Verbal learning and memory outcome in selective amygdalohippocampectomy versus temporal lobe resection in patients with hippocampal sclerosis.

PURPOSE: With the advent of new very selective techniques like thermal laser ablation to treat drug-resistant focal epilepsy, the controversy of resection size in relation to seizure outcome versus cognitive deficits has gained new relevance. The purpose of this study was to test the influence of the selective amygdalohippocampectomy (SAH) versus nonselective temporal lobe resection (TLR) on seizure outcome and cognition in patients with mesial temporal lobe epilepsy (MTLE) and histopathological verified hippocampal sclerosis (HS). METHODS: We identified 108 adults (>16years) with HS, operated between 1995 and 2009 in Denmark. Exclusion criteria are the following: Intelligence below normal range, right hemisphere dominance, other native languages than Danish, dual pathology, and missing follow-up data. Thus, 56 patients were analyzed. The patients were allocated to SAH (n=22) or TLR (n=34) based on intraoperative electrocorticography. Verbal learning and verbal memory were tested pre- and postsurgery. RESULTS: Seizure outcome did not differ between patients operated using the SAH versus the TLR at 1year (p=0.951) nor at 7years (p=0.177). Verbal learning was more affected in patients resected in the left hemisphere than in the right (p=0.002). In patients with left-sided TLR, a worsening in verbal memory performance was found (p=0.011). Altogether, 73% were seizure-free for 1year and 64% for 7years after surgery. CONCLUSION: In patients with drug-resistant focal MTLE, HS and no magnetic resonance imaging (MRI) signs of dual pathology, selective amygdalohippocampectomy results in sustained seizure freedom and better memory function compared with patients operated with nonselective temporal lobe resection.

Pharmacodynamics of remifentanil. Induced intracranial spike activity in mesial temporal lobe epilepsy.

Patients with medically refractory epilepsy may benefit from resective epilepsy surgery. However even the best centers experience surgical failures. It is therefore important to find techniques that may aid in neurosurgical planning of epileptic focus resection. Recordings of electrical brain activity with EEG during seizures reveal abnormal cortical hypersynchronization. Between seizures the EEG often shows interictal depolarizing phenomena such as spikes reflecting an irritable focus of the brain. In the present study we investigated the effect of intravenous remifentanil on the spike activity in the temporal neocortex and hippocampus. We examined 65 patients with mesial temporal lobe epilepsy during surgery, prior to resection. We used a 20-lead grid on the cortex and a 4-lead strip in the lateral ventricle on the hippocampus. At least two 3-min periods of ECoG were recorded - before and after remifentanil injection. In a number of patients we examined the effect of repeated injections in order to estimate the dose-response curve. We describe a significant effect of remifentanil on the average spike activity with an increment from 16 spikes per minute at baseline to 36 spikes per minute after remifentanil injection (p<0.0001). The increase in spike activity was typically seen after 40-50s. When mu-receptors were antagonized with a preceding injection of naloxone, spike activity increased 25% in response to remifentanil as opposed to 80% when remifentanil was preceded by placebo. In only seven out of 59 patients did the injection of remifentanil change the topographic location of the spike focus. Typically administration of remifentanil led to a focus of increased spike count. Activity in other areas was suppressed making the focus stand out from the background. Our observation that remifentanil potentiates spike activity is in agreement with previous findings from smaller studies. Furthermore, we were able to describe the pharmacodynamics of the remifentanil effect on spike activity. Peri-operative provocation with remifentanil may play a future role in guiding neurosurgical intervention during epilepsy resection surgery.

Danish experience with paediatric epilepsy surgery.

INTRODUCTION: Epilepsy surgery is increasingly used to treat children with medically intractable epilepsy. This study investigates the aetiology and seizure outcome in Danish children operated between 1996 and 2010. METHODS: Retrospectively collected data on structural magnetic resonance imaging (MRI) diagnoses, surgical procedures and seizure outcomes classified according to the Engel Classification were used. Changes over time grouped as 1996-2000, 2001-2005 and 2006-2010 were analysed. RESULTS: A total of 95 children underwent epilepsy surgery. Sixty-three operations were performed in Denmark and 50 abroad. In all, 14 children needed reoperation. The median follow-up period was four years. At the latest follow-up, Engel class I (indicating no disabling seizures) was found in 67% of the patients. Cortical dysplasia, mesial temporal sclerosis and tumour were the most common MRI findings. The percentage of tumours operated decreased over time, and frontal lobe resections increased. In the 2006-2010 period, resections with normal MRI were performed, resulting in a less favourable Engel outcome. Persistent, unexpected complications were seen in three of 113 operations. CONCLUSIONS: The majority of children who undergo epilepsy surgery have a good, worthwhile seizure outcome. The seizure outcome for Danish children corresponds to that of other epilepsy surgery centres. The clinical criteria for selection of patients changed over time. FUNDING: none. TRIAL REGISTRATION: The Danish Data Protection Agency approved the project with record number: 2013-41-2459.

[Epilepsy surgery of Danish children 1996-2002]. / Epilepsikirurgisk behandling af danske børn 1996-2002.

INTRODUCTION: Epilepsy surgery is done in order to obtain seizure freedom or to reduce the number of epileptic seizures in selected patients not responding to medical treatment. Few Danish children have had this treatment, most probably because of some restrictions imposed by The Danish National Health Board. We present the results of the first 22 Danish children who have had epilepsy surgery. MATERIAL AND METHODS: All children up to the age of 15 operated from January 1st 1996 to May 1st 2002 are included. According to the guidelines of The Danish National Health Board, 17 children have been operated abroad because the epileptic focus was extratemporal or intracranial EEG-monitoring was necessary. Follow-up varied from five years and six months to one month. RESULTS: At the time of the operation, all children had a long-lasting medical intractable epilepsy. 18 children had daily seizures and 15 were mentally retarded. Multi-lobar resection was performed in ten, hemispherectomy in three and lobar resection in eight children. Total seizure-free outcome was seen in 12 children, whereas three only had simple partial seizures (totally 68 per cent). The remaining children had at least a 50 per cent seizure reduction. On an average, the cognitive function was unchanged one year after the surgery. The majority of the parents stated that the behaviour of the child had improved on one or more specific issues. One mother stated that to a certain degree she regretted the operation. In four children, an unexpected complication was registered (slight hemiparesis and a hemianopsia). DISCUSSION: The results documented that epilepsy surgery is effective for selected children in spite of long-lasting severe epilepsy. In order to alleviate the consequences of severe epilepsy it is, however, important to refer the patients early. There seems to be a need for more and early referrals for childhood epilepsy surgery in Denmark.