Cervical Spine Fracture Grading and Management
Primary Grading System
The Subaxial Injury Classification (SLIC) System is the gold standard for grading cervical spine fractures (C3-C7), providing Level I evidence with excellent reliability for determining instability and guiding surgical decision-making. 1
The SLIC system assigns weighted scores across three critical domains:
1. Fracture Morphology
2. Discoligamentous Complex (DLC) Integrity
- Intact DLC: 0 points
- Indeterminate: 1 point
- Disrupted DLC: 2 points 1
3. Neurological Status
- Intact: 0 points
- Nerve root injury: 1 point
- Complete cord injury: 2 points
- Incomplete cord injury: 3 points 1
The total SLIC score ranges from 0-10 points and directly determines treatment approach. 2
Treatment Algorithm Based on SLIC Score
SLIC Score ≥5: Surgical Intervention Required
A SLIC score of ≥5 mandates surgical decompression, realignment, and stabilization. 1 This threshold demonstrates 93.3% agreement among experienced spine surgeons for surgical recommendations. 2
SLIC Score 3-4: Clinical Judgment Zone
- Consider patient-specific factors including age, comorbidities, and ability to tolerate prolonged immobilization
- Neurological deficits attributable to the fracture warrant immediate surgery regardless of SLIC score 3
- Multiple non-contiguous cervical injuries (present in up to 31% of cases) may require surgical stabilization even with borderline scores 3
SLIC Score <3: Conservative Management
- Rigid cervical collar immobilization for 4-8 weeks achieves solid bony union in stable fractures 3
- Prohibit all neck extension and rotational movements during immobilization period 3
Neurological Status Integration
Cervical injuries comprise 55% of all spinal cord injuries, making neurological assessment paramount. 4
Complete Cord Injury (ASIA Grade A)
- Represents 45% of spinal cord injuries in developed countries 4
- Adds 2 points to SLIC score 1
- Poor prognosis with minimal functional recovery expected, but surgery still indicated for spinal stability 2
Incomplete Cord Injury (ASIA Grades B-D)
- Adds 3 points to SLIC score (highest neurological weighting) 1
- Surgical decompression within appropriate timeframe offers potential for neurological recovery
- Post-operative ASIA score improvement averages 1.2 grades with surgical treatment versus 0.3 grades with conservative management 5
Nerve Root Injury Only
- Adds 1 point to SLIC score 1
- May benefit from surgical decompression if compression is radiographically evident
Critical Diagnostic Imaging Requirements
Immediate CT Imaging Protocol
Plain radiographs miss up to 77% of cervical spine abnormalities and 15% of cervical injuries, making them inadequate for clearance. 4, 3
- Obtain CT with 1.5-2mm collimation of entire cervical spine immediately 3
- 20% of spine trauma patients have non-contiguous injuries at multiple levels requiring full spine imaging 4
MRI Indications
Normal CT does not exclude significant injury in patients with neurological symptoms, as purely ligamentous injuries and cord contusions are invisible on CT. 4
- MRI is mandatory for any patient with neurological deficits 4
- Over 13% of post-traumatic epidural hematomas have normal CT scans 4
- Up to 25% of cervical spine injuries involve unstable ligamentous injuries invisible on plain radiographs and CT 4
- MRI directly visualizes cord injury, ligamentous disruption, and epidural hematoma 4
Upper Cervical Spine (C1-C2) Considerations
Upper cervical injuries require separate classification systems as they follow different biomechanical patterns than subaxial injuries:
- Occipital condyle fractures
- Atlas (C1) fractures
- Atlantoaxial dislocations
- Odontoid (C2) fractures
- Hangman's fractures 6
High cervical injuries carry the highest immediate mortality risk due to proximity to the respiratory center and phrenic nerve involvement (C3-C5). 4
Follow-Up Imaging Protocol
Serial CT Assessment
- Baseline CT within first week after initiating treatment 3
- Repeat CT at 4-6 weeks to assess healing progression and detect delayed instability 3
- Final CT at 8-12 weeks to confirm solid bony union before discontinuing collar 3
Avoid Dynamic Fluoroscopy
Routine dynamic fluoroscopy should be avoided in the acute phase (first 6-8 weeks) as neck pain and muscle spasm limit diagnostic utility. 3
Critical Pitfalls to Avoid
Missed Injury Prevention
A missed or delayed diagnosis produces 10 times the rate of secondary neurological injury (10.5% vs 1.4%). 7 Up to 4.3% of cervical fractures are missed, with 67% of these patients suffering neurological deterioration. 7
- Clinical examination alone has only 85% sensitivity and misses 10-15% of injuries 3
- Maintain cervical spine immobilization until imaging definitively clears the spine 7
- Presence of severe head injury (GCS <8) increases cervical spine injury incidence to 7.8-10.2% 7
Immobilization Complications
- Prolonged immobilization carries significant attributable morbidity 7
- Monitor for skin breakdown and muscle atrophy during collar use 3
- Do not permit chiropractic manipulation as high-velocity rotational techniques risk worsening nerve compression 3
MRI Over-Interpretation
MRI has high sensitivity but poor specificity, potentially leading to unnecessary prolonged collar use in 25% of patients. 3 Do not rely on MRI abnormalities alone to guide immobilization duration without correlating with clinical instability.
Reliability Data
The SLIC system demonstrates superior reliability compared to older classification systems: