All posts by TheTraumaPro

Contrast Extravasation Into The Psoas Muscle

Contrast extravasation after major trauma can be very problematic. Extravasation into a solid organ (liver, spleen) generally requires a quick trip to interventional radiology or the operating room. Bleeding from the bowel mesentery assures an exploratory laparotomy. Gluteal vessel extravasation is best treated with angioembolization.

But what about extravasation from off the beaten path areas like the psoas muscle? This is an uncommon finding on trauma CT, so less is known about the usual clinical course. A group in Okayama Japan performed a 10-year retrospective review of data from their hospital. They reviewed hematoma size, associated injuries, and the relationship to treatment options.

Here are the factoids:

  • 762 contrast CTs were performed due to blunt trauma over the 10 year period (only 76 per year?!)
  • About 15% (117 patients) had either lumbar process fracture or psoas hematoma, and about one quarter had obvious contrast extravasation into the muscle
  • Patients with contrast extravasation were significantly older, had higher ISS, and were more likely to require transfusion
  • There was an association between the number of transverse process fractures and “need for” angioembolization
  • Size of the psoas hematoma was predictive of the need for angioembolization
  • Angioembolization of the psoas was frequently associated with  embolization of the pelvis

The right psoas has both contrast extravasation and a sizable hematoma

Bottom line: This study has many weaknesses, but does show that psoas extravasation occurs somewhat frequently, even at a low volume center. I always worry about studies that state something like “and xx patients required intervention.” Generally, this means that it was performed at the discretion of the clinician and no consistent rules were applied. And even though hematoma size was significantly correlated with angioembolization, it’s probably not worth the effort to have your radiologist calculate it. But it does illustrate one nearly universal trauma rule:

Patients with active extravasation on CT are bleeding to death until proven otherwise

Do not sit back and manage expectantly! The corollary to this rule is:

Contrast extravasation on CT always requires active measures to stop it

These active measures are typically angioembolization for difficult to reach areas in hemodynamically stable patients (gluteal artery for buttock, lumbar artery for psoas muscle, solid organs). Unstable patients absolutely require a trip to the OR for control. Superficial muscular bleeding frequently stops with good pressure dressings or positioning the patient so they lie on the affected area. Just don’t sit around and watch these patients bleed when you see extravasation on the CT.

Reference: Impact of contrast extravasation on computed tomography of thepsoas major muscle in patients with blunt torso trauma. J Trauma 86(2):268-273, 2019.

The Newest Flavor Of 3D Printing

I’m fascinated with 3D printing, and have written a number of posts on the topic. There are numerous applications in medicine, and particularly in trauma care. We are currently able to print substitutes for bone, cartilage (trachea), bladder, skin, and more. To date, all of these use the same 2D technology found in ink-jet printers. But instead of 2D splashes of ink, three dimensional bits of plastic or metal are stacked on top of each other one layer at a time and fused by a laser.

UC Berkeley and Lawrence Livermore National Laboratory have developed a new 3D printing technology that coalesces an entire object at once using 3D information projected by shining light fro a standard LED projector into a column containing a special resin. The device has been renamed the “replicator” since it functions like the device seen in various Star Trek series. Here’s a brief video:

Bottom line: This is new technology, so it’s still a bit glitchy. The surface definition is lower than conventional 3D printing, which will limit its usefulness in some medical applications. And currently, the size limit is only four inches. But it will allow printing over existing objects, which may give it some real advantages. I’m sure there’s more to come with this promising new technology.

Related posts:

 

Does The Tertiary Survey Really Work?

Delayed diagnoses / missed injuries are with us to stay. The typical trauma activation is a fast-paced process, with lots of things going on at once. Trauma professionals are very good about doing a thorough exam and selecting pertinent diagnostic tests to seek out the obvious and not so obvious injuries.

But we will always miss a few. The incidence varies from 1% to about 40%, depending on who your read. Most of the time, they are subtle and have little clinical impact. But some are not so subtle, and some of the rare ones can be life-threatening.

The trauma tertiary survey has been around for at least 30 years, and is executed a little differently everywhere you go. But the concept is the same. Do another exam and check all the diagnostic tests after 24 to 48 hours to make sure you are not missing the obvious.

Does it actually work? There have been a few studies over the years that have tried to find the answer. A paper was published that used meta-analysis to figure this out. The authors defined two types of missed injury:

  • Type I – an injury that was missed during the initial evaluation but was detected by the tertiary survey.
  • Type II – an injury missed by both the initial exam and the tertiary survey

Here are the factoids:

  • Only 10 observational studies were identified, and only 3 were suitable for meta-analysis
  • The average Type I missed injury rate was 4.3%. The number tended to be lower in large studies and higher in small studies.
  • Only 1 study looked at the Type II missed injury rate – 1.5%
  • Three studies looked at the change in missed injury rates before and after implementation of a tertiary survey process. Type I increased from 3% to 7%, and Type II decreased from 2.4% to 1.5%, both highly significant.
  • 10% to 30% of missed injuries were significant enough to require operative management

Bottom line: In the complex dance of a trauma activation, injuries will be missed. The good news is that the tertiary survey does work at picking up many, but not all, of the “occult” injuries. And with proper attention to your patient, nearly all will be found by the time of discharge. Develop your process, adopt a form, and crush missed injuries!

