Anatomy, Physiology & Mechanisms of Spinal Cord Injury (SCI)
High-Risk Mechanisms for SCI
Identify high-risk mechanisms early. The most common in pre-hospital practice include:
- Motor vehicle collisions (MVCs) with entrapment (up to 40% of cases remain trapped)
- Falls from height (>3 metres or equivalent)
- Diving injuries / axial loading
- High-speed pedestrian strikes or motorcycle collisions
The 4 Common Mechanisms of SCI
| Mechanism | Typical Injury Pattern | Common Scenario |
|---|---|---|
| Hyperflexion | Anterior wedge fractures, anterior cord syndrome | MVC with head striking dashboard/windscreen |
| Hyperextension | Posterior element fractures, central cord syndrome | Rear-end MVC or fall with chin strike |
| Axial Loading / Compression | Burst fractures, Jefferson fracture | Diving into shallow water or vertical fall landing on head/feet |
| Rotation / Lateral Flexion | Rotational or facet dislocations | MVC rollover or side-impact trauma |
Assessment & Spinal Clearance Tools
Systematic Approach to Physical & Risk Assessment
Use a structured ABCDE approach with high index of suspicion for SCI in any trauma patient with neck/back pain, neurological deficit or high-risk mechanism.
- History: Mechanism, neck/back pain, paraesthesia, weakness, loss of sensation
- Examination: Midline cervical tenderness, neurological deficit, altered mental status, intoxication
Evidence-Based Clearance Tools: Canadian C-Spine Rule (CCR) vs NEXUS Low-Risk Criteria
Both rules have near-100% sensitivity, but the CCR is superior in direct comparison (Stiell et al., 2003).
| Feature | Canadian C-Spine Rule (CCR) | NEXUS Low-Risk Criteria |
|---|---|---|
| Sensitivity (for clinically important injury) | 99.4% | 90.7% |
| Specificity | 45.1% | 36.8% |
| Radiography rate if rule applied | 55.9% | 66.6% |
| Patients missed in validation | 1 | 16 |
Key takeaway: CCR would reduce unnecessary imaging and is preferred when range-of-motion assessment is possible.
Spinal Immobilisation – Evidence Update
Soft Collars vs Rigid Collars (Bruton et al., 2024)
NSW Ambulance cohort study (n=2,098 soft collars):
- Only 3.5% had cervical spine injury
- 8 spinal cord injuries – none attributed to soft collar use
- Patients found soft collars comfortable and complied well with immobility
- Paramedics reported easy application and effective movement minimisation
Conclusion: Soft collars do not increase risk of neurological worsening and are better tolerated.
NEANN Immobilisation & Extrication Jacket (NIEJ) – NSW Ambulance Procedure
- Apply manual in-line stabilisation + cervical collar
- Prepare NIEJ (check straps, pads, safe working load 130 kg)
- Insert NIEJ behind patient, add yellow lumbar pad
- Secure green shoulder straps, yellow/red chest straps, blue groin straps
- Position head pads + head/chin straps
- Extricate to scoop/extrication board then transfer to stretcher (remove board for transport)
Extrication Techniques – Paradigm Shift (Nutbeam et al., 2025)
Key Consensus Recommendations (FPHC 2025)
Move away from “absolute movement minimisation” toward time-critical, patient-centred care.
- Self-extrication is the preferred primary approach when clinically appropriate
- U-STEP OUT algorithm endorsed for decision-making (clinicians & FRS)
- Empower firefighters and lay persons (with appropriate training/tools)
- Reduce entrapment time – prolonged extrication increases mortality
Biomechanical Evidence – Spinal Movement (Nutbeam et al., 2022)
| Extrication Method | AP Max Movement (mm) | Total Travel (mm) |
|---|---|---|
| Self-extrication | 2.6 | 4.9 |
| Roof removal | ~5.0 | ~12.0 |
| B-post rip | ~5.5 | ~13.0 |
| Rapid removal | 6.21 | 20.51 |
Conclusion: Self-extrication causes the least spinal movement and is fastest (mean 6.4 s).
Quality Management of Suspected SCI
Step-by-Step Pre-Hospital Care
- Scene safety & PPE – consider high-risk mechanism
- ABCDE with manual in-line stabilisation (MILS) only if required
- Apply soft collar (preferred) or rigid if indicated
- Decision-making using U-STEP OUT algorithm for extrication
- Self-extrication or rapid gentle assisted extrication (do NOT delay for absolute minimisation)
- Package on scoop stretcher or vacuum mattress – remove extrication board for transport
- Neurovascular observations + SPEED tool monitoring
- Rapid transport with pre-notification (consider retrieval team for time-critical cases)
Special Populations
Paediatric Patients (≤2 years)
Challenges: Large head-to-body ratio, non-verbal, difficult to assess.
Approach: Use age-appropriate padding under shoulders, soft collar or manual stabilisation, avoid over-immobilisation. Consider carer-assisted self-extrication where possible.
Elderly Patients with Kyphosis
Harms of forced supine positioning: Increased pain, respiratory compromise, pressure injuries, worsened spinal alignment.
Appropriate approach: Position of comfort (slight head elevation or vacuum mattress contouring), soft collar, minimal movement, rapid transport.
Reflective Practice
Consider these clinical scenarios:
- A 2-year-old with suspected SCI – how would you immobilise and what challenges arise?
- A 75-year-old with kyphosis – what harms could forced supine positioning cause and how do you adapt?
- Balancing rapid extrication vs movement minimisation in a time-critical MVC.
- Barriers to using clearance rules in the field and risks of unnecessary immobilisation.