Quality control of elective surgery for drug-resistant epilepsy in a German reference centre--a long-term outcome study.

PURPOSE: Resective epilepsy surgery is the recommended treatment for a well-defined group of patients with drug-resistant epilepsy. Long-term outcome studies are an appropriate quality control to assess the value of elective surgical procedures ethically and economically. This paper reports the long-term post-surgical follow-up of adult patients of the Kork Epilepsy Centre. METHOD: Data collection was performed by means of a questionnaire to obtain updated information about postsurgical outcome, frequency and postsurgical seizure semiology in case of relapse, postsurgical use of antiepileptic drugs, social issues and satisfaction rates. We classified seizure outcome according to the ILAE surgery outcome scale (OC 1-OC 6). RESULTS: Outcome data of 340 adult patients were obtained. Mean post-operative follow-up was 6.7 years (range 1.0-21.6 years). Seizure remission was 67% if comprising patients with postoperative auras only (OC 1+OC 2). Sixty-two per cent of patients were completely seizure free. The majority of patients (78%) underwent temporal lobe resections. Sixty-four per cent of these and 52% of the patients with extra-temporal resections became completely seizure-free (OC 1). Only 34% of the patients with negative MRI achieved complete seizure-freedom. CONCLUSION: In line with others our huge cohort sample that covers decades of experience with epilepsy surgery revealed satisfying long-term outcome results. Best results were obtained in lesional temporal lobe epilepsy, least favourable results in MRI-negative epilepsy.

Memory outcome after hippocampus sparing resections in the temporal lobe.

BACKGROUND AND OBJECTIVE: Epilepsy surgery within the temporal lobe of the language dominant hemisphere bears the risk of postoperative verbal memory decline. As surgical procedures have become more tailored, the question has arisen, which type of resection within the temporal lobe is more favourable for memory outcome. Since the hippocampus (HC) is known to play an essential role for long-term memory, we examined whether HC sparing resections help to preserve verbal memory functions. METHODS: We retrospectively analysed neuropsychological data (prior to and 1 year after surgery) of patients undergoing either HC sparing resections (HC-S, N=65) or resections including the hippocampus (HC-R, N=62). RESULTS: Prior to surgery, the HC-R group showed worse memory performance as compared to HC-S patients. Both patient groups revealed further deterioration over time, but in verbal learning HC-R patients demonstrated a stronger decline. Predictors for verbal learning decline were left-sided surgery, better preoperative performance, higher age at surgery, hippocampus resection, and lower preoperative IQ. In patients with spared HC, resection of the left-sided parahippocampal gyrus was rather accompanied by a decline in verbal learning performance. For visual memory, better preoperative performance best predicted deterioration after surgery. Seizure outcome was comparable between the two groups (HC-S: 66%, HC-R: 65% Engel 1a). CONCLUSIONS: Temporal lobe resections within the language dominant hemisphere can be accompanied by a decline in verbal memory performance, even if the HC is spared. Yet, HC sparing surgery is associated with a benefit in verbal learning performance. These results can help when counselling patients prior to epilepsy surgery.

Selective amygdalohippocampectomy versus standard temporal lobectomy in patients with mesial temporal lobe epilepsy and unilateral hippocampal sclerosis.

Several studies have demonstrated the positive effect of resective epilepsy surgery in drug-resistant temporal lobe epilepsy (TLE). However, it is still a matter of debate whether selective amygdalohippocampectomy (SAH) or standard temporal lobectomy (STL) are the most effective approaches concerning seizure outcome, quality of life and memory. In each of the two centers participating in this study either SAH or STL was the neurosurgical standard procedure irrespective of contextual aspects. Thus, with this postoperative assessment of resected patients we sought to avoid any selection bias that usually impaired comparative trials of both surgical approaches. We finally identified and studied 95 adult patients who had undergone either SAH (n=46) or STL (n=49) between 1999 and 2009 and fulfilled the inclusion criteria, namely drug-resistant unilateral mesial TLE with hippocampal sclerosis without any further structural lesions. We assessed the postoperative seizure outcome according to the ILAE criteria and postoperative quality of life by means of standardized questionnaires. Finally, we compared postoperative neuropsychological performance in 60 completely seizure-free patients (n=27 after SAH, n=33 after STL) prior to, one year after surgery and at a long-term follow-up with a mean of seven years. 78.2% of SAH and 85.7% of STL were seizure-free at the last observation. Quality of life had improved in 95.6% of the SAH patients and 89.8% of the STL patients. These differences were not statistically significant. Left-sided TLE patients had a significantly worse verbal memory outcome irrespective of the surgical method. However, SAH patients had a significantly better outcome concerning visual encoding, verbal and visual short-term memory and visual working memory. In this study, seizure outcome and quality of life did not differ depending on the surgical approach. However, a more selective resection led to better neuropsychological performances.

Impact of side of lesion, seizure outcome and interictal epileptiform discharges on attention and memory after surgery in temporal lobe epilepsy.

To determine the impact of side of surgery, seizure outcome and interictal epileptiform discharges (IEDs) on attention and memory in a cohort of patients with temporal lobe epilepsy who had undergone unilateral mesial temporal lobe resection. Ninety-four patients were investigated pre- and postoperatively by means of a standardised neuropsychological battery measuring subcomponents of attention, as well as short-term, working and long-term memory. The side of epilepsy surgery, seizure outcome and the presence of postoperative IEDs, as well as their possible relationship to the neuropsychological changes, were assessed. Statistical data were analysed using a repeated-measures MANOVA. The absence of seizures following surgery had a positive effect on short-term memory and attentional control. The occurrence of IEDs was found in patients with impaired figural learning. In terms of attentional control and working memory, patients who continued to present IEDs had also scored lower in these domains prior to surgery. IEDs had an effect independent of seizure presence, but were found to have a "supplementary negative effect" when the two variables were combined.