SCIWORA

Definition. SCIWORA is spinal cord injury without radiographic abnormality: objective signs of myelopathy with normal plain radiographs and CT. Pang and Wilberger coined the term in 1982, when the imaging that had to be normal was plain films and tomography. MRI now often shows the "abnormality" in the soft tissues, but the term persists.

Who. Predominantly children under 8. The elasticity of the spine decreases with age, so true SCIWORA becomes rarer in adolescents. It accounts for 20-30% of paediatric spinal cord injuries and is the most common pattern of cord injury in young children; series that count all paediatric spinal injuries, not only cord injuries, put it at 6-19% (see the evidence below).

Where. The cervical spine is most commonly involved: the upper cervical spine in the very young, the lower cervical spine in older children. Thoracic SCIWORA is rare and often associated with high-velocity distraction (lap-belt injury).

Why the original series mattered. Pang and Wilberger shifted the focus from fractures to neurology. Before them, many children with normal X-rays were dismissed as malingerers or "hysterical". They found that 52% of these children had a delayed onset of severe paralysis, typically between 30 minutes and 4 days after injury, and from that came the cardinal rule: treat the symptoms, not the X-ray.

The mismatch (Leventhal). The spinal column can be distracted up to 2 inches without structural failure, because its ligaments and discs are elastic, but the spinal cord ruptures after only 1/4 inch. Hyperextension or distraction stretches the column and tractions the cord to failure, and the column then recoils to normal alignment. The cord is injured; the X-ray and CT look perfect.

Why the child's spine. The paediatric cervical spine has biomechanical properties that predispose to SCIWORA:

• Ligamentous laxity - generalised joint hypermobility allows excessive intersegmental motion
• Horizontal facet joints - flatter than the vertical adult facets, so they allow significant AP translation (sliding) without fracture or dislocation
• Large head-to-body ratio - the head is disproportionately large and heavy, and in young children the fulcrum of motion is at C1-C2 rather than the adult C5-C6, which puts the upper cervical cord at highest risk in toddlers
• Undeveloped uncinate processes - the joints of Luschka are flat until they ossify and heighten by age 10, and without these bony side-walls there is less resistance to lateral and rotational forces
• Anterior wedging of the vertebral bodies, which facilitates hyperflexion
• Incomplete ossification of the odontoid
• Cartilaginous endplates, which allow deformation

The cord's blood supply. It is tenuous, particularly the anterior spinal artery. Watershed zones (T4-T8) are vulnerable, but in cervical SCIWORA the mechanism is often traction injury to the penetrating vessels. The vampire bite sign, tiny paired hyperintensities on axial MRI, represents disruption of the central sulcal arteries and specifically predicts poor motor recovery (LMN injury).

Patterns of cord injury. The injury to the cord itself takes one of these patterns:

• Concussion - transient dysfunction, rapid recovery
• Contusion and oedema - structural change, variable recovery
• Infarction - the vampire bite sign (vascular disruption)
• Transection - complete loss

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Pang's MRI classes (2004). Reviewing two decades of data, Pang described five classes of cord finding on MRI, and they are highly predictive of outcome, which is why MRI is the single most useful prognostic test in SCIWORA. The gradient turns on blood in the cord: oedema alone is compatible with near-complete recovery, while major haemorrhage or transection essentially fixes the deficit.

Extraneural injury matters separately. MRI in SCIWORA frequently shows damage to the non-bony supporting structures, and these findings are the structural basis for the occult instability that justifies bracing and delayed dynamic films:

• Anterior and posterior longitudinal ligament rupture
• Disc disruption
• Interspinous and muscular tears
• Tectorial membrane rupture
• Shearing of the subepiphyseal growth zone of the vertebral endplates

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The ASIA Impairment Scale (AIS) is the standardised grading of spinal cord injury severity, used to communicate completeness and prognosis. It rests on the International Standards for Neurological Classification of Spinal Cord Injury (ISNCSCI): 10 key muscles and 28 dermatomes (light touch and pin-prick) tested on each side, plus voluntary anal contraction and S4-S5 sensation.

