Review Question - QID 211916

The combined sum of lateral mass displacement (LMD) greater than or equal to 7 mm is indicative of transverse ligament rupture (> 8.1 mm with radiographic magnification).

In Jefferson type burst fractures, the integrity of the transverse ligament of the atlas is a key predictor of fracture stability. Fractures with combined lateral mass displacement of less than 7 mm are generally considered stable. These are amenable to non-surgical treatments including rigid cervical orthosis. In patients with transverse ligament ruptures, more rigid fracture stabilization is necessary such as halo vest orthosis or surgical stabilization.

Bransford et al. provided a comprehensive review of upper cervical spine trauma. They noted that treatment for burst fractures includes rigid cervical orthosis, halo vest or surgical fusion depending on transverse ligament stability. The authors conclude that the outcomes following this injury are challenging with >90% of patients subjectively reporting an inability to return to a pre-injury state of health.

Dvorak et al. evaluated the long-term health-related quality of life outcomes in 34 patients with Jefferson fractures. The authors noted that the physical function, pain, and disability scores were all lower than non-injured patients at a mean follow-up of 75 months. The authors concluded specifically that factors predicting worse outcomes following Jefferson burst fractures included LMD > 7 mm which was indicative of a transverse ligament rupture.

Illustration A demonstrates how to measure LMD in a patient with concern for transverse ligament rupture.

Incorrect Answers:
Answer 1: The space available for cord is normal when the value is >= 13 mm. Furthermore, the SAC measurement does not correlate to the likelihood of a transverse ligament injury.
Answer 2: The atlanto-dens interval (posterior cortex of C1 and anterior cortex of odontoid) is considered normal for values <= 3 mm. A value of 3-5 mm indicates potential transverse ligament instability.
Answer 3: The Basion-dens interval is normal with values < 12 mm and indicates the alignment of the craniocervical junction.
Answer 5: Pre-vertebral soft tissue swelling at the C2 level is normal at < 7 mm and does not specifically correlate with a transverse ligament injury.