Tag Archives: BCVI

Complications, Head

Screening For BCVI

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In my last post, I described how common we think blunt carotid and vertebral injury (BCVI) really is. Today, I’ll review how we screen for this condition.

Currently, there are three systems in use: Denver, Expanded Denver, and Modified Memphis. Let’s look at each in detail.

Denver BCVI Screening

There is an original Denver screening system, and a more recent modification. The original system was divided into mechanism, physical signs, and radiographic findings. It was rather rudimentary and evolved into the following which uses both signs and symptoms, and high-risk factors.

Signs and symptoms

  • potential arterial hemorrhage from the neck, nose, or mouth
  • cervical bruit in patients <50 years of age
  • expanding cervical hematoma
  • focal neurologic deficit (transient ischemic attack, hemiparesis, vertebrobasilar symptoms, Horner syndrome) incongruous with head CT findings
  • stroke on CT

Risk factors

  • Le Fort II or III mid-face fractures
  • Cervical spine fractures (including subluxations), especially fractures involving transverse foramen or C1-C3 Vertebrae
  • Basilar skull fracture and involvement of carotid canal
  • Diffuse axonal injury with GCS <8
  • Near hanging with anoxic brain injury
  • Seat belt sign (or other soft tissue neck injury) especially if significant associated swelling or altered level of consciousness

The Denver group reviewed their criteria in 2012 and found that 20% of the patients who had identified BCVI did not meet any of their criteria. And obviously, this number cannot include those who were never symptomatic and therefore never discovered.

Based on their analysis, they added several additional risk factors to the original system:

  • Mandible fracture
  • Complex skull fracture/basilar skull fracture/occipital condyle fracture
  • TBI with thoracic injuries
  • Scalp degloving
  • Thoracic vascular injuries
  • Blunt cardiac rupture

The downside of these modifications is that they are a little more complicated to identify. The original criteria were fairly straightforward yes/no items. But “TBI with thoracic injuries?” Both the TBI part and the thoracic injury part are very vague. This modification casts a wider net for BCVI, but the holes in the net are much larger.

Memphis BCVI Screening

Let’s move on to the modified Memphis system for identifying BCVI. It consists of seven findings that overlap significantly with the Denver criteria. The underlined phrases indicated the modifications that were applied to the original criteria.

  • base of skull fracture with involvement of the carotid canal
  • base of skull fracture with involvement of petrous temporal bone
  • cervical spine fracture (including subluxation, transverse foramen involvement, and upper cervical spine fracture)
  • neurological exam findings not explained by neuroimaging
  • Horner syndrome
  • Le Fort II or III fracture pattern
  • neck soft tissue injury (e.g. seatbelt sign, hanging, hematoma)

Interestingly, these modifications were first described in an abstract which was never published as a paper. Yet somehow, they stuck with us.

So there are now two or three possible systems to choose from when deciding to screen your blunt trauma patient. Which one is best?

Let’s go back to the AAST abstract presented by the Birmingham group this year that I mentioned previously. Not only did they determine a more accurate incidence, but they also tested the three major screening systems to see how each fared. See Table 1.

Look at these numbers closely. When any of these systems were applied and the screen was negative, the actual percentage of patients who still actually had the injury ranged from about 25% to 50%! Basically, it was a coin toss with the exception of the Expanded Denver criteria performing a little better.

If you are a patient and you actually have the injury, how often does any screening system pick it up? Oh, about one in five times. Again, this is not what we want to see.

So what to do? The Expanded Denver screen has a lower false negative rate, but the total number of positive screens, and hence the number of studies performed, doubles when it is used.

Here’s how I think about it. BCVI is more common than we thought in major blunt trauma. If not identified, a catastrophic stroke may occur. Current screening systems successfully flag only 50% of patients for imaging. So in my opinion, we need to consider imaging every patient who is already slated to receive a head and cervical spine CT after major blunt trauma! At least until we have a more selective (and reliable) set of screening criteria.

References:

  • (Denver) Optimizing screening for blunt cerebrovascular injuries. Am J Surg. 1999;178:517–522.
  • (Expanded Denver) Blunt cerebrovascular injuries: Redefining screening criteria in the era of noninvasive diagnosis. J Trauma 2012;72(2):330-337.
  • (Memphis) Prospective screening for blunt cerebrovascular injuries: analysis of diagnostic modalities and outcomes. Ann Surg. 2002, 236 (3): 386-393.
  • (Modified Memphis) Diagnosis of carotid and vertebral artery injury in major trauma with head injury. Crit care. 2010;14(supp1):S100.
Head, Thorax

How Common Is BCVI, Really?