When the injury is incomplete, the pattern of deficit localises the damage within the cord and predicts recovery. The anterior cord pattern, with motor and pain/temperature lost and the dorsal columns spared, is the clinical face of the anterior spinal artery (vampire-bite) injury seen in SCIWORA.

History. The mechanism is a motor vehicle collision, a fall or sport. Ask about transient symptoms: "stingers", burning hands, electric shocks (Lhermitte's). Ask specifically about the time between injury and the onset of weakness; the lucid interval between trauma and paralysis runs from hours to 4 days, and its warning signs are paraesthesia and Lhermitte's. Any child with neck pain and a normal X-ray requires careful clearance; do not dismiss transient symptoms.

Examination. Neurology is the key, classified on the ASIA examination (below):

• Motor: weakness, often bilateral
• Sensory: a level to pin-prick and light touch
• Reflexes: hyperreflexia (upper motor neuron) or absent (spinal shock)
• Tone: flaccid initially (shock), then spasticity later
• Autonomic: priapism, bradycardia (neurogenic shock, hypotension)

Spinal shock and neurogenic shock often coexist in severe SCIWORA, and it is vital to distinguish them. Spinal shock is physiological: a loss of all cord function caudal to the level of injury, with flaccid paralysis and areflexia. It is transient, usually 24-48 hours, and recovery is heralded by the return of the bulbocavernosus reflex.

Neurogenic shock is haemodynamic, the result of loss of sympathetic tone with injuries at T6 and above. The triad is hypotension, bradycardia and peripheral vasodilatation (warm peripheries). Treat with fluids and inotropes (noradrenaline or dopamine) to maintain perfusion, and atropine for severe bradycardia.

Differential diagnosis. Other causes of acute weakness to distinguish from SCIWORA:

• Transverse myelitis - often a viral prodrome, slower onset (hours to days), fever; MRI shows enhancement
• Guillain-Barré syndrome - ascending paralysis, areflexia, normal MRI spine; lumbar puncture shows albuminocytologic dissociation
• Spinal cord tumour - insidious onset, night pain
• Conversion disorder - inconsistent examination, positive Hoover's sign; a diagnosis of exclusion
• Brachial plexus injury - unilateral, lower motor neuron signs only (root level)

Non-accidental injury. Red flags:

• An inconsistent history
• Delayed presentation (parents waited days)
• Multiple fractures or bruises in different stages of healing
• SCIWORA in a non-ambulatory infant (e.g. "fell from couch")

Radiographs. AP, lateral and odontoid views, which are often normal. Look for:

• Prevertebral soft-tissue swelling (greater than 6mm at C2)
• ADI widening
• Subtle kyphosis

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CT. CT rules out an occult fracture and is usually normal in SCIWORA; it is indicated if the plain films are inadequate or suspicion of bony injury is high. A normal CT is false reassurance: CT shows only bone, and in children the injury is often purely ligamentous or discal, or a direct cord contusion without fracture.

MRI. The gold standard, and mandatory for any child with transient neurological symptoms or persistent neck pain after trauma. It must be performed urgently, within 24-48 hours, to detect signal changes. Its findings are extraneural (ligament disruption, disc herniation, epidural haematoma) or intraneural (oedema, haemorrhage, transection). The sequences:

• T2-weighted - best for oedema and ligament disruption
• STIR - highlights oedema in the soft tissues
• Gradient echo (GRE) - detects haemorrhage
• DWI - early infarction

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Other tests. Blood tests are usually normal; consider a metabolic work-up if the aetiology is weak (for example, with transverse myelitis in the differential). Electrophysiology (SSEP/MEP) is mandatory if surgery is planned and can help prognosticate in comatose patients. Diffusion tensor imaging is an emerging research tool that may show tract disruption even when T2 is normal, and fMRI evaluates cortical reorganisation in chronic cases.

Surgery is rarely the first line for SCIWORA unless mechanical instability is proven.