Related posts:

Reference: The effect of tertiary surveys on missed injuries in trauma: a systematic review. Scand J Trauma Resusc Emerg Med 20:77, 2012.

The Tertiary Survey for Trauma

Major trauma victims are evaluated by a team to rapidly identify life and limb threatening injuries. This is accomplished during the primary and secondary surveys done in the ED. The ATLS course states that it is more important for the team to identify that the patient has a problem (e.g. significant abdominal pain) than the exact diagnosis (spleen laceration). However, once the patient is ready for admission to the trauma center, it is desirable to know all the diagnoses.

This is harder than it sounds. Physical examination tends to direct diagnostic testing, and some patients may not be feeling pain, or be awake enough to complain of it. Injuries that are painful enough may distract the patient’s attention away from other significant injuries. Overall, somewhere between 7-13% of patients have injuries that are missed during the initial evaluation.

A well-designed tertiary survey helps identify these occult injuries before they are truly “missed.” This survey consists of a structured and comprehensive re-examination that takes place within 48-72 hours, and includes a review of every diagnostic study performed. Ideally, it should be carried out by two people: one familiar with the patient, and the other not. It is desirable that the examiners have some experience with trauma (sorry, medical students).

The patients at highest risk for a missed injury are those with severe injuries (ISS>15) and/or impaired mental status (GCS<15). These patients are more likely to be unable to participate in their exam, so a few injuries may still go undetected despite a good exam.

I recommend that any patient who triggers a trauma team activation should receive a tertiary survey. Those who have an ISS>15 should also undergo the survey. Good documentation is essential, so an easy to use form should be used. Click here to get a copy of our original paper form. We have changed over to an electronic record, and have created a dot phrase template, which you can download here.

Tomorrow: Does the tertiary survey actually work?

Detecting Rib Fractures In The Elderly

It’s well known that our elders do less well than younger folks after injury. The number of complications is higher, there tends to be more loss of independence during recovery, and mortality is increased. This is not only true of high energy trauma like car crashes, but also much lower energy events such as a fall from standing.

Rib fractures are common after falls in the elderly and contribute to significant morbidity if not treated adequately. Traditionally, they are identified through a combination of physical exam and chest x-ray. Unfortunately, only half of rib fractures are visible on x-ray. It falls to the physical exam to detect the rest.

A group at Beth Israel Hospital in Boston explored the utility of using chest CT in an attempt to determine if this would result in more appropriate and cost-efficient care in the elderly. They performed a retrospective study of 3 years of their own data on patients aged 65 or more presenting after a mechanical fall and receiving a rib fracture diagnosis. Imaging was ordered at the discretion of the physician. A total of 330 patients were elderly, fell, and had both chest x-ray and chest CT obtained. This was a very elderly group, with a mean age of 84 years!

Here are the factoids:

  • Rib fractures were seen on chest x-ray in 40 patients (12%) and on CT in an additional 56 ; 234 patients had no fractures on either
  • When fractures were seen on both studies, CT identified a median of 2 more fractures than chest x-ray
  • Patients with fractures not seen on chest x-ray were admitted significantly more often than those without fractures (91% vs 78%)
  • Mortality, admission to ICU, ICU length of stay, and hospital length of stay were not different if fractures were seen only on CT
  • CT scan identified new issues or clarified diagnoses suggested by chest x-ray in 14 cases, including one malignancy
  • Rib detail images were obtained in 13 patients and proved to be better than chest x-ray, but not quite as good as CT scan

Conclusion: use of CT for rib fracture diagnosis resulted in a few more admissions, but no change in hospital resource utilization, complications, or mortality.

Bottom line: Hmm…, read the paper closely. The authors conclude that more patients with CT-only identified rib fractures are admitted. But compared to what? Unfortunately, patients without rib fractures on CT. What about comparing to patients who had fractures seen on chest x-ray too? If that number is the same, then of what additional use is CT? Identifying a few incidentalomas?

Given that there is no change in the usual outcome measures listed here, it doesn’t seem like there is any additional benefit to adding CT. And I can see a lot of downsides: cost, radiation, and possible exposure to IV contrast. In my mind, there is still nothing that beats a good physical exam and a chest x-ray. Skip the CT scan. And don’t even think about ordering rib detail images! That’s so 1990s. And even if no rib fractures are seen on imaging, physical exam is the prime determinant for admitting your patient for aggressive pain management and pulmonary toilet.

Reference: Chest CT imaging utility for radiographically occult rib fractures in elderly fall-injured patients. J Trauma ePub ahead of print, Jan 23, 2019.