Low prevalence of neural autoantibodies in perioperative cerebrospinal fluid samples of epilepsy surgery patients: A multicenter prospective study.

OBJECTIVE: Refractory epilepsy may have an underlying autoimmune etiology. Our aim was to assess the prevalence of neural autoantibodies in a multicenter national prospective cohort of patients with drug-resistant epilepsy undergoing epilepsy surgery utilizing comprehensive clinical, serologic, and histopathological analyses. METHODS: We prospectively recruited patients undergoing epilepsy surgery for refractory focal epilepsy not caused by a brain tumor from epilepsy surgery centers in the Czech Republic. Perioperatively, we collected cerebrospinal fluid (CSF) and/or serum samples and performed comprehensive commercial and in-house assays for neural autoantibodies. Clinical data were obtained from the patients' medical records, and histopathological analysis of resected brain tissue was performed. RESULTS: Seventy-six patients were included, mostly magnetic resonance imaging (MRI)-lesional cases (74%). Mean time from diagnosis to surgery was 21 ± 13 years. Only one patient (1.3%) had antibodies in the CSF and serum (antibodies against glutamic acid decarboxylase 65) in relevant titers; histology revealed focal cortical dysplasia (FCD) III (FCD associated with hippocampal sclerosis [HS]). Five patients' samples displayed CSF-restricted oligoclonal bands (OCBs; 6.6%): three cases with FCD (one with FCD II and two with FCD I), one with HS, and one with negative histology. Importantly, eight patients (one of them with CSF-restricted OCBs) had findings on antibody testing in individual serum and/or CSF tests that could not be confirmed by complementary tests and were thus classified as nonspecific, yet could have been considered specific without confirmatory testing. Of these, two had FCD, two gliosis, and four HS. No inflammatory changes or lymphocyte cuffing was observed histopathologically in any of the 76 patients. SIGNIFICANCE: Neural autoantibodies are a rare finding in perioperatively collected serum and CSF of our cohort of mostly MRI-lesional epilepsy surgery patients. Confirmatory testing is essential to avoid overinterpretation of autoantibody-positive findings.

Ultrasound-Navigated Multiple Hippocampal Transections: An Anatomical Study.

BACKGROUND: Multiple hippocampal transection (MHT) is a surgical technique used for the treatment of drug-resistant mesial temporal lobe epilepsy in situations where standard procedures would pose a high risk for memory deterioration. During MHT, the longitudinal fibers of the hippocampus, implicated in epilepsy spreading, are interrupted, while the transverse memory circuits are spared. The extent of MHT is governed by intraoperative electrocorticography; abolition of epileptic discharges serves as an end point to terminate the transection. In other words, the aim of MHT is not the anatomical completeness of hippocampal transection. In contrast, we hypothesize that only the complete transection of hippocampal cross-section is needed to durably terminate epilepsy, avoiding possible postoperative reorganization of longitudinal pathways. Here, we report an anatomical study designed to evaluate the feasibility of complete transection of hippocampus with the aid of ultrasound neuronavigation and we propose new instruments to reach this goal. METHODS: Five cadaveric brains were analyzed in this study. MHT was performed on both sides of each brain either with or without ultrasound neuronavigation. The percentage of transected cross-section of the hippocampus was measured using magnetic resonance imaging (MRI) and both sides were compared. RESULTS: The ultrasound-guided MHTs were more likely to achieve complete hippocampal transection compared with the nonnavigated MHT transection (73 vs 58%; p < 0.01). Our study also allowed us to propose specialized transectors to minimize invasivity of this procedure. CONCLUSION: Completeness of MHT can be better reached with the aid of an ultrasound neuronavigation system; modified instruments for this procedure were also designed.

One-year neuropsychological outcome after temporal lobe epilepsy surgery in large Czech sample: Search for factors contributing to memory decline.