Small anatomy. Pedicles in children under 8 are minuscule, often less than 3-4mm, which makes screw fixation risky.

Growth. Fusing the spine arrests vertical growth. Fusing C1-C2 loses very little height, and subaxial fusion loses 0.07mm per segment per year, which is negligible. A posterior-only fusion in growing scoliosis induces the crankshaft phenomenon, which is less relevant here.

Healing. Healing potential is massive: nonunion is rare, but overgrowth can occur.

Recurrence. A "second hit" within 2 weeks is often more severe than the first, and preventing it is the entire purpose of bracing. That makes the collar non-negotiable in the children who meet the bracing criteria (Management) and unnecessary in those who do not.

Neuromuscular scoliosis. 98% of children with SCI before skeletal maturity will develop neuromuscular scoliosis, and they require 6-monthly spine X-rays until maturity.

Mortality. High in upper cervical transections, from respiratory arrest.

The recovery protocol below is for the child who is immobilised.

Acute nursing care. Strict spinal precautions with log rolling until the spine is cleared. Avoid hypotension: maintain a MAP greater than 85mmHg (adult targets) or an age-appropriate equivalent (e.g. greater than 70-75mmHg) to ensure cord perfusion. Intermittent catheterisation if there is retention.

The collar and the skin. Regular collar care, changing the liners, prevents occipital and mandibular pressure ulcers, a high risk in children with thin skin.

Long-term rehabilitation. Spasticity is managed with baclofen, and Botox injections for contractures. PTSD is common in both the child and the parents (guilt), and both need psychological support.

The MRI class predicts recovery (see the table under Classification). Three points sit outside the table.

Normal cord signal is a prognosis for the cord, not a discharge instruction. A child with persistent myelopathy and a normal MRI is still braced.

Oedema varies by length. Short-segment oedema recovers well; long-segment oedema does poorly.

Minor haemorrhage is not major haemorrhage. Do not write these children off with the major-haemorrhage group; for major haemorrhage or complete transection, recovery is not expected.

Global epidemiology:

• SCIWORA accounts for roughly 6-19% of paediatric and 9-14% of adult spinal injuries across reported series (Szwedowski 2014), and is the predominant cord-injury pattern in young children.
• The cervical spine dominates (around 46% of cases in nationwide US data), with upper cervical injury concentrated in children under 8 and lower cervical/sport-related injury in adolescents (Knox 2016).
• Mechanism shifts with age and region: motor vehicle collisions predominate in young children, contact sport in adolescents, and diving, falls and road trauma are leading causes in many limited-resource settings.

Side-by-side guidance:

Prevention Strategies

• Child restraints: appropriate car seats with rear-facing use kept as long as the seat allows markedly reduce cervical distraction forces in crashes — the single most effective prevention in young children.
• Sport: contact and collision sports (rugby codes, American football, wrestling, diving) demand strict "no return to play" after any transient cord symptom ('stinger', burning hands) until cleared; neck-strengthening and safe-tackle programmes reduce risk.
• Recreational hazards: trampolines and diving into shallow water are recurrent causes of severe cervical trauma in children; supervision and age-appropriate restrictions are advised.

Is SCIWORA still a valid term? With universal MRI, most "SCIWORA" now has visible cord or ligamentous signal change. Some authors argue the term is obsolete and propose SCIWORET (without radiographic evidence of trauma) or simply MRI-based grading. Examiners may probe whether you understand that the concept (normal X-ray/CT, abnormal cord) still matters even if the label is debated.

How long to brace. The 12-week collar comes from Pang's 1982 instability concerns, and there is no high-level evidence for the exact duration. Who to brace is settled published practice from the syndrome's own author; only how long remains genuinely uncertain. Many units shorten immobilisation further when the MRI is normal and the spine is dynamically stable, balancing recurrence risk against skin breakdown and deconditioning.

MRI timing and DTI. The ideal window for prognostic MRI (24-72 hours, to capture peak oedema and haemorrhage) and the added value of diffusion tensor imaging over standard T2/GRE remain research questions rather than settled practice.