Defining the optimal target for anterior thalamic deep brain stimulation in patients with drug-refractory epilepsy

Abstract

<jats:sec><jats:title>OBJECTIVE</jats:title><jats:p>The anterior thalamic nucleus (ATN) is a common target for deep brain stimulation (DBS) for the treatment of drug-refractory epilepsy. However, no atlas-based optimal DBS (active contacts) target within the ATN has been definitively identified. The object of this retrospective study was to analyze the relationship between the active contact location and seizure reduction to establish an atlas-based optimal target for ATN DBS.</jats:p></jats:sec><jats:sec><jats:title>METHODS</jats:title><jats:p>From among 25 patients who had undergone ATN DBS surgery for drug-resistant epilepsy between 2016 and 2018, those who had follow-up evaluations for more than 1 year were eligible for study inclusion. After an initial stimulation period of 6 months, patients were classified as responsive (≥ 50% median decrease in seizure frequency) or nonresponsive (&lt; 50% median decrease in seizure frequency) to treatment. Stimulation parameters and/or active contact positions were adjusted in nonresponsive patients, and their responsiveness was monitored for at least 1 year. Postoperative CT scans were coregistered nonlinearly with preoperative MR images to determine the center coordinate and atlas-based anatomical localizations of all active contacts in the Montreal Neurological Institute (MNI) 152 space.</jats:p></jats:sec><jats:sec><jats:title>RESULTS</jats:title><jats:p>Nineteen patients with drug-resistant epilepsy were followed up for at least a year following bilateral DBS electrode implantation targeting the ATN. Active contacts located more adjacent to the center of gravity of the anterior half of the ATN volume, defined as the anterior center (AC), were associated with greater seizure reduction than those not in this location. Intriguingly, the initially nonresponsive patients could end up with much improved seizure reduction by adjusting the active contacts closer to the AC at the final postoperative follow-up.</jats:p></jats:sec><jats:sec><jats:title>CONCLUSIONS</jats:title><jats:p>Patients with stimulation targeting the AC may have a favorable seizure reduction. Moreover, the authors were able to obtain additional good outcomes after electrode repositioning in the initially nonresponsive patients. Purposeful and strategic trajectory planning to target this optimal region may predict favorable outcomes of ATN DBS.</jats:p></jats:sec>

Anterior Nucleus of Thalamus Deep Brain Stimulation: A Clinical-Based Analysis of the Ideal Target in Drug-Resistant Epilepsy

“…However, it may be explained, by the fact that the z coordinates of nonresponder contacts were substantially lower than ours. Guo et al [47] obtained a mean z coordinate in MNI space, of 6.01 mm for nonresponders and 9.50 for responders, while in our study, 40% of nonresponders presented a z coordinate superior to 9.50. This appears to demonstrate that both z inferior to 6 and much superior to 9.5 may not confer a benefit, which stands into agreement to our defined HELIA.…”

“…Koeppen et al [46] found better response rates with a center of stimulation 5 mm lateral to the wall of the third ventricle and 10 mm superior to the mid-commissural plane. Guo et al [47] found a positive relationship between the z coordinate of the final active contact and seizure reduction percentage, with a mean z coordinate in MNI space of approximately 9.5 mm and 6 mm in responders and nonresponders, respectively. They also found a negative relationship between distance of active contact to the center of the anterior half of ANT and seizure reduction percentage, suggesting this may be an optimal target for ANT-DBS.…”

Centromedian thalamic nucleus with or without anterior thalamic nucleus deep brain stimulation for epilepsy in children and adults: A retrospective case series

“…In the case of CM stimulation for LGS, patients with >80 % seizure frequency reduction had electrodes within the anterolateral CM, whereas in those with <80 % reduction, electrodes tended more towards the superior, medial and posterior aspect of the CM [ 16 ]. For ANT stimulation, active contacts closer to the anterior half of the ANT were associated with improved seizure frequency reduction [ 26 ]. Here, we evaluated mean electrode distance from target and did not find a significant difference between responders and non-responders for either CM or ANT nuclei.…”

Prognostic potential of a voxelwise invasion risk map of nasopharyngeal carcinoma based on a coordinate system of the nasopharynx

“…_ 1 ( _ _ ) / 2 y y y P C P LAS P RAS = + [10] and where S z =Cz/Pz is used to describe the scale transformation of the y-axis, and Cz and Pz are the differences between the z-axis coordinate values of PC and MC in the coordinate system and patient image, respectively, as defined below:…”

“…Coordinate systems have been successfully applied in many studies (5,6), and anatomical landmarks have often been used to define coordinate systems. The results of most neuroimaging studies have been reported with Montreal Neurological Institute (MNI) coordinates (7)(8)(9)(10). In addition, a nonrigid image registration method, namely, large deformation diffeomorphic metric mapping, has been used to transform the MRI data of participants into the standard coordinate system (11,12).…”