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Blunt carotid and vertebral artery injuries (BCVI) are an under-appreciated problem after blunt trauma. Several screening tools have been published over the years, but they tend to be unevenly applied at individual trauma centers. I will discuss them in detail in the next section.

For the longest time, the overall incidence of BCVI was thought to be low, on the order of 1-2%. This is the number I learned years ago, and it has not really changed over time.

But how do we know for sure? Well, the group at Birmingham retrospectively reviewed every CT angiogram (CTA) of the neck they did in a recent two-year period. They did this after adopting a policy of imaging each and every one of their major blunt trauma patients for BCVI. Each patient chart was also evaluated to see if the patient met any of the criteria for the three commonly used screening systems.

During the study period, a total of 6,287 of 6,800 blunt trauma patients underwent BCVI screening with CTA of the neck. They discovered that 480 patients (7.6%) were positive for BCVI!

This is a shocking 8x higher than we expected! Why hasn’t this been obvious until now? Most likely because we were previously only aware of patients who became symptomatic. Luckily, many of these patients dodge the proverbial bullet and never exhibit any symptoms at all.

So why should we be worried? This is one of those clinical entities like blunt thoracic aortic disruption that potentially has terrible consequences if ignored. Although the number of patients who develop sequelae from their BCVI is small, suffering a stroke can be catastrophic.

Should we perform a screening study for all blunt trauma patients? Seems like overkill, or is it? Is there any way we be more selective about it?

In the next post, I’ll review the three current screening tools  used to determine which patients should receive CTA, and how good they are.

Reference: Universal screening for blunt cerebrovascular injury. J Trauma 90(2):224-231, 2021.

Head, Thorax

It’s BCVI Week!

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This post will kick off a series of posts on BCVI. What is that, you ask? There seems to be some confusion as to what the acronym BCVI actually stands for. Some people believe that it means blunt cerebrovascular injury. This is not correct, because that term refers to injury to just about any vessel inside the skull.

The correct interpretation is blunt carotid and vertebral artery injury. This term refers to any portion and any combination of injury to those two pairs of vessels, from where they arise on the great vessels, all the way up into the base of the skull. Here’s a nice diagram:

Note that we will be excluding the external carotid arteries from this discussion, since injuries to them do not have any impact on the brain. They can cause troublesome bleeding, though.

These arteries are relatively protected from harm during blunt trauma. But given enough energy, bad things can happen. Fortunately, injuries to these structures are not very common, but unfortunately many trauma professionals under-appreciate their frequency and severity.

Over the next four posts, I’m going to provide an update on what we know about BCVI. I will try to tease out the true incidence, review the (multiple) screening systems, and discuss various ways to manage these injuries.

In the next post, we’ll explore the incidence of this injury. Is it truly as uncommon as we think?

Abstracts, Complications

Best Of AAST #9: Blunt Carotid And Vertebral Injuries

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Blunt carotid and vertebral artery injuries (BCVI) are an under-appreciated problem after blunt trauma. Several screening tools have been published over the years, but they tend to be unevenly applied at individual trauma centers. For an unfortunate few, the only indication of BCVI is a stroke while in hospital.

The overall incidence of BCVI is thought to be small, on the order of 1-2%. But how do we know? Well, the group at Birmingham retrospectively reviewed every CT angiogram (CTA) of they did in a recent two year period. They did this after adopting a policy of screening all their major blunt trauma patients. Each patient chart was also evaluated to see if they met any of the criteria for the three commonly used screening systems.

Here are the factoids:

  • 5,634 of 6,800 blunt trauma patients underwent BCVI screening with CTA of the neck
  • 471 patients (8.4%) were found to have BCVI
  • Here are the accuracy statistics for the three screening systems

Here are my comments: The authors found that the incidence of BCVI is about 8x what we previously thought. What we don’t know is the percentage of these patients that go on to cause stroke or other neurologic deficits. But this is somewhat frightening.

Even more frightening is that the screening systems that we rely on fare so poorly. The Denver and Modified Memphis criteria have a true positive rate that is the same as a coin toss. And even if the patient meets none of the criteria in any system, about 5% BCVI will sneak through (NPV 95%).

So the question becomes, do we all perform universal screening for blunt trauma? Or do we still use one of the three systems and keep our fingers crossed that the ones we miss will not progress? Or maybe just give everybody an aspirin a day for a while. And still keep our fingers crossed!

Here are some questions for the presenter and authors:

  • Why did you decide to implement a universal screening protocol in the first place? Bad experience(s)?
  • Do you have any screening recommendations other than to screen everybody? How do you decide which blunt trauma patients to screen? Every car crash? What level of fall? The devil is in the details!

This is an easy to follow paper with a solid analysis and real world implications. Excellent work!