Prove it: Does assisted extrication increase cervical motion?
One study examined four different extrication methods using multiple cameras and reflective tape along victims' spines
By Kenny Navarro
Rescue 47 and Engine 36 respond to a traffic collision at an intersection. After verifying the absence of hazards, the medics approach the drivers of both vehicles. Despite the moderate damage to both vehicles, one of the drivers claims that he is not injured and does not think he wants to go to the hospital.
The other driver is still sitting behind the wheel of his car. According to witnesses, this driver ran through a changing traffic light and his vehicle was struck on the passenger’s side quarter panel. The patient says his neck is sore and he would like to be evaluated at the hospital.
While Medic Wilson completes the electronic patient record for the patient who does not want the go to hospital, Medic Moore completes his patient assessment, and he and the engine crew begin removing the other patient from his vehicle.
First, one of the firefighters gets into the back seat and holds the patient’s head still. Moore applies a cervical collar and asks the patient to step out of the vehicle and turn to get onto the backboard.
Moore then takes control of the patient’s head while the patient follows the direction. After securing the patient with straps and applying head blocks, the team moves the patient to a stretcher and into the ambulance. Transport to the hospital was uneventful.
On the way back to the station, Wilson asks why Moore allowed the patient to walk a few steps to get to the stretcher instead of using the short board to remove the patient from the vehicle. Moore responded that he didn’t think there was much difference between the two techniques, and he doesn’t think his actions were harmful to the patient.
Researchers in St. Louis studied movement of the head relative to the torso during various extrication techniques in a simulated vehicle collision. To accurately model vehicle damage, the research team used a 2001 Toyota Corolla that was involved in a high-speed crash. The team recreated the occupant compartment of the vehicle in the laboratory including all deformities that occurred in the crash. The team even went so far as to use the actual seats from the vehicle.
The researchers used 16 volunteers recruited by word-of-mouth. Ten of the volunteers were paramedics, each having more than five years of experience. The remaining six did not have any EMS or extrication experience and served as injured drivers in the exercise. None of these six served as rescuers during the simulation.
The EMS volunteers worked in pairs to extricate one simulated driver from the vehicle. Four of the EMS volunteers served dual roles, rescuers for some patients and patients for other teams of EMS personnel.
Before the exercise began, the researchers placed reflective surface markers at predetermined locations on the patient’s head, neck, and trunk. Video recorders placed at various locations around the simulated car documented patient movement.
The patient started from a sitting position in the driver’s seat and a two-person team of paramedics performed the extrication. The researchers tested each patient three times in each of four randomly selected extrication techniques for a total of 12 extrications per patient. Here are the four techniques.
1. Unassisted/Unprotected (UU): The EMS crew asked the patient to exit the vehicle, walk to the stretcher and lie down on the backboard. The patient was not given a cervical collar nor assisted in any way.
2. Unassisted/Collar (UC): The EMS crew applied a cervical collar and then asked the patient to exit the vehicle, walk to the stretcher and lie down on the backboard.
3. Assisted/Collar (AC): The EMS crew applied a cervical collar and then performed standard head-first extrication from the vehicle onto a backboard.
4. KED/Collar (KC): The EMS crew applied a cervical collar and a KED before removing the patient from the vehicle onto a backboard.
After collecting and digitizing the video data from each of the extrications and using special computer software, the researchers created a three-dimensional model of spinal movement for each type of extrication procedure. Because of the reflective surface markers on the patient’s body, the research team could compare the different techniques using common points of reference.
As one might expect, patients who walked to the stretcher after EMS applied a cervical collar (UC) had significantly less flexion/extension in the sagittal plane, lateral flexion in the frontal plane, and rotation in the transverse plane when compared with patients who walked to the stretcher with no cervical collar in place (UU).
Similarly, there was significantly less head movement in patients who were removed from the car in the traditional way (AC) and with the KED (KED/C) when compared with patients who walked without a cervical collar.
However, the two methods of assisted extrication did not offer the same degree of cervical protection when compared with the UC movement despite all three methods having cervical collars in place.
For example, pivoting in the seat produced significantly more lateral flexion in the frontal plane for both groups of assisted extrication compared to allowing the patient wearing a cervical collar to exit under her own power.
On the other hand, during the recline onto the backboard, patients who walked with a cervical collar had significantly less lateral flexion in the frontal plane and rotation in the transverse plane than did patients who were moved to a backboard with a KED and cervical collar in place.
What this means for you
Cervical spine injuries caused by a traumatic event are relatively rare. Only about 3.5 percent of patients over the age of 16 admitted to a hospital following a traumatic injury have a cervical spine injury.
The overwhelming majority of those involved fractures without spinal cord injury. The incidence of cervical spine injury in children ranges from 0.4 percent for infants to 2.6 percent for adolescents.
Cervical collars along with other spinal motion restrictions should, in theory, protect the spinal cord from further injury following a traumatic event. However, the spine must be subject to a considerable amount of force to produce a fracture, and it is reasonable to believe the relatively low-energy movements produced during extrication and ambulance transport are unlikely to result in additional injury.
Further when primary injury does occur, muscle spasms in conscious patients work to increase resistance to movement and may therefore prevent the injury from worsening. It seems reasonable, then to conclude that the risks of dangerous spinal movement during extrication may have historically been overemphasized[6, 7].
A Cochrane review published in 2001 and updated in 2007 noted that while “the effect of pre-hospital spinal immobilization on mortality, neurological injury, spinal stability, and adverse effects remains uncertain” one cannot exclude the possibility of an increase in morbidity and mortality caused by the procedure.
A small pilot study involving extrication from a simulated vehicle crash found the least amount of cervical movement occurred when paramedics applied a cervical collar and allowed the patient to step out the vehicle on their own. However, the sole patient in that study was a paramedic with more than five years of experience.
In this study, four of the 10 patients had similar professional credentials. It is possible their knowledge of the principles of extrication may have influenced the outcome of this study.
Similarly, the subjects used in this simulation were not injured. Conscious patients with actual spinal injury often report pain that intensifies with movement. As a result, real patients suffering from spinal injury may self-splint in order to reduce the pain resulting in further limitations in movement. Muscle spasms that occur following acute injury may provide additional splinting.
The researchers also report that a variety of factors occasionally blocked the camera’s view of the surface markers used on the patient’s body. This made it very difficult for the team to top track movements continuously and resulted in an average of 3 percent missing data points.
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