title: The University Münster model surgery system for orthognathic surgery. Part I--the idea behind.
abstract: BACKGROUND
  We describe a procedure for diagnosis and planning for orthognathic surgery based on international standards. A special 2D planning based on lateral cephalograms (Axis Orbital Marker Lines System) realize a transmission to the SAM 2P articulator (3D) by means of the Axis Orbital Plane.
  
  
  METHODS
  Former intraoperative measurement of the average height of the LeFort I osteotomy plane relative to the molar occlusal plane allow to construct a virtual osteotomy plane in the lateral cephalogram. This is the basis for the development of the Axis Orbital Marker Lines System (AO-MLS).
  
  
  RESULTS
  The AO-MLS is presented graphically, and in detail, with construction guidelines. The system could be integrated into various lateral cephalometric analysis- and surgical prediction schemes. It forms the basis for a standardized transfer of the 2D planning to the 3D planning in the articulator, and vice versa. This procedure makes it possible to generate surgical planning protocols based on the model surgery, which represent the dislocations in the proximity of the real osteotomy planes.
  
  
  CONCLUSIONS
  The Axis Orbital Marker Lines System (software component) in conjunction with the University Münster Model Surgery System (hardware system) increases the predictability of model operations in orthognathic surgery.
authors.affiliation: Department of Maxillofacial Surgery, University of Münster, Albert-Schweitzer-Campus 1, Münster, Germany. ulrich.joos@ukmuenster.de
authors.forename: Ulrike
authors.initials: U
authors.lastname: Ehmer
authors.forename: Ulrich
authors.initials: U
authors.lastname: Joos
authors.forename: Stefanie
authors.initials: S
authors.lastname: Flieger
authors.forename: Dirk
authors.initials: D
authors.lastname: Wiechmann
mesh_terms: D002508:Cephalometry / Q000379:methods*; D003198:Computer Simulation; D006801:Humans; D008953:Models, Anatomic; D057909:Orthognathic Surgery / Q000295:instrumentation* / Q000379:methods; D014495:Universities