Good Seizure Outcome Research Articles

Stereotactic radiofrequency amygdalohippocampectomy: Does reduction of entorhinal and perirhinal cortices influence good clinical seizure outcome?

Stereotactic radiofrequency amygdalohippocampectomy (SAHE) has been modified recently in our center for the therapy of mesial temporal epilepsy (MTLE). It has promising clinical results comparable with microsurgical amygdalohippocampectomy despite smaller volume reduction of the hippocampus. We hypothesized that the extent of perirhinal and entorhinal cortex (PRC, EC) reduction could explain the clinical outcome. Therefore, we performed, retrospectively, volumetric analysis of PRC and EC and compared it with the seizure control. Twenty-six consecutive patients with MTLE treated by SAHE were included. PRC and EC volumes were measured from magnetic resonance imaging (MRI) records obtained before and 1 year after SAHE. The clinical outcome was assessed each year after SAHE using Engel's classification. Twenty-six patients were analyzed. The volume of PRC decreased by 46 ± 17% (p < 10(-12) ); EC volume decreased by 56 ± 20% (p < 10(-10) ). Two years after the procedure, 73% of patients were classified as Engel's I, 19% as Engel's II; in 2 (8%) the treatment failed (were reoperated). Eighteen patients finished 3 years follow-up; 72% of them were classified as Engel's I, 17% as Engel's II, and in 2 (11%) above-mentioned patients the treatment failed. Thirteen patients finished 4 years of follow-up, 11 of them as Engel's I. There was no significant correlation of the clinical outcome to PRC and EC volume reductions. The clinical effect of SAHE is not clearly explained by the volume reductions of PRC and EC (nor of the hippocampus and the amygdala). It promotes opinion that the extent of resection/destruction is not important for seizure outcomes.

Presurgical evaluation and postoperative seizure-outcome in children and adolescents with intracranial tumors and drug resistant focal epilepsy

Objective: Patients with intractable focal epilepsy due to intracranial tumors are excellent candidates for epilepsy surgery. According to the literature the percentage of seizure-free patients post surgery varies between 65–90%. Incomplete tumor resection and/or insufficient removal of tumor-associated focal cortical dysplasia are risk factors for good seizure outcome. Role of invasive diagnostic is not fully established yet.

"Everything but motor (EBM)" – subtotal hemispherectomy sparing the primary sensori-motor region in children with hemispheric epilepsies but without hemiparesis

Rationale: It is well established that for hemiparetic children suffering from intractable focal epilepsy caused by a hemispheric pathology, hemispherotomy is for most patients the surgical option with the best chance for a good seizure outcome. In children without or with only a very mild hemiparesis, the decision to perform a hemispherotomy is extremely difficult. As an alternative surgical approach, we present the subtotal hemispherectomy sparing the primary sensori-motor region (EBM).

Tailored resections for intractable rolandic cortex epilepsy in children: a single-center experience with 48 consecutive cases

A single-center experience with pediatric patients who underwent surgery for intractable rolandic epilepsy was reviewed with the aim of identifying putative factors that could influence postoperative seizure outcome in this population. Clinical data of 48 patients under 18 years of age with diagnosis of intractable rolandic epilepsy who underwent surgery from January 1996 to September 2009 were reviewed. Patients' mean age at surgery was 9.9 ± 5.3 years; mean age at epilepsy onset was 3.9 years; mean seizure duration prior to surgery was 6 years; and mean follow-up was 5.1 years. The most frequent etiologies were cortical dysplasia, astrogliosis, tumors, tuberous sclerosis complex, and Sturge-Weber syndrome, which were observed in 20/48 (41.6%), 10/48 (20.8%), 10/48 (20.8%), 5/48 (10.4%), and 3/48 (6.2%) of the patients, respectively. After surgery, 20 patients (41.6%) showed neurological deficits, which in turn recovered within no longer than 6 months after surgery. Seizure outcome was classified as Engel class I in 29 (60.4%), Engel class II in 10 (20.8%), and Engel class III in 9 (18.8%) of the patients. The factors significantly related with seizure outcome were histological features (tumor versus non-tumor cases, p = 0.04) and lesion site (focal lesions versus non-focal lesions, p = 0.04). Tailored resection of rolandic cortex for intractable epilepsy can be safely performed in children. Accurate mapping of both functional cortex and epileptogenic areas may lead to improved seizure outcome. Tumor as well as focal lesions in hand and face motor areas are associated with good seizure outcome.

