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Direct visual targeting versus preset coordinates for ANT‐DBS in epilepsy
Author(s) -
Nome Terje,
Herrman Helle,
Lehtimäki Kai,
Egge Arild,
Konglund Ane,
Ramm-Pettersen Jon,
Taubøll Erik,
Dietrichs Espen
Publication year - 2020
Publication title -
acta neurologica scandinavica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.967
H-Index - 95
eISSN - 1600-0404
pISSN - 0001-6314
DOI - 10.1111/ane.13233
Subject(s) - deep brain stimulation , position (finance) , medicine , epilepsy , epilepsy surgery , ant , nuclear medicine , computer science , artificial intelligence , audiology , physical medicine and rehabilitation , neuroscience , psychology , pathology , disease , finance , parkinson's disease , economics , computer network
Objectives Deep brain stimulation (DBS) of the anterior thalamic nucleus (ANT) may be used against refractory focal epilepsy, but only two randomized double‐blinded trials have been performed. The Oslo study was discontinued prematurely since reduction in seizure frequency was less than expected. The aim of the present study was to review the targeting used in the Oslo study and to identify the actual positions of the contacts used for stimulation. Material and methods BrainLab MRI data were available from 12 Oslo study patients. Based on MRI the coordinates of the center of the ANT were identified. The coordinates were considered as the visually identified preferred target and were compared with the target originally used for ANT electrode implantation and with the actual electrode positions estimated from post‐operative CT scans. Results We found considerable differences between the visually identified preferred target, the originally planned target, and the actual electrode position. The total distance between the active electrode position and the visually identified preferred target was on average 3.3 mm on the right and 2.9 mm on the left side. Conclusion Indirect targeting based on preset coordinates may contribute to explain the modest effect of ANT‐DBS on seizure frequency seen in the Oslo study. Observed differences between the center of the ANT and the actual electrode position may at least in part be explained by variations in position and size of the ANT. Direct identification of the target using better MRI imaging protocols is recommended for future ANT‐DBS surgery.