Monthly Archives: July 2010

General

Inline Stabilization vs Inline Traction of the Cervical Spine

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Members of the trauma team must frequently protect the cervical spine when moving the patient or performing certain procedures. In most cases, a cervical collar is placed which does a fine job of this. Occasionally, though, the collar must be removed to provide access to areas near or under the collar.

When the collar is off, someone must be charged with immobilizing the cervical spine. Sometimes this is incorrectly referred to as providing inline traction and not inline stabilization.There is a big difference!

Inline traction is used to try to realign cervical vertebra that are malpositioned due to fracture or ligamentous injury. This should only be performed under the guidance of a neurosurgeon!

Inline stabilization merely means that the patient (or trauma professional) is restrained from moving the cervical spine. This is commonly needed while intubating the patient, so that the intubator does not extend the neck when trying to visualize the cords.

Why is this important? Check out the images below. If a severe injury has already occurred, traction on the neck may have devastating consequences! Inline stabilization is the only way to go.

Spine injury AO dissociation

General

How Much Radiation is the Trauma Team Really Exposed To?

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Okay, so you’ve seen “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?

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”:

  • 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. 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 every hour!

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!

History

Trauma 20 Years Ago: Early vs Delayed Femur Fixation

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Today, we take for granted that fixing fractures early is a good thing. However, this topic was still under debate 20 years ago. Trauma care has always been prioritized, with life-threatening injuries taking precedence. It was very common for major trauma patients to undergo operation for their torso injuries, and then be deemed “too unstable” to undergo repair of their extremities.

Weigelt et al reported decreased pulmonary complications with early fixation in 1989. A study published in July 1990 looked at 121 early vs 218 late femur fixations with respect to more concrete outcomes. The patients were similar with respect to hypotension, transfusions and associated injuries.

They found that delayed fixation increased pulmonary shunt, especially in patients with more severe injuries, and increased the incidence of pneumonia in older patients. It also resulted in more ICU days and a significantly longer hospital stay in the more severely injured group.

This paper was a valuable addition that began to shape our appreciation for the importance of early fixation of most fractures. Major trauma makes patients sick, but they are in the best condition they will be in for weeks at the time they arrive at the hospital. This makes it the ideal time to take care of injuries that may otherwise contribute to morbidity and mortality.

Reference: Fabian et al. Improved outcome with femur fractures: early vs delayed fixation. J Trauma 30(7):792, 1990.

General

Thoracic Aortic Injury in Very Young Children

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Trauma professionals routinely worry about the thoracic aorta when evaluating adults after major blunt trauma. The question is, how much do we have to worry about blunt thoracic aortic injury in children?

Younger children are more elastic, and their organs tend to withstand more punishment than adults. After reviewing the literature, I’ve come to the conclusion that this injury is very rare in children in the single digit age range. It’s difficult to find a good paper that addresses this question. The majority include kids up to age 16 or 18, which really skews the results. These patients are most commonly involved in motor vehicle crashes, although a significant number are also pedestrians struck by cars. 

The National Trauma Data Bank (NTDB) was queried for all children <18 years old sustaining blunt injury with at least 1 diagnosis code. There were nearly 27,000 records matching these criteria. Of these, only 34 had an injury to the thoracic aorta. And in the age range under 10, there were only 2! Both of these children were in very high energy car crashes.

The bottom line: Injury to the thoracic aorta practically never happens in children in the single digit age range. As they get closer to adolescence, they behave more like adults and become more susceptible. The diagnosis should be only be entertained in small children who are involved in very high-energy car crashes. Falls from the usual heights (2-3 stories) are probably not significant enough to cause it. A chest xray may show a full mediastinum, but this will most likely be due to a normal thymus. If investigation is warranted, the standard is to obtain a helical CT of the chest. This study would most likely be obtained anyway to evaluate the torso in a high-energy mechanism. Aortorgraphy is no longer used.

Reference: Trooskin, et al. Risk factors for blunt thoracic injury in children. J Pediatric Surg 40(1):98, 2005.