Surgery, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246 Hamburg, Germany.
authors.forename: Lars
authors.initials: L
authors.lastname: Grossterlinden
authors.affiliation: Institute of Forensic Medicine, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246 Hamburg, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Kammal
authors.affiliation: Department of Trauma, Hand and Reconstructive Surgery, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246 Hamburg, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Hoffmann
mesh_terms: D000077:Acetabulum / Q000033:anatomy & histology / Q000000981:diagnostic imaging* / Q000601:surgery; D001863:Bone Screws; D002102:Cadaver; D060733:Electromagnetic Radiation; D005240:Feasibility Studies; D005471:Fluoroscopy; D005593:Fracture Fixation, Internal / Q000295:instrumentation*; D050723:Fractures, Bone / Q000000981:diagnostic imaging* / Q000601:surgery; D006801:Humans; D015203:Reproducibility of Results; D025321:Surgery, Computer-Assisted; D014057:Tomography, X-Ray Computed
keywords: Acetabulum; Electromagnetic; Navigation; Pelvis Fractures; Screw-Osteosynthesis