IS Case 253: Type 2 dens fracture
Imaging Sciences URMC 2008
Publication Date: 2009-05-26
Type 1 is an oblique avulsion fracture of the superolateral tip of the dens by the alar ligament which connects the dens to the occiput. This type is rare and considered stable. and must be distinguished from an os odontoideum which is a congenital non-union of a secondary ossification center. The os odontoideum will have well-corticated margins while acute fractures should have sharp radiolucent margins.
Type 2 is a transverse fracture at the base of the odontoid. This is the most common type and is unstable. Treatment is to wear an immobilization halovest for 3 months if the initial displacement is less than 5 mm, otherwise a surgical posterior antlanto axial arthrodesis should be performed. Type 2 dens fractures must be distinguished from an os odontoideum which is a congenital non-union of a secondary ossification center. The os odontoideum will have well-corticated margins while acute fractures should have sharp radiolucent margins.
Type 3 is a fracture of the superior portion of the C2 vertebral body which extends to one or both superior articular facets. This allows the atlas and occiput to move together and is also an unstable fracture. Typical treatment is an immobilization halovest for 3 months.
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