What is the efficacy of a C (cervical) collar in immobilizing the cervical spine?

Efficacy of Cervical Collars in Immobilizing the Cervical Spine

There is very limited, low-quality evidence supporting the efficacy of cervical collars with regards to limitation of cervical spinal movement, and no evidence of improved outcomes in terms of neurological injury or mortality. 1

Current Evidence on Cervical Collar Efficacy

• Cervical collars provide incomplete immobilization of the cervical spine, with limited ability to restrict movement, particularly at the craniocervical and cervicothoracic junctions 2
• The practice of using cervical collars is based primarily on expert consensus and tradition rather than strong scientific evidence 1
• In cadaveric models with surgically induced injuries, application of a cervical collar caused a greater degree of cervical spine movement (anterior-posterior subluxation) compared with manual in-line stabilization during direct laryngoscopy 1
• Studies on healthy volunteers and cadavers show that while collars may limit some movement, they do not prevent all motion of the cervical spine 2, 3

Potential Harms of Cervical Collar Use

• Cervical collars increase intracranial pressure, which is particularly concerning in patients with co-existing head trauma 1, 2
• The presence of rigid/semi-rigid collars during airway management is associated with an increased incidence of difficult tracheal intubation, primarily due to reduction in mouth opening 1
• Pressure sores develop with prolonged collar use, which may require skin grafting and can become sources of sepsis 2, 4
• Prolonged immobilization leads to higher rates of ventilator-associated pneumonia and delirium 2
• A recent retrospective cohort study found that C-spine immobilization was significantly linked to an elevated risk of mortality in older adults, patients with unclear consciousness, those with major traumatic injuries, and individuals in shock 5

Current Guidelines and Recommendations

• The American Heart Association recommends against routine application of cervical collars by first aid providers due to growing evidence of harm and lack of proven benefit 2, 6
• During airway management, guidelines recommend removal of semi-rigid or rigid cervical collars (at least the anterior portion) to facilitate intubation while minimizing cervical spine movement 1
• If cervical spine injury is suspected, the person should remain as still as possible while awaiting emergency medical services 2
• Manual in-line stabilization (MILS) is suggested during airway management procedures, though evidence for its efficacy is also limited 1

Alternative Approaches to Cervical Spine Protection

• Sandbags and tape in combination have been shown to be more effective than cervical collars alone in limiting cervical spine motion 3
• The combination of sandbags, tape, and a Philadelphia collar provides the most effective immobilization, particularly for limiting extension 3
• Manual stabilization may be considered in certain high-risk circumstances, though this approach has not been thoroughly evaluated in research 6
• Avoiding unnecessary movement of the patient is a key principle regardless of immobilization method 2

Clinical Application

• For airway management in patients with suspected cervical spine injury, remove at least the anterior portion of the collar during intubation attempts to improve glottic exposure 1
• Consider using videolaryngoscopy rather than direct laryngoscopy for intubation in patients with suspected cervical spine injury 1
• Use adjuncts such as a stylet or bougie when performing tracheal intubation in patients whose cervical spine is immobilized 1
• Apply cervical collars more selectively, particularly in older individuals, those with unclear consciousness, patients with major traumatic injuries, and those in shock 5

Pitfalls to Avoid

• Prolonged use of collars when not indicated by clinical or radiographic findings should be avoided 2
• Delaying removal of collars in patients who have been cleared by appropriate imaging is unnecessary 2
• Relying solely on cervical collars for complete immobilization gives a false sense of security, as they permit fine flexion and extension movements 4
• The long-standing practice of attempted cervical spine immobilization using sandbags and tape alone is not recommended; a combination approach with rigid collar and supportive blocks is more effective 7