It's the middle of the night when the paramedics roll into the ED with a pedestrian that was struck by a car. The patient reports that the car came around the corner and hit his leg. He remembers everything about the accident and complains only of his leg hurting. He appears to have an open, compound fracture to his leg, which was splinted in the field. In addition, the paramedics inform you that, on his initial exam, he did not have any midline neck tenderness or any pain with full range of motion. However, secondary to his distracting injury, a C-collar and backboard were placed on the patient. After the paramedics leave, you're left wondering what the evidence is on C-collar immobilization, and if it was really necessary to place a collar and backboard on this patient without any neck or back pain.

Current EBM Evidence

The first notable study on the implementation of backboards and C-collars was conducted in the 1960s, but most of the recommendations have been based on tradition and informed opinion, and not necessarily validated, scientific evidence.

For example, while the American Association of Neurological Surgeons and the Congress of Neurological Surgeons Joint Commission have made recommendations to support the use of spinal immobilization (as defined as C-collar and backboard), most of those are based on Level III evidence. Unfortunately, there is a paucity of evidence for the implementation and continued use of spinal immobilization. A Cochrane review from 2007 noted, for example, that there wasn't a single prospective, randomized controlled trial on spinal immobilization.

Currently, most of the validated evidence on spinal cord protection is derived from studies evaluating which patients require imaging prior to clearance. Both the NEXUS criteria and the Canadian C-spine rules are validated and are cited by the American Association of Neurological Surgeons and the Congress of Neurological Surgeons Joint Commission in their official recommendations on the management of acute spinal cord injury. The NEXUS criteria and the Canadian C-spine rules have been applied in the pre-hospital setting; those who will require imaging are placed in a cervical collar for C-spine stabilization. However, there has never been a controlled trial on patients examining if C-collars actually stabilize the spine. There have been a multitude of trials on volunteers and models, many of which have contradictory results. While some studies show that C-collars do stabilize the neck, others show that collars may actually increase neck movement.

While the data to support spinal immobilization are weak, there is an increasing amount of evidence noting potential risks and morbidity associated with spinal immobilization. Spinal immobilization has been used to prevent aggravating spinal cord injury. However, in a controversial study done by Hauswald et al., non-immobilized patients in Malaysia had better neurological outcomes than similar injury-matched patients who were immobilized in New Mexico (OR 2.03). While these studies were conducted in vastly different countries, the overall notion that secondary injury to the cord due to transport is rare because the forces exerted during transport are weak compared with that required to injure the spinal cord may still hold true. Other studies have shown increased mortality (OR 2.06-2.77) in patients with penetrating trauma and spinal immobilization, most likely because it takes time (approximately 5 minutes, at best) to place a patient into full immobilization, which delays resuscitation and getting the patient into an operating room.

While the goal of C-collars is to reduce movement of the cervical spine and protect the spinal cord, a few case studies have shown that forcing a neck into "anatomical position" can actually cause spinal cord injury, particularly in patients with ankylosing spondylitis and the elderly. A study on cadavers noted that extrication collars caused an increased degree of separation between vertebrae when there was a dissociative injury.

Placing a patient in spinal immobilization can adversely affect breathing and airway management. One study conducted on healthy volunteers showed that placing a patient on a backboard restricts respiration, with older patients having a greater degree of restriction. It is not difficult to imagine that the restriction can have a significant impact on patients with respiratory distress or in those patients with baseline pulmonary disease. Spinal immobilization also can make airway management more difficult, as it is often much more difficult to intubate a patient in a C-collar. In addition, patients not requiring airway management are at an increased risk of aspiration from vomiting.

In a systematic review done by Sparke et al., there were a few studies noting an increase in intracranial pressure with the placement of C-collar. In a study by Kolb, an increase of almost 25 mmHg (as measured by LP pressures) was measured when C-collars were placed on healthy volunteers. The risk of increased ICP is 35.8%, as estimated by Dunham in his review comparing ICP of injury-matched patients with C-collar to those without C-collars in various studies. It is thought that the increased ICP is secondary to pressure placed on the jugular vein (causing venous congestion); however, there is no real knowledge of the etiology of the increased ICP.

In addition, pressure ulcers are very painful complications from spinal immobilization. Pressure ulcers begin forming within 30 minutes of immobilization. This is particularly troubling as another study demonstrated that the average time a patient spends on a backboard is approximately an hour. The process of immobilization has been shown to cause increased pain scores in healthy volunteers, so even those without midline spinal tenderness in the field may have tenderness on arrival to the emergency department.

Finally, once patients are immobilized, they are more likely to undergo imaging to have their C-spine cleared. In a study by Leonard et al., children who were placed in a C-collar were much more likely to undergo imaging to clear the C-spine (56.6 versus 13.4%) and were much more likely to be admitted to the hospital (41.6 versus 14.3%). These results held even after adjustment for those with spinal injury. This has serious implications on length of stay and cost to both the patient and the hospital.

While the evidence supporting spinal immobilization is minimal, especially in patients who are awake and have no neurologic symptoms, the preserved consequence of causing additional spinal cord injury is so severe that randomized, controlled studies on this topic are rare and difficult to do. However, there is increasing evidence of potential harm with full spinal immobilization. In response to the research, the St. Louis Fire Department-Emergency Medical Services Division, American Medical Response/Abbott EMS, and Clayton Fire Department removed backboards from their protocol in September 2014, although C-collar and C-spine stabilization still remain a part of their pre-hospital care.

Spinal Immobilization

Key Recommendations:

Use longboards for extrication purposes only, not for transportation. Longboards are not a benign procedure. The evidence to date does not show that longboards reduce movement of the spine or limit neurological complications. Instead, the evidence shows that such use increases mortality, particularly in penetrating trauma, as well as causing greater difficulties with ventilation, pain, and pressure ulcers.

Use C-collars and C-spine immobilization per the NEXUS criteria. However, as newer studies are published, this may be subject to change.

Summary of NEXUS Criteria on Imaging Spinal Cord Injuries

No imaging is necessary if all of the following are present:

No posterior midline cervical tenderness Normal level of alertness No evidence of intoxication No abnormal neurologic findings No painful distracting injuries

Melissa Kroll, MD, is a second year Emergency Medicine Resident at Washington University in St. Louis. Hawnwan Philip Moy, MD, is the Assistant Medical Director of the Emergency Medicine Services Division of the St. Louis City Fire Department and a faculty member in Emergency Medicine at Washington University in St. Louis. Evan Schwarz, MD, is a faculty member in Emergency Medicine at Washington University in St. Louis. This story was originally published in Emergency Physicians Monthly and is reposted here by permission.