Experimental acute subdural hematoma in infant piglets.

Traumatic acute subdural hematoma is associated with high mortality in the pediatric population, yet the pathophysiology remains poorly understood. The objective of this study was to develop a pediatric model of acute subdural hematoma, and to evaluate the resultant histopathological changes in the brain. Ten 3-week-old piglets were studied. A 5-mm craniotomy was made in the right frontal skull. A small silastic tube was inserted through the underlying intact dura into the subdural space. A craniotomy was made posterior to the right coronal suture with underlying dura left intact (closed cranial window model). Injection of 5 ml autologous, nonheparinized blood was accomplished through the silastic tube. Animals were sacrificed after 72 h or 1 week. During the subdural injection, intracranial pressure rose to 62 +/- 8 mm Hg, and returned to baseline within 1 h of surgery. Mean arterial blood pressure increased transiently. Cresyl violet and hematoxylin and eosin staining demonstrated extensive areas of white matter necrosis under the hematoma after 72 h survival (n = 7). Zones of necrosis were also noted in cortex, but were less extensive than those seen in white matter. These results differ from adult rodent models in which cortex is primarily affected. This is the first reported pediatric model of traumatic acute subdural hematoma. This model can be used in future studies to investigate pharmacological or other therapies which may improve outcome after this type of injury.