EMS

Cervical Collar: Friend or Foe?

Most emergency medicine systems (EMS) around the world apply semi-rigid cervical collars routinely to all injured patients with a significant mechanism of injury. While placing these patients in cervical collars is one of the most common interventions performed by EMS providers, the science behind this practice is limited, and the consequences may not always be beneficial. Re-evaluation of routine cervical spine immobilization is challenging the current dogma.1,2

Benefits of Cervical Spine Immobilization
The concept of cervical spine immobilization was developed as a mechanism to keep the spine in neutral alignment after a suspected injury and to prevent further harm by immobilizing a potentially unstable injury. This practice has been adopted by the American College of Surgeons, which recommends immediate neck immobilization for all trauma patients, since all are considered to be at risk of cervical spine injury.3 However, the evidence behind this practice originated from expert and consensus opinion after minimal studies performed in hospital-based spinal units at a time when EMS and trauma systems were in their infancy.4-6

While efficacy of cervical spine immobilization has never been examined in actual trauma patients, there remains a limited number of studies examining spine movement in a simulated environment. For example, one study used healthy volunteers and measured their neck movements in a variety of immobilization devices. Results showed that sandbags, rigid collar, and tape were the most effective form of neck immobilization.7

Overall, there doesn’t seem to be any clear evidence available to support the use of cervical collars — the benefit seems to be largely theoretical.

Risks of C-Spine Immobilization
Although the data describing the benefits of spinal immobilization is limited, several studies have questioned the near-universal use of c-collars given that the overall incidence of cervical spine injury in trauma patients is low. In two studies on trauma patients who were considered at high risk for head and neck trauma, there was an overall incidence of 0.7% for significant cervical spine injury.8,9

Furthermore, multiple studies have shown that cervical collars do not restrict neck movement, but allow for approximately 30 degrees of flexion/ extension/rotation.10,11

Likewise, immobilization has not been shown to affect the incidence of neurological injuries in patients with cervical spine trauma. In a 4-year prospective patient cohort with confirmed cervical vertebral injury, 8% of patients did not have their spine immobilized — resulting in no clinical consequences or progress to neurological deficits.12

In a recent study comparing the incidence of neck injuries in a first-world country in which cervical collars are almost universally applied, to a third-world country that does not use cervical collars, there was less neurologic disability in the non-immobilized patients.13 While there are numerous flaws in this study, we would still expect to see a sharp rise in the number of secondary spine injuries in the non-immobilized patients, but that was not found.

Finally, there is a growing body of literature showing that cervical collars are downright harmful,14 as they increase aspiration risk,15 make airway management more difficult,16 and increase intra-cranial pressure (ICP) by reducing venous return.17,18

Current Recommendations
Within the guidelines from the American College of Emergency Physicians, the American Association for Neurological Surgeons, the National Registry of Emergency Medical Technic.ians, and the Congress of Neurological Surgeons, there is a clear consensus in recommending spinal immobilization of all trauma patients with a known or suspected cervical spine injury in the prehospital setting.17-19

Additionally, multiple guidelines recommend utilizing clinical decision tools — the NEXUS criteria or the Canadian C-spine rule — to guide cervical spine immobilization use and recommend that the fully awake and communicable patients who are not intoxicated, without neck pain or tenderness, without distracting injuries, and are neurologically intact should not be immobilized.

These guidelines are generally in line with the ACS policy statements as well as the growing body of pre-hospital literature and management guidelines for cervical spine injuries, as they all state that collars are effective in limiting motion of the cervical spine and should therefore be used until the patient is properly assessed and the cervical spine is cleared.

Conclusions
Cervical spine immobilization has long been a staple of out-of-hospital medicine. It has been instituted as a necessity of prehospital management though benefits of universal immobilization are unclear and potential harm has been demonstrated. While guidelines continue to support cervical spine immobilization, there is a growing body of literature challenging the current dogma and prompting re-evaluation of cervical spine immobilization.


References
1. Deasy C, Cameron P. Routine application of cervical collars--what is the evidence?. Injury. 2011;42(9):841-842.
2. ScanCrit.com. The Curse of the Cervical CollarScanCrit.com. 2013. Accessed March 9, 2018.
3. Advanced trauma life support, 9th ed., American College of Surgeons; 2012.
4. Rogers WA. Fractures and dislocations of the cervical spine; an end-result study. J Bone Joint Surg Am. 1957;39A(2):341–376.
5. Bohlman H. Acute fractures and dislocations of the cervical spine. An analysis of three hundred hospitalized patients and review of the literature. J Bone Joint Surg Am. 1979;61(8):1119–42.
6. Gunby I. New focus on spinal cord injury. JAMA. 1981;245(12):1201–6.
7. Podolsky S, Baraff LJ, Simon RR, Hoffman JR, Larmon B, Ablon W. Efficacy of cervical spine immobilization methods. J Trauma. 1983;23(6):461–5.
8. Hoffman JR, Mower WR, Wolfson AB, Todd KH, Zucker MI. Validity of a set of clinical criteria to rule out injury to the cervical spine in patients with blunt trauma. N Engl J Med. 2000;343(2):94–99.
9. Stiell IG, Wells GA, Vandemheen KL, et al. The Canadian C-spine rule for radiography in alert and stable trauma patients. JAMA. 2001;286(15):1841–8.
10. Graziano AF, Scheidel EA, Cline JR, Baer LJ. A radiographic comparison of prehospital cervical immobilization methods. Ann Emerg Med. 1987;16(10):1127-31.
11. Lador R, Ben-galim P, Hipp JA. Motion within the unstable cervical spine during patient maneuvering: the neck pivot-shift phenomenon. J Trauma. 2011;70(1):247-50.
12. Domeier RM, Frederiksen SM, Welch K. Prospective performance assessment of an out-of-hospital protocol for selective spine immobilization using clinical spine clearance criteria. Ann Emerg Med. 2005;46(2):123-31.
13. Hauswald M, Ong G, Tandberg D, Omar Z. Out-of-hospital spinal immobilization: its effect on neurologic injury. Acad Emerg Med. 1998;5(3):214-9.
14. Sundstrøm T, Asbjørnsen H, Habiba S, Sunde GA, Wester K. Prehospital use of cervical collars in trauma patients: a critical review. J Neurotrauma. 2014;31(6):531-40.
15. Lockey DJ, Coats T, Parr MJ. Aspiration in severe trauma: a prospective study. Anaesthesia. 1999;54(11):1097–8.
16. Goutcher CM, Lochhead V. Reduction in mouth opening with semi-rigid cervical collars. Br J Anaesth. 2005;95(3):344–8.
17. Stone MB, Tubridy CM, Curran R. The effect of rigid cervical collars on internal jugular vein dimensions. Acad Emerg Med. 2010;17(1):100-2.
18. Mobbs RJ, Stoodley MA, Fuller J. Effect of cervical hard collar on intracranial pressure after head injury. ANZ J Surg. 2002;72(6):389-91.
19. American College of Emergency Physicians. EMS Management of Patients with Potential Spinal Injury. Ann Emerg Med. 2015;66(4):445. 
20. National Association of State EMS Officials. National Model EMS Clinical Guidelines: Spinal Care.
21. Joint Section on Disorders of the Spine and Peripheral Nerves of the American Association of Neurological Surgeons (AANS) and the Congress of Neurological Surgeons (CNS) (2013). Guidelines for the management of acute cervical spine and spinal cord injuriesNeurosurgery. 2013; 60 Suppl. 1:82-91.

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