Classification of sacral fractures

Category	A	B	C
Prevalent Injury Zone	Pelvic Ring	Lumbosacral junction	Sacrum
Classification System	Tile Letournel AO/ASIF	Isler	Denis Roy-Camille (Subclassification of Denis Zone III) Descriptive alphabet patterns

Classification of sacral fractures fall into three basic categories:

• Component of pelvic ring fractures - which are usually vertical or longitudinal - (Tile, Letournel, AO-ASIF)
• Lumbosacral junction disruption (Isler) and Longitudinal Sacral body fracture (Denis)
• Transverse Sacral body fractures (Roy-Camille)

It is important to realize these three categories of sacral injury are not mutually exclusive and often coexist.

The classification of sacral fractures as a component of patterns of pelvic ring fractures has been discussed elsewhere in this lecture series.

Image 1 shows the types of lumbosacral disruption as described by Isler in 1990. As the fractures progress further medial (i.e. Types 2 and 3), there is a greater degree of lumbosacral instability.

Image 2 shows the Denis Classification. Any fractures coursing lateral to the neural foramina are Type 1. Fractures involving the neural foramina but not the sacral canal are Type 2. Type 3 fractures are central sacral fractures - medial to the neural foramina - which involve the spinal canal.

Image 3 shows the Roy-Camille and Strange-Vognsen classification. This is a further transverse fracture sub-classification of the Denis Type 3 sacral body injury.

• Type 1 is kyphosis alone with minimal to no translation.
• Type 2 is kyphosis with incomplete translation.
• Type 3 is kyphosis with a complete displacement and
• Type 4 is a broad category involving any of the aforementioned types associated with a relatively common comminution of the S1 vertebral body.

Though not standardized for clinical research purposes, of use for communicating sacral injuries amongst colleagues is a descriptive "alphabet" classification (e.g. "H" type, "U" type, "T" type, "lamda" type) as seen in Image 4.