title: Computed tomography-based virtual fracture reduction techniques in bimandibular fractures.
abstract: OBJECTIVE
  Computer-assisted preoperative planning (CAPP) usually relies on computed tomography (CT) or cone beam CT (CBCT) and has already become an established technique in craniomaxillofacial surgery. The purpose of this study was to implement CT-based virtual fracture reduction as a key planning feature in patients with bimandibular fractures.
  
  
  METHODS
  Nine routine preoperative CT scans of patients with bilateral mandibular fractures were acquired and post-processed using a mean model of the mandible and Amira software extended by custom-made scripting and programming modules.
  
  
  RESULTS
  A computerized technique was developed that allowed three-dimensional modeling, separation of the mandible from the cranium, distinction of the fracture fragments, and virtual fracture reduction. User interaction was required to label the mandibular fragments by landmarks. Virtual fracture reduction was achieved by optionally using the landmarks or the contralateral unaffected side as anatomical references.
  
  
  CONCLUSIONS
  We successfully elaborated an effective technique for virtual fracture reduction of the mandible using a standard CT protocol. It offers expanded planning options for osteosynthesis construction or the manufacturing of personalized rapid prototyping guides in fracture reduction procedures. CAPP is justified in complex mandibular fractures and may be adopted in addition to routine preoperative CT assessment.
authors.affiliation: AO Research Institute Davos, Clavadelerstrasse 8, 7270 Davos, Switzerland; Department of Oral & Maxillofacial Surgery, Charité Universitätsmedizin Berlin, Campus Virchow- Klinikum, Augustenburger Platz 1, Berlin, 13353, Germany. Electronic address: jan.voss@charite.de.
authors.forename: Jan Oliver
authors.initials: JO
authors.lastname: Voss
authors.affiliation: AO Research Institute Davos, Clavadelerstrasse 8, 7270 Davos, Switzerland. Electronic address: viktor.varjas@aofoundation.org.
authors.forename: Viktor
authors.initials: V
authors.lastname: Varjas
authors.affiliation: Department of Oral & Maxillofacial Surgery, Charité Universitätsmedizin Berlin, Campus Virchow- Klinikum, Augustenburger Platz 1, Berlin, 13353, Germany. Electronic address: jan-dirk.raguse@charite.de.
authors.forename: Jan-Dirk
authors.initials: JD
authors.lastname: Raguse
authors.affiliation: Department of Radiology, Charité Universitätsmedizin Berlin, Campus Virchow-Klinikum, Augustenburger Platz 1, Berlin, 13353, Germany. Electronic address: nadine.thieme@charite.de.
authors.forename: Nadine
authors.initials: N
authors.lastname: Thieme
authors.affiliation: AO Research Institute Davos, Clavadelerstrasse 8, 7270 Davos, Switzerland. Electronic address: geoff.richards@aofoundation.org.
authors.forename: R Geoff
authors.initials: RG
authors.lastname: Richards
authors.affiliation: AO Research Institute Davos, Clavadelerstrasse 8, 7270 Davos, Switzerland. Electronic address: lukas.kamer@aofoundation.org.
authors.forename: Lukas
authors.initials: L
authors.lastname: Kamer
mesh_terms: D005593:Fracture Fixation, Internal / Q000295:instrumentation / Q000379:methods*; D006801:Humans; D021621:Imaging, Three-Dimensional; D008337:Mandibular Fractures / Q000601:surgery*; D025321:Surgery, Computer-Assisted / Q000379:methods*; D014584:User-Computer Interface
keywords: Computed tomography; Computer-assisted preoperative planning; Condylar fracture; Mandibular fracture; Virtual fracture reduction