Age at onset predicts good seizure outcome in sporadic non-lesional and mesial temporal sclerosis based temporal lobe epilepsy

PurposeTo study prognosis and prognostic predictors of sporadic non-lesional temporal lobe epilepsy (TLE).Method474 patients with TLE were consecutively seen from April 1987 to April 2004. 190 had a sporadic non-lesional...

Utility of 3‐T FLAIR and 3D short tau inversion recovery MR imaging in the preoperative diagnosis of hippocampal sclerosis: Direct comparison with 1.5‐T FLAIR MR imaging

To examine the utility of fluid-attenuated inversion recovery (FLAIR) imaging and three-dimensional short tau inversion recovery (3DSTIR) imaging using a 3-Tesla (3-T) magnetic resonance (MR) imager in the preoperative evaluation of hippocampal sclerosis (HS). Thirteen patients with intractable medial temporal lobe epilepsy who underwent anterior temporal lobectomy with amygdalohippocampectomy were studied. MR images were obtained twice, once with a 1.5-T imager and once with a 3-T imager. The extent of hippocampal resection was determined according to the findings on intraoperative hippocampal electroencephalography. We compared the diagnostic utility of FLAIR for HS between 1.5-T and 3-T MR imaging. In addition, the relationship between the existence of hypointense areas in the hippocampus (HIAs) on 3DSTIR and the severity of HS pathology (as evaluated using Watson's grading) was examined. The relationship between postoperative seizure outcome and postoperatively remaining HIAs was also evaluated. There was no difference between FLAIR images from 1.5-T and 3-T imaging in the detection of HS. With 3DSTIR, an HIA in unilateral hippocampus was observed in all of the nine cases exhibiting severe pathologic HS (Watson's grade III-V). In seven cases with HIA, the extent of hippocampal resection was smaller than the HIAs. Every case showed good seizure outcome (Engel's class I and II). In the diagnosis of HS, no substantial difference was noted between 1.5-T and 3-T MR imaging. However, 3DSTIR using 3-T MR imaging is useful for evaluating the extent of HS, although postoperative HS remnants are not correlated with surgical outcomes.

Apical temporal lobe resection; “tailored” hippocampus-sparing resection based on presurgical evaluation data

It is the aim of epilepsy surgery in patients with lesional epilepsy for the surgeon to not only remove the lesion itself, but also the epileptogenic zone. Here, we report our experience with a modified temporal resection technique confined to the apical temporal lobe, i.e., sparing the hippocampal formation in patients with epileptogenic lesions in the anterior part of the temporal lobe. This apical temporal lobe resection (aTLR) includes tailored lesionectomy, amygdalectomy, and resection of the mesial structures only in the apex of the temporal lobe. This paper presents our surgical technical details and the outcome of aTLR. Between 2001 and 2008, aTLR was performed in 61 patients. All patients underwent comprehensive presurgical evaluation including video-EEG monitoring, magnetic resonance imaging (MRI), and neuropsychological testing. All patients had a lesion in the apex of the temporal lobe and a normal hippocampus as seen in MRI, as well as intact memory functions in neuropsychological examination. There were 33 males (54.1%) and 28 females (45.9%). The mean age in years at epilepsy onset was 20.2 ± 13.4, the mean age at epilepsy surgery was 32.1 ± 11.9, the mean preoperative epilepsy duration was 11.8 ± 8.8 years and the mean duration of follow-up was 2.1 ± 1.3 years (range 0.5-6 years). Fifty-four (88.5%) of 61 patients were in Engel Class 1 at 6 months, 38 (80.9%) of 47 at 2 years and nine (81.8%) of 11 at the 5 year follow-up. Histopathological examination showed tumors in 31 patients, FCD in ten patients, amygdala sclerosis in seven patients, cavernomas in six patients, unspecific reactions in eight patients, and gliosis in one patient. Surgical complications occurred in four patients: one had a permanent and three had transient complications which could be successfully treated. Fifty (82%) resections were considered to be complete resections as evaluated by serial postoperative MRI, seven patients (11.5%) had incomplete resection of the preoperative MRI lesion and in four patients (6.6%) it remained unclear. Fifteen patients (29.4%) were withdrawn from antiepileptic drugs for more than 2 years without relapse. Postoperative neuropsychological examination revealed worsening of memory performance in two patients (3.2%) and improved or no changes in the rest of the patients. Apical temporal resection sparing the mesial temporal structures is an effective procedure with good long-term seizure outcome in patients with refractory epilepsy due to lesions confined to the apex of the temporal lobe.

