Resident Epilepsy Center, Department of Neurology, University Hosipital, LMU Munich Munich, Bayern, Germany
Rationale: Deep brain stimulation of the anterior nucleus of the thalamus (ANT-DBS) is supported by high-level clinical evidence (the SANTE randomized controlled trial) and is CE marked for patients with drug-resistant focal epilepsy. However, open questions remain concerning patient selection, patient management and outcome evaluation and guiding reports on practical treatment principles remain scarce. This initiative, thus, aimed to evaluate the current knowledge on ANT-DBS therapy and to share European experts´ opinion and experience. Methods: The independent Expert Panel (EP) encompassed ten neurologists and four neurosurgeons from eight different European countries. A Delphi approach was used, which included (1) a review of the current literature on ANT-DBS as first step. The literature search was limited to reports on at least three patients published between January 2000 and January 2019. The extracted data was summarized as pre-reading material and served as a basis for the creation of the survey questions. The online survey (2) was completed anonymously by the EP prior to a (3) face-to-face meeting held in November 2019. After discussing the first survey round results and modifying the questions, a second survey round was completed by the EP. An agreement level of ≥71% (10/14 panelists) was considered as consensus. Results: The literature search yielded a total of 323 publications, whereof 46 studies were selected for data extraction of the most reported criteria for patient selection, management, and outcome. The EP board agreed on the importance of a presurgical evaluation of ANT-DBS candidates and achieved consensus on four complementary parameters for patient selection and management, i.e., patient´s preference, operability, occurrence and frequency of psychogenic seizures, and psychiatric history. Patients with temporal lobe epilepsy having no resective therapy option, as well as patients who failed prior VNS and/or resection were classified as good patient candidates. Reasons for concern were seen in unreliable seizure documentation, history of frequent psychogenic seizures, progressive etiologly, history of psychosis or depression, especially in case of an history of suicidal attempts, and general MRI contraindications. Due to the low level of evidence on device programming, it was not possible to give strict recommendations. The EP thus shared their clinical practice instead: all centers start with monopolar stimulation and typically (79%) use the cycling mode. Stimulation frequency and pulse width are mostly (93%) set according to the SANTE parameters, whereas half of the experts prefer to start with lower amplitudes than 5V. Agreement was further achieved on strategies for electrode selection and management of side effects or insufficient clinical response. A set of seven outcome parameters was defined to be monitored during the follow-up in