Category Archives: General

Repeated Head CT Scans: Are They Really Necessary?

There is an increasing public interest regarding exposure to medical radiation. It represents the major exposure source for the population at large. There may be a presumption on the part of medical providers that “what you can’t see can’t hurt you” but this is just not the case.

A number of studies have shown that there is risk association with repeated exposure to xray. This risk is particularly important when dealing with pediatric patients. It’s time to start critically looking at our imaging practices and to start critically thinking about every one that we order.

One common source of repeat radiation is the repetitive CT scans of the head that patients who suffer TBI undergo. Frequently, there is little rhyme or reason to the patter of these scans. Should we repeat in 6 hours? 24 hours? When any lesions finish evolving?

It turns out that there is a reasonable amount of guidance in the brain literature. For the most part, they suggest that patients who are not in an ICU only need a repeat CT if their mental status changes. Any others obtained did not result in any management change. The first 6 papers listed below agree with this.

However, number 7 is interesting. It was published in the Journal of the American College of Surgeons and was a retrospective study of patients seen at a Level I Trauma Center. All patients had a lesion seen on initial scan, and underwent repeat scanning. The authors found that 6% of their patients underwent a surgical or medical “intervention” based on changes on the repeat head CT. What troubled them the most was that 21 of these 51 patients did not have any substantial neurologic change. They conclude that routine repeat head CT is very useful.

It’s not clear why their results are so disparate from the others. It is retrospective, and the authors do not state what the interventions exactly are. Nor do they speculate on why their results are so different from others. Nor do they show any difference in outcomes.

The bottom line: Repeat head CT is probably not needed in patients with mild TBI who are not on anti-coagulants or anti-platelet agents. However, regular mental status checks and GCS measurements must be taken.

References:

  1. Is repeated head computed tomography necessary for traumatic intracranial hemorrhage? American Surgeon 2005 Sep;71(9):701-4.
  2. Routine repeat head CT for minimal head injury is unnecessary. J Trauma 2006, Mar;60(3):494-9.
  3. A prospective evaluation of the value of repeat cranial computed tomography in patients with minimal head injury and an intracranial bleed. J Trauma 2006 Oct;61(4):862-7.
  4. Indications for routine repeat head computed tomography (CT) stratified by severity of traumatic brain injury. J Trauma 2007 Jun;62(6):1339-44.
  5. The role of early follow-up computed tomography imaging in the management of traumatic brain injury patients with intracranial hemorrhage. J Trauma 2007 Jul;63(1):75-82.
  6. Value of repeat cranial computed tomography in pediatric patients sustaining moderate to severe traumatic brain injury. J Trauma 2008 Dec;65(6):1293-7.
  7. Schedule repeat CT scanning for traumatic brain injury remains important in assessing head injury progression. J Amer Coll Surgeons 2010 May;210:824-32.
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Pediatric ATV Injuries: A Look At The Data

ATVs (all-terrain vehicles) are motor vehicles that are designed for use on uneven surfaces. Full-size ATVs can weigh up to 600 pounds and reach speeds of 75mph. There are up to 7 million ATVs currently being used in this country.

Unfortunately, young riders make up a disproportionate number of injuries and fatalities. About a third of all ATV-related deaths and ED visits involve riders under the age of 16. The risk factors for ATV injuries are well known:

  • No helmet
  • Risk-taking behaviors
  • Male (seems to go along with the previous one)
  • Large engine
  • Small child
  • 3-wheeled ATVs
  • Driving on public roads
  • Riding with a passenger

The University of Connecticut published a recent study in which they surveyed youths at four major agricultural fairs covering the 4 major geographic areas of the state. The average age that the kids began riding was 9 years. The majority rode for fun, but more than a third admitted to racing informally with friends. 70% engaged in double-riding, 59% rode alone without family present, and 46% rode after dark. Most kids were trained on ATVs by family or friends, although 25% were self-taught. The majority wore appropriate clothing and 80% wore a helmet.

Nearly half of these kids admitted to being involved in at least one ATV crash. The most frequent type of crash was a rollover, followed by collision with a stationary object. 10% were pinned under the ATV. Commonly reported causes of the crash were poor driving conditions, lack of experience, and lack of strength to control the ATV. Those who reported crashing were also more likely to engage in risky ATV behavior like racing, riding after dark, riding without supervision, or riding a large ATV.

