Transverse atlantal ligament disruption associated with odontoid fractures.

OBJECTIVES

The authors evaluated transverse atlantal ligament integrity in patients with fractures of the odontoid process of the axis.

SUMMARY OF BACKGROUND DATA

Injuries of the transverse atlantal ligament can result in atlantoaxial instability after fractures of the atlas or axis, even if osseous healing occurs.

METHODS

The clinical histories and follow-up examinations and radiographic data of 30 patients with odontoid fractures were reviewed, using a combination of magnetic resonance (MR) imaging, thin-cut computed tomography (CT), and plain radiographs to evaluate osseous and ligamentous injuries.

RESULTS AND CONCLUSIONS

Osteoperiosteal ligamentous avulsion injuries were identified on MR imaging in three patients and were associated with acute and delayed instability and nonunion. The combination of MR imaging, CT, and plain radiographs is useful in evaluating unstable odontoid fractures to facilitate rational treatment planning. Odontoid fractures with transverse ligament injuries should be considered for early surgical stabilization because this combination of injuries is unlikely to heal nonoperatively. Anterior odontoid screw fixation should be avoided when the ligament is injured.