Over the past two days, I’ve reviewed the new AAST organ injury scaling updates for spleen and liver injuries. Today, I’ll cover the new kidney grading scale.

Liver and spleen grading is generally simple, focusing on laceration depth and subcapsular hematoma coverage to determine the exact value. However, the kidney is totally different. Although technically a solid organ, it’s got a bunch of hollow, urine-containing stuff inside. This is the main determinant of the original scaling system: collection system involvement.

Like liver and spleen, the kidney scale was updated to take advantage of CT information. But once again, bleeding identified via the CT angiogram is incorporated into the higher grades. Active bleeding contained within Gerota’s fascia is assigned a grade of III. Extravasation escaping this fascia is assigned a IV.  The other grades remain unchanged.

Here are the updated guidelines. Click the image or link below it to open a bigger image in a new window.

Click to download larger image

Links:

• Updated AAST spleen scaling system
• Updated AAST liver scaling system
• Updated AAST kidney scaling system

In my last post, I reviewed the updated AAST organ injury scaling (OIS) for the spleen. Today, I’ll share details of the new version of liver grading.

First, the overall focus of the updated liver scale is similar to the spleen one: it incorporates a listing of criteria identified by CT scan that parallels the old anatomic criteria. The CT column contains all the old anatomic stuff, but now includes scaling for active bleeding.

The confusing part? Whereas contained active bleeding within the spleen was Grade IV and active bleeding escaping the spleen was Grade V in the updated scale, these drop down a grade in the liver. So bleeding contained with the liver parenchyma is Grade III and active extravasation escaping into the peritoneal cavity is only Grade IV. I presume this has to do with the abbreviated injury score (AIS) used to calculate ISS, and that the mortality hit from this degree of bleeding is less than that of the spleen.

The final difference between the updated scale and the original is the removal of Grade VI. This was previously described as hepatic avulsion, which is a nonsurvivable injury. The AIS for Grade VI liver used to be 6, which causes an immediate ISS calculation short circuit to 75. Which also means that survival is approximately 0%. This is not part of the OIS update, which may be due to the fact that it never occurs in anyone who makes it to a trauma center alive.

Here are the updated guidelines. Click the image or link below it to open a bigger image in a new window.

Click to download larger image

In the next post, I’ll review the new features of the kidney injury scale.

Over the years, the American Association for the Surgery of Trauma (AAST) has developed and maintained a library of organ injury scales. Organ injury scaling allows us to compare apples to apples in research studies, and in many cases enables us to tailor interventions and predict outcomes. Many of the scales have been in place for decades and have not been updated. The spleen, liver, and kidney scales were introduced 25 year ago, and received their first update last December. During the next three posts, I’ll review what’s new and different with them.

The biggest change to all three scales has been the incorporation of specific vascular injuries seen on modern-day CT scans. It is recommended that scanning for solid organ injury be conducted using dual phase (arterial and portal venous) scanning techniques. This increases study sensitivity and provides the best images for accurate diagnosis and scaling. Also note that specific criteria are now provided for CT, intraoperative, and pathologic diagnosis.

Let’s start with the spleen today. Here are the updated guidelines. Click the image or link to get a bigger image in a new window.

Click to download larger image

The main change to this scale is the addition of active bleeding contained within the spleen (pseudo-aneurysm or contained extravasation) to Grade IV, and uncontained extravasation to Grade V.

In my next post, I’ll discuss the new features of the liver injury scale.