Plain English Summary

Background and study aims

It is estimated that 4,000 head-injured patients have emergency brain surgery each year in the NHS. Two-thirds of head-injured patients requiring emergency surgery have a blood clot between the outer lining of the brain and the brain itself. This is called an acute subdural haematoma (ASDH). The pressure this clot puts on the brain can be life threatening, so an urgent operation is needed to remove it. When an ASDH is surgically removed, a piece of skull can be left out or replaced before closing the skin. When a piece of skull is replaced before closing the skin, the operation is named craniotomy. On the other hand, when a piece of skull is left out, the operation is named decompressive craniectomy (DC). The advantage of a DC is that it is more effective in controlling brain swelling, which is often a problem in the days after the operation. After a few months, the patient has another operation to rebuild the skull (with the patient's own bone or an artificial material). The advantage of a craniotomy is that the patient will not need a later operation to rebuild the skull. However, craniotomy may fail to control the brain swelling in some patients. All neurosurgeons are capable of performing both types of operation. Currently, there is no high-quality evidence showing if one operation is better than the other. This study aims to provide this much needed evidence.

Who can participate?

Adult patients with head injuries and acute subdural haematoma can take part.

What does the study involve?

Patients will be randomly allocated to one of the two above mentioned treatments. Participants of the study will fill in a short questionnaire at 6 months and 12 months after the initial injury – this is the only additional thing they will be asked to do. This questionnaire will help us find out about their recovery.

What are the possible benefits and risks of participating?

There are no direct benefits for study participants. However, the study may help doctors in the future decide which operation to use for patients who sustain severe brain injury with an acute subdural haematoma. Both types of operation are currently carried out routinely for patients with ASDH. The risks to participants are minimal. If there is a significant brain swelling preventing safe replacement of the bone flap, the patient will not be allocated but will have the bone flap left out as per standard clinical practice. Moreover, patients allocated to undergo craniotomy who go on to develop brain swelling due to their underlying injury will be allowed to return to the operating theatre to have the bone flap removed if this is deemed necessary by the clinical team.