How to clear a cervical spine to relieve a cervical collar

Cervical Spine Clearance Protocol

In alert, cooperative patients without midline cervical tenderness, neurological deficits, or distracting injuries, the cervical collar can be removed based on clinical examination alone using validated decision rules (NEXUS or Canadian C-Spine Rules). For obtunded or unconscious patients, a high-quality cervical CT scan (axial cuts <3mm) with radiologist interpretation is sufficient to safely remove the collar, though this remains controversial 1.

Alert, Cooperative Patients

Clinical clearance without imaging is safe when ALL of the following criteria are met:

• No midline cervical tenderness on palpation 2
• No neurological deficits (motor or sensory) 2
• Normal level of consciousness (GCS 15, alert and oriented) 2
• No distracting injuries (major fractures, visceral injuries causing significant pain) 2
• No intoxication (alcohol or drugs) 2

Emergency nurses can safely apply these clinical decision rules with high inter-rater reliability (kappa 0.61-0.80) compared to physicians, reducing time to collar removal 2.

Obtunded or Unconscious Patients

This population presents the greatest challenge and controversy. The 2015 Eastern Association for the Surgery of Trauma (EAST) guidelines conditionally recommend cervical collar removal after a negative high-quality cervical CT scan alone in obtunded adult blunt trauma patients 1.

High-Quality CT Requirements:

• Axial slice thickness <3mm (ideally 1.5-2mm) 1
• Complete visualization from skull base through C7-T1 junction 3
• Sagittal and coronal reconstructions 3
• Formal radiologist interpretation 4

Evidence Supporting CT-Only Clearance:

• In 350 intubated patients (70% sedated/comatose, 51% with traumatic brain injury, average GCS 9), collar removal based on normal CT resulted in zero missed neurological injuries (100% negative predictive value) 4
• Across 1,017 obtunded patients in multiple studies, no new neurologic changes (paraplegia or quadriplegia) occurred after collar removal following negative high-quality CT 1
• The incidence of unstable injuries missed by high-quality CT is 0% (0 of 1,718 subjects across 11 studies) 1
• The risk of isolated ligamentous injury in blunt polytrauma patients ranges from 0.1-0.7%, consistently under 1% 3

Critical Imaging Pitfalls:

Plain radiographs alone are inadequate and dangerous:

• A single lateral cervical X-ray misses approximately 15% of cervical injuries 3
• Three-view cervical series still miss up to 10% of injuries, with 25-50% of films being anatomically or technically inadequate 3
• The cervicothoracic junction (where up to 60% of injuries occur) cannot be visualized in up to 49% of plain films even with arm traction 3
• The functional sensitivity of an adequate three-view series is only 89.4% 3

CT must include specific high-risk regions:

• Directed CT of C1-C2 (craniocervical junction) detects fractures in an additional 10% of patients with normal plain films 3
• Directed CT of C7-T1 (cervicothoracic junction) detects fractures in another 10% of patients 3
• 40.3% of patients who cannot be cleared on plain films have non-visualization of the craniocervical junction 3

The Morbidity of Prolonged Immobilization

Complications escalate rapidly after 48-72 hours of collar immobilization 3, 5:

• Pressure sores requiring skin grafting, costing approximately $30,000 per ulcer 3
• Increased intracranial pressure (critical in the one-third of patients with concomitant head injury) 3, 5
• Life-threatening airway complications 3, 5
• Aspiration pneumonia and ventilator-associated pneumonia 3
• Failed enteral nutrition requiring parenteral nutrition 3
• Thromboembolic events in 7-100% of inadequately prophylaxed patients 3
• Among elderly patients with cervical spine injuries, 26.8% died during treatment, primarily from respiratory complications 3

Rigid cervical collars paradoxically may not prevent injury progression: They do not adequately restrict displacement of unstable cervical injuries and may cause paradoxical movement at the craniocervical and cervicothoracic junctions—the two most common injury sites 3, 5.

Controversial Adjunct Imaging

MRI:

• Very sensitive for soft tissue injury but not validated for routine clearance 3
• High false-positive rate: only 60.7% of MRI abnormalities correlate with anatomic findings at autopsy 3
• Many detected soft tissue injuries are of uncertain clinical significance, leading to unnecessary prolonged immobilization 3
• Significant failure rate at upper and posterior cervical spine 3
• Must complement, not replace, plain films and CT 3

Dynamic Fluoroscopy:

• Involves passive flexion/extension under real-time imaging in sedated, paralyzed patients 3
• The 2000 EAST guidelines recommended this after normal CT, but this remains a Level II-III recommendation based on limited evidence 3
• Number needed to treat (NNT) of 295-500 to detect significant injuries makes clinical yield questionable 3
• No formal prospective comparison with high-resolution CT or MRI exists 3

Practical Algorithm

For alert patients:

1. Apply NEXUS or Canadian C-Spine Rules clinically
2. If all criteria met, remove collar without imaging
3. If any criteria failed, obtain CT

For obtunded patients:

1. Obtain high-quality cervical CT (<3mm cuts, skull base through T1, with reconstructions)
2. Ensure formal radiologist interpretation
3. If completely normal with adequate visualization, remove collar 4, 1
4. If inadequate visualization or any abnormality, obtain directed CT of problem areas or consider MRI
5. Do not delay collar removal beyond 48-72 hours without compelling reason 3, 5

Critical caveat: One case report documents catastrophic spinal cord injury after collar removal based on a CT misinterpreted as normal, which retrospectively showed subtle spinous process widening 6. This emphasizes the absolute necessity of high-quality imaging with expert interpretation, but should not prevent appropriate collar removal when imaging is truly normal, as prolonged immobilization carries its own substantial morbidity and mortality 3, 5.