title: Stabilization of the Craniovertebral Junction with Clivus Plate Constructs: Biomechanical Comparison with Conventional Technique.
abstract: BACKGROUND
  Ventral defect caused by resection of the lesions involving the upper cervical spine commonly has been reconstructed with a fabricated mesh cage. Recently, a clival screw and plate fitted to the osseous anatomy of the craniovertebral junction was developed for this pathologic status.
  
  
  OBJECTIVE
  To evaluate the stability a clivus plate system fixation (CPSF) for the craniovertebral junction and compare it with a conventional fashioned mesh cage fixation (FMCF).
  
  
  METHODS
  Seven human fresh cadaveric specimens (occiput [Oc], atlas [C1], axis [C2], third cervical vertebra [C3], fourth cervical vertebra [C4]) were tested with intact and destabilization-reconstruction conditions. FMCF and CPSF were applied randomly to the clivus to the C3 segment combined with posterior occipitocervical fixation applied from the occiput to C4 segment, respectively. Specimens were subjected to a pure moment of 1.5 Nm in flexion, extension, lateral bending, and axial rotation, respectively. The range of motion (ROM) and neutral zone (NZ) from the occiput to C3 were calculated and compared between two anterior fixations.
  
  
  RESULTS
  Motions were reduced significantly in all directions following FMCF and CPSF fixations when compared with the intact. The CPSF resulted in smaller ROM in lateral bending (0.3° vs. 0.6°, P = 0.015), axial rotation (0.6° vs. 1.2°, P = 0.023) and flexion (0.1° vs. 0.3°, P = 0.019), but similar ROM in extension (0.2° vs. 0.4°, P = 0.273) when compared with the FMCF. NZs with the CPSF were 0.1° in flexion-extension, 0.1° in lateral bending and 0.2° in axial rotation, respectively, and similar to NZs with the FMCF.
  
  
  CONCLUSIONS
  The clivus plate system fixation is biomechanically superior to the conventional fashioned mesh cage fixation in flexion, lateral bending and axial rotation, but equavalent in extension.
authors.affiliation: Department of Spinal Surgery, Nanfang Hospital, Southern Medical University, Guangzhou, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Ji
authors.affiliation: Department of Spine Surgery, The First People's Hospital of Chenzhou, Chenzhou, Hunan, China.
authors.forename: Jie
authors.initials: J
authors.lastname: Tong
authors.affiliation: Department of Spinal Surgery, Nanfang Hospital, Southern Medical University, Guangzhou, China.
authors.forename: Zhiping
authors.initials: Z
authors.lastname: Huang
authors.affiliation: Department of Spinal Surgery, Nanfang Hospital, Southern Medical University, Guangzhou, China.
authors.forename: Minghui
authors.initials: M
authors.lastname: Zheng
authors.affiliation: Department of Spinal Surgery, Nanfang Hospital, Southern Medical University, Guangzhou, China.
authors.forename: Xiuhua
authors.initials: X
authors.lastname: Wu
authors.affiliation: Department of Spinal Surgery, Nanfang Hospital, Southern Medical University, Guangzhou, China.
authors.forename: Jianting
authors.initials: J
authors.lastname: Chen
authors.affiliation: Department of Spinal Surgery, Nanfang Hospital, Southern Medical University, Guangzhou, China. Electronic address: qinganzhu@gmail.com.
authors.forename: Qingan
authors.initials: Q
authors.lastname: Zhu
mesh_terms: D000328:Adult; D001269:Atlanto-Occipital Joint / Q000601:surgery*; D001696:Biomechanical Phenomena; D001860:Bone Plates; D001863:Bone Screws; D002102:Cadaver; D002574:Cervical Vertebrae / Q000601:surgery*; D003388:Cranial Fossa, Posterior / Q000601:surgery*; D005260:Female; D006801:Humans; D007593:Joint Instability / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D019635:Neurosurgical Procedures; D016059:Range of Motion, Articular; D019651:Plastic Surgery Procedures / Q000379:methods*; D013123:Spinal Fusion / Q000379:methods*
keywords: Biomechanics; Clivus; Craniovertebral junction; Mesh cage; Vertebrae body reconstruction