Elysa Widjaja

Neurosurgical management of intractable rolandic epilepsy in children: role of resection in eloquent cortex. Clinical article.

OBJECTnThe authors undertook this study to review their experience with cortical resections in the rolandic region in children with intractable epilepsy.nnnMETHODSnThe authors retrospectively reviewed the medical records obtained in 22 children with intractable epilepsy arising from the rolandic region. All patients underwent preoperative electroencephalography (EEG), MR imaging, prolonged video-EEG recordings, functional MR imaging, magnetoencephalography, and in some instances PET/SPECT studies. In 21 patients invasive subdural grid and depth electrode monitoring was performed. Resection of the epileptogenic zones in the rolandic region was undertaken in all cases. Seizure outcome was graded according to the Engel classification. Functional outcome was determined using validated outcome scores.nnnRESULTSnThere were 10 girls and 12 boys, whose mean age at seizure onset was 3.2 years. The mean age at surgery was 10 years. Seizure duration prior to surgery was a mean of 7.4 years. Nine patients had preoperative hemiparesis. Neuropsychological testing revealed impairment in some domains in 19 patients in whom evaluation was possible. Magnetic resonance imaging abnormalities were identified in 19 patients. Magnetoencephalography was performed in all patients and showed perirolandic spike clusters on the affected side in 20 patients. The mean duration of invasive monitoring was 4.2 days. The mean number of seizures during the period of invasive monitoring was 17. All patients underwent resection that involved primary motor and/or sensory cortex. The most common pathological entity encountered was cortical dysplasia, in 13 children. Immediately postoperatively, 20 patients had differing degrees of hemiparesis, from mild to severe. The hemiparesis improved in all affected patients by 3-6 months postoperatively. With a mean follow-up of 4.1 years (minimum 2 years), seizure outcome in 14 children (64%) was Engel Class I and seizure outcome in 4 (18%) was Engel Class II. In this series, seizure outcome following perirolandic resection was intimately related to the childs age at the time of surgery. By univariate logistic regression analysis, age at surgery was a statistically significant factor predicting seizure outcome (p < 0.024).nnnCONCLUSIONSnResection of rolandic cortex for intractable epilepsy is possible with expected morbidity. Accurate mapping of regions of functional cortex and epileptogenic zones may lead to improved seizure outcome in children with intractable rolandic epilepsy. It is important to counsel patients and families preoperatively to prepare them for possible worsened functional outcome involving motor, sensory and/or language pathways.

Evaluation of subcortical white matter and deep white matter tracts in malformations of cortical development.

Summary:u2002 Aims: Abnormal cortical development will lead to abnormal axons in white matter. The purpose was to investigate (1) the microstructural changes in subcortical white matter adjacent to malformations of cortical development (MCD) and (2) the deep white matter tracts using diffusion tensor imaging (DTI).

Characteristics of MEG and MRI between Taylor's focal cortical dysplasia (type II) and other cortical dysplasia: surgical outcome after complete resection of MEG spike source and MR lesion in pediatric cortical dysplasia.

PURPOSEnCortical dysplasia (CD) has been classified as Taylors focal cortical dysplasia (FCD type II) or other CD (FCD type I and mild malformation of cortical development) based on histological findings. The aims of this study were to determine whether MRI and magnetoencephalography (MEG) could distinguish between these two groups and to evaluate surgical outcomes.nnnMETHODSnWe evaluated the MRI features, MEG spike source (MEGSS) patterns (clusters or scatters) and postsurgical seizure outcomes of 27 children with CD.nnnRESULTSnThirteen patients had Taylors FCD and 14 had other CD. MRI showed visible lesion in 22 (81%) patients. Tapering of abnormal white matter signals to the ventricles and cortical thickening were more prevalent in Taylors FCD; focal hypoplasia and white matter atrophy were more prevalent in other CD. MEG showed spike sources in 26 (96%) patients. Taylors FCD showed clustered MEGSSs in 6, both clustered and scattered MEGSSs in 5 and scattered MEGSSs in 2; other CD demonstrated clusters in 2, cluster and scatter in 10 and scatter in 1. Eleven (85%) of 13 patients who had complete resection of clustered MEGSSs achieved Engel class I outcome, but 4 (44%) of 9 patients with incomplete resections achieved class I. Fifteen (88%) of 17 patients who had complete resection of MRI lesions achieved class I, but 1 (33%) of 3 patients with incomplete lesionectomy was class I. There was no difference in surgical outcomes between Taylors FCD and other CD.nnnCONCLUSIONSnSurgical outcome was the same in both groups following complete removal of areas containing clustered MEGSSs and MR lesions.

