Changes of brainstem and perimesencephalic cistern: dynamic predictor of outcome in severe head injury

Based on the findings in computed tomography scans, we defined a grading system that is well correlated to the changes of the brainstem and its perimesencephalic cistern during intracranial hypertension.

The grades are defined as follows: Grade 0 is normal, grade 1 represents widening of the perimesencephalic cistern without brainstem change, grade 2 represents obliteration of the cistern without brainstem change, grade 3 represents a deformed brainstem; grade 4 represents brainstem density change, and grade 5 represents any combination of grades 3 and 4. As a comparison to the Glasgow Coma Scale (GCS) system, we examined this new system in 334 cases, in which 138 cases were classified as severe head injuries.

In cases of mild head injury (GCS score > 8), this new system was correlated to the GCS system well in grades 0 to 2. In cases of severe head injury, the prediction of outcome is better in our system because it is well correlated to dynamic change of intracranial hypertension, especially in cases with nonsurgical masses of grades 3 and 5.

Our grading system is easy to use, and is well correlated to give an accurate prediction of outcome in cases with severe head injury based primarily on the results of an initial computed tomography scan, even without clinical information, and it should play a role in the classification of head injury.