C3-C7 Injuries | SLIC Score Guides Treatment | Anterior vs Posterior Approach
- SLIC score (morphology + DLC + neurology) guides surgical decision-making
- Disco-ligamentous complex (DLC) is the key determinant of instability
- MRI essential to assess DLC integrity and cord compression
- Anterior approach for disc/vertebral body pathology, posterior for facet/lamina
- Combined approach for severe instability or when anterior alone insufficient
- “SLIC 4 or more indicates surgical management
- “Indeterminate DLC on MRI = 1 point, disrupted = 2 points
- “Incomplete cord injury with ongoing compression = urgent surgery
- “Facet dislocations often require posterior reduction first
Three components: Morphology (0-4) + DLC status (0-2) + Neurological status (0-4). Score of 4 or more indicates surgical intervention. Know each component scoring.
Disco-ligamentous complex includes disc, ALL, PLL, ligamentum flavum, interspinous ligaments, facet capsules. MRI required for assessment. Disrupted DLC = unstable.
Anterior approach: corpectomy/discectomy, kyphosis correction, ventral compression. Posterior approach: facet injuries, lamina fractures, posterior tension band disruption.
Complete injury: stable neurology, timing less critical. Incomplete injury with compression: urgent decompression within 24 hours improves outcomes (STASCIS data).
- Injury Pattern
- Compression fracture, intact DLC
- Treatment
- Rigid collar 6-12 weeks
- Key Pearl
- Non-op if DLC intact - most common scenario
- Injury Pattern
- Indeterminate stability
- Treatment
- Surgeon preference
- Key Pearl
- MRI critical - DLC status determines treatment
- Injury Pattern
- Burst + DLC disruption
- Treatment
- Surgical stabilization
- Key Pearl
- Consider anterior corpectomy with cage
- Injury Pattern
- Fracture-dislocation + incomplete SCI
- Treatment
- Urgent surgical decompression
- Key Pearl
- Within 24h for incomplete SCI with compression
MDNSLIC Score Components
Hook:MDN - Morphology, DLC, Neurology determine stability - score 4 or more means surgery!
CBDTMorphology Scoring
Hook:C1-B2-D3-T4: Compression 1, Burst 2, Distraction 3, Translation 4 - easy to remember!
DAPLICDLC Components
Hook:The DLC is the key - if disrupted, the spine is unstable regardless of bone injury!
AVPApproach Selection
Hook:Anterior pathology = Anterior approach; Posterior pathology = Posterior approach - match the pathology to the approach!
Overview and Epidemiology
Subaxial cervical spine injuries (C3-C7) represent approximately 50% of all cervical spine fractures. These injuries carry significant morbidity due to the high rate of associated spinal cord injury.
Epidemiology:
- Bimodal age distribution (young trauma, elderly falls)
- Male predominance (3:1)
- Most common at C5-C6 level (greatest mobility)
- MVA and falls are primary mechanisms
- Associated spinal cord injury in up to 55%
The C5-C6 level is most commonly injured because it represents the transition zone between the more mobile middle cervical spine and the relatively stiffer lower cervical spine. This biomechanical transition creates a stress concentration point.
Mechanism patterns:
- Flexion-compression: Burst fractures, teardrop fractures
- Extension-compression: Lamina fractures, hangman's variants
- Flexion-distraction: Facet dislocations, posterior ligament disruption
- Axial compression: Burst fractures
- Lateral flexion: Unilateral injuries
Anatomy and Biomechanics
Key anatomical structures:
The subaxial cervical spine (C3-C7) has consistent anatomy with:
- Vertebral body - primary load-bearing structure
- Facet joints - 45-degree orientation, guide motion
- Uncovertebral joints - resist lateral translation
- Intervertebral disc - shock absorption, motion
- Ligamentous structures - stability through ROM
The DLC is the primary determinant of stability. It includes:
- Intervertebral disc
- Anterior longitudinal ligament (ALL)
- Posterior longitudinal ligament (PLL)
- Ligamentum flavum
- Interspinous and supraspinous ligaments
- Facet capsules
If the DLC is disrupted, the injury is unstable regardless of bony injury severity.
