title: Mandible reconstruction using patient-specific pre-bent reconstruction plates: comparison of standard and transfer key methods.
abstract: OBJECTIVE
  Mandible reconstruction with reconstruction plates requires bending the plates during the operation and fixation using the "standard method" (ST-method). The ST-method is limited when a pathological process has perforated the mandibular outer cortex. A transfer key method (TK-method) was developed where plates are pre-bent using a patient-specific mandible model and positioned on the mandible with the help of transfer keys. The ST-method and TK-method were compared in a clinical trial.
  
  
  METHODS
  Mandibular reconstruction was performed on 42 patients in this study: 22 were performed using the TK-method and 20 using the ST-method. Pre- and postoperative CT scans were evaluated by measuring the distances between six corresponding landmarks on the mandibular condyles and rami. The difference between pre- and postoperative distances was used to evaluate reconstruction accuracy.
  
  
  RESULTS
  The median deviation of the unsigned/ absolute values of all six distances was 1.07 mm for the TK-method and 1.67 mm for the ST-method. The TK-method showed significantly better results. For the signed values, the median deviation of the six distances was -0.6 mm for the TK-method and -1.47 mm for the ST-method, indicating that the mandibles became narrower with both methods. This width difference was not statistically significant.
  
  
  CONCLUSIONS
  The TK-method was more accurate than the ST-method in a clinical trial. The TK-method was effective and accurate for mandible reconstruction using pre-bent fixation plates.
authors.affiliation: Department of Oral and Maxillofacial Surgery, Facial Plastic Surgery, Military Hospital Ulm and Academic Hospital Ulm University, Oberer Eselsberg 40, 89081 , Ulm, Germany, frank.wilde@extern.uni-ulm.de.
authors.forename: Frank
authors.initials: F
authors.lastname: Wilde
authors.forename: Karsten
authors.initials: K
authors.lastname: Winter
authors.forename: Katharina
authors.initials: K
authors.lastname: Kletsch
authors.forename: Kai
authors.initials: K
authors.lastname: Lorenz
authors.forename: Alexander
authors.initials: A
authors.lastname: Schramm
mesh_terms: D001860:Bone Plates; D005260:Female; D006801:Humans; D008297:Male; D008334:Mandible / Q000000981:diagnostic imaging / Q000601:surgery*; D011859:Radiography; D019651:Plastic Surgery Procedures / Q000379:methods*; D016896:Treatment Outcome