title: Biomechanical evaluation of the Facet Wedge: a refined technique for facet fixation.
abstract: OBJECTIVE
  Purpose of this paper is to evaluate the primary stability of a new approach for facet fixation the so-called Facet Wedge (FW) in comparison with established posterior fixation techniques like pedicle screws (PS) and translaminar facet screws (TLS) with and without anterior cage interposition.
  
  
  METHODS
  Twenty-four monosegmental fresh frozen non-osteoporotic human motion segments (L2-L3 and L4-L5) were tested in a two-arm biomechanical study using a robot-based spine tester. Facet Wedge was compared with pedicle screws and translaminar screws as a stand-alone device and in combination with an anterior fusion cage.
  
  
  RESULTS
  Pedicle screws, FW and translaminar screws could stabilize an intact motion segment effectively. Facet Wedge was comparable to PS for lateral bending, extension and flexion and slightly superior for axial rotation. Facet Wedge showed a superior kinematic capacity compared to translaminar screws.
  
  
  CONCLUSIONS
  Facet Wedge offers a novel posterior approach in achieving primary stability in lumbar spinal fixation. The results of the present study showed that the Facet Wedge has a comparable primary stability to pedicle screws and potential advantages over translaminar screws.
authors.affiliation: Department of Trauma-, Hand- and Reconstructive Surgery, Wilhelms-University of Muenster, Albert-Schweitzer-Campus 1, W1, 48149, Münster, Germany, hartensuer@uni-muenster.de.
authors.forename: René
authors.initials: R
authors.lastname: Hartensuer
authors.forename: Oliver
authors.initials: O
authors.lastname: Riesenbeck
authors.forename: Martin
authors.initials: M
authors.lastname: Schulze
authors.forename: Dominic
authors.initials: D
authors.lastname: Gehweiler
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Raschke
authors.forename: Paul W
authors.initials: PW
authors.lastname: Pavlov
authors.forename: Thomas
authors.initials: T
authors.lastname: Vordemvenne
mesh_terms: D001696:Biomechanical Phenomena; D001863:Bone Screws; D002102:Cadaver; D005471:Fluoroscopy; D006801:Humans; D016268:Internal Fixators; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging / Q000601:surgery*; D008422:Materials Testing; D008875:Middle Aged; D012371:Robotics; D021801:Zygapophyseal Joint / Q000000981:diagnostic imaging / Q000601:surgery*