Acute traumatic midbrain hemorrhage: experimental and clinical observations with CT.

Traumatic brain stem hemorrhage (TBH) after blunt head impact is an uncommon injury and has historically been associated with high mortality. Retrospective clinical review identified 64 patients with TBH admitted during a 5-year period. Complete imaging and clinical records for 45 of these patients demonstrated that TBH could be categorized into three groups. The most frequent site of hemorrhage, in 31 (69%) of 45 patients (group 1), was the midline rostral anterior brain stem, posterior to the interpeduncular cistern, and this injury was associated with a 71% survival rate. This pattern was also associated with a predominantly anterior site of head and/or face impact. Eight (18%) patients (group 2) had miscellaneous foci of acute brain stem hemorrhage with seven (88%) surviving. Six (13%) patients (group 3) had brain stem hemorrhage associated with transtentorial herniation and brain stem compression, with 100% mortality. Experimental findings in a canine model and clinical results indicate that the anterior rostral midbrain is a common site of TBH and appears to arise from sudden craniocaudal displacement of the brain at impact. Survival is unexpected high with this location of traumatic midbrain hemorrhage.