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seizures, and a demonstrable structural lesion. We can therefore only assume that with early
cessation of seizures, we allow the child to achieve its optimal learning potential.
Longitudinal studies post surgery are lacking, not least because of a lack of standardised tools
to assess cognitive performance across all ages. However, at the very least, children have
been demonstrated to maintain their developmental trajectory post surgery, that would
otherwise have been lost, and recent data looking at children who have undergone early
surgery suggests improved developmental outcome may be achieved4. More recent data
suggest greater benefits may be achieved in the longer term, with studies demonstrating
greater developmental gains in seizure-free patients the longer time passes after surgery5,6.

The group of children for whom surgery is considered is also more diverse than the adult
group. A significant number will have developmental compromise, in whom an improved
quality of life is a priority rather than solely freedom from seizures (although this is obviously
a consideration). Assessment for surgery should therefore be in the context of a complex
epilepsy service7. The need for concentration of resources required for epilepsy surgery in
children has recently been recognised in England and Wales with the designation of four
nationally funded centres as part of the Children’s Epilepsy Surgery Service (CESS).

Types of surgery

The types of surgery performed in children do not differ a great deal from those in adults, but
the proportion of each procedure carried out, and the type of patient on which it is performed,
both vary. An international survey of 458 operations performed in 450 children over a 12-
month period (2004) revealed two-thirds (63%) to be hemispherectomy or multilobar
resections (Figure 1). Unilobar resections or lesionectomies were undertaken in 30%, with
only a very small number of functional procedures being performed8. Furthermore, 63% were
due to underlying developmental as opposed to acquired pathology8.

Focal resection involves removal of a small part or the whole of one lobe. Seizures should be
shown to arise from one area of the brain, the removal of which will not interfere significantly
with function. Hemispherectomy is considered in children with a pre-existent hemiparesis (in
the absence of progressive disease) with a demonstrable structural abnormality of the
contralateral hemisphere. In a small number of children with Rasmussen’s syndrome (chronic
encephalitis involving one cerebral hemisphere) surgery may be considered prior to the
development of a dense hemiparesis. This may also be considered in children with Sturge-
Weber syndrome with early onset seizures and recurrent status epilepticus.

Corpus callosotomy is considered in children with ‘drop’ attacks, whatever the seizure type
(e.g. akinetic, myoclonic, tonic). This procedure is unlikely to have any effect on other seizure
types, and a child is highly unlikely to be rendered seizure free by the procedure. Subpial
transection has been considered for children with acquired epileptic aphasia (Landau-
Kleffner syndrome), although more often in combination with resection where the seizure
focus lies within eloquent cortex. The procedure involves transection of transverse fibres,
theoretically leaving vertical functional tracts intact. In Landau-Kleffner syndrome the
technique has been performed over Wernicke’s area of the driving hemisphere (determined
by presurgical investigation) under electrocorticographic guidance. Data on outcome and
relative benefits of this procedure compared to medical treatment are limited, although recent
data suggest no benefit of surgery over and above the natural history of the condition.