The Wada memory test and prediction of outcome after anterior temporal lobectomy

We reviewed the records of 77 Chinese-speaking adult patients to investigate the relationship between the Wada memory test and outcomes after anterior temporal lobectomy (ATL). The ipsilateral memory scores, contralateral memory scores and Wada asymmetry index (WAI) were calculated to evaluate their relationships with seizure and cognitive outcomes. The seizure outcomes did not correlate with the unilateral memory scores or the WAI. Patients who had a smaller WAI tended to have a post-operative decline in verbal intelligence quotient (VIQ) (odds ratio: 13.54, 95% confidence interval: 1.17–156.11, p = 0.037). The seven patients who failed the Wada memory test after ipsilateral injection had a higher percentage of VIQ deterioration than the 70 who passed ( p = 0.039). However, no patient displayed global amnesia after surgery. The Wada memory test was a predictor for post-operative VIQ changes in our study. Patients who failed the Wada memory test still benefitted from the ATL and showed good seizure outcomes.

Thalamic changes in temporal lobe epilepsy with and without hippocampal sclerosis: A diffusion tensor imaging study

The seizure network may be different between temporal lobe epilepsy with hippocampal sclerosis (TLE+HS) and without HS (TLE-HS). Chronic seizure activity may alter the diffusion properties of a seizure network. The thalamus is known to have an anatomical connection to the medial temporal area and to play a role in seizure modulation. This study aimed to evaluate differences in thalamic changes between TLE+HS and TLE-HS with diffusion tensor imaging (DTI). Nine patients with TLE+HS and nine patients with TLE-HS were included in the study. All patients underwent surgery with good seizure outcomes. Hippocampal sclerosis was verified pathologically. Sixteen right-handed, normal subjects were enrolled as controls. DTI was acquired using 3.0 T MRI. The mean diffusivity (MD) and fractional anisotropy (FA) were calculated in the center of the bilateral thalamus with the DTIstudio program. The MD of bilateral thalami increased in both TLE groups compared to controls (p<0.05), while FA values did not differ from controls. The MD of the thalamus ipsilateral to the epileptogenic side was higher in the TLE+HS group than in the TLE-HS group (p=0.007). Onset age, seizure duration, seizure frequency and total seizure number were not correlated with FA and MD changes (p>0.05). Bilateral thalamic diffusion properties are altered in temporal lobe epilepsy. The presence of hippocampal sclerosis enhances the change ipsilaterally.

Outcome of resective surgery for intractable partial epilepsy guided by subdural electrode arrays.

The aim of this paper was to evaluate the outcome and the factors predictive for a good prognosis of resective surgery for intractable partial epilepsy guided by subdural electrode arrays (SEA's) and operative electrocorticography. Sixty-four patients, aged 8-52 years, were evaluated with chronic SEAs in order to record interictal and ictal activity and delineate speech and motor areas by functionally mapping. Resection were individualized to each patient's SEA recorded electrocorticogram and operative electrocorticogram and functional mapping results (tailored resection). The follow-up time was a minimum of one year. Good seizure outcome was defined as seizure free from complex partial and secondary generalized seizures. After one year 70% of the patients with a temporal ictal focus was seizure free compared to 55% of the patients with an extra-temporal focus. Complete resection of interictal or ictal fields as mapped with SEAs, gave better prognosis than partial resection. Patients with no postresection spikes had a better prognosis than patients with residual postresection spikes evaluated with operative electrocorticography. Sex, age, duration of epilepsy prior to surgery, extent of temporal lobe resection and structural abnormalities determined by MRI were not associated with a favorable seizure outcome after surgery. We conclude that complete resection of the interictal and ictal field mapped with SEA's and absence of postresection spikes on operative electrocorticography are associated with an excellent seizure outcome.

