A design for evaluation of the trauma apportionment in cerebral infarction after trauma

Posttraumatic cerebral infarction (CI) is a well-known complication of traumatic brain injury (TBI). However, the causation and apportionment of trauma in patients with CI after TBI is not easy. There is a scoring method, so-called trauma apportionment score (TAS) for CI, consisted with the age, the interval, and the severity of the TBI. We evaluated the reliability of this score.

We selected two typical cases of traumatic CI. We also selected consecutive 50 patients due to spontaneous CI. We calculated TAS in both patients with traumatic and spontaneous CI. To enhance the reliability, we revised TAS (rTAS) adding three more items, such as systemic illness, bad health habits, and doctor's opinion. We also calculated rTAS in the same patients.

Even in 50 patients with spontaneous CI, the TAS was 4 in 44 patients, and 5 in 6 patients. TAS could not assess the apportionment of trauma efficiently. We recalculated the rTAS in the same patients. The rTAS was not more than 11 in more than 70% of the spontaneous CI. Compared to TAS, rTAS definitely enhanced the discriminating ability. However, there were still significant overlapping areas.

TAS alone is insufficient to differentiate the cause or apportionment of trauma in some obscure cases of CI. Although the rTAS may enhance the reliability, it also should be used with cautions.