Denis classification of sacral fractures

⚪️ There are several classification systems for sacral fractures, but the most commonly employed are the Denis classification and subclassification systems, and the Isler classification system.

⚪️ Denis classification: 

• zone 1: fracture involves the sacral ala lateral to the neural foramina

• zone 2: fracture involves the neural foramina, but does not involve the spinal canal.

• zone 3: fracture is medial to the neural foramen, involving the spinal canal; these may be transverse or longitudinal, and can be sub-classified into 4 types:

• type 1: only kyphotic angulation at the fracture site (no translation).

• type 2: kyphotic angulation with anterior translation of the distal sacrum.

• type 3: kyphotic angulation with complete offset of the fracture fragments.

• type 4: comminuted S1 segment, usually due to axial compression.

⚪️ Morphologic injury patterns of zone 3 fractures:

🔶️ “H” shaped fracture

🔶️ “U” shaped fracture

🔶️ “ʎ” (lambda) shaped fracture

🔶️ “T” shaped fracture