F2 facet fracture

F2 is a facet fracture with potential for instability from the AOSpine subaxial cervical spine injury classification system. Fracture fragments are greater than 1 cm and comprise less than 40% lateral mass or displaced.

There was significant variability in diagnostic accuracy for F1 facet fracture through F3-type fractures, whereas almost universal agreement was achieved for F4-type injuries ¹⁾.

F2-injuries are usually components of unstable B- or C-injuries, which dictate the surgical strategy. Possible nerve root compression by the facet fragment may therefore require an additional posterior approach in case of an anterior stabilization.

Facet fractures with transverse process involvement or comminution have a higher probability of being an F2 fracture. These characteristics may be helpful when categorizing facet fractures using the AOSpine classification ²⁾.