Spine (Trauma)

Question 1

In the cervical spine, what kind of injuries arise from hyperextension fracture-dislocations?

Answer 1

A. posterior fracture-dislocation of the dens
B. traumatic spondylolisthesis of the axis (ie. Hangman’s Fracture)
C. Hyperextension sprain (momentary dislocation) with fracture
D. Hyperextension fracture-dislocation with fractured articular pillar
E. Hyperextension fracture dislocation with comminution of the vertebral arch

Question 2

In the cervical spine, what kind of injuries arise from hyperflexion fracture-dislocations?

Answer 2

A. anterior fracture-dislocation of the dens
B. hyperflexion sprain: rare. Occurs when posterior ligaments are disrupted but locking of articular facets does not occur
C. locked articular facets with fracture
D. “teardrop” fracture-dislocation

Question 3

What are anatomical reasons for children to have higher rates of atlantooccipito dislocation (AOD) than adults?

Answer 3

1. Flatter occipital condyles in kids
2. Higher ratio of cranium to body weight
3. Increased ligament laxity

Question 4

What is cruciate paralysis?

Answer 4

Uncommon neurological injury at the level of the cervicomedullary junction. It is characterized by bilateral upper extremity paresis or paralysis with minimal or no lower extremity involvement. Sensory function is also spared. Anatomically, it is thought to represent selective injury to descending corticospinal tracts as they decussate at the CMD.

Question 5

What are types of atlantooccipito dislocation?

Answer 5

Type 1 - anterior dislocation of occiput relative to the atlas
Type 2 - longitudinal (upward) dislocation, ie. distraction
Type 3 - posterior dislocation of occiput

Question 6

What is the Power’s Ratio and what is it used for?

Answer 6

The power’s ratio is calculated by dividing the distance of B (basion) C (posterior arch of C1) by AO (anterior arch of atlas to opisthion).

Normal value 0.9 and = 1

Cannot be used with fractures of C1

Question 7

What is the BAI?

Answer 7

Basion-Axial Interval

Calculated by the distance from the basion (inferior tip of the clivus) to rostral extension of the posterior axial line (imaginary line drawn from posterior boundary of dens (C2) all the way upward).

Normal

Question 8

What is the BDI?

Answer 8

Basion-Dental Interval
Distance between the basion and the closest point of the tip of the dens. Better for distracted AOD.

Normal