SplintER Series: The Tooth of the Cervical Spine

Odontoid fracture, type II. The odontoid process, or dens, is a superior bony projection of C2 that, along with the transverse ligament, is a key stabilizer of C1.

Figure 2. Case courtesy of Dr. Talal F M Abdullah, Radiopaedia.org, rID: 58030. Annotations by author, fracture highlighted in red

• Pearl: Odontoid fractures can occur in elderly patients via a low energy mechanism like ground-level falls. They may also occur in younger patients during high-energy trauma that causes hyperflexion or hyperextension.

Type I: Alar ligament avulsion fracture of the apex. Stable

Type II: Fracture at the waist of the odontoid process. Unstable

Type III: Fracture of the body of C2 with involvement of the lateral masses. Unstable

Figure 3. Case courtesy of Dr. Mohammad Taghi Niknejad, Radiopaedia.org, rID: 21310. Odontoid fractures type 1, 2, and 3 from left to right

• Pearl: Type II fractures have a high nonunion rate because the waist of the odontoid process has limited blood supply for two reasons [1]:
  • Vascular supply arrives from the apex and the base, forming a watershed area at the waist.
  • The waist lacks cancellous bone, which contains a highly vascularized meshwork of bone and blood vessels that allows for faster healing.

The patient should be placed in a cervical collar and maintained in strict spinal precautions. A spine surgeon should be consulted emergently as guided by institutional protocols. MRI can be obtained if neurologic symptoms are present. 

• PEARL: Management typically includes the following
  • Type I   -> hard cervical collar for 6-12wk.
  • Type II  -> operative management (screw fixation or C1-2 posterior fusion) [1-2].
  • Type III -> hard cervical collar or halo immobilization [1].