Surgery for posterior quadrantic cortical dysplasia. A review

Abstract

Seizures appear most commonly in infants and rapidly progress to a catastrophic course. They are mostly represented by focal seizures and spasms. Surface interictal video-EEG is characterized by background flattening and paroxysmal discharges prevalent on the affected side but not unusually extending to the controlateral hemisphere. The last occasionally shows an independent irritative activity in spite of the absence of further visible structural abnormalities. Most of the patients have visual field or visual attention deficits at diagnosis. Resective as well as disconnective surgical procedures have been proposed for the management of this condition, none of them having shown clear advantages in terms of seizure outcome and complications. Intraoperative electrocorticography (EcoG) and sensorimotor monitoring have been successfully used to improve the localization of the epileptic focus and reduce surgical complication rates. Undistincted lesion borders, independent controlateral ictal or/and interictal EEG activity, and incomplete resections/disconnections are among the main factors that have resulted to be associated with a worse seizure outcome.

Influence of the location and type of epileptogenic lesion on scalp interictal epileptiform discharges and high‐frequency oscillations

“…Lesions were classified by type: MCDs, hippocampal abnormalities (HAs), gliosis, neoplasias, and vascular malformations. Lesions were also classified by region: anterior frontal lobe (anterior to the precentral sulcus), anterior part of temporal lobe, central region (anterior and postcentral gyrus), and posterior quadrant (posterior part of the parietal and temporal lobes and the whole occipital lobe) …”

“…• IEDs, equally likely to be visible in deep and superficial lesions, can be generated from a nearby focus or from a deep lesion, then propagate to the surface • Predominant interictal patterns could provide useful information in the process of diagnosing the lesion type • Sharp waves as predominant pattern are more prevalent in hippocampal abnormalities, whereas bursts predominate in MCDs quadrant (posterior part of the parietal and temporal lobes and the whole occipital lobe). 13 We also classified lesions according to their depth in the brain into three categories: superficial, lesions involving the neocortex adjacent to the skull including the bottom of the sulcus; deep, lesions involving the medial aspects of the frontal, parietal, occipital, and temporal lobes and temporooccipital basal regions; and intermediate, lesions found in regions not fitting the above two categories (Fig. S2).…”

Three cases of right frontal megalencephaly: Clinical characteristics and long-term outcome

“…In contrast, the onset of epilepsy in patients with posterior quadrant megalencephaly is usually during infancy [3]. This trend may be common to the cases of focal cortical dysplasia, whereby seizure onset occurs at an earlier age if the dysplasia is located posteriorly than if the dysplasia is located frontally [14,15]. Certain factors including postnatal evolution of synaptogenesis may explain this difference between locations of dysplastic lesions.…”

Posterior quadrantic dysplasia: MRI diagnosis of a lesser known cause of pediatric intractable epilepsy

“…[ 4 ] Etiology of this condition is unknown and all reported cases are sporadic. [ 1 3 5 6 7 8 ] Neuropathologic features of PQD may range from cortical dyslamination without abnormal cellular elements to coexistence of dysmorphic and ectopic neurons and balloon cells of undetermined lineage with abnormal white matter. [ 1 ]…”