Background: Assessment of cognitive functions is an integral part of the evaluation the efficacy of temporal resections. We studied postoperative neuropsychological changes and factors contributing to worse memory outcomes in patients who experienced a significant decline using reliable change indices. Methods: We prospectively studied 110 patients in whom we indicated anteromesial temporal resection (AMTR) and 46 patients who underwent selective amygdalohippocampectomy (SAHE). We administrated Wechsler Adult Intelligence Scale-Revised, Wechsler Memory Scale-Revised, and the Verbal Fluency Test before and 1 year after the operation. Results: At a group level, we did not observe any statistically significant changes in global, verbal, and visual MQ in either the AMTR or the SAHE group. At an individual level, we found a mean decrease of verbal MQ after left-sided AMTR by -4.43 points (P = 0.01). We detected no significant differences between the left and right side of surgery in the SAHE group. In patients with significant postoperative memory decline, we found either pre-existing extrahippocampal deficits/postoperative complications or incomplete hippocampal resection or a combination of these factors. Conclusion: In addition to the side of surgery, structural integrity and functional adequacy of resected hippocampus and volume of resected tissue and preoperative extrahippocampal lesions/postoperative complications also contribute to postoperative memory decline after temporal lobe epilepsy surgery.

An epileptologist's view: Seizure-related outcomes after radiofrequency ablation for mesial temporal lobe epilepsy.

In this article, we provide an overview of the reasons for the introduction of less invasive treatment modalities in the management of intractable mesial temporal lobe epilepsy (mTLE). We summarize our published research on stereotactic amygdalohippocampectomy (SAHE) and recalculate our data for the patients' last visit. In our previous work, we found that patients achieved long-term seizure-free outcomes in 70.5%. Re-analysis of results in a subgroup of patient who were diagnosed and followed-up at Epilepsy Center, Na Homolce Hospital, Prague, indicate that these outcomes are durable. Re-treatment in treatment failures was successful in all cases. The discussion compares novel treatment options and defines the place of SAHE among them.

A neuropsychologist's view: Outcome after RF-ablation for mTLE.

Concern about postoperative worsening of cognitive functions after temporal lobe epilepsy surgery is an important issue. In this article we review our data on neuropsychological outcome after radiofrequency (RF) ablation of amygdalohippocampal complex (AHC). On a group level we found initial improvement in intelligence domains and unchanged memory scores one year after the surgery. During longitudinal follow-up, we found improvement in both intellectual and memory domains. This improvement was most pronounced up to two years after surgery. On an individual level, no patient worsened in any intellectual domain and most patients improved in memory. We hypothesize that this favorable outcome may be a consequence of minimization of collateral damage and incomplete destruction of target structures. We also summarize our experience with psychiatric complications of the procedure.

Five-Year Neuropsychological Outcome after Stereotactic Radiofrequency Amygdalohippocampectomy for Mesial Temporal Lobe Epilepsy: Longitudinal Study.

PURPOSE: To assess the neuropsychological performance recoded over a period of 5 years after stereotactic radiofrequency amygdalohippocampectomy (SAHE) in the treatment of mesial temporal lobe epilepsy. MATERIAL AND METHODS: Thirty patients (mean age 38 years, 14 females/16 males) were included in this study. Twenty-one patients were treated on the left side, 9 on the right. Patients underwent neuropsychological evaluation by the Wechsler Adult Intelligence Scale-Revised and the Wechsler Memory Scale-Revised preoperatively and 5 years after SAHE. RESULTS: Twenty-three (77%) patients were classified as Engel class I. At the group level, we found significant increases in all intelligence domains (Global, Visual, and Performance) by 19.1 (7.4), 15.8 (6.1), and 19.1 (7.9) points, respectively. Significant improvements were also detected in all memory measures (Global, Verbal, Visual, Attention/Concentration, Delayed Recall) by 19.4 (14.2), 16.9 (13.3), 19.0 (14.7), 15.3 (15.0), and 24.6 (13.4), respectively. Patients with left-sided surgery improved significantly more in Attention/Concentration. Otherwise, there were no statistically significant differences in memory function improvements between subgroups according to the operated side. CONCLUSION: After SAHE, we found favorable long-term neuropsychological outcomes. These results could be caused by incomplete destruction of target structures and minimization of collateral damage that possibly enables adaptive postoperative neuronal reorganization.

Late morphological changes after radiosurgery of brain arteriovenous malformations: an MRI study.

