Craniocervical fixation with occipital condyle screws

Biomechanical analysis of a novel technique

Juan S. Uribe, Edwin Ramos, A. Samy Youssef, Nick Levine, Alexander W.L. Turner, Wesley M. Johnson, Fernando Vale Diaz

Research output: Contribution to journalArticle

26 Citations (Scopus)

Abstract

Study Design: A human cadaveric biomechanical study comparing craniocervical fixation techniques. Objective: To quantitatively compare the biomechanical stability of a new technique for occipitocervical fixation using the occipital condyles with an established method for craniocervical spine fusion. Summary of Background Data: Stabilization of the occipitocervical junction remains a challenge. The occiput does not easily accommodate instrumentation because of access and spatial constraints. In fact, the area available for the implant fixation is limited and can be restricted further when a suboccipital craniectomy has been performed, posing a challenge to current fixation techniques. Occipital screws are also associated with the potential for intracranial complications. Methods: Six fresh frozen cadaveric specimens occiput-C4 were tested intact, after destabilization and after fixation as follows: (1) occipital plate with C1 lateral mass screws and C2 pars screws and (2) occipital condyle screws with C1 lateral mass screws and C2 pars screws. Specimens were loaded in a custom spine testing apparatus and subjected to the following tests, all performed under 50-N unconstrained axial preload: flexion, extension, lateral bending, and axial rotation at 1.5 Nm. The constructs were statistically compared with a one-way analysis of variance and compared with the intact condition. Results: Motions were reduced by ∼80% compared with the intact condition for both configurations under all motions. There were no statistically significant differences in the range of motion (ROM) between the 2 instrumentation conditions. The mean values indicated decreased ROM with the novel occipital condyle screw construct in comparison with the standard occipital plate and rod system. Conclusion: Craniocervical stabilization using occipital condyle screws as the sole cephalad fixation point is biomechanically equivalent with regard to the modes tested (ROM and stiffness) to the standard occipital plate construct.

Original languageEnglish (US)
Pages (from-to)931-938
Number of pages8
JournalSpine
Volume35
Issue number9
DOIs
StatePublished - Apr 1 2010
Externally publishedYes

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Articular Range of Motion
Bone and Bones
Spine
Analysis of Variance

Keywords

  • Biomechanics
  • Condyle screw
  • Craniocervical instability
  • Craniocervical junction
  • Craniovertebral junction
  • Occipital condyle
  • Occipitalcondyle cervical fusion
  • Occipitocervical fusion
  • Occipitocervical junction

ASJC Scopus subject areas

  • Orthopedics and Sports Medicine
  • Clinical Neurology

Cite this

Uribe, J. S., Ramos, E., Youssef, A. S., Levine, N., Turner, A. W. L., Johnson, W. M., & Vale Diaz, F. (2010). Craniocervical fixation with occipital condyle screws: Biomechanical analysis of a novel technique. Spine, 35(9), 931-938. https://doi.org/10.1097/BRS.0b013e3181c16f9a

Craniocervical fixation with occipital condyle screws : Biomechanical analysis of a novel technique. / Uribe, Juan S.; Ramos, Edwin; Youssef, A. Samy; Levine, Nick; Turner, Alexander W.L.; Johnson, Wesley M.; Vale Diaz, Fernando.

In: Spine, Vol. 35, No. 9, 01.04.2010, p. 931-938.

