title: Biomechanical evaluation of the impact of various facet joint lesions on the primary stability of anterior plate fixation in cervical dislocation injuries: a cadaver study: Laboratory investigation.
abstract: OBJECTIVE
  Injuries of the subaxial cervical spine including facet joints and posterior ligaments are common. Potential surgical treatments consist of anterior, posterior, or anterior-posterior fixation. Because each approach has its advantages and disadvantages, the best treatment is debated. This biomechanical cadaver study compared the effect of different facet joint injuries on primary stability following anterior plate fixation.
  
  
  METHODS
  Fractures and plate fixation were performed on 15 fresh-frozen intact cervical spines (C3-T1). To simulate a translation-rotation injury in all groups, complete ligament rupture and facet dislocation were simulated by dissecting the entire posterior and anterior ligament complex between C-4 and C-5. In the first group, the facet joints were left intact. In the second group, one facet joint between C-4 and C-5 was removed and the other side was left intact. In the third group, both facet joints between C-4 and C-5 were removed. The authors next performed single-level anterior discectomy and interbody grafting using bone material from the respective thoracic vertebral bodies. An anterior cervical locking plate was used for fixation. Continuous loading was performed using a servohydraulic test bench at 2 N/sec. The mean load failure was measured when the implant failed.
  
  
  RESULTS
  In the group in which both facet joints were intact, the mean load failure was 174.6 ± 46.93 N. The mean load failure in the second group where only one facet joint was removed was 127.8 ± 22.83 N. In the group in which both facet joints were removed, the mean load failure was 73.42 ± 32.51 N. There was a significant difference between the first group (both facet joints intact) and the third group (both facet joints removed) (p < 0.05, Kruskal-Wallis test).
  
  
  CONCLUSIONS
  In this cadaver study, primary stability of anterior plate fixation for dislocation injuries of the subaxial cervical spine was dependent on the presence of the facet joints. If the bone in one or both facet joints is damaged in the clinical setting, anterior plate fixation in combination with bone grafting might not provide sufficient stabilization; additional posterior stabilization may be needed.
authors.affiliation: Departments of 1 Trauma, Hand, and Reconstructive Surgery and.
authors.forename: Ludwig
authors.initials: L
authors.lastname: Oberkircher
authors.forename: Sebastian
authors.initials: S
authors.lastname: Born
authors.forename: Johannes
authors.initials: J
authors.lastname: Struewer
authors.forename: Christopher
authors.initials: C
authors.lastname: Bliemel
authors.forename: Benjamin
authors.initials: B
authors.lastname: Buecking
authors.forename: Christina
authors.initials: C
authors.lastname: Wack
authors.forename: Martin
authors.initials: M
authors.lastname: Bergmann
authors.forename: Steffen
authors.initials: S
authors.lastname: Ruchholtz
authors.forename: Antonio
authors.initials: A
authors.lastname: Krüger
mesh_terms: D001696:Biomechanical Phenomena; D001860:Bone Plates; D002102:Cadaver; D002574:Cervical Vertebrae / Q000293:injuries*; D006801:Humans; D004204:Joint Dislocations / Q000601:surgery*; D007593:Joint Instability / Q000601:surgery*; D012399:Rotation; D013314:Stress, Mechanical; D014057:Tomography, X-Ray Computed; D021801:Zygapophyseal Joint / Q000293:injuries*
keywords: DXA = dual-energy x-ray absorptiometry; SLIC = Subaxial Injury Classification; biomechanical; cadaver; cervical spine; facet joint; luxation; trauma