BACKGROUND: Radiosurgery by Gamma Knife (GK) is an effective treatment for brain arteriovenous malformations (AVM). The aim of the present study was to evaluate late, radiation-induced changes detectable by MRI after AVM radiosurgery in patients treated minimally 10 years prior, with AVM obliteration proven by angiography. METHODS: Thirty-five patients with 37 AVMs were included. AVMs were irradiated 16.6 ± 3.5 years prior with AVM obliteration proven 13 ± 4 years prior. All patients underwent recent MRI examinations, including application of gadolinium-based contrast. RESULTS: In one case, post-irradiative cystic formation with mass effect and signs of hemorrhage requiring surgery was found. Post-gadolinium enhancement at the site of obliterated nidi was apparent in 28 of 37 cases (76 %). In all cases except one, the mean volume of enhancement at the time of review was clearly lower than the volume of the originally irradiated AVM (88 ± 20 %; median 92 %); in one case the extent was 142 % greater than the irradiated AVM. When we compared enhancing and non-enhancing nidi, we found that enhancing nidi were significantly larger than non-enhancing nidi at the time of radiosurgery (4.39 ± 3.35 cc vs. 0.89 ± 0.79 cc, p = 0.004). Enhancement was not influenced by total radiation dose, patient age at the time of irradiation, duration since radiosurgery, or the number of irradiations. Wallerian degeneration was found in nine of 37 cases (24 %); in six cases the optical tracts were affected and visual field defects were proven. In five of nine cases (55.6 %) with Wallerian degeneration previous hemorrhage was present. Dual vascular pathology was found in eight of 35 patients (23 %). CONCLUSIONS: GK radiosurgery for AVM is a safe treatment method although delayed complications may occur. Post-gadolinium enhancement of obliterated nidi may indicate an active post-irradiative process.

Relationship between remnant hippocampus and amygdala and memory outcomes after stereotactic surgery for mesial temporal lobe epilepsy.

BACKGROUND AND PURPOSE: Mesial temporal structures play an important role in human memory. In mesial temporal lobe epilepsy (MTLE), seizure activity is generated from the same structures. Surgery is the definitive treatment for medically intractable MTLE. In addition to standard temporal lobe microsurgical resection, stereotactic radiofrequency amygdalohippocampectomy (SAHE) is used as an alternative MTLE treatment. While memory impairments after standard epilepsy surgery are well known, it has been shown that memory decline is not a feature of SAHE. The aim of the present study was to correlate the volume of the remnant hippocampus and amygdala in patients treated by SAHE with changes in memory parameters. MATERIALS AND METHODS: Thirty-seven MTLE patients treated by SAHE (ten right, 27 left) were included. Patients underwent magnetic resonance imaging examinations including hippocampal and amygdalar volumetry and neuropsychological evaluation preoperatively and 1 year after surgery. RESULTS: Using Spearman correlation analyses, larger left-sided hippocampal reductions were associated with lower verbal memory performance (ρ=-0.46; P=0.02). On the contrary, improvement of global memory quotient (MQ) was positively correlated with larger right-sided hippocampal reduction (ρ=0.66; P=0.04). Similarly, positive correlations between the extent of right amygdalar reduction and verbal MQ (ρ=0.74; P=0.02) and global MQ change (ρ=0.69; P=0.03) were found. Thus, larger right hippocampal and amygdalar reduction was associated with higher global and verbal MQ change after SAHE. CONCLUSION: Larger left-sided hippocampal reductions were associated with lower verbal memory performance. This finding is in accordance with the material-specific model of human memory, which states that the dominant hemisphere is specialized for the learning and recall of verbal information. We hypothesize that larger right-sided ablations enable the left temporal lobe to support memory more effectively, perhaps as a consequence of epileptiform discharges spreading from remnants of right mesiotemporal structures to the left.

Morphological changes after radiosurgery for mesial temporal lobe epilepsy.

