Is MRI required to clear a cervical collar in patients with suspected cervical spine injury, or can clearance be based on mechanism of injury, neurological status, physical exam, and plain radiographs or CT?

MRI for Cervical Collar Clearance

MRI is not required to clear the cervical collar in obtunded patients with a negative high-quality CT scan, as CT alone is sufficient to exclude clinically significant unstable injuries that would require continued immobilization or surgical intervention. 1

Clinical Decision Algorithm

For Alert, Examinable Patients

• CT cervical spine is adequate for clearance when the patient has no neurologic deficits and a normal neurologic examination, even in the presence of neck tenderness 1
• Remove the collar based on negative CT findings combined with clinical assessment 1

For Obtunded/Unexaminable Patients (GCS ≤14)

CT alone is sufficient for collar removal when:

• High-quality multidetector CT with sagittal and coronal reconstructions shows no fracture or malalignment 1
• No neurologic deficits are present that could be attributable to spinal cord injury 2, 3
• The Eastern Association for Surgery of Trauma explicitly does not endorse routine follow-up MRI in this population 1

The evidence strongly supports CT-only clearance:

• CT has 98.5% sensitivity for clinically significant injuries 1
• In obtunded patients with negative CT, MRI identifies soft-tissue abnormalities in 21-24% of cases, but none require surgery or develop delayed instability 2, 4
• CT has 100% sensitivity and specificity for detecting unstable injuries in obtunded patients without high-impact trauma 3

When MRI Is Indicated

Obtain MRI only in these specific circumstances:

• Confirmed or suspected spinal cord injury with neurologic deficits unexplained by intracranial pathology 1
• Clinical concern for cord compression from disc herniation, hematoma, or fracture fragments 1
• Neurologic examination findings inconsistent with CT results 3, 5

Critical Evidence Against Routine MRI

The 2025 ACR guidelines provide the strongest evidence against routine MRI:

• MRI has a false-positive rate of 20-40% for clinically significant ligamentous injury 1
• Adding MRI to CT clearance protocols prolongs ICU stay, increases duration of rigid collar immobilization, and increases mechanical ventilation time with associated morbidities 1
• Omitting MRI does not result in missed unstable cervical spine injuries or differences in patient mortality 1

Supporting research demonstrates:

• Among 180 obtunded patients with negative CT, 38 (21%) had MRI abnormalities, but zero required surgery or developed delayed instability 2
• In a 2-year consecutive cohort, all patients with MRI ligamentous signal changes had normal dynamic X-rays, successful collar removal, and no late surgical interventions 4

Practical Implementation

Remove the collar based on:

1. Negative high-quality multidetector CT with reconstructions 1
2. Absence of neurologic deficits referable to the spinal cord 2, 3
3. No clinical suspicion for vascular injury requiring CTA 1

The morbidity of prolonged collar use outweighs the negligible risk of missed injury:

• Pressure ulcers, aspiration risk, increased delirium, and prolonged ventilation are documented complications of extended collar immobilization 1
• The incidence of unstable injury missed on modern CT is <1%, and these rarely require intervention 1

Common Pitfalls to Avoid

• Do not obtain MRI reflexively in obtunded patients with negative CT – this increases morbidity without improving outcomes 1
• Do not interpret MRI ligamentous signal changes as automatically indicating instability – these have 20-40% false-positive rates and poor clinical correlation 1, 4
• Do not delay collar removal waiting for the patient to become examinable if CT is negative and no neurologic deficits exist 1
• Do obtain MRI immediately if any neurologic deficit exists that could represent cord injury, as this changes management 1