Principles of Spinal Stability
The stability of the spine is assessed using the Denis Three-Column Model. Understanding which columns are disrupted is fundamental to determining if surgery is required.
Anterior 2/3 of vertebral body, anterior annulus, and anterior longitudinal ligament (ALL).
Posterior 1/3 of vertebral body, posterior annulus, and posterior longitudinal ligament (PLL).
Posterior elements (pedicles, facets, lamina) and the posterior ligamentous complex (PLC).
Injuries involving the Middle Column (e.g., Burst Fractures) or the PLC (e.g., Chance Fractures) are considered unstable and typically necessitate surgical stabilization.
Common Fracture Patterns
Vertebral fractures are classified by the AO Spine system or mechanism of injury:
Axial load leads to anterior wedge collapse. The middle column remains intact. Usually stable unless height loss > 50% or kyphosis > 30°.
High-energy vertical compression shatters the vertebral body. Retropulsed bone fragments into the spinal canal can cause neurologic deficit.
Tension injury (often lap-belt MVA). Horizontal fracture through bone and ligaments. Highly unstable with high risk of internal organ injury.
Complete failure of all columns with translation/rotation. Very high risk of complete spinal cord injury.
Neurological Assessment (ASIA)
The ASIA (American Spinal Injury Association) Impairment Scale is the global standard for documenting spinal cord injury (SCI) severity.
Complete: No motor or sensory function in the lowest sacral segments (S4-S5).
Sensory Incomplete: Sensory preserved below level, but no motor function.
Motor Incomplete: Motor function preserved. D is stronger (half of key muscles ≥ grade 3).
Early surgical decompression (within 24 hours) is strongly associated with improved neurological recovery in incomplete cord injuries.
Surgical Decision & Techniques
Surgical Decision Scales
Surgeons use TLICS (Thoracolumbar) and SLICS (Cervical) scores to decide management. A score > 4 indicates surgery; < 4 indicates bracing/observation.
Stabilization Approaches
- 1
Posterior Fixation: Pedicle screws and rods are used to provide rigid internal bracing. Can be performed via open or Minimally Invasive (MISS) percutaneous methods.
- 2
Anterior Corpectomy: Removal of the vertebral body and replacement with a cage. Indicated for severe canal compromise from retropulsed bone.
- 3
Decompression: Laminectomy or ligamentotaxis to relieve pressure on the spinal cord or cauda equina.
Prognosis & Long-term Care
Intensive PT/OT focusing on mobility, bladder/bowel management, and adaptive skills.
Fusion typically takes 3–6 months. Smoking and certain medications (NSAIDs) can delay this process.
For patients with SCI, secondary complications like pressure sores, autonomic dysreflexia, and UTIs must be aggressively monitored throughout recovery.