BACKGROUND: To review our experience with morphological developments during the long-term follow-up of patients treated by Gamma Knife radiosurgery for mesial temporal lobe epilepsy. METHOD: Between 1995 and 1999, we treated 14 patients with marginal doses of 24 Gy (n = 6) and 18-20 Gy (n = 8). Nine of these were operated on for insufficient seizure control. We reviewed seizure outcome and magnetic resonance images in both operated and unoperated patients and also re-examined histopathology specimens. RESULTS: Of the nine operated patients, two were Engel IIIA, one was IVA, five were IVB, and one was Engel IVC prior to surgery. At their final visit, five cases had become Engel class IA, one patient was ID, and two were IIC. In one patient the follow-up was not long enough for classification. Of the five unoperated patients, one was Engel class IB, one was IIIA, one IIB and one IVB at their final visit. Radionecrosis developed in 11 patients, occurring more often and earlier in those treated with higher doses. Collateral edema reached outside the temporal lobe in six patients, caused uncal herniation in two and intracranial hypertension in three. During longer follow-up, postnecrotic pseudocysts developed in 9 patients, and postcontrast enhancement persisted for 2.5-16 years after GKRS in all 14 patients. In five of them we detected its progression between 2 and 16 years after treatment. Signs of neoangiogenesis were found in two patients and microbleeds could be seen in five. Histopathology revealed blood vessel proliferation and macrophage infiltration. CONCLUSIONS: Early delayed complications and morphological signs suggesting a risk of development of late delayed complications are frequent after radiosurgery for mesial temporal lobe epilepsy. Together with its unproven antiseizure efficacy, these issues should be taken into account when planning future studies of this method.

MRI-guided stereotactic amygdalohippocampectomy: a single center experience.

BACKGROUND: This paper presents our experience of stereotactic radiofrequency amygdalohippocampectomy performed for intractable mesial temporal lobe epilepsy. METHODS: The article describes the cases of 61 patients who were treated during the period from 2004 to 2010. Mean postoperative follow-up was 5.3 years. Neuropsychological results were obtained for a subset of 31 patients. RESULTS: At their last postsurgical visit, 43 (70.5%) patients were Engel class I, six (9.8%) class II, nine (14.8%) class III, and three (4.9%) class IV. The surgery was complicated by four intracranial hematomas. One of them caused acute hydrocephalus and was treated by shunting and resolved without sequelae, while another caused transitory aphasia. The remaining hematomas were asymptomatic. There were two cases of meningitis which required antibiotic treatment. One patient committed suicide due to postoperative depression. After the procedure, we performed open epilepsy surgery and rethermolesions in three and two patients, respectively (8.2%). Patients showed increases in their mean full scale, verbal, and performance intelligence quotient (IQ) scores of 4, 3, and 4 IQ points, respectively (P<0.05). Five (17.2%), four (13.8%), and four (13.3%) patients improved their full scale, verbal, and performance IQ scores, respectively. No significant changes were found in memory performance, with a mean increase of 1, 3, and 0 memory quotient points in global, verbal, and visual memory, respectively (P<0.05). Global memory improved in three (10.3%) patients, verbal memory in one (3.4%), and one patient (3.3%) showed deterioration in visual memory. CONCLUSION: Stereotactic radiofrequency amygdalohippocampectomy offers a safe, effective, and less aggressive treatment modality in cases of well-defined mesial temporal lobe epilepsy. Seizure outcome is comparable with the results of conventional epilepsy surgery and cognitive results could be even better.

Neuropsychological results after gamma knife radiosurgery for mesial temporal lobe epilepsy.

OBJECTIVES: The aim of this study is to summarize our experience with neuropsychological changes after radiosurgical treatment for mesial temporal lobe epilepsy and subsequent surgery due to insufficient seizure control. METHODS: Between November 1995 and May 1999, 14 patients underwent radiosurgical entorhinoamygdalohippocampectomy with a marginal dose of 18, 20 or 25 Gy to the 50% isodose. 9 of these patients subsequently underwent surgery. We compared Memory Quotients and Intelligence Quotients before and after the interventions. RESULTS: We found a slight, but nonsignificant decline in intelligence and memory quotients one year after GKRS. Two years after radiosurgery there were no significant changes in any of the quotients. After surgery, we found significant increase in Global and Visual MQ, (p<0.05). There were no statistically significant changes in verbal memory and intelligence performance after surgery. CONCLUSION: Epilepsy surgery after unsuccessful radiosurgery could lead to improvements in cognitive functions in patients with mesial temporal lobe epilepsy.

Different surgical approaches for mesial temporal epilepsy: resection extent, seizure, and neuropsychological outcomes.