This study points to the need for additional education and training for both children who want to ride an ATV and their parents. The only way to reduce the number of children injured or killed by these vehicles is to make sure both groups understand the need for safe riding practices.

Reference: Campbell et al, J Pediatric Surg 45:925-929, 2010.

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Contrast Blush in Children

A contrast blush is occasionally seen on abdominal CT in patients with solid organ injury. This represents active arterial extravasation from the injured organ. In most institutions, this is grounds for call interventional radiology to evaluate and possibly embolize the problem. The image below shows a typical blush.

Splenic contrast blush

This thinking is fairly routine and supported by the literature in adults. However, it cannot be generalized to children!

Children have more elastic tissue in their spleen and tend to do better with nonoperative management than adults. The same holds true for contrast blushes. The vast majority of children will stop bleeding on their own, despite the appearance of a large blush. In fact, if children are taken to angiography, it is commonplace for no extravasation to be seen!

Angiography introduces the risk of local complications in the femoral artery as well as more proximal ones. That, coupled with the fact that embolization is rarely needed, should keep any prudent trauma surgeon from ordering the test. A recently released paper confirms these findings.

The only difficult questions is “when is a child no longer a child?” Is there an age cutoff at which the spleen starts acting like an adult and keeps on bleeding? Unfortunately, we don’t know. I recommend that you use the “eyeball test”, and reserve angiography for kids with contrast extravasation who look like adults (size and body habitus).

Reference: What is the significance of contrast “blush” in pediatric blunt splenic trauma? Davies et al. J Pediatric Surg 2010 May; 45(5):916-20.

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The Seat Belt Sign

Officially, a seat belt sign consists of contusions and abrasions on the abdomen of a restrained occupant involved in a motor vehicle crash. The seat belt syndrome takes this one step further, with injury to the abdominal organs or spine.

Seat belts save lives by reducing the number of people dying from head injury after a car crash. However, they do so by diverting energy from the head to the chest and abdomen. Overall, people who don’t wear seat belts have a 10% chance of abdominal injury. With seat belts in place, this increases to 15%. And if the person is wearing seat belts and has a seat belt sign, the risk of injury increases to 65%!

This isn’t a bad thing, however. We can fix abdominal injuries, but we can’t fix the brain; it has to heal on its own, and slowly at that.

Seat belts are associated with the Chance fracture, an uncommon fracture of the lumbar spine, usually at L1. These usually only occur with the use of lap belts without shoulder restraints, which is found less and less in cars today. These used to be located in the center of the rear seat, but most new cars offer shoulder restraints in this location now.

Chance fractures need to be assessed by a spine surgeon so that stability can be determined. If stable and there is minimal kyphosis, a brace may be appropriate for treatment. However, if the fracture is not stable or there is more than about 15 degrees of angulation, surgery will be necessary.

As seat belt use increases, seat belt signs are becoming more common. Any patient with a seat belt sign must have an abdominal CT. If any abnormal findings are noted, a surgeon must be consulted because it is very likely that operative intervention will be required. 

To view a slideset about seat belt sign, click here.

Seat belt sign

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Trauma 20 Years Ago: The MESS Score

This month is the 20th anniversary of the MESS score, a system that helps predict salvageability of mangled extremities (Mangled Extremity Scoring System). Obviously, the acronym was chosen to help describe the clinical problem.

The system was originated at the Harborview Medical Center in Seattle. The development was not very scientific; the authors put their heads together and made a list of the four things that they observed predicted limb salvage:

  • Degree of skeletal and soft tissue injury
  • Presence of limb ischemia
  • Presence of shock
  • Age

The system was used retrospectively in a group of 25 patients(!) and the authors found a nice breakpoint at 7. Any mangled extremities with a MESS of 7 or more required amputation. They then applied this to 26 patients prospectively(!) and got the same result.

As you can see, the numbers were small, and there was no followup information. Nevertheless, MESS still stands today, and the critical MESS score has not changed much. It has been validated by a number of other studies during the past 20 years. It is conceivable that the critical score will slowly creep upward with advancements in flap coverage and surgical technique, but it hasn’t done so yet.

Reference: Objective Criteria Accurately Predict Amputation Following Lower Extremity Trauma. Johansen, et al. J Trauma 30(5): 568, 1990.

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