Spinal cord considerations:
- Cervical cord enlargement (C4-T1) - higher injury consequence
- Space available for cord = canal diameter minus cord diameter
- Normal canal diameter approximately 17mm
- Cord diameter approximately 10mm
- Stenosis increases injury severity for same energy
- Primary Motion
- Flexion/extension
- Clinical Significance
- Early degenerative changes
- Primary Motion
- Flexion/extension
- Clinical Significance
- Common stenosis level
- Primary Motion
- Maximum motion
- Clinical Significance
- Most common injury level
- Primary Motion
- Transition zone
- Clinical Significance
- Stress concentration
- Primary Motion
- Cervicothoracic junction
- Clinical Significance
- Mechanically critical
Neurological anatomy:
- Cervical nerve roots exit above their numbered vertebra (C6 root exits C5-C6 foramen)
- Exception: C8 root exits below C7 (no C8 vertebra)
- Root injury more common than cord injury in unilateral facet injuries
- Cord injury more common with bilateral facet dislocations
Classification Systems
Subaxial Cervical Spine Injury Classification (SLIC)
The SLIC system is the most widely used classification for guiding treatment decisions.
Component 1: Morphology (0-4 points)
- Points
- 0
- Description
- Normal alignment and structure
- Points
- 1
- Description
- Loss of anterior height, intact posterior
- Points
- 2
- Description
- Anterior and posterior cortex involved
- Points
- 3
- Description
- Abnormal separation of vertebrae
- Points
- 4
- Description
- Horizontal displacement or rotation
Component 2: Disco-Ligamentous Complex (0-2 points)
- Points
- 0
- MRI Findings
- Normal signal, no disruption
- Points
- 1
- MRI Findings
- Isolated interspinous widening, subtle changes
- Points
- 2
- MRI Findings
- High signal in disc, widened facets, ligament rupture
Component 3: Neurological Status (0-4 points)
- Points
- 0
- Modifier
- No neurological deficit
- Points
- 1
- Modifier
- Single nerve root deficit
- Points
- 2
- Modifier
- ASIA A
- Points
- 3
- Modifier
- ASIA B, C, or D
- Points
- +1
- Modifier
- Add to incomplete score
- SLIC 0-3: Non-operative (rigid collar 6-12 weeks)
- SLIC 4: Indeterminate (surgeon preference)
- SLIC 5+: Operative treatment recommended
Clinical Assessment
History:
- Mechanism of injury (high vs low energy)
- Time since injury
- Any neurological symptoms (weakness, numbness, bladder/bowel)
- Previous cervical spine problems
- Medical comorbidities affecting surgical decision
Physical examination:
- Airway: Consider early intubation if unstable
- Breathing: Diaphragmatic if high cord injury
- Circulation: Neurogenic shock (bradycardia + hypotension)
- Associated injuries: Head, chest, polytrauma
- Inspection: Bruising, deformity, step-off
- Palpation: Tenderness, interspinous widening
- Range of motion: Do NOT test if unstable suspected
- Log-roll: Clear entire spine
Neurological examination:
- Description
- Complete
- Motor/Sensory
- No motor or sensory below level
- Description
- Sensory incomplete
- Motor/Sensory
- Sensory but no motor below level
- Description
- Motor incomplete
- Motor/Sensory
- Motor below level, less than half key muscles grade 3+
- Description
- Motor incomplete
- Motor/Sensory
- Motor below level, at least half key muscles grade 3+
- Description
- Normal
- Motor/Sensory
- Normal motor and sensory
Complete neurological examination documented at presentation is essential for:
- Baseline for monitoring deterioration
- Surgical decision-making
- Prognostication
- Medicolegal protection
- C4: Shoulder
- C5: Lateral arm, deltoid
- C6: Thumb, wrist extensors
- C7: Middle finger, triceps
- C8: Little finger, finger flexors
- T1: Medial arm, intrinsics
- C5: Deltoid, biceps
- C6: Wrist extensors, brachioradialis
- C7: Triceps, wrist flexors
- C8: Finger flexors
- T1: Finger abduction (intrinsics)
The key reasoning step is separating a genuinely unstable subaxial fracture (operative threshold) from mimics that change urgency or treatment.