BACKGROUND: Surgical therapy of intractable mesial temporal lobe epilepsy (MTLE) is an effective and well-established treatment. OBJECTIVES: We compared two different surgical approaches, standard microsurgical anterior temporal resection (ATL) and stereotactic radiofrequency amygdalohippocampectomy (SAHE) for MTLE, with respect to the extent of resection or destruction, clinical outcomes, and complications. MATERIAL AND METHODS: 75 MTLE patients were included: 41 treated by SAHE (11 right sided, 30 left sided) and 34 treated by ATL (21 right sided, 13 left sided). RESULTS: SAHE and ATL seizure control were comparable (Engel I in 75.6 and 76.5% 2 years after surgery and 79.3 and 76.5% 5 years after procedures, respectively). The neuropsychological results of SAHE patients were better than in ATL. In SAHE patients, no memory deficit was found. Hippocampal (60.6 ± 18.7%) and amygdalar (50.3 ± 21.9%) volume reduction by SAHE was significantly lower than by ATL (86.0 ± 12.7% and 80.2 ± 20.9%, respectively). The overall rate of surgical nonsilent complications without permanent neurological deficit after ATL was 11.8%, and another 8.8% silent infarctions were found on MRI. The rate of clinically manifest complications after SAHE was 4.9%. The rate of visual field defects after SAHE was expectably less frequent than after ATL. CONCLUSION: Seizure control by SAHE was comparable to ATL. However, SAHE was safer with better neuropsychological results.

Long-term seizure outcome after stereotactic amygdalohippocampectomy.

BACKGROUND: The aim of the study was to evaluate the long-term seizure outcome and complications after stereotactic radiofrequency amygdalohippocampectomy (SAHE) performed for mesial temporal lobe epilepsy (MTLE). METHODS: The article describes the cases of 61 patients who were treated at our institution during the period 2004-2010. Mean post-operative follow-up was 5.3 years. RESULTS: At the last postsurgical visit, 43 (70.5 %) patients were Engel Class I, six (9.8 %) Class II, nine (14.8 %) Class III and three (4.9 %) Class IV. The surgery was complicated by four intracranial haematomas. One of them caused acute hydrocephalus and was treated by shunting and resolved without sequelae. After SAHE, we performed open epilepsy surgery and re-thermo lesions in three and two patients, respectively (8.2 %). There were two cases of meningitis which required antibiotic treatment. In six patients psychiatric disorders developed and one of these committed suicide due to postoperative depression. CONCLUSIONS: Our results provide preliminary evidence for good long-term seizure outcomes after SAHE. SAHE could be an alternative therapy for MTLE.

Stereotactic radiofrequency amygdalohippocampectomy: two years of good neuropsychological outcomes.

PURPOSE: To provide two-year seizure and neuropsychological outcomes in patients treated by stereotactic radiofrequency amygdalohippocampectomy (SAHE), an alternative, minimally invasive method for the treatment of mesial temporal lobe epilepsy (MTLE). MATERIAL AND METHODS: Thirty-seven MTLE patients treated by SAHE (26 left-sided, 11 right-sided) were included. Patients underwent neuropsychological evaluation by the Wechsler Adult Intelligence Scale-Revised and the Wechsler Memory Scale-Revised preoperatively, 1 year and 2 years after SAHE. RESULTS: Two years after SAHE twenty-eight (75.5%) patients were assessed as Engel Class I and seven (18.9%) patients as Engel Class II. In two patients (5.4%) treatment failed, one of them was classified as Class III and one as Class IV. Irrespective of the laterality of the procedure, the group improved significantly in Global and Verbal Memory Quotients, Attention, Delayed Recall, Semantic Long-term memory subtest and Working Memory. Additionally, increases in Full-scale, Verbal and Visual Intelligence Quotients were detected on the group level. CONCLUSION: In the present study we report good seizure control and neuropsychological outcomes after SAHE in our patients. We hypothesize that good neuropsychological results were achieved by the incomplete destruction of target structures, sparing the lateral temporal neocortex, and also partially by practice effect. Treatment failures in seizure control may be attributed to larger epileptogenic zones.

Stereotactic radiofrequency amygdalohippocampectomy for the treatment of temporal lobe epilepsy: do good neuropsychological and seizure outcomes correlate with hippocampal volume reduction?

