Pathophysiology of Different Mechanisms of Spinal Trauma
Introduction
Understanding the biomechanical mechanism that produced a cervical spine injury helps predict which anatomical structures have failed, the pattern of instability, likely neurological consequences and the immediate priorities for emergency assessment and investigation.
Mechanism‑based reasoning guides the choice of imaging (CT for bone, MRI for cord/ligaments), the threshold for specialist referral, and early management steps (airway and motion restriction).
UK guidance recommends using validated decision rules (Canadian C‑spine rule in alert adults) and treating certain mechanisms as “dangerous” with a low threshold for immobilisation and imaging (NICE NG41, NG232).
Practical pre‑hospital and ED motion‑restriction principles emphasise airway first, minimal movement and encouraging self‑stabilisation when possible (Resuscitation Council UK).
Biomechanical principles - the three‑column model The Denis three‑column model remains a useful clinical framework:
- Anterior column: anterior longitudinal ligament, anterior half of vertebral body and disc.
- Middle column: posterior half of vertebral body and disc, posterior longitudinal ligament.
- Posterior column: posterior ligament complex, facets, laminae, spinous processes.
Direction, magnitude and duration of force determine whether bone or ligament fails and which column(s) are injured. Pre‑existing changes (degeneration, osteoporosis, congenital variants) alter failure thresholds. Clinically the two key questions are:
- Is columnal integrity disrupted such that the column is unstable?