Symptomatic epilepsy of the frontal lobe caused by focal cortical dysplasia type ii in the left precentral region – pre-operative evaluation

Patients with focal cortical dysplasia (FCD) type II (Taylor’s type) are excellent candidates for surgical treatment of epilepsy when the localization of the lesion does not coincide with the eloquent area or when it is not in the vicinity of the eloquent cortical region. New research shows that for a good post-operative result it is not always necessary to completely remove the FCD (type II b with ballooned cells). Whether the patient or his/her parents will agree to the pre-operative evaluation and finally the surgical procedure depends on the information they receive, including the benefits and possible risks of surgical treatment. The development of new non-invasive methods offers valuable information about the localization of the functional regions, the vicinity of the epileptogenic lesion and the pyramid paths which must not be damaged during the operation. Results: We present three patients with pharmocoresistent epilepsy of the frontal lobe caused by FCD type 11 localized left precentrally, which either coincides or is in the vicinity of the eloquent region During pre-operative work up the fact was considered that the effect of the operation is favourable and acceptable primarily in cases when the lesion may be removed completely. In all three patients there was an increased risk of development of hemiparesis due to the vicinity of the primary cortical motor area for the area and the corticospinal tracts which pass through that area, and the Broka region in the third patient. Neuronavigation and tractography may help in preventing damage to the corticospinal tracts. Invasive recording with subdural and deep electrodes is vital, after evaluation with surface electrodes. In the past these patients would not undergo surgery due to the uncertain prognosis since the lesions could not be removed completely and due to the risk of postoperative damage and complications. In line with the latest results of clinical research founded on the fact that it is not necessary to remove the lesion completely in order to attain excellent surgical outcome and with the new non-invasive techniques, such as computerized tomography, functional magnetic resonance and tractography, which can help to reduce the risk of neurological complications, today more patients suffering from pharmacoresistant epilepsy caused by dysplasia in the area or the vicinity of the eloquent regions may undergo surgery successfully. Conclusion: New techniques such as fMR, computerized tomography and tractography provide the possibility of a reasonable assessment between a favourable outcome of surgical treatment and possible damage after surgery in patients with FCD, where the lesions coincide with the eloquent cortical areas.

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