Research output: Contribution to journalArticle

Uribe, JS, Ramos, E, Youssef, AS, Levine, N, Turner, AWL, Johnson, WM & Vale Diaz, F 2010, 'Craniocervical fixation with occipital condyle screws: Biomechanical analysis of a novel technique', Spine, vol. 35, no. 9, pp. 931-938. https://doi.org/10.1097/BRS.0b013e3181c16f9a
Uribe JS, Ramos E, Youssef AS, Levine N, Turner AWL, Johnson WM et al. Craniocervical fixation with occipital condyle screws: Biomechanical analysis of a novel technique. Spine. 2010 Apr 1;35(9):931-938. https://doi.org/10.1097/BRS.0b013e3181c16f9a
Uribe, Juan S. ; Ramos, Edwin ; Youssef, A. Samy ; Levine, Nick ; Turner, Alexander W.L. ; Johnson, Wesley M. ; Vale Diaz, Fernando. / Craniocervical fixation with occipital condyle screws : Biomechanical analysis of a novel technique. In: Spine. 2010 ; Vol. 35, No. 9. pp. 931-938.
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abstract = "Study Design: A human cadaveric biomechanical study comparing craniocervical fixation techniques. Objective: To quantitatively compare the biomechanical stability of a new technique for occipitocervical fixation using the occipital condyles with an established method for craniocervical spine fusion. Summary of Background Data: Stabilization of the occipitocervical junction remains a challenge. The occiput does not easily accommodate instrumentation because of access and spatial constraints. In fact, the area available for the implant fixation is limited and can be restricted further when a suboccipital craniectomy has been performed, posing a challenge to current fixation techniques. Occipital screws are also associated with the potential for intracranial complications. Methods: Six fresh frozen cadaveric specimens occiput-C4 were tested intact, after destabilization and after fixation as follows: (1) occipital plate with C1 lateral mass screws and C2 pars screws and (2) occipital condyle screws with C1 lateral mass screws and C2 pars screws. Specimens were loaded in a custom spine testing apparatus and subjected to the following tests, all performed under 50-N unconstrained axial preload: flexion, extension, lateral bending, and axial rotation at 1.5 Nm. The constructs were statistically compared with a one-way analysis of variance and compared with the intact condition. Results: Motions were reduced by ∼80{\%} compared with the intact condition for both configurations under all motions. There were no statistically significant differences in the range of motion (ROM) between the 2 instrumentation conditions. The mean values indicated decreased ROM with the novel occipital condyle screw construct in comparison with the standard occipital plate and rod system. Conclusion: Craniocervical stabilization using occipital condyle screws as the sole cephalad fixation point is biomechanically equivalent with regard to the modes tested (ROM and stiffness) to the standard occipital plate construct.",
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AB - Study Design: A human cadaveric biomechanical study comparing craniocervical fixation techniques. Objective: To quantitatively compare the biomechanical stability of a new technique for occipitocervical fixation using the occipital condyles with an established method for craniocervical spine fusion. Summary of Background Data: Stabilization of the occipitocervical junction remains a challenge. The occiput does not easily accommodate instrumentation because of access and spatial constraints. In fact, the area available for the implant fixation is limited and can be restricted further when a suboccipital craniectomy has been performed, posing a challenge to current fixation techniques. Occipital screws are also associated with the potential for intracranial complications. Methods: Six fresh frozen cadaveric specimens occiput-C4 were tested intact, after destabilization and after fixation as follows: (1) occipital plate with C1 lateral mass screws and C2 pars screws and (2) occipital condyle screws with C1 lateral mass screws and C2 pars screws. Specimens were loaded in a custom spine testing apparatus and subjected to the following tests, all performed under 50-N unconstrained axial preload: flexion, extension, lateral bending, and axial rotation at 1.5 Nm. The constructs were statistically compared with a one-way analysis of variance and compared with the intact condition. Results: Motions were reduced by ∼80% compared with the intact condition for both configurations under all motions. There were no statistically significant differences in the range of motion (ROM) between the 2 instrumentation conditions. The mean values indicated decreased ROM with the novel occipital condyle screw construct in comparison with the standard occipital plate and rod system. Conclusion: Craniocervical stabilization using occipital condyle screws as the sole cephalad fixation point is biomechanically equivalent with regard to the modes tested (ROM and stiffness) to the standard occipital plate construct.

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KW - Occipitocervical junction

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