Which type of fracture is always considered an unstable spinal injury: burst fracture, Clay-shoveler’s fracture, flexion teardrop fracture, or simple wedge fracture?

Flexion Teardrop Fracture Is Always Considered an Unstable Spinal Injury

The flexion teardrop fracture is always considered an unstable spinal injury as it represents a highly unstable three-column injury pattern that typically causes significant instability and neurological compromise. 1

Understanding Spinal Fracture Stability

Spinal fractures are classified based on their stability, which directly impacts patient management, morbidity, mortality, and quality of life outcomes. When evaluating the stability of different fracture types:

Unstable Fracture Types:

1. Flexion Teardrop Fracture

   • Involves fracture of the anteroinferior corner of a vertebral body with displacement
   • Associated with posterior ligamentous disruption
   • Highly unstable and frequently associated with spinal cord injury 1
   • Characterized by two fracture lines: a frontal fracture (flexion mechanism) and a sagittal fracture (compression mechanism) 2
   • Requires surgical management due to its inherent instability 3

2. Burst Fracture

   • While serious, not all burst fractures are inherently unstable
   • Neurologically intact patients with burst fractures can be managed with or without bracing 4
   • Management options include both operative and non-operative approaches depending on neurological status and degree of vertebral collapse 4

Stable Fracture Types:

1. Clay-shoveler's Fracture

   • Avulsion fracture of the spinous process
   • Typically stable and rarely associated with neurological deficit
   • Usually managed conservatively

2. Simple Wedge Fracture

   • Compression of the anterior portion of the vertebral body
   • Generally stable if posterior elements are intact
   • Often managed non-operatively unless severe kyphosis is present

Clinical Implications of Flexion Teardrop Fractures

Flexion teardrop fractures have significant clinical implications:

• High incidence of neurological complications due to posterior displacement of the fractured vertebra into the spinal canal 3
• Often results in complete tetraplegia or anterior spinal cord injury when posterior displacement and kyphosis exceed 20 degrees 2
• May present with Brown-Sequard syndrome in cases of asymmetrical posterior displacement 2
• Requires surgical intervention for stabilization 3, 2

Diagnostic Approach

CT is the gold standard for identifying spinal fractures with a reported sensitivity of 94% to 100% 4. MRI should be performed when there is:

• Possible spinal cord injury
• Clinical concern for cord compression due to disc protrusion or hematoma
• Suspicion of ligamentous instability 4

Management Considerations

For flexion teardrop fractures, surgical management is typically required due to the inherent instability:

• Traditional approach includes complete excision and grafting of the vertebral body through an anterior approach 3
• Alternative posterior reduction and fixation techniques have shown promising results 3
• Spinal fractures in the setting of ankylosis are particularly unstable, with a high associated rate of neurologic injury 4

Conclusion

Among the fracture types mentioned (burst fracture, Clay-shoveler's fracture, flexion teardrop fracture, and simple wedge fracture), the flexion teardrop fracture is the only one that is always considered unstable. This fracture pattern disrupts all three columns of the spine, causing significant instability and requiring surgical intervention to prevent further neurological compromise and to restore spinal alignment.