title: Approach to intraoperative electromagnetic navigation in orthognathic surgery: A phantom skull based trial.
abstract: BACKGROUND
  Intraoperative guidance using electromagnetic navigation is an upcoming method in maxillofacial surgery. However, due to their unwieldy structures, especially the line-of-sight problem, optical navigation devices are not used for daily orthognathic surgery. Therefore, orthognathic surgery was simulated on study phantom skulls, evaluating the accuracy and handling of a new electromagnetic tracking system.
  
  
  METHODS
  Le-Fort I osteotomies were performed on 10 plastic skulls. Orthognathic surgical planning was done in the conventional way using plaster models. Accuracy of the gold standard, splint-based model surgery versus an electromagnetic tracking system was evaluated by measuring the actual maxillary deviation using bimaxillary splints and preoperative and postoperative cone beam computer tomography imaging. The distance of five anatomical marker points were compared pre- and postoperatively.
  
  
  RESULTS
  The electromagnetic tracking system was significantly more accurate in all measured parameters compared with the gold standard using bimaxillary splints (p < 0.01). The data shows a discrepancy between the model surgical plans and the actual correction of the upper jaw of 0.8 mm. Using the electromagnetic tracking, we could reduce the discrepancy of the maxillary transposition between the planned and actual orthognathic surgery to 0.3 mm on average.
  
  
  CONCLUSIONS
  The data of this preliminary study shows a high level of accuracy in surgical orthognathic performance using electromagnetic navigation, and may offer greater precision than the conventional plaster model surgery with bimaxillary splints.
  
  
  CONCLUSIONS
  This preliminary work shows great potential for the establishment of an intraoperative electromagnetic navigation system for maxillofacial surgery.
authors.affiliation: Department of Oral and Maxillofacial Surgery, University Hospital Heidelberg, Germany. Electronic address: moritz.berger@med.uni-heidelberg.de.
authors.forename: Moritz
authors.initials: M
authors.lastname: Berger
authors.affiliation: Institute of Medical Biometry and Informatics, University Hospital Heidelberg, Germany.
authors.forename: Sebastian
authors.initials: S
authors.lastname: Kallus
authors.affiliation: Institute of Medical Biometry and Informatics, University Hospital Heidelberg, Germany.
authors.forename: Igor
authors.initials: I
authors.lastname: Nova
authors.affiliation: Department of Oral and Maxillofacial Surgery, University Hospital Heidelberg, Germany.
authors.forename: Oliver
authors.initials: O
authors.lastname: Ristow
authors.affiliation: Institute of Medical Biometry and Informatics, University Hospital Heidelberg, Germany.
authors.forename: Urs
authors.initials: U
authors.lastname: Eisenmann
authors.affiliation: Institute of Medical Biometry and Informatics, University Hospital Heidelberg, Germany.
authors.forename: Hartmut
authors.initials: H
authors.lastname: Dickhaus
authors.affiliation: Department of Oral and Maxillofacial Surgery, University Hospital Heidelberg, Germany.
authors.forename: Reinald
authors.initials: R
authors.lastname: Kuhle
authors.affiliation: Department of Oral and Maxillofacial Surgery, University Hospital Heidelberg, Germany.
authors.forename: Jürgen
authors.initials: J
authors.lastname: Hoffmann
authors.affiliation: Department of Oral and Maxillofacial Surgery, University Hospital Heidelberg, Germany.
authors.forename: Robin
authors.initials: R
authors.lastname: Seeberger
mesh_terms: D055590:Electromagnetic Phenomena; D006801:Humans; D007432:Intraoperative Period; D008437:Maxilla / Q000601:surgery*; D008953:Models, Anatomic; D056948:Orthognathic Surgical Procedures / Q000379:methods*; D010347:Patient Care Planning; D012984:Software; D025321:Surgery, Computer-Assisted / Q000379:methods*; D014584:User-Computer Interface
keywords: Electromagnetic tracking; Guided surgery; Navigation; Orthognathic surgery