- Distinguishing feature
- Cortical break, malalignment, DLC disruption on MRI
- Key discriminator
- CT fracture + SLIC/AO Spine pattern; MRI confirms DLC
- Distinguishing feature
- Neurological deficit with normal CT and X-ray
- Key discriminator
- MRI cord signal change without bony injury
- Distinguishing feature
- Trivial mechanism, rigid spine, transverse 'carrot-stick' fracture
- Key discriminator
- Whole-spine CT; treat as unstable even if subtle
- Distinguishing feature
- Hands worse than legs, hyperextension, frequently no fracture
- Key discriminator
- MRI cord oedema, pre-existing canal stenosis
- Distinguishing feature
- Normal CT but interspinous widening / facet fluid
- Key discriminator
- MRI STIR high signal; flexion-extension only when safe
- Distinguishing feature
- Chronic radiculopathy, no acute trauma
- Key discriminator
- Osteophytes, disc desiccation, no acute oedema
- Distinguishing feature
- Posterior circulation symptoms, transverse foramen fracture
- Key discriminator
- CT angiography
A subaxial fracture in an ankylosed spine (ankylosing spondylitis or DISH) is the highest-stakes pattern and is repeatedly examined because it is so often missed and mismanaged:
- Mechanism and pattern: the fused, brittle spine behaves like a long bone - even a trivial low-energy fall produces a transverse, highly unstable three-column "carrot-stick" fracture, often through a fused disc space, with long lever arms above and below.
- Why it is missed: the fracture line is subtle against the abnormal fused/ossified spine, plain films are unreliable, and the patient often has a pre-existing kyphotic deformity - so whole-spine CT (and a low threshold for MRI) is mandatory in any ankylosed patient with neck pain after even minor trauma. There is a high rate of epidural haematoma and delayed neurological deterioration.
- Positioning trap: never force the neck into "neutral" or extension - support the patient in their fixed pre-injury deformity (reverse Trendelenburg, padding); forcing alignment can complete the injury and cause catastrophic cord injury.
- Treatment: these are unstable and treated surgically even when subtle - typically long-segment posterior fixation (often multiple levels above and below), or a combined construct; short anterior-only fixation fails. Mortality and complication rates are high.
Exam point: an ankylosed (AS/DISH) cervical spine fracture from a trivial fall is an unstable transverse three-column injury - image the whole spine with CT, don't realign the fixed deformity, watch for epidural haematoma, and stabilise with a long posterior/combined construct.
Investigations
Imaging Protocol
First-line imaging for trauma. Thin-cut CT from occiput to T1. Sagittal and coronal reconstructions essential. Sensitivity more than 99% for fractures.
Essential for DLC assessment. Shows disc herniation, ligament rupture, cord contusion, epidural hematoma. STIR sequences best for ligament injury.
Extend imaging to assess cervicothoracic junction. Often obscured on plain films.
Thin-cut CT at 3-6 months to assess fusion. Earlier if concerns about hardware.
CT interpretation:
Key features to document:
- Vertebral body morphology (compression, burst, translation)
- Facet alignment (subluxation, perched, locked)
- Canal compromise (percentage)
- Fragment retropulsion
- Spinous process widening (suggests posterior ligament injury)
MRI is mandatory for SLIC scoring because DLC status cannot be determined from CT alone. Indeterminate or disrupted DLC significantly changes the score and treatment recommendation.
MRI interpretation:
- T2/STIR high signal in disc: Disruption
- Widened interspinous space with edema: Posterior ligament injury
- Facet fluid/widening: Capsule disruption
- Cord signal change: Contusion/hemorrhage (poor prognostic sign)
- Epidural hematoma: May require urgent decompression
- Primary Imaging
- CT cervical spine
- Additional Imaging
- MRI if surgery planned
- Primary Imaging
- CT then urgent MRI
- Additional Imaging
- CT angiography if high suspicion dissection
- Primary Imaging
- MRI for DLC
- Additional Imaging
- Flexion-extension rarely indicated acutely
- Primary Imaging
- X-ray series
- Additional Imaging
- CT at 3-6 months for fusion
Management Algorithm
All patients with suspected cervical spine injury require:
- Immobilization with rigid collar
- Log-roll precautions
- Neurological documentation
- MAP optimization (target 85-90mmHg for incomplete SCI)
Indications for Non-Operative Treatment
SLIC score 0-3 with:
- Intact disco-ligamentous complex
- No neurological deficit
- Minimal displacement
- Stable fracture pattern
- Hard collar (Miami J, Philadelphia) for 6-12 weeks
- Serial lateral X-rays at 2, 6, and 12 weeks
- Assess for progressive kyphosis or translation
- ROM exercises after collar removed
- Physiotherapy for strengthening
- Kyphosis progression more than 10 degrees = surgical consideration
- Development of neurological symptoms = urgent MRI
- Failure to heal at 12 weeks = consider surgery
Conversion to surgery indicated for:
- Progressive kyphosis more than 10-15 degrees
- Late neurological deterioration
- Persistent instability on flexion-extension films
- Non-union at 3-6 months
The commonest incomplete cord syndrome and a quintessentially subaxial problem - it is distinct from the unstable-fracture algorithm above and is examined as the "old person who fell and can't use their hands":
- Who/mechanism: typically an older patient with a spondylotic, stenotic cervical spine sustaining a hyperextension injury (often a fall onto the face/forehead) - frequently with no fracture or only minor injury. The cord is pinched between anterior osteophytes/disc and the inbuckling ligamentum flavum posteriorly.
