SCIWORA

Definition

Spinal cord injury without radiographic abnormality (SCIWORA) denotes a clinical syndrome of post-traumatic spinal cord injury (objective neurological deficits) with normal plain radiographs and computed tomography (CT).

• Historical context: Coined by Pang and Wilberger in 1982 (pre-MRI era).
• Modern context: With the advent of magnetic resonance imaging (MRI), many cases show detectable soft tissue or cord injury. If MRI is also normal, the term SCIWONA (Spinal cord injury without neuroimaging abnormality) is occasionally used, though SCIWORA remains the standard nomenclature in most exam settings.

Epidemiology

• Demographics: Predominantly paediatric population (specifically <8 years old).
• Incidence: Accounts for ~20–30% of paediatric spinal cord injuries.
• Location: Cervical spine is the most common site (C-spine), specifically the upper cervical spine in younger children due to biomechanics.

Pathophysiology

These are biology and physical factors that predispose children to SCIWORA.

1. Biomechanics: Disparity in elasticity between the highly stretchable vertebral column and the rupture prone spinal cord.
2. Anatomical predisposing factors:
   • Generalised ligamentous laxity.
   • Shallow, horizontally oriented facet joints.
   • Relative head-to-body mass ratio disproportion (high fulcrum of movement).
   • Uncalcified synchondroses.
3. Mechanism of injury: usually hyperextension or distraction. The spinal column transiently subluxes, compresses/stretches the cord, and recoils to a normal alignment.

Clinical presentation

• History: High-energy trauma (RTA, fall from height) or sports injury.
• Neurology: Variable. Ranges from transient paraesthesia/stinger to complete cord transection syndrome (tetraplegia).
• Delayed onset: Neurological deficits may be delayed (hours to days) in up to 25–50% of cases ('lucid interval').

Imaging findings

Plain radiograph & CT

• Findings: By definition, normal.
• Role: To exclude fractures, permanent subluxation, or bony malalignment.
• Note: In exams, look closely for subtle signs of instability which would technically exclude the diagnosis of SCIWORA (e.g., widening of interspinous distance).

MRI (Gold standard)

MRI is required to assess cord integrity and ligamentous injury.

• Protocol: Sagittal T1, T2, STIR; Axial T2/MERGE.
• Patterns of injury:
  1. Cord oedema: Focal T2 hyperintensity.
  2. Cord haemorrhage: T1/T2 hypointensity (blooming on GRE/SWI).
  3. Ligamentous injury: Disruption of ALL, PLL, or ligamentum flavum (T2 hyperintense signal).
  4. Normal MRI: True SCIWONA (prognostically better).

Differential diagnosis

• Traumatic myelopathy: Associated with fracture/dislocation.
• Spinal shock: Transient physiological reflex depression (clinical diagnosis).
• Guillain-Barré syndrome: Ascending paralysis (unlikely in acute trauma context).
• Transverse myelitis: Inflammatory aetiology.

Management & prognosis

Management

1. Immobilisation: Strict external immobilisation (rigid collar) for 12 weeks to prevent recurrent injury during the healing of occult ligamentous damage.
2. Steroids: Methylprednisolone (NASCIS protocols). Controversial.
   • NICE Guidelines (UK): Do not routinely use high-dose steroids for acute spinal cord injury.
3. Neurosurgical input: Rarely requires decompression unless there is disc herniation or evolving instability.

Prognosis

• Complete cord injury: Poor recovery.
• Incomplete injury: Good potential for recovery, especially in young children.
• MRI correlation: Normal MRI > Oedema only > Haemorrhage (worst).

Key exam points

• The "mismatch": Remember the elasticity difference (column stretches more than cord).
• The "lucid interval": Be aware that paralysis can occur after the initial event.
• Recurrence: Re-injury rate is high if not immobilised; advise against contact sports initially.
• NICE NG41: MRI is mandatory for unexplained neurological signs.