In head trauma, a general distinction can be made between primary and secondary brain injury:

Primary lesions include hemorrhagic focal contusions, mechanical damage of nerve fibers, and vascular lesions. Such injuries are caused by the trauma itself and thus cannot be influenced by therapy.

The opposite is true of secondary brain damage. Unlike primary lesions, secondary damage is avoidable and thus treatable. Causes of secondary brain damage can be divided into extracranial and intracranial sources:

– The most important extracranial causes are arterial hypoxia and arterial hypotension. Even a brief drop in blood pressure to systolic values <90 mmHg doubles the risk of fatality in patients with severe head trauma.

– The most important intracranial causes are intracranial hemorrhage and posttraumatic brain swelling or edema.

Secondary cerebral injury manifests clinically as increased intracranial pressure (ICP), which leads to impaired cerebral perfusion with the associated risk of cerebral ischemia.

Intracranial hemorrhage diagnosed on computed tomography (CT) scans must therefore be decompressed or evacuated promptly. In the acute phase, this includes epidural and subdural hematomas; and in the subacute phase occasionally also intracerebral hematomas:

Epidural hematomas often arise from hemorrhagic oozing from a fracture gap in the skull vault or an interruption of dural vessels. They are particularly common in the temporal and frontal lobe regions. Adequate therapy of epidural hematomas consists of rapid surgical decompression, whereby the source of hemorrhage is identified and managed simultaneously.

Acute subdural hematomas often arise from injury to bridge veins or from cortical focal contusions. Because subdural hematomas spread out over the entire hemisphere, there is disparity between the diameter of the hematoma and its effect as an intracerebral mass, i. e., midline shift, on CT scans. Management with a large osteoplastic trephination has proven itself in the surgical decompression of acute subdural hematomas. The dura is “slit” at various sites and the hematoma suctioned through these incisions under irrigation.

Immediately following evacuation of the hematoma, an ICP catheter is placed in order to quantify the extent of posttraumatic brain swelling and guide specific treatment. It cannot be assumed that unconscious patients will regain consciousness immediately following decompression of intracranial hemorrhage. Placement of an ICP catheter is also possible even if evacuation is not required, i. e., at the “bedside” in intensive care or in the shock room.