Temporal lobe surgery bears the risk of a decline of neuropsychological functions. Stereotactic radiofrequency amygdalohippocampectomy (SAHE) represents an alternative to mesial temporal lobe epilepsy (MTLE) surgery. This study compared neuropsychological results with MRI volumetry of the residual hippocampus. We included 35 patients with drug-resistant MTLE treated by SAHE. MRI volumetry and neuropsychological examinations were performed before and 1 year after SAHE. Each year after SAHE clinical seizure outcome was assessed. One year after SAHE 77% of patients were assessed as Engel Class I, 14% of patients was classified as Engel II and in 9% of patients treatment failed. Two years after SAHE 76% of subjects were classified as Engel Class I, 15% of patients was assessed as Engel II and in 9% of patients treatment failed. Hippocampal volume reduction was 58±17% on the left and 54 ± 27% on the right side. One year after SAHE, intelligence quotients of treated patients increased. Patients showed significant improvement in verbal memory (p=0.039) and the semantic long-term memory subtest (LTM) (p=0.003). Patients treated on the right side improved in verbal memory, delayed recall and LTM. No changes in memory were found in patients treated on the left side. There was a trend between the larger extent of the hippocampal reduction and improvement in visual memory in speech-side operated.

Cognitive outcome after stereotactic amygdalohippocampectomy.

PURPOSE: We sought to determine the neuropsychological outcome after stereotactic radiofrequency amygdalohippocampectomy performed for intractable mesial temporal lobe epilepsy. METHODS: The article describes the cases of 31 patients who were evaluated using the Wechsler Adult Intelligence Scale-Revised and the Wechsler Memory Scale-Revised prior to, and one year after, surgery. KEY FINDINGS: Patients showed increases in their mean Full Scale, Verbal and Performance IQ scores of 4, 3 and 4 IQ points respectively (p<.05). 5 (17.2%), 4 (13.8%) and 4 (13.3%) patients improved in their Full-scale, Verbal and Performance IQ respectively. No significant changes were found in memory performance - with a mean increase of 1, 3 and 0 MQ points in Global, Verbal and Visual memory respectively (p<.05). Global memory improved in 3 (10.3%) patients, verbal memory in 1 (3.4%) and 1 patient (3.3%) showed deterioration in visual memory. SIGNIFICANCE: Our results provide evidence for unchanged memory in patients with MTLE after the procedure. No verbal memory deterioration was detected in any of our patients, while improvements were found in intellectual performance. The results suggest that stereotactic radiofrequency amygdalahippocampectomy could be superior to open surgery in terms of its neurocognitive outcomes. A larger randomised trial of these approaches is justified.

[Temporal lobe epilepsy in adults and possibilities of neurosurgical treatment: the role of magnetic resonance]. / Temporální epilepsie dospelých a moznosti neurochirurgické lécby: úloha magnetické rezonance.

Temporal lobe epilepsy is the most common type of focal epilepsy diagnosed in adult patients. According to the location of seizure generation it is classified as mesial temporal lobe epilepsy and neocortical lateral lobe epilepsy. Diagnosis of temporal lobe epilepsy can be proved by the combination of the clinical manifestation of partial complex seizures, scalp-video EEG monitoring, results of magnetic resonance imaging (MRI) and imaging of interictal fluoro-deoxy-glucose positron emission tomography. Mesial temporal sclerosis is the most common finding on MRI. Temporal lobe epilepsy is the most surgically amenable diagnosis and results of surgery treatments are clearly superior to the prolonged medical therapy; surgical treatment of the mesial temporal epilepsy with mesial temporal sclerosis has the best clinical results. Except for standard microsurgical approaches such as anterior temporal resection and selective amygdalo-hippocampectomy, stereotactic thermocoagulation amygdalo-hippocampectomy is provided in our epilepsy centre. This alternative approach has comparable clinical outcome to the standard surgery approaches in 2 years clinical follow-ups. MRI is important not only in diagnostic procedures, but also in neuronavigation of surgery approaches, per operation control of the extent of resections and postoperative follow-ups, especially in failed epilepsy surgery.

[Contemporary pharmacotherapy of epilepsy]. / Soucasná farmakoterapie epilepsie.

The epilepsies are a frequent group of neurologic disorders. We have witnessed significant advances in their medical treatment recently. About 70 % of newly diagnosed patients are rendered seizure-free. Antiepileptic drug treatment has become more complex. The choice of antiepileptic drug is based on seizure type. However, special patient's needs (drug tolerability, toxicity, ease of use and cost and age, sex and commorbidities) should be considered. The article deals with these special situations. In case of seizure persistence epilepsy surgery could be an option.

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

PURPOSE: 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. METHODS: 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. KEY FINDINGS: 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. SIGNIFICANCE: 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.