The basics of cervical stabilization
By Arthur Hsieh
Imagine this scenario:
You arrive on the scene of a motor vehicle crash. Based on the obvious damage to the two vehicles, you recognize that this is a moderate speed event. One driver remains in his vehicle, with first responder EMTs surrounding him.
You can see that one EMT is holding manual stabilization of the head. The other is searching inside his trauma bag. You ask if you can help. The second EMT replies, "Yeah, I can't find the C-collars, can you get one for me?" "Sure," you reply. "What size do you need?" The EMT says, "Oh a 'no-neck' should be fine. It fits everyone."
Is this true?
EMS medical equipment has come along way since the 1970s. This includes one of the staples of prehospital equipment, the cervical collar. Over the years, cervical collars have evolved from simple soft, foam-filled devices to more rigid, complex devices that, when properly sized and fitted, can go a long way toward minimizing inadvertent movement of the cervical spine. The key principle to remember is that they must be sized correctly and fitted properly in order to work.
Here's a challenge: Have you ever read the manufacturer's directions for usage of the cervical collar? I'm referring to the printed instructions that come packaged inside the plastic wrapper that contains the collar. So far, I haven't seen one that didn't come with directions. If you read them, you may be surprised at the level of detail that is provided. There's often more to cervical spine stabilization than you might think.
How they work
Cervical collars come in a variety of shapes, sizes, and constructions. Nevertheless, their design is relatively uniform: Anteriorly, the collar is designed to prevent the patient's chin from dipping down towards the chest by placing stiff foam and/or plastic between the shoulders, clavicles, and chin. This section of the collar is held in place by the posterior section, which wraps around the posterior neck and is anchored in place with loop-and-hook fasteners.
Sizing the collar
The length and width of the neck varies from one person to the next. It is crucial to note that the height of an individual has no relationship to the length of his or her neck. In another words, a very tall male may have a very short, squat neck, while a petite female may have a slender, long neck. In order to pick the correct collar, you must measure the neck. One common method is as follows:
1) Achieve a lateral view of the patient's neck by looking from the side of the body.
2) Bring your fingers and thumb together as if you were going to salute.
3) Rest your outstretched hand on the base of the patient's shoulder, pinky finger side down.
4) With your eye, draw an imaginary line sticking straight forward from the bottom of the patient's chin.
5) Note which finger matches the level of that imaginary line.
6) Count the number of your fingers, from the pinky to the imaginary line. For example: if your index finger matches the line, you have 4 fingers worth of space to fill with the collar.
Following the manufacturer's guidelines, find the appropriate measurement tool on the collar itself. It may be line-etched in the plastic or a post. Place your fingers in the specified space to determine how to select the right collar, or adjust the size of the collar so it fills the space appropriately.
Fitting the collar
Placing the cervical collar on the patient should be accurate and precise. Often, the chin section of the collar is placed in the correct position first, with the rest of the collar carefully wrapped around the neck and affixed with hook-and-loop fasteners. Once secured, the collar should be snug enough to keep your patient from nodding his head downward, but not so tight as to keep him from opening his mouth. Adjust the collar as necessary until it fits correctly; if it is the wrong size, replace it immediately.
Stabilizing the cervical spine
Throughout this discussion, you may have realized that the collar only really controls the flex motion of the cervical spine. This is because that cervical collar is always used in conjunction with some type of head immobilizing device and a long back board. The rotational movement is restricted with the head immobilizer, and extension movements are restricted with the back board. To prevent hyperextension of the head and neck, padding between the occiput and the board must be used in the vast majority of patients who are immobilized.
Remember to immobilize the torso first, followed by the head and neck. The key areas to apply appropriate straps are the primary points of contact between the body and the board: the shoulder, pelvis, and the occiput region of the head. Pad all voids between the body and the board; it improves the patient's comfort and may help to prevent further injury from the immobilization itself. Finally, just like the cervical collar, one size doesn't fit all in terms of immobilization technique. Some patients with excessive curvature of the back and neck, or with lower back disorders, may need significant padding and/or flexion of the knees in order to achieve a neutral position of the spine.
The equipment we use is only as good as our technique. It is important to remember that there is a right way, and many wrong ways, to use a device. For something as seemingly simple as a cervical collar, this is especially true. We don't want to cause further harm to our patients, which we can avoid by making sure we use cervical collars appropriately and correctly.