Odontoid process fractures: the role of the ligaments in maintaining stability. A biomechanical, cadaveric study
File(s)
Published version
Author(s)
Boughton, OR
Bernard, J
Szarko, M
Type
Journal Article
Abstract
Aims: We wished to investigate the role of the cervical ligaments in maintaining atlantoaxial stability
after fracture of the odontoid process.
Methods: We dissected eight fresh-frozen cadaveric cervical spines to prepare the C1 and C2 vertebrae for biomechanical
analysis. The C1 and C2 blocks were mounted and biomechanical analysis was performed to test the stability
of the C1-C2 complex after cutting the odontoid process to create an Anderson and D’Alonzo type II fracture then
successive division of the atlantoaxial ligaments. Biomechanical analysis of stiffness, expressed as Young’s modulus,
was performed under right rotation, left rotation and anterior displacement.
Results: The mean Young’s modulus in anterior displacement decreased by 37% when the odontoid process was fractured
( p = 0.038, 95% confidence interval 0.04–1.07). The mean Young’s modulus in anterior displacement decreased
proportionally (compared to the previous dissection) by the following percentages when the structures were divided:
facet joint capsules (bilateral) 16%, ligamentum flavum 27%, anterior longitudinal ligament 10%. These differences
did not reach statistical significance ( p > 0.05).
Discussion: We have found that the odontoid process itself may account for up to 37% of the stiffness of the C1-C2
complex and that soft tissue structures account for further resistance to movement. We suggest magnetic resonance
imaging (MRI) of the soft tissues in the acute setting of a minimally displaced odontoid process fracture to plan management
of the injury. If the MRI determines that there is associated ligament injury it is likely that the fracture is
unstable and we would suggest operative management.
after fracture of the odontoid process.
Methods: We dissected eight fresh-frozen cadaveric cervical spines to prepare the C1 and C2 vertebrae for biomechanical
analysis. The C1 and C2 blocks were mounted and biomechanical analysis was performed to test the stability
of the C1-C2 complex after cutting the odontoid process to create an Anderson and D’Alonzo type II fracture then
successive division of the atlantoaxial ligaments. Biomechanical analysis of stiffness, expressed as Young’s modulus,
was performed under right rotation, left rotation and anterior displacement.
Results: The mean Young’s modulus in anterior displacement decreased by 37% when the odontoid process was fractured
( p = 0.038, 95% confidence interval 0.04–1.07). The mean Young’s modulus in anterior displacement decreased
proportionally (compared to the previous dissection) by the following percentages when the structures were divided:
facet joint capsules (bilateral) 16%, ligamentum flavum 27%, anterior longitudinal ligament 10%. These differences
did not reach statistical significance ( p > 0.05).
Discussion: We have found that the odontoid process itself may account for up to 37% of the stiffness of the C1-C2
complex and that soft tissue structures account for further resistance to movement. We suggest magnetic resonance
imaging (MRI) of the soft tissues in the acute setting of a minimally displaced odontoid process fracture to plan management
of the injury. If the MRI determines that there is associated ligament injury it is likely that the fracture is
unstable and we would suggest operative management.
Date Issued
2015-06-15
Date Acceptance
2015-04-29
Citation
SICOT-J, 2015, 1 (11)
ISSN
2426-8887
Publisher
EDP Sciences
Journal / Book Title
SICOT-J
Volume
1
Issue
11
Copyright Statement
© The Authors. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0),
which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
License URL
Subjects
Odontoid process
Odontoid process fracture
Ligament
Biomechanical
Cadaveric
Publication Status
Published