Diagnostic and coding process
The classification system presented above includes both morphological characteristics of injuries
within the TL spine as well as neurological and patient-specific modifiers to augment clinical
relevance. In order to be comprehensive from an anatomic standpoint, morphological
characterization should include a combination of all identified injuries with their localization
although the need for surgical intervention will likely be made based on the most severely injured
level(s).
Diagnostic algorithm and final coding for the morphological injury pattern
A systematic approach ensures that all injuries are accurately classified. The first step is to
determine which vertebra or motion segment is involved. A diagnostic algorithm guides the
classification process (Figure 2) and should be employed for each injury.
First, the observer must ask whether the injury demonstrates translation or vertical displacement
with separation. If yes, the injury is labeled as a C-type injury.
If the answer is no, the second question asks whether a tension band injury is present. If yes, then
a B-type injury is diagnosed. In case of a classic “Chance” type fracture that involves bony tension
failure, a subtype B1 is coded. Alternatively, disruption of the posterior tension band which
includes a ligamentous component should be coded as a subtype B2. Any sign of hyperextension
injury leads to a subtype B3 coding.
Any motion segment for which these two questions are answered negatively will be considered
uninjured. The third question asks if a vertebra is fractured. If yes, the posterior vertebral wall
should be examined for signs of involvement. If the posterior vertebral wall is involved, this is a
burst fracture; a subtype A4 coding will be made if both endplates of the vertebra are involved,
otherwise the fracture has a subtype A3 coding designating fracture of a single endplate. Without
posterior wall involvement, a subtype A2 coding is made if both endplates of the vertebra are
involved; otherwise the vertebra has a subtype A1 fracture. Finally, clinically insignificant
fractures such as transverse or spinous process fractures should be coded as A0. A designation of
A0 should also be used when no fracture is identified to the vertebral body but it is involved in a
dislocation or translational injury.