INTRACRANIAL TENSION

Increased intracranial tension or pressure will cause secondary injury to the brain. It results from:

The clinical features of increased intracranial pressure include:

Acute extradural and acute subdural haematomas are the only two conditions that may benefit from burr holes. A history of trauma and a clear clinical diagnosis are essential before undertaking the procedure.

Acute extradural haematoma

The signs classically consist of:

Acute subdural haematoma

Acute subdural haematoma, with clotted blood in the subdural space accompanied by severe contusion of the underlying brain, occurs from the tearing of bridging vein between the cortex and the dura.

Management is surgical and every effort should be made to do burr-hole decompressions. The diagnosis can be made on history and examination.

Creating burr holes through the skull to drain the haematoma is often an emergency and life-saving procedure.

Technique

1	Shave and prepare the skull over the temporal region between the ear and the external limit of the orbit on the side of the suspected compression (Figure 17.43).
Figure 17.43
2	Infiltrate the scalp with a local anaesthetic, and make a 3 cm incision through skin and temporal fascia. Separate the temporalis muscle and incise the periosteum. Control bleeding with retractors or electric cautery. Epinephrine in the local anaesthetic will also help control superficial bleeding (Figure 17.44).
Figure 17.44
3	Make the burr hole 2 cm above and behind the orbital process of the frontal bone. Using a drill cutter, begin to make a hole through the outer and inner tables. Use little pressure when cutting the inner table to avoid plunging through into the brain. Switch to a conical or cylindrical burr to carefully enlarge the opening (Figure 17.45).
Figure 17.45
4	If necessary, enlarge the opening further with a ronguer (Figure 17.46): • Control bleeding from the anterior branch of the middle meningeal artery using cautery or ligature • Control venous bleeding with a piece of crushed muscle or a gelatin sponge • Control bone bleeding with bone wax.
Figure 17.46
5	Wash out the extradural haematoma with a hand syringe. If an extradural haematoma is not found, look for a subdural haematoma. If present, consider opening the dura to release it or arranging for care at a referral hospital. If no haematoma is found, create a burr hole on the opposite side to exclude contra coup bleeding.
6	Close the scalp in two layers. If there is a dural fluid leak, do not use a drain but close the wound tightly to prevent persistent drainage and a secondary infection.