- The signature deficit: upper limbs affected more than lower limbs (hands worst of all), with variable sensory loss and sometimes bladder dysfunction - because the centrally located cervical (hand) motor fibres are preferentially injured.
- Diagnosis: MRI shows central cord oedema/haemorrhage on a background of stenosis, usually without instability on CT (contrast with the SLIC fracture pathway).
- Management controversy: many patients recover substantially with supportive care (MAP support, no fracture to fix), so historically treatment was non-operative - but the modern trend favours decompression (often subacute/early) for significant ongoing cord compression, especially if recovery plateaus; timing is debated and individualised. Recovery follows a typical pattern: legs recover before the hands, with hand intrinsic function the last and least to return.
Exam point: an elderly patient with a hyperextension injury, hands-worse-than-legs weakness and a stenotic spine without a fracture is central cord syndrome - confirm on MRI, support the MAP, and decompress for significant persisting compression; the hands recover last.
Surgical Technique
Pre-operative Planning
- Neurological injury: Risk of worsening (1-2%)
- Infection: Superficial 2-3%, deep less than 1%
- Dysphagia (anterior): 50% early, 5% persistent
- Hardware failure: 5-10%
- Adjacent segment disease: Long-term risk
- Recurrent laryngeal nerve (anterior): 2-5%
- Imaging: Fluoroscopy or navigation
- Implants: Plates/screws (anterior), lateral mass screws (posterior)
- Cage/graft: Structural allograft or cage for corpectomy
- Neuromonitoring: SSEPs and MEPs
- Cell saver: For multilevel procedures
Anterior Cervical Approach (Smith-Robinson)
Step-by-Step Technique
Supine on radiolucent table. Head in neutral with gentle traction (Gardner-Wells if needed). Shoulder roll to extend neck. Arms tucked at sides.
Transverse incision at appropriate level (C5-6 at thyroid cartilage). Develop plane between carotid sheath laterally and trachea/esophagus medially. Retract longus colli muscles.
Identify level with fluoroscopy. Mark with needle if uncertain. Expose vertebral bodies and discs. Preserve anterior longitudinal ligament if possible.
Discectomy or corpectomy as indicated. Remove PLL to decompress canal. Visualize dura. Remove retropulsed fragments.
Cage or graft to restore height. Size appropriately (1-2mm larger). Position centrally. Confirm alignment on fluoroscopy.
Anterior plate spanning construct. Bicortical screws (4-5mm engaging posterior cortex). Confirm position with lateral fluoroscopy.
Esophageal perforation is rare but devastating. Risk factors include:
- Previous anterior surgery
- Prominent osteophytes
- Excessive retraction
- Long operative time
Protect with gentle retractor placement and intermittent release.