Corpus callosotomy in children and the disconnection syndromes: a review

ObjectsDisconnection syndromes following corpus callosotomy represent complex and variably expressed groupings of signs and symptoms affecting motor control, spatial orientation, vision, hearing, and language. Little is known, however, about the functional topography of callosal fiber pathways. In addition, most published case reports and case series of corpus callosotomy seldom report neurological deficits. We sought to categorize these deficits based on surgical anatomy.MethodsWe comprehensively reviewed the literature and described, compiled, and tabulated the most common disconnection syndromes complicating corpus callosotomy. We depict the topography of the cerebral cortex and associated commissural fibers of the corpus callosum through illustrations and diffusion tensor imaging tractography.ConclusionsAnatomical classification of disconnection syndromes will provide great value to neurosurgeons embarking on callosotomy, whether partial or complete. Such information will apply to procedures performed for epilepsy and to procedures where the corpus callosum is sectioned for access to lesions within the ventricular system.

Bilateral diffusion tensor abnormalities of temporal lobe and cingulate gyrus white matter in children with temporal lobe epilepsy.

PURPOSEnBilateral diffusion tensor imaging (DTI) abnormalities have been reported in the white matter associated to the hippocampus in adults with mesial temporal lobe epilepsy (TLE). In children with a shorter duration of epilepsy, such changes may not have yet emerged. The aim of this study was to investigate interictal changes in the temporal lobe white matter (TLWM) and cingulate gyrus white matter (CGWM) of children with TLE using DTI.nnnMETHODSnDTI was performed in eight children with TLE and 10 healthy, age-matched controls. Fractional anisotropy (FA), trace, parallel (lambda(||)) and perpendicular (lambda( perpendicular)) diffusivity were calculated for a volume of interest in the TLWM and CGWM on the seizure focus side and the contralateral side. Data were compared for differences between sides for patients and between patients and controls.nnnRESULTSnThere was no significant difference in FA, trace, lambda(||) and lambda( perpendicular) between TLWM and CGWM on the seizure focus side versus the contralateral side in TLE patients. Increased diffusivity, lambda(||) and lambda( perpendicular) within the TLWM and CGWM were found in TLE patients compared to controls, but no significant difference in FA was seen.nnnCONCLUSIONSnBilaterally increased diffusivity, lambda(||) and lambda( perpendicular) in the white matter in children with TLE may be related to seizure induced functional or structural changes. The preserved FA in our pediatric cohort is in contrast to the reduced FA in the white matter of adults with TLE and may relate to differences in the duration of epilepsy or in the vulnerability of white matter to seizures.

Diffusion tensor imaging identifies changes in normal-appearing white matter within the epileptogenic zone in tuberous sclerosis complex.

PURPOSEnTo evaluate diffusion tensor imaging (DTI) indices of (i) cortical tubers and (ii) normal-appearing subcortical white matter adjacent to cortical tubers within the epileptogenic zone and non-epileptogenic zone.nnnMETHODSnTwelve children with tuberous sclerosis complex underwent MRI, DTI and magnetoencephalography (MEG). Regions of interest (ROIs) were placed within cortical tubers and normal-appearing subcortical white matter adjacent to cortical tubers within MEG identified epileptogenic zone and non-epileptogenic zone. Fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (lambda(parallel)) and radial diffusivity (lambda(perpendicular)) were calculated.nnnRESULTSn26 out of 104 cortical tubers were in the epileptogenic zone. FA of cortical tubers in the epileptogenic zone was significantly lower than non-epileptogenic zone (p=0.015). There were no significant differences between MD (p=0.896), lambda(parallel) (p=0.672) and lambda(perpendicular) (p=0.651) of cortical tubers in the epileptogenic and non-epileptogenic zone. In normal-appearing subcortical white matter within the epileptogenic zone, FA was lower (p=0.001) and lambda(perpendicular) (p=0.011) was higher than non-epileptogenic zone. There were no significant differences between MD (p=0.110) and lambda(parallel) (p=0.735) of normal-appearing subcortical white matter within the epileptogenic and non-epileptogenic zone.nnnCONCLUSIONnDTI changes in normal-appearing white matter within the epileptogenic zone could represent abnormal white matter related to MRI-occult dysplastic cortex or ictal/interictal activity.

Cost-effectiveness of pediatric epilepsy surgery compared to medical treatment in children with intractable epilepsy

PURPOSEnDue to differences in epilepsy types and surgery, economic evaluations of epilepsy treatment in adults cannot be extrapolated to children. We evaluated the cost-effectiveness of epilepsy surgery compared to medical treatment in children with intractable epilepsy.nnnMETHODnDecision tree analysis was used to evaluate the cost-effectiveness of surgery relative to medical management. Fifteen patients had surgery and 15 had medical treatment. Cost data included inpatient and outpatient costs for the period April 2007 to September 2009, physician fee, and medication costs. Outcome measure was percentage seizure reduction at one-year follow-up. Incremental cost-effectiveness ratio (ICER) was assessed. Sensitivity analysis was performed for different probabilities of surgical and medical treatment outcomes and costs, and surgical mortality or morbidity.nnnRESULTSnMore patients managed surgically experienced Engel class I and II outcomes compared to medical treatment at one-year follow-up. Base-case analysis yielded an ICER of

Diffusion tensor imaging of midline posterior fossa malformations.

369 per patient for each percentage reduction in seizures for the surgery group relative to medical group. Sensitivity analysis showed robustness for the different probabilities tested.nnnCONCLUSIONnSurgical treatment resulted in greater reduction in seizure frequency compared to medical therapy and was a cost-effective treatment option in children with intractable epilepsy who were evaluated for epilepsy surgery and subsequently underwent surgery compared to continuing medical therapy. However, larger sample size and long-term follow-up are needed to validate these findings.

Diffusion Tensor Imaging of Commissural and Projection White Matter in Tuberous Sclerosis Complex and Correlation with Tuber Load

BackgroundDiffusion tensor imaging and tractography have been used to evaluate a variety of brain malformations. However, these studies have focused mainly on malformations involving the supratentorial compartments. There is a paucity of data on diffusion tensor imaging of posterior fossa malformations.ObjectiveTo describe the color vector maps and modified or abnormal tracts of midline posterior fossa malformations.Materials and MethodsDiffusion tensor imaging was performed in one patient with rhombencephalosynapsis and two with Joubert syndrome. Color vector maps of fractional anisotropy were used to place a region of interest for seed point of fiber tracking.ResultsThe vermis was severely hypoplastic or absent in rhombencephalosynapsis and Joubert syndrome. In rhombencephalosynapsis, vertically oriented fibers were visualized in the midportion of the cerebellum. The location of the deep cerebellar nuclei could be inferred from the amiculum and were medially located in rhombencephalosynapsis. In the two patients with Joubert syndrome, the horizontally arranged superior cerebellar peduncles were well demonstrated on the color vector maps. Failure of the superior cerebellar peduncles to decussate in the mesencephalon was also well demonstrated on both color vector maps and tractography. The deep cerebellar nuclei were more laterally located in Joubert syndrome.ConclusionThe use of tractography in midline posterior fossa malformations expands our understanding of these malformations.

PRESURGICAL LOCALIZATION OF PRIMARY MOTOR CORTEX IN PEDIATRIC PATIENTS WITH BRAIN LESIONS BY THE USE OF SPATIALLY FILTERED MAGNETOENCEPHALOGRAPHY

BACKGROUND AND PURPOSE: Cortical and white matter changes have been identified outside the MR imaging–visible cortical/subcortical tubers in the tuberous sclerosis complex. The aim of this study was to evaluate DTI changes in the corpus callosum and internal capsules and to correlate the DTI changes with cortical/subcortical tuber load. MATERIALS AND METHODS: Twelve TSC patients and 23 controls underwent MR imaging including DTI. FA, trace, D‖, and D⫠ of genu and splenium of corpus callosum and right and left internal capsules were assessed. The number and volume of cortical/subcortical tubers were correlated with DTI indices of corpus callosum and internal capsules. RESULTS: In the genu and splenium, FA was lower and trace (P < .01) and D⫠ were higher (P < .01), and in the internal capsules, trace was higher (P = .04) in TSC patients compared with controls. The total tuber volume correlated positively with trace of genu (r = 0.77, P < .01) and splenium (r = 0.69, P = .01) and with D⫠ of splenium (r = 0.68, P = .01), and negatively with FA of splenium (r = −0.60, P = .04) of corpus callosum. The left and right hemispheric tuber volume correlated positively with trace of left (r = 0.56, P = .05) and right (r = 0.67, P = .02) internal capsules. CONCLUSIONS: Our findings of reduced FA, elevated trace, and elevated D⫠ in the corpus callosum and internal capsules may be related to abnormalities in myelin. The correlations between tuber volume and DTI indices in corpus callosum and internal capsules suggested that more extensive malformation as demonstrated by larger tuber load was more likely to be associated with more severe DTI changes in the commissural and projection white matter.