Bilateral stereotactic lesions and chronic stimulation of the anterior thalamic nuclei for treatment of pharmacoresistant epilepsy.

BACKGROUND: The use of the anterior nucleus of thalamus (ANT) as a target for treatment of pharmacoresistant epilepsy is based on its crucial role in seizure propagation. We describe results of chronic bilateral ANT stimulation and bilateral ANT lesions in 31 patients with refractory epilepsy. METHODS: ANT DBS was performed in 12 patients (group I) and bilateral stereotactic radiofrequency lesions of ANT were performed in 19 patients (group II). Targeting was based on stereotactic atlas information with correction of the final coordinates according to the location of anatomical landmarks and intraoperative microelectrode recording data. RESULTS: Both groups were similar in age, gender, seizures frequency, and duration of disease. The median x, y, and z coordinates of ANT were found to be 2.9, 5, and 11 mm anterior, lateral, and superior to the mid-commissural point, respectively. Mean seizures reduction reached 80.3% in group of patients with ANT DBS with two nonresponders and 91.2% in group of patients with lesions. Five patients from group I and three patients from group II became seizure-free. The morbidity rate was low in both groups. CONCLUSIONS: Stereotactic anterior thalamotomy and chronic ANT stimulation are both effective for seizure control in epilepsy originated from frontal and temporal lobes. ANT lesions and stimulation were more effective for secondary-generalized seizures compared to simple partial seizures.

[Surgical treatment of epilepsy in patients with mediobasal temporal cavernous malformations]. / Khirurgicheskoe lechenie épilepsii u patsientov s mediobazal'nymi visochnymi kavernoznymi mal'formatsiiami.

OBJECTIVE: Epilepsy is a frequent clinical manifestation of cavernous malformations (CMs) of the mediobasal temporal region (MBTR). Surgical removal of CMs is an excellent technique for treating associated epilepsy and may range from pure lesionectomy to tailored resection of the temporal lobe. PURPOSE: The study purpose was to determine the optimal surgical management for epilepsy in patients with CMs of the MBTR. MATERIAL AND METHODS: We retrospectively analyzed the clinical data, neuroimaging findings, surgical techniques, and surgical outcomes in 11 patients with epilepsy and CMs of the MBTR. All patients underwent video-electroencephalography, magnetic resonance imaging, and computed tomography in the pre- and postoperative periods. Nine patients underwent preoperative implantation of foramen ovale electrodes. In all cases, surgery was accompanied by electrocorticography (ECoG). RESULTS: CMs were located in the anterior MBTR in 7 cases, anterior and middle thirds of the MBTR in 1 case, middle third in 2 cases, and middle and posterior thirds in 1 case. In 8 patients, preoperative monitoring revealed a seizure onset area in the MBTR. These patients underwent cavernomectomy with ECoG-guided resection of the hemosiderin ring and adjacent tissue using the pterional (4 cases) or supracerebellar transtentorial approach (4). In 3 cases, anterior temporal lobectomy with cavernomectomy was additionally used due to spreading of pathological activity to the lateral temporal neocortex. Seizure control after surgery was excellent in 7 patients (class 1 ILAE) and good in 4 (class 2 ILAE). CONCLUSION: Surgery in patients with epilepsy caused by CMs of the MBTR should be performed based on non-invasive and invasive presurgical evaluation. If the seizure onset area is located in the MBTR, lesionectomy with ECoG-guided resection of the adjacent temporal cortical areas can be performed using the pterional or supracerebellar transtentorial approach. Lateral spread of epileptic activity requires cavernomectomy and anterior temporal lobectomy.

[Bilateral radiofrequency anterior thalamotomy in intractable epilepsy patients]. / Dvustoronnyaya radiochastotnaya perednyaya talamotomiya u patsientov s farmakorezistentnoi epilepsiei.

BACKGROUND: Identification of the crucial role of the anterior thalamic nuclei (ATN) in the generalization of seizures led to increased interest in surgical interventions in this particular area in intractable epilepsy patients. Simulation of ATN destruction in animals demonstrated its high efficacy for both preventing the seizure development and reducing the seizure rate. However, bilateral radiofrequency destruction of the anterior thalamic nuclei in humans has not yet bee described. AIM: The study objective was to perform bilateral radiofrequency anterior thalamotomy in intractable epilepsy patients and to evaluate its MATERIAL AND METHODS: We performed for the first time bilateral stereotactic radiofrequency thermocoagulation of ATN in 13 patients with long-term intractable epilepsy. Before surgery, we assessed the disease duration, age of seizure onset, localization of pathological activity sources, and types of seizures, morphological damages, and ongoing pharmacotherapy. All interventions were performed under local anesthesia and were accompanied by intraoperative microelectrode monitoring of the neuronal activity and by EEG. RESULTS: Seven males and 6 females, aged 22 to 48 years, were operated on. All patients had epileptogenic foci in the frontal and/or temporal lobes. MRI revealed epileptogenic structural abnormalities in 3 patients. There were no postoperative complications. According to a postoperative examination, 5 patients were seizure-free; a decrease in the seizure rate was 70% in 6 patients and 50% in 1 patient; 1 patient had no response to the surgery. The resulting effect was manifested not only in a reduction in the frequency and severity of seizures but also in a decrease in the dose of administered anticonvulsants. EEG also showed a significant improvement in the majority of patients. CONCLUSION: Our experience demonstrates that bilateral radiofrequency anterior thalamotomy is a safe and effective technique to control seizures in humans. Further research will clarify, based on the clinical and EEG data, the patient selection criteria for surgical treatment.