Intraoperative Troubleshooting
- Cause
- Locked facet, interposed fragment
- Solution
- Increase distraction, open facet capsule, remove fragment
- Cause
- Lateral screw trajectory, dissection too lateral
- Solution
- Pack with hemostatic agent, complete surgery, do NOT attempt repair
- Cause
- Dural tear during decompression
- Solution
- Primary repair if possible, dural sealant, lumbar drain
- Cause
- Cord compression, hypotension, positioning
- Solution
- Stop, check BP, optimize positioning, consider wake-up test
Complications
- Incidence
- 1-3%
- Prevention/Management
- Careful reduction, neuromonitoring, appropriate timing
- Incidence
- Up to 50% early
- Prevention/Management
- Gentle retraction, minimize operative time
- Incidence
- 2-5%
- Prevention/Management
- Left-sided approach traditionally preferred (more consistent RLN course); careful retraction
- Incidence
- 5-10%
- Prevention/Management
- Appropriate construct length, bone quality assessment
- Incidence
- 5-10%
- Prevention/Management
- Adequate graft, smoking cessation, consider BMP
- Incidence
- Up to 25% at 10 years
- Prevention/Management
- Limit fusion length, preserve motion where possible
- Incidence
- 1-3%
- Prevention/Management
- Prophylactic antibiotics, meticulous technique
- Incidence
- Less than 1%
- Prevention/Management
- Preoperative CT angiography, careful screw placement
- Most feared complication
- Risk higher with incomplete SCI
- Prevention: neuromonitoring, careful reduction, avoid over-distraction
- Very common early (50%)
- Usually resolves within weeks
- Persistent in 5-10%
- Consider thin liquids initially, speech pathology review
Left-sided approach is traditionally preferred because the recurrent laryngeal nerve has a more consistent course in the tracheoesophageal groove. On the right, it loops around the subclavian artery and has a variable course. However, right-sided revision is preferred if previous left approach.
Postoperative Care and Rehabilitation
Rehabilitation Timeline
- ICU monitoring if SCI or high-risk
- Neurological checks every 4 hours
- DVT prophylaxis
- Early mobilization assessment
- Speech pathology if anterior (nil by mouth initially)
- Transition to ward if stable
- Begin mobilization with collar
- Physiotherapy assessment
- Diet advancement (anterior)
- Wound check
- Wound review at 2 weeks
- Continue hard collar
- X-ray at 6 weeks
- Progressive mobilization
- SCI rehabilitation if indicated
- X-ray assessment of fusion
- Consider collar weaning if stable
- Increase activity
- Physio for strengthening
- CT to confirm fusion
- Collar removal if fused
- Return to work assessment
- Long-term follow-up for adjacent segment disease
Collar protocol:
- Most surgeons use hard collar for 6-12 weeks post-operatively
- Earlier removal if rigid internal fixation and good bone quality
- Longer if osteoporosis, multilevel, or concern about stability
Outcomes and Prognosis
- Complete SCI (ASIA A): Minimal recovery expected, focus on rehabilitation
- Incomplete SCI: Significant potential for recovery, especially with early decompression
- Root injury: Usually good recovery over 6-12 months
- Severity of initial injury
- Timing of decompression (for incomplete SCI)
- Quality of reduction and stabilization
- Patient factors (age, comorbidities, smoking)
- Compliance with rehabilitation
Early surgery (less than 24 hours) for incomplete SCI results in:
- 19.8% improve at least 2 ASIA grades (vs 8.8% late)
- Lower complication rates
- Shorter ICU stay
- Faster rehabilitation
Long-term considerations:
- Adjacent segment disease in up to 25% at 10 years
- Hardware removal rarely needed unless symptomatic
- Ongoing surveillance for late instability
- Return to contact sports controversial
Guidelines, Registries & Global Practice
Global epidemiology. Subaxial injuries account for approximately half of cervical spine fractures, with C5-C6 the most frequently injured level (the mobile-to-stiff transition zone). Across resource settings the demographic is consistent: predominantly young males injured by road traffic accidents, with falls dominating in the elderly. In a meta-analysis of 11,639 patients across 16 African countries, road traffic accidents caused 49.5% of traumatic spine injuries, the cervical spine was the most common level (51.6%), patients were 81% male with a mean age of 34.5 years, and surgery was performed in only 31.9% versus a majority managed conservatively, with 12.1% mortality (Darko et al, J Neurosurg Spine 2024, DOI). This contrasts with high-income systems where most unstable injuries are operated early.
