Tag Archives: xray

Metal Splints – Can You X-ray Through Them?

Splinting is an important part of the trauma resuscitation process. No patient should leave your trauma resuscitation room without splinting of all major fractures. It reduces pain, bleeding, and soft tissue injury, and can keep a closed fracture from becoming an open one.

But what about imaging? Can’t the splint degrade x-rays and hamper interpretation of the fracture images? Especially those pre-formed aluminum ones with the holes in them? It’s metal, after all.

Some of my orthopedic colleagues insist that the splint be removed in the x-ray department before obtaining images. And who ends up doing it? The poor radiographic tech, who has no training in fracture immobilization and can’t provide additional pain control on their own.

But does it really make a difference? Judge for yourself. Here are some knee images with one of these splints on:

Amazingly, this thin aluminum shows up only faintly. There is minimal impact on interpretation of the tibial plateau. And on the lateral view, the splint is well posterior to bones.

On the tib-fib above, the holes are a little distracting on the AP view, but still allow for good images to be obtained.

Bottom line: In general, splints should not be removed during the imaging process for acute trauma. For most fractures, the images obtained are more than adequate to define the injury and formulate a treatment plan. If the fracture pattern is complex, it may be helpful to temporarily remove it, but this should only be done by a physician who can ensure the fracture site is handled properly. In some cases, CT scan may be more helpful and does not require splint removal. And in all cases, the splint should also be replaced immediately at the end of the study.


Don’t Repeat Trauma Activation X-rays!!

You are in the middle of a fast-paced trauma activation. The patient is awake, and mostly cooperative. The x-ray plate is under the patient and everyone stands back as the tech gets ready to fire the x-ray machine. At that very moment, your patient reaches up and places his hand on his chest. Or one of the nurses reaches over to check an IV site.

The x-ray tech swears, and offers to re-shoot the image. What do you do? Is it really ruined? They have an extra plate in hand and are ready to slide it under the patient bed.

The decision tree on this one is very simple. There are two factors in play: what do you need to see, and how hard is it to see? The natural reaction is to discard the original image and immediately get a new one. It’s so easy! Plus, the techs will take heat from the radiologist because of the suboptimal image. But take a look at this example of a “ruined” chest xray.

It’s just the patient’s hand! You can still see everything that you really need to.

Bottom line: You are looking for 2 main things on the chest x-ray: big air and big blood. Only those will change your management in the trauma bay. And they are very easy to see. Couple that with the fact that an arm overlying the image does not add a lot of “noise” to the image. So look at the processed image first. 99% of the time, you can see what you need, and will almost never have to repeat. [Hint: the same holds true for the pelvic x-ray, too. You are mainly looking for significant bony displacements, which are also easy to see.]

Related posts:

The Final X-Ray In Damage Control Surgery

Damage control surgery for trauma is over 20 years old, yet we continue to find ways to refine it and make it better. Many lives have been saved over the years, but we’ve also discovered new questions. How soon should the patient go back for definitive closure? What is the optimal closure technique? What if it still won’t close?

One other troublesome issue surfaced as well. We discovered that it is entirely possible to leave things behind. Retained foreign bodies are the bane of any surgeon, and many, many systems are in place to avoid them. However, many of these processes are not possible in emergent trauma surgery. Preop instrument counts cannot be done. Handfuls of uncounted sponges may be packed into the wound.

I was only able to find one paper describing how often things are left behind in damage control surgery (see reference below), and it was uncommon in this single center study (3 cases out of about 2500 patients). However, it can be catastrophic, causing sepsis, physical damage to adjacent organs, and the risk of performing an additional operation in a sick trauma patient.

So what can we do to reduce the risk, hopefully to zero? Here are my  recommendations:

  • For busy centers that do frequent laparotomy or thoracotomy for trauma and have packs open and ready, pre-count all instruments and document it
  • Pre-count a set number of laparotomy pads into the packs
  • Use only items that are radiopaque or have a marker embedded in them. This includes surgical towels, too!
  • Implement a damage control closure x-ray policy. When the patient returns to OR and the surgeons are ready to begin the final closure, obtain an x-ray of the entire area that was operated upon. This must be performed and read before the closure is complete so that any identified retained objects can be removed.

Tomorrow, a sample damage control closure x-ray.

Related post:

Reference: Retained foreign bodies after emergent trauma surgery: incidence after 2526 cavitary explorations. Am Surg 73(10):1031-1034, 2007.

How Much Radiation is the Trauma Team Really Exposed To?

Previously, I posted about “other people” wearing perfectly good lead aprons lifting them up to their chin during portable xrays in the trauma bay. Is that really necessary, or is it just an urban legend?

Lead apron fly

After hitting the medical radiation physics books (really light reading, I must say), I’ve finally got an answer. Let’s say that the xray is taken in the “usual fashion”:

  • Portable technique in your trauma bay
  • Tube is approximately 5 feet above the xray plate
  • Typical chest settings of 85kVp, 2mAs, 3mm Al filtration
  • Xray plate is 35x43cm

The calculated exposure to the patient is 52 microGrays. Most of the radiation goes through the patient onto the plate. A very small amount reflects off their bones and the table itself. This is the scatter we worry about.

So let’s assume that the closest person to the patient is 3 feet away (1 meter). Remember that radiation intensity diminishes as the square of the distance. So if the distance doubles, the intensity decreases to one fourth. By calculating the intensity of the small amount of scatter at 3 feet from the patient, we come up with a whopping 0.2 microGrays. Since most people are even further away, the dose is much, much less for them.

Let’s put it perspective now. The background radiation we are exposed to every day (from cosmic rays, brick buildings, etc) amounts to about 2400 microGrays per year. So 0.2 microGrays from chest xray scatter is less than the radiation we are exposed to naturally in about 44 minutes!

The bottom line: unless you need to work out you shoulders and pecs, don’t bother to lift your lead apron every time the portable xray unit beeps. It’s a waste of time and effort, unless you are dealing with xray imaging on a very regular basis! And that 52 microGrays the patient absorbed? That’s 8 days worth of background radiation.