Risk factors for complications during intracranial electrode recording in presurgical evaluation of drug resistant partial epilepsy

Intracranial electrode monitoring is still required in epilepsy surgery; however, it is associated with significant morbidity. To identify risk factors associated with complications during invasive intracranial EEG monitoring. Retrospective study of all patients undergoing invasive monitoring at Westmead between 1988-2004. From detailed chart reviews, the following variables were recorded: duration of intracranial monitoring, the site of grid implantation, number of grids and electrodes, seizure frequency, postoperative complications and seizure outcome. Seventy-one patients (median age: 24 years) underwent subdural electrode implantation; 62% had extratemporal lobe epilepsy and 46% were non-lesional. Of the 58 monitored patients who had cortical resections, 45 had good seizure outcomes. Complications related to subdural electrode implantation included transient complications requiring no treatment (12.7%), transient complications requiring treatment (9.9%) and two deaths (2.8%). Specific complications included subdural haemorrhage, transient neurological deficit, infarction and osteomyelitis. The two deaths occurred within 48 h of implantation were related to raised intracranial pressure (one venous infarction, one unexplained). Complications were associated with maximal size of grid (p < 0.001), greater number of electrodes (p < 0.001), electrode density per cortical surface implanted (p < 0.001), right central surface implantation (p = 0.003) and left central surface implantation (p = 0.013). Multiple logistic regression identified larger size grids and right central surface implantation as independent predictors of complications. There are significant complications during intracranial EEG evaluations but the majority of these are transient. We found a relationship between the size of the electrode arrays and the incidence of complications. The results of this study have been used to modify our implantation and monitoring protocols.

Predictors of outcome after temporal lobectomy for refractory temporal lobe epilepsy

To identify predictors of outcome after epilepsy surgery in patients with temporal lobe epilepsy (TLE). Seventy-six patients with normal magnetic resonance imaging (MRI) or hippocampal sclerosis on MRI who underwent anterior temporal lobe resections were included. Outcome 2 years after surgery was classified as good (Engel I and II) or poor (Engel III and IV). Gender, age at onset and duration of epilepsy, history of febrile convulsions, auras, right- or left-sided TLE, memory ipsilateral to seizure onset (Wada test), hippocampal asymmetry (HA) and T2 relaxation time, amygdala, temporal lobe and hemispheral volume were tested for associations with outcome. Sixty-seven percent had a good outcome. Of all parameters tested, only a history of febrile convulsions and HA on quantitative MRI were significantly associated with a good seizure outcome. The absence of these parameters did not exclude a good outcome, but only five of 18 patients (28%) without HA and without a history of febrile convulsions had a good outcome. Febrile convulsions and HA were predictors of outcome after epilepsy surgery in TLE. Subtle volume loss in amygdala, temporal lobe or hemispheres and the memory ipsilateral to the side of resection were not associated with outcome.

Déconnexion chirurgicale des hamartomes hypothalamiques

Surgical resection of hypothalamic hamartomas (HHs) associated with drug-resistant gelastic epilepsy carries a considerable risk of neurological and endocrine morbidity. Alternative surgical routes and techniques have therefore been proposed, especially for broadly attached lesions and for those with a third ventricular location. We present an updated series of 43 patients (aged nine months to 34 years), operated on from 1998 through 2005 at our institution. The hamartoma was disconnected using a microsurgical pterional approach of those lesions extending from the hypothalamic floor downward into the interpeduncular cistern. When the HH presented as a paramedian mass, partly or exclusively bulging into the third ventricle, with a rather vertical plane of attachment, we chose a frameless stereotactic endoscopic technique to disconnect the lesion. In several of our patients, both methods were applied subsequently. Surgery-related morbidity was lower with the ventricular endoscopic technique. Twenty-one patients (50%) are seizure-free and two patients (5%) almost seizure-free, while in 17 patients (40%), there was a significant seizure reduction. Two patients (5%) had no postoperative improvement. According to the different topographic features of the HHs, for which we have recently proposed a classification into four subtypes, the intraventricularly located hamartoma had the best prognosis following endoscopic disconnection. Ten of the 12 patients (83%) with this HH location became seizure-free. Resection of epilepsy-related HHs can be replaced by disconnective procedures. Our results confirm their feasibility and acceptable morbidity, with particularly good seizure outcome in patients with intraventricularly located HHs.