- Region
- International
- Core recommendation
- Decompression within 24h for any-level acute SCI; no recommendation for ultra-early (<12h)
- Evidence basis
- GRADE guideline; RR 2.76 for 2-grade AIS gain at 6 months (PMID 38526922)
- Region
- International
- Core recommendation
- Operate if score 5 or more; 4 indeterminate; 0-3 non-operative
- Evidence basis
- Consensus + validation, 93.3% treatment-algorithm agreement (PMID 17906580)
- Region
- International
- Core recommendation
- Morphology A/B/C + facet (F) + neurology (N) + modifiers (M) for communication and research
- Evidence basis
- Consensus, substantial reliability kappa 0.64-0.75 (PMID 25716661)
- Region
- USA
- Core recommendation
- Closed reduction acceptable in awake, examinable patients; MRI before reduction in obtunded patients
- Evidence basis
- Systematic review, mostly low-level evidence
- Region
- UK
- Core recommendation
- CT first line for adults with suspected significant cervical injury; MRI if neurology or ligamentous concern
- Evidence basis
- Guideline development group review
Registry & systematic-review evidence. Cervical trauma is not captured by arthroplasty joint registries; the comparative evidence base is national trauma databases and pooled reviews rather than a single implant registry. Pooled data in rigid (ankylosing) cervical spines - a high-risk subaxial subgroup - confirm the C6-C7 / C5-C6 predominance and show combined anterior-posterior constructs carry the lowest reoperation rate (1.7%) versus anterior-only fixation (11.1%) (Musa et al, Neurosurg Rev 2025, DOI).
- Variation
- Awake closed reduction (some N. American/European units) vs MRI-first then open reduction
- Driver
- Concern over traumatic disc herniation; obtunded vs examinable patient
- Variation
- Largely abandoned in UK/Australasia; occasional optional use within 8h elsewhere
- Driver
- Net harm signal; weak guideline support
- Variation
- Within 24h standard in high-income systems; often delayed in limited-resource settings
- Driver
- Theatre access, transfer distance, surgical capacity
- Variation
- MAP 85-90 mmHg for ~7 days widely used; duration and target debated
- Driver
- Low-level supportive evidence only
- Baseline neurological examination documented before any intervention or transfer (ASIA/AIS grade, single root vs cord)
- SLIC or AO Spine classification and MRI DLC status recorded with the management rationale and timing decision
- Informed consent covering neurological risk, approach-specific complications and possible revision
- Transfer: notify the receiving spinal unit early, maintain MAP 85-90 mmHg, and avoid secondary insults (hypoxia, hypotension) en route
- Common pitfalls: delayed diagnosis, missed injury on plain films, and neurological deterioration during reduction or transfer
MCQ Practice Points
Q: A patient has a C6 burst fracture (CT), high signal in disc on MRI, and no neurological deficit. What is the SLIC score? A: Morphology (burst) = 2 + DLC (disrupted) = 2 + Neurology (intact) = 0 = SLIC 4 (indeterminate - surgeon discretion)
Q: Which MRI finding indicates disrupted disco-ligamentous complex? A: High signal in disc, widened interspinous space with edema, facet widening with fluid. All three suggest DLC disruption = 2 points on SLIC.
Q: What is the preferred approach for a C5 burst fracture with retropulsed fragment causing cord compression? A: Anterior corpectomy - allows direct decompression of ventral canal compression and restoration of anterior column height.
Q: What does STASCIS show about timing of surgery for incomplete SCI? A: Surgery within 24 hours results in 19.8% improving at least 2 ASIA grades vs 8.8% for late surgery.
Q: What is the trajectory for lateral mass screws in the subaxial cervical spine? A: Entry 1mm medial and caudal to center of lateral mass. Trajectory 30 degrees lateral and 15-20 degrees cephalad (Magerl technique).
Q: A C5-6 disc herniation will compress which nerve root? A: C6 nerve root - cervical nerve roots exit above their numbered vertebra (C6 root exits C5-6 foramen).
Exam Viva Scenarios
Practise clinical reasoning and management decisions out loud
“A 35-year-old motorcyclist presents after an MVA. CT shows a C5 burst fracture with 50% canal compromise. He has weakness in his right deltoid (4/5) but otherwise intact neurology. MRI shows high signal in the C5-6 disc and widened interspinous space at C5-6. What is your assessment and management?”
“Walk me through your approach selection for a C6-7 fracture-dislocation with bilateral facet dislocation and an associated C6-7 disc herniation causing cord compression. The patient has ASIA C incomplete SCI.”
“You have performed an anterior cervical discectomy and fusion at C5-6 for a trauma patient. Post-operatively, he develops increasing stridor and respiratory distress 6 hours after surgery. How do you manage this?”
