title: Osteosynthesis using cannulated headless Herbert screws in mandibular angle fracture treatment: A new approach?
abstract: BACKGROUND
  Fractures of the mandibular angle are a common type of facial skull fracture. Although operative treatment includes a wide range of fixation techniques, a definite gold standard method has yet to be established. Headless, cannulated Herbert screws, often used in many forms of minimally invasive trauma surgery, provide functional and stable fracture fixation.
  
  
  METHODS
  In a prospective, double-randomised, controlled, parallel-group - designed, in vitro trial, the biomechanical behaviour of the Herbert bone screw system was compared to that of a conventional locking plate system in 40 mandibular angle fractures of human mandible cadaver phantoms.
  
  
  RESULTS
  The mean stress values were 250 (±68.0) N in the plate subgroup and 200 (±61.0) N in the screw subgroup. The respective mean strain values were 7.90 (±2.7) mm and 6.90 (±2.2) mm, and the respective mean stiffness were values 1.10 (±0.61) N/m and 0.78 (±0.40) N/m. The differences in the results obtained using the two treatments were not significant (p = 0.55).
  
  
  CONCLUSIONS
  The biomechanical behaviour of the two fixation systems within the tested loads did not significantly differ with respect to postoperative parameters clinically relevant in osteosynthesis. Both systems met the mandibular angle assessment criterion, which is considered to be sufficient for clinical use. The results indicate the potential clinical utility of these two systems, and recommend further testing.
authors.affiliation: Department of Oral and Maxillofacial Surgery, Medical University of Graz, Auenbruggerplatz 5/1, A-8036 Graz, Austria. Electronic address: j.wallner@medunigraz.at.
authors.forename: Jürgen
authors.initials: J
authors.lastname: Wallner
authors.affiliation: Department of Oral and Maxillofacial Surgery, Medical University of Graz, Auenbruggerplatz 5/1, A-8036 Graz, Austria.
authors.forename: Knut
authors.initials: K
authors.lastname: Reinbacher
authors.affiliation: Department of Oral and Maxillofacial Surgery, Medical University of Graz, Auenbruggerplatz 5/1, A-8036 Graz, Austria.
authors.forename: Matthias
authors.initials: M
authors.lastname: Feichtinger
authors.affiliation: Department of Oral and Maxillofacial Surgery, Medical University of Graz, Auenbruggerplatz 5/1, A-8036 Graz, Austria.
authors.forename: Mauro
authors.initials: M
authors.lastname: Pau
authors.affiliation: Department of Anatomy, Medical University of Graz, Harrachgasse 21/1, A-8010 Graz, Austria.
authors.forename: Georg
authors.initials: G
authors.lastname: Feigl
authors.affiliation: Department for Medical Informatics, Statistics and Documentation, Medical University of Graz, Auenbruggerplatz 2, A-8036 Graz, Austria.
authors.forename: Franz
authors.initials: F
authors.lastname: Quehenberger
authors.affiliation: Department of Oral and Maxillofacial Surgery, Medical University of Graz, Auenbruggerplatz 5/1, A-8036 Graz, Austria.
authors.forename: Katja
authors.initials: K
authors.lastname: Schwenzer-Zimmerer
authors.affiliation: Department of Oral and Maxillofacial Surgery, Medical University of Graz, Auenbruggerplatz 5/1, A-8036 Graz, Austria.
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Zemann
mesh_terms: D000368:Aged; D001696:Biomechanical Phenomena; D001860:Bone Plates; D001863:Bone Screws; D002102:Cadaver; D000072601:Cannula; D004867:Equipment Design; D005260:Female; D005593:Fracture Fixation, Internal / Q000295:instrumentation*; D006801:Humans; D008297:Male; D008337:Mandibular Fractures / Q000601:surgery*; D019047:Phantoms, Imaging; D011446:Prospective Studies
keywords: Headless cannulated Herbert screw; Mandibular angle fracture; Osteosynthesis