Odontoid Fractures in Children

Odontoid fractures usually occur with forceful distension of the cervical spine. They are normally divided into three types:

Type I Odontoid Fracture

• Fracture above insertion of transverse ligament: This is a fracture of the odontoid process at its rostral end and is usually stable.
• Must be differentiated from persisting ossification center: This fracture can mimic a persisting ossiculum terminale, a congenital secondary ossification center at the rostral end of the odontoid.

Type I odontoid fracture: The fracture line is at the level of the transverse ligament. The transverse ligament is rendered incompetent, and thus this is an unstable injury.

Os odontoideum: In contrast to the fracture, the os odontoideum has smooth, well- corticated margins.

Type II Odontoid Fracture

• Fracture across base of the odontoid process: The location of this fracture is below the transverse ligament, and it is usually unstable.
• Must be differentiated from persisting os odontoideum: This fracture can be mimicked by os odontoideum, a congenital failure of fusion of the odontoid process to the base. It is also unstable in most cases.
• Fracture through growth plate: In children, epiphysiolysis may also occur and is usually unstable.

Type II Odontoid Fracture, coronal and sagittal views: There is a non-displaced fracture through the base of the odontoid.

Odontoid Fracture, Type II Repaired: A compression screw has been placed across the fracture.

Type III Odontoid Fracture

• Fracture through C2 body: The type 3 fracture is through the vertebral body of C2 below its juncture with the odontoid. It may be stable or unstable depending on amount of body involvement
• Frequently unstable: If fracture prevents the transverse ligament from applying force to the body of C2 then consider fracture unstable

Epiphysiolysis Injury

• Epiphysiolysis Injury of the odontoid: This is a fracture of the odontoid that is peculiar to young children. It occurs at the dentocentral synchondrosis.

Epiphysiolysis injury in a 22-month-old child after MVA:The injury has occurred through the C2 synchondrosis. The fracture was reduced under fluoroscopy and managed with a halo vest for 2 months. Assessment of healing is difficult because of the radiolucent growth plate. Flexion/extension x-rays are needed to confirm complete healing.