SLIC Classification
- Morphology: Compression=1, Burst=2, Distraction=3, Translation=4
- DLC: Intact=0, Indeterminate=1, Disrupted=2
- Neurology: Intact=0, Root=1, Complete SCI=2, Incomplete=3, +1 if ongoing compression
- SLIC 0-3=non-op, 4=indeterminate, 5+=surgical
Key Anatomy
- C5-C6 most common injury level
- DLC = disc + ALL/PLL + posterior ligaments + facet capsules
- Cervical roots exit ABOVE numbered vertebra (C6 at C5-6)
- Vertebral artery at risk with lateral screw trajectory
Approach Selection
- Anterior: burst, disc, ventral compression, kyphosis
- Posterior: facet injury, posterior ligaments, multilevel
- Combined: severe instability, 3-column injury
- Posterior first if facet dislocation + disc herniation
Surgical Pearls
- Lateral mass screws: 1mm medial/caudal, 30deg lateral, 15-20deg cephalad
- Neuromonitoring essential for reduction
- Left approach traditionally preferred (more consistent RLN course); right for revision
- Consider combined if DLC disrupted with corpectomy
Complications
- Dysphagia 50% early, 5% persistent
- RLN injury 2-5%
- Hardware failure 5-10%
- Adjacent segment disease 25% at 10 years
Evidence Base
STASCIS: Surgical Timing in Acute Spinal Cord Injury Study
- Multicentre prospective cohort study of 313 adults with acute cervical SCI
- Early surgery (less than 24h, mean 14.2h) vs late (24h or more, mean 48.3h)
- Early surgery: 19.8% improved at least 2 ASIA grades vs 8.8% (OR 2.57, 95% CI 1.11-5.97)
- Adjusted odds of 2-grade AIS improvement 2.8x higher with early surgery; no increase in complications
SLIC: The Subaxial Cervical Spine Injury Classification System
- Derived by the Spine Trauma Study Group from literature review and expert consensus, then tested by 20 surgeons on 11 cases
- Three weighted domains: morphology, disco-ligamentous complex (DLC) and neurological status, summed to a severity score
- Interrater ICC: morphology 0.57, DLC 0.49, neurology 0.87; raters agreed with the algorithm's treatment recommendation in 93.3% of cases
- Reliability compared favourably with the Harris and Allen-Ferguson systems
AO Spine Subaxial Cervical Spine Injury Classification System
- Morphology-based system mirroring the thoracolumbar AO scheme: A (compression), B (tension band) and C (translation), plus facet (F) subtypes
- Adds neurological status (N0-Nx) and case-specific modifiers (M1-M4)
- Intraobserver reliability kappa 0.75, interobserver kappa 0.64 (substantial) in the validation exercise
- Developed by international consensus for both clinical and research communication
AO Spine / GSJ Updated Clinical Practice Guideline: Role and Timing of Decompressive Surgery in Acute SCI
- International multidisciplinary GRADE guideline updating the 2017 recommendations
- Early surgery (24h or less) recommended as the preferred option for adult acute SCI regardless of level
- Patients 2.76x more likely to gain at least 2 AIS grades at 6 months (RR 2.76, 95% CI 1.60-4.98) and 1.95x at 12 months
- Mean additional 4.50-point ASIA Motor Score gain; no recommendation for ultra-early (<12h) surgery on current evidence
Approach Selection in Rigid (Ankylosing) Cervical Spine Fracture: Systematic Review and Meta-analysis
- 66 studies, 1972 patients with cervical fracture in ankylosing spondylitis (a high-risk subaxial subgroup)
- Most fractures at C6-C7 (36.7%) and C5-C6 (27.7%), echoing the subaxial transition-zone pattern
- Posterior fusion most utilised (40.0%); combined anterior-posterior fusion had the lowest reoperation rate (1.7%) vs anterior alone (11.1%)
- Good neurological outcome in 63.4%; overall mortality 2.9%
Global Burden of Traumatic Spine Injury: Systematic Review and Meta-analysis (Africa)
- 105 studies, 11,639 patients across 16 African countries - illustrating practice in limited-resource settings
- Road traffic accidents the leading mechanism (49.5%); cervical the most common level (51.6%); 81% male, mean age 34.5 years
- Mean time injury-to-presentation 60.8 hours and mean 272.6 km to a facility - major access barriers
- Only 31.9% underwent surgery (vs majority conservative); mortality 12.1%, reflecting the high-income vs LMIC outcome gap