The majority of candidates for
epilepsy surgery, in both children and adults, belong to the syndromic category of
partial epilepsies. However, particularly in children, the clinical expression of
epilepsy may sometimes be misleading, as paroxysmal events may present as
generalized seizures although having a focal onset. The spectrum of surgical possibilities for early-onset
epilepsy has tended to widen rapidly and to include not only other
focal epilepsies but also more difficult types. This is because developmental lesions that are the major cause of infantile
epilepsy are often poorly localized, involve extensive brain areas and require extensive operations (e.g. hemispherotomy). Surgery is also used for progressive conditions such as Rasmussen's
encephalitis or
Sturge-Weber syndrome. Some forms of generalized symptomatic
epilepsy may also benefit from palliative
surgical procedures (callosotomy in cases with repetitive
drop attacks often as a manifestation of a
Lennox-Gastaut syndrome). The timing of surgery partly depends on the probable effectiveness of the operation available for each particular patient. Candidates for
epilepsy surgery must be identified early in the process of the disease, thus increasing the chances for a satisfactory cognitive and behavioral outcome. The decision should be taken by experienced multidisciplinary groups, that will also ensure post-operative follow-up, both in terms of medical management and psycho-social integration. Prospective studies are still needed, to evaluate the long-term cognitive evolution of children operated on early for their
epilepsy and cured. Increasing evidence indicates that
drug therapy is likely to fail to achieve control of the
seizures when two-three of the major drugs, properly chosen by competent clinicians, have not obtained satisfactory results, i.e. full control of
seizures and absence of side effects. Testing of all possible drugs is not advisable, because this process would be excessively long when surgery is a reasonable possibility. The requirements for resective surgery in children with partial
drug-resistant epilepsy vary with the type of resection considered. Three basic requirements apply to almost all cases: (a) the epileptogenic area must be localized to a territory whose removal is contemplated; (b) that no other independent epileptogenic area exists in those areas that are not included in the planned resection, and (c) that any possible deficit resulting from resection must be acceptable. The current experience confirms that the complete resection of the epileptogenic area is the major condition for a satisfactory surgical result. The possibilities for resective surgery depend upon the localization of the ictal onset zone, its relationship with adjacent functional brain areas and the availability of convergent data that point to a single localization.
Epilepsy surgery mandates a multidisciplinary approach that requires special skills and sophisticated instruments and materials that cannot be improvised. A global evaluation of risks and expected benefits is always required. All decisions require a close collaboration between the
epilepsy team, the patient and the family. With the exception of high quality MRI and video-EEG recording of
seizures, the need to perform any other complementary presurgical investigation should be evaluated on an individual basis.