Cervical trauma

Anatomy

One of the most critical aspects of paediatric cervical spine injuries is the presence of synchondroses:

- Synchondroses are hyaline cartilage joints synonymous with long bone growth plates.

- All ossification centres should be closed by the age of 6-8 years.

Development of the Paediatric Cervical Spine

Atlas (C1)

  • 3 Primary Ossification Centres:
    • Lateral masses (x2)
    • Body

Axis (C2)

  • 5 Primary Ossification Centres:
    • Lateral masses (x2)
    • Vertically oriented centre for the odontoid (x2)
    • Body
  • Secondary Ossification Centres:
    • Tip of Dens
    • Ring Apophysis
  • The Dens is connected to the body by the Dentocentral Synchondrosis.

Subaxial Spine (C3-C7)

  • 3 Ossification Centres:
    • Neural arches (x2)
    • Body

Stability of Paediatric Cervical Spine

Children’s cervical spines have greater range of motion (ROM) and less stability due to:

1. Increased ligamentous laxity.

2. Wedge-shaped vertebrae (<8 years).

3. Facets that are more horizontal (<8 years).

4. Uncinate processes not fully developed until >8 years, which provide rotational stability.

5. The fulcrum of rotation is more cephalad (C2-3) in children under 8 years, compared to C5-6 in those older than 8.

Atlanto-Occipital Region

The stability of the Atlanto-Occipital Region is based on:

- Congruency of superior articular facets and occipital condyles.

- Alar Ligaments. - Joint capsule.

- Tectorial membrane (continuation of the posterior longitudinal ligament - PLL).

Atlanto-Axial Region

Primary Stability:

  • PEG (Dens)
  • Transverse Ligament

Secondary Stability (Check Reins):

  • Alar ligaments (Dens tip to occipital condyles)
  • Apical ligament (Dens tip to foramen magnum)

Modes of Injury

  • Fracture
  • Fracture Subluxation
  • Subluxation
  • SCIWORA (Spinal Cord Injury Without Radiographic Abnormality)

Pattern of Injury by Age

  • >8 years: Adult-like injury pattern:
    • Sub-axial spine involvement.
    • Wedge fractures, burst fractures, dislocations.
  • <8 years: Paediatric injury pattern:
    • Axial spine involvement.
    • Subluxations, fracture-subluxations, SCIWORA.
    • End plate fractures (endplate is cartilaginous and weaker than the body or disc).

Paediatric Risk Factors for C-Spine Injury

  • Cephalad fulcrum of rotation.
  • The head is disproportionately large and heavy, increasing the risk of injury.

Pseudosubluxation

  • An anatomical variant, more common in children under 8 years old.
  • Usually observed at C2-3, less frequently at C3-4.

Diagnosis

  • Swischuk’s line:
    • Spinolaminar line drawn from C1 to C3.
    • Should not show more than a 1mm step.
Injury Type Characteristics
Pseudosubluxation More common in children under 8 years old, usually at C2-3
True Subluxation Can occur after endplate fracture

Atlanto-Occipital Dissociation

  • The Atlanto-Occipital region is highly unstable in children.
  • Mortality rate: 50%.

Atlanto-Axial Rotatory Subluxation (AARS)

  • Results in Torticollis.
  • Causes:
    • Traumatic.
    • Neuromuscular, congenital, muscular (SCM), inflammatory (Grisel’s syndrome).

Atlanto-Axial Anteroposterior (AP) Instability

  • Abnormal ADI (Atlantodens Interval):
    • >5mm if the child is under 8 years.
    • >3mm if the child is over 8 years.
  • Space Available for Cord (SAC) should be greater than 13mm.
    • Reduced SAC and increased ADI may indicate potential cord compromise.

Steel’s Rule of Thirds

  • At the level of the odontoid, the space is taken up in thirds by:
    1. Cord
    2. Odontoid
    3. CSF

SCIWORA (Spinal Cord Injury Without Radiologic Abnormality)

  • Requires MRI to detect signal changes in the cord.
  • May appear normal in 30% of cases despite neurological symptoms.
  • Occurs more frequently in young children.
  • The spinal column can stretch up to 2 inches, but cord injury occurs if stretch exceeds 1cm.

Main Predictor of Outcome

  • Neurologic status at the time of presentation.

Management

  • Maintain blood pressure.
  • Use advanced imaging techniques.
  • Immobilise spine for 3 months.
  • Restrict activity for an additional 3 months.

Outcome:

  • Poor if the injury is complete.
  • Reasonable if the injury is partial.

Odontoid Fracture

  • Typically occurs through the synchondrosis in children under 3 years.
  • Results from sudden deceleration and flexion during a road traffic accident (RTA).
  • Management:
    • Immobilisation with HALO or Minerva for 3 months.

HALO Usage in Paediatrics

  • Skull considerations:
    • Thinner skull with open sutures requires special care.
    • Use more pins with less torque.
    • Example: 8-12 pins at 2-4 lb/inch torque.

Surgical Stabilisation

  • Indications:
    • Gross instability.
    • Failure to reduce closed.
    • Neurologic deficit requiring decompression.
  • Workhorse Procedure:
    • Posterior fusion up to the occiput.
    • Pre-op MRI and combine with an anterior approach if the disc needs removal.
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