Neuroimaging in tuberous sclerosis complex

In this review we discuss recent advances in the neuroimaging of patients with tuberous sclerosis complex (TSC), highlighting its application in improving clinical management, particularly in the case of intractable epilepsy. Progress in structural and functional imaging has led to further characterization of the brain lesions in TSC. New magnetic resonance imaging techniques that can delineate the extent of structural brain abnormalities in TSC have been developed. Diffusion tensor imaging unveils the microstructural abnormalities of the brain lesions and of the morphologically normal appearing white matter in TSC. It can potentially identify the epileptogenic zone. Positron emission tomography scanning with 2-deoxy-2-[18F]fluoro-D-glucose can assess the full extent of functional brain abnormalities in TSC. The use of alpha [11C] methyl-L-tryptophan positron emission tomography scanning has proven to be a useful tool in the identification of epileptogenic tubers and has improved the outcome of surgery for epilepsy in TSC. Major advances of neuroimaging in TSC have shown evidence of widespread structural and functional brain abnormalities. In TSC patients with intractable epilepsy, new neuroimaging modalities can now provide an accurate assessment of the epileptogenic zone, thereby permitting improved identification of patients who can have good seizure outcome following surgery for epilepsy.

Seizure Outcome after Resection of Supratentorial Cavernous Malformations: A Study of 168 Patients

The optimal management of cerebral cavernous malformations (CCMs) with epileptic seizures is still a matter of debate. The aim of our study was to examine seizure outcome in the largest published series of surgically treated patients with epilepsy due to a supratentorial CCM, and to define predictors for good surgical outcome. We retrospectively studied 168 consecutive patients with a single supratentorial CCM and symptomatic epilepsy in a multicenter study. Pre- and postoperative clinical examinations, age at epilepsy onset, age at operation, type of symptoms due to the CCM (seizures, headache, hemorrhage, focal deficits), type and frequency of epileptic seizures, and the localization and size of the CCM were assessed. Seizure outcome was determined in the first, second, and third postoperative years. The CCM was completely resected in all patients. More than two thirds of the patients were classified as seizure free in the first 3 postoperative years. Predictors for good seizure outcome were age older than 30 years at the time of surgery, mesiotemporal CCM localization, CCM size <1.5 cm, and the absence of secondarily generalized seizures. No mortality occurred in our series, but only mild postoperative neurologic deficits in 12 (7%) patients. Considering the natural history of CCMs, the favorable neurologic and seizure outcome, surgical resection of CCMs should be considered in all patients with supratentorial CCMs and concomitant epilepsy, irrespective of the presence or absence of predictors for a favorable seizure outcome.

Health-related quality of life using QOLIE-31: Before and after epilepsy surgery a prospective study at a tertiary care center

Outcome following epilepsy surgery has traditionally been measured in terms of relief of seizures. However, changes in health-related quality of life (HRQOL) after surgery for intractable epilepsy are also important to document. There are no studies on the Indian population which assess the outcome of epilepsy surgery in terms of HRQOL. We conducted a prospective study on the patients undergoing epilepsy surgery for intractable seizures, between February 2004 and May 2006 at our center. All patients cleared for epilepsy surgery by the epilepsy surgery team were taken up for study. All patients Thirty-six patients satisfying the inclusion/exclusion criteria were included in the analysis. Twenty-nine of these (Group 1) had good seizure outcome (Engel 1 and 2), while seven patients (Group 2) had poor seizure outcome (Engel 3 and 4) at six months. Overall, 77% of all study patients were completely seizure-free at follow-up. There was no baseline difference in the seven domains of QOLIE-31 between the two groups. There was very significant improvement (P value>0.005 using paired sample T test) in all the domains of QOLIE-31 in the good outcome group after surgery. Health-related quality of life improvement was seen in all the domains in the poor outcome group also, however, it was statistically significant only for the following parameters: seizure worry, overall QOL, emotional wellbeing, energy fatigue and social functioning domains. Improvement in seizure worry, overall QOL, emotional wellbeing and social functioning was significantly more in Group 1 as compared to Group 2. Complete seizure-free state after surgery is associated with very significant improvement in HRQOL parameters. Several, but not all parameters of HRQOL as assessed by QOLIE-31, improved after surgery even in the poor seizure outcome group. The improvement in domains of seizure worry, overall QOL, emotional wellbeing and social functioning is significantly more in those patients in whom complete seizure-free state is achieved.

