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EMS Immobilization Protocol
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One study recommends securing both the head and the trunk during EMS transport of patients with unstable spine, while another questions the necessity of immobilization itself.

by Douglas Page,   2001

Paramedics could reduce the potential for further injuries to patients involved in blunt trauma by improving standard immobilization procedures used during transport, says a study in the journal Spine.

Properly immobilizing the trunk is just as crucial as securing the head during emergency transport, says the study (Spine, 1999;24:17).

"A commonly used method of strapping the patient down does not prevent the body from swinging around and can lead to further cervical spine injury," said Stephen Perry, now a post-doctoral fellow in the Department of Kinesiology at the University of Waterloo in Ontario, Canada. The research was done while he was a research fellow at Sunnybrook and Women’s College Health Science Center at the University of Toronto. "Other research has shown that up to 25 percent of cervical spine injuries arise or are aggravated during transport and that 40 percent of those injuries result in neurological damage." The statistics cited are from 1980 and 1983 publications.

Dr. Perry and his team set out to evaluate three different head immobilization techniques using a moving platform designed to simulate the swaying and jarring that can occur during ambulance or air transport. One method evaluated was a new custom fit, self-adhesive styrofoam wedge product, whose manufacturer financed the study. While Dr. Perry indeed found that the method of using the styrofoam wedges to fit the patient to the backboard worked better at securing the head, he also discovered the crucial factor is to some degree restrict mobility of the trunk as well as head.

"Even though some head immobilization techniques are more effective, the sheer mass of a poorly immobilized trunk swinging back and forth can cause large movements in the neck that can lead to serious injuries," he said.

After comparing the different fixation methods, which included the use of towels and Headbed II as well as the wedges, the authors conclude that it may be possible to achieve some small improvements in fixation of the head to the fracture board by placing wedges under the head. However, in terms of cervical spine immobilization, the benefits of any fixation method are likely to be limited unless the motion of the trunk is also controlled effectively.

At the heart of the Perry work, however, is the assumption that immobilization makes a difference in outcome. Two recent articles actually question this key assumption.

"This study by Perry, et al, is a very important and meticulous effort to improve our immobilization methods," said Paul E. Pepe, MD, MPH, incoming chair of emergency medicine at the University of Texas Southwestern Medical School in Dallas. "Still, the absolute need for spinal immobilization itself might be questioned, specifically in terms of ‘when’, ‘for whom’ and ‘does it really make a difference’ in actual patients.

A study by Mark Hauswald and colleagues (Acad Emerg Med, 1998;5:214), comparing outcomes in locales where out-of-hospital immobilization was used (New Mexico) to locales where immobilization was not used (Malaysia), actually found more neurologic disability in immobilized patients.

While there were clear design limitations in this study, the results are still striking, Dr. Pepe said, responding in an editorial in the same issue (Acad Emerg Med, 1998;5:203).

Current spinal immobilization protocols have been based on the concern that a patient with an injured spine may deteriorate neurologically without immobilization. Traditionally, all paramedics are instructed that spinal immobilization in blunt trauma is as crucial as control of bleeding and airway management.

However, Hauswald, et al, maintain it has been shown in the literature "that subsequent movements of the spine made by the patient after the initial impact are several orders of magnitude less than the forces required to cause damage to the spinal cord." In addition, they argue that the subsequent spasm and guarding that occurs after injury may also prevent further damage. "They make a good case that cord damage may occur only at the time of initial impact," Dr. Pepe said.

The number of people receiving spinal immobilization annually in the United State is estimated as high as five million. This raises cost issues related to cervical collars, unreplaced backboards, tape and other devices. Dr. Pepe estimates might conservatively exceed $15 per person, or $75 million a year, a figure not including charges for hospital visits prompted by the act of universal immobilization.

The cost of universal immobilization protocols concerns other experts.

"With the millions of people who get cervical spine immobilization (many unnecessarily, some with complications, all with cost), verses the very tiny number who might benefit, a careful analysis might find this practice does not meet contemporary cost-benefit ratios," said Michael Callaham, MD, chief of the division of emergency medicine at the University of California, San Francisco. "The Perry work makes reference to the frequency of cervical injuries with movement after the initial trauma, but these are ancient references. Most people now think that probably movement after the initial trauma causes very few cord injuries."

Based on their respective study limitations, the Perry and Hauswald papers are not likely to change EMS practice in the near future.

"I would draw no conclusions from the Perry study and change nothing," Dr. Callaham said. "We need large, clinically relevant studies that determine what is a clinically significant amount of movement, and how often this problem actually occurs, before we decide in what ways to change immobilization devices."

While the Hauswald paper challenges dogma and opened the door for more research, Dr Pepe said that for now we should still error on the side of caution and continue to immobilize spines the best way possible.

"That’s why thoughtful studies like Perry’s are useful and appreciated."

-end-

Comments? Questions? Corrections? Assignments? douglaspage@earthlink.net
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