Head injury
It has been estimated that in the UK, between
200 and 300 per 100 000 of the population are admitted to hospital each year
with a head injury, making it one of the most common causes for attending
accident and emergency departments. Trauma, in which severe head injury often
plays a major role, is also the leading cause of death in the population below
45 years of age. Craniocerebral trauma is consequently a source of major
disability and a huge financial and psychological burden upon society.
Despite
being encased in a rigid protective skull and cushioned by CSF, the brain is
still very vulnerable to trauma, having only the consistency of a well-set
jelly. This trauma can take the form of translational acceleration/deceleration
forces, rotational forces or direct local sharp penetrating or blunt trauma to
the cranium and can involve the scalp, skull or brain, in any combination.
Scalp
Scalp lacerations are common and can give rise
to exanguinating haemorrhage if not controlled. This is due to the vessels in
the dense fibrous layer being held open. Scalp hair plays an important
protective role and by matting into wounds can effectively assist haemostasis
but likewise mask significant scalp lacerations. The scalp’s rich vascular
supply plays an important role in healing, making it a very resilient structure.
Skull
Different types of skull injury may follow
blunt trauma.
Simple linear fractures
These require no specific neurosurgical
management but are usually markers of the force to which the head was subjected.
Patients are usually CT scanned but should also be admitted for at least 48
hours’ observation.
Depressed skull fracture
These fractures are a result of blunt trauma,
usually to the left -frontal region. If the pericranium has been breached the
The
damage done at the time of impact with subsequent risk of epilepsy is
irreversible. Surgery is usually undertaken to prevent the risk of infection, to
alleviate mass effect and for cosmetic purposes. Contaminated wounds require
extensive debridement, a duraplasty and irrigation before closure. A full
course of intravenous antibiotics should be administered.
Base of skull fracture
These are relatively frequent fractures,
usually diagnosed on clinical grounds. They often result in CSF fistula which
may persist but usually seal off after a few days. Anterior fossa fractures
present with subconjunctival haematomas, anosmia, epistaxis and CSF rhinorrhoea
and may occasionally be associated with caroticocavernous fistulae (Fig. 35.11).
Periorbital haematomas or ‘racoon eyes’ indicate subgaleal haemorrhage
and not necessarily base of skull fracturing as do subconjuntival haemorrhages
extending beyond the conjunctival reflections (Fig. 35.12).
Middle fossa fractures present with CSF otorrhoea or rhinorrhoea via the
eustachian tube, heamotympanum, ossicular disruption, ‘battle sign’ (Fig.
35.13) or VII and VIII cranial nerve palsies.
There
is no evidence that prophylactic~ antibiotics diminish the incidence of
meningitis. Administering them may just select out more virulent organisms in
those that become infected, increasing morbidity and mortality. If one suspects
a CSF fistula, the fluid should be screened for beta-transferrin to confirm that
it is in fact CSF. Before repair of CSF fistula, it is mandatory to exclude the
presence of hydrocephalus. The dura should then be sealed with autologous,
vascularised grafts and fibrin glue after cranialisation of the frontal sinuses.
Ping-pong fracture
This is a smooth depression of the cranial
vault usually seen in children. Also known as a ‘pond’ fracture.
Blow-out fracture
These are caused by fracturing of the orbital walls with herniation of orbital contents and subsequent tethering of the globe, resulting in pain and diplopia.