Long-term evolution of EEG in Unverricht-Lundborg disease

Unverricht-Lundborg disease (ULD) is a progressive myoclonus epilepsy characterized by myoclonus, epilepsy, and ataxia, without major cognitive decline. There is no systematic study on the long-term evolution of EEG in this condition. Twenty-five patients with ULD who came to our observation before 1995 and periodically followed in our Epilepsy Centres were included. All waking EEG traces were visually reviewed for the characterization background activity, with particular regard to the frequency of the posterior dominant rhythm (PR), and for the occurrence of spontaneous generalized spike or polyspike and wave discharges (GSWD) and photoparoxysmal response (PPR). Sleep recordings were analyzed with particular regard to the preservation of the physiological sleep patterns and the occurrence of GSWD and other epileptic abnormalities. PR was normal in 68% of patients at the beginning of the disease and kept stable over the years. GSWD were present in 92% of patients at the onset of the disease and gradually disappeared during the follow-up with a significant difference (p<0.001) after the 15th year of disease. PPR was present in 88% of patients at the disease onset and gradually disappeared with a significant difference (p<0.001) after the 10th year of disease. A gradual reduction of GSWD and a progressive disappearance of physiological sleep patterns were observed in sleep EEGs. In patients with ULD followed for an extended period of time, EEG shows no relevant deterioration of BA while a gradual reduction of GSWD and PPR is observed over time, well correlating with the good seizure outcome in this condition.

Good seizure outcome after epilepsy surgery in young children with tuberous sclerosis complex

Introduction: Severe and drug-resistant epileptic syndroms are a frequent CNS manifestation in children with tuberous sclerosis complex. Single reports since 1960 show that a group of children with multiple tubers became seizure free or had a significant seizure reduction after surgery if it is possible to determine a leading epileptogenic tuber. We report the experience of this treatment in our epilepsy surgery program.

Cognitive functioning following epilepsy surgery

Temporal lobe resection is the most common surgery for intractable epilepsy because of its proven efficacy in seizure control. However, patients who may benefit from the procedure might be deterred from surgical evaluation due to concerns of postoperative cognitive decline. Recent reports on long-term follow-up indicate that, similar to findings within the year after surgery, cognition remains relatively stable in the years following right temporal resection. The verbal memory decline often observed 1 year after left temporal resection persists over time, yet is mitigated to some extent by good seizure outcome. Although memory decline observed on testing is not typically accompanied by functional decline, a small proportion of patients do experience reductions in occupational or academic status. Recent advances in functional imaging and refinements in preoperative mapping promise better prediction and protection of cognitive functioning. Additionally, results from studies comparing cognitive outcome among different surgical techniques suggest that more restricted resections benefit some patients, whereas more extended resections might be appropriate in a select group of well-defined patients. Preliminary reports on alternate treatments such as vagal nerve stimulation suggest no direct influence on cognition, although improvement in quality of life has been reported. The decision to pursue surgical treatment must balance the potential benefit of seizure control with the potential impact and probability of cognitive decline.

Hippocampal transection for treatment of left temporal lobe epilepsy with preservation of verbal memory

Despite good seizure outcome with temporal lobectomy, postoperative impairment of verbal memory remains unsolved. To address this problem we developed a new method, applying the rationale of multiple subpial transection (MST) to the hippocampus. The inferior ventricle is accessed without disrupting the neuronal pathways related to verbal memory. Intraoperative electrocorticography is recorded over the hippocampus and amygdala. After the extent of the epileptic area is determined, multiple transections of the pyramidal layer under the alveus is performed using specially designed ring transectors. After this procedure, epileptic discharges from the hippocampus can be completely abolished. Of 21 cases undergoing this operation, 12 left-sided and nine right-sided, 17 were followed up for more than one year. Fourteen (82%) are seizure free, two (12%) have rare seizures, and one (6%) has significantly improved. Of eight patients who underwent a battery of neuropsychometric tests both before and after left hippocampal transection, postoperative verbal memory was completely preserved in seven cases, and one transiently worsened patient recovered within 6 months. However, these results are still preliminary as the number of patients is small and the follow-up time short. The accumulation of cases and follow-up of greater duration will be necessary to precisely confirm the efficacy of this new technique.