Is a C5 (fifth cervical vertebra) endplate fracture considered an unstable fracture?

C5 Endplate Fracture Stability Assessment

A C5 endplate fracture cannot be definitively classified as stable or unstable based solely on the endplate involvement—stability depends on the extent of injury to the three-column spinal architecture, associated ligamentous disruption, and degree of vertebral body comminution.

Key Determinants of Stability

The stability of any cervical spine fracture, including C5 endplate fractures, requires comprehensive evaluation of:

• Three-column integrity: Endplate fractures involving only the anterior column (minor superior or inferior endplate compression) without posterior element involvement are typically stable 1
• Ligamentous structures: Isolated bony injuries without ligamentous disruption generally maintain mechanical stability 1
• Degree of displacement: Non-displaced endplate fractures are commonly stable and may not alter clinical management 1

Imaging Requirements for Stability Assessment

CT imaging with sagittal and coronal reconstructions is essential to distinguish "major" injuries (associated with mechanical instability or neurological findings) from "minor" stable injuries 1:

• Plain films alone have only 54.3% sensitivity for detecting cervical fractures and frequently miss unstable injuries 1
• Combined plain films and directed CT achieves >99% sensitivity for detecting cervical injuries 1
• Entire cervical spine CT is recommended once any fracture is identified, as 10-31% of cervical fractures have non-contiguous injuries 1

When MRI is Indicated

MRI cervical spine without IV contrast is usually appropriate when there is confirmed or suspected spinal cord injury, nerve root injury, or concern for ligamentous instability 1:

• MRI should be performed in patients with possible spinal cord injury or clinical concern for cord compression 1
• Isolated ligamentous injury without fracture is extremely rare in the cervical spine but can occur 1
• MRI helps characterize the severity of injury including intramedullary hemorrhage and cord compression 1

Clinical Context Matters

The most commonly missed fractures on routine imaging are nondisplaced endplate fractures that do not alter clinical management 1. However, this does not mean all endplate fractures are stable:

• Minor superior endplate fractures without displacement are typically stable 1
• Burst-type fractures involving the endplate with posterior element involvement or canal compromise represent unstable injuries 2
• Associated findings such as facet dislocation, subluxation, or multi-level injury indicate instability 1

Common Pitfalls to Avoid

• Do not assume all endplate fractures are benign: While minor endplate compression fractures are often stable, burst fractures or those with associated ligamentous injury can be highly unstable 3, 2
• Do not rely on plain films alone: Plain radiography misses a significant percentage of unstable cervical injuries, particularly at C5 level 1
• Do not miss associated injuries: Always image the entire cervical spine when a C5 fracture is identified 1

Practical Management Algorithm

1. Obtain CT cervical spine with thin-cut sagittal and coronal reconstructions to fully characterize the fracture pattern 1
2. Assess for three-column involvement, displacement, and posterior element integrity 1
3. Perform MRI if neurological symptoms present or if ligamentous injury suspected based on CT findings showing widening of interspinous distance or facet malalignment 1
4. Image entire cervical spine to exclude non-contiguous fractures 1
5. Neurosurgical or spine surgery consultation for definitive stability assessment and treatment planning 1

The designation of a C5 endplate fracture as stable versus unstable requires this comprehensive evaluation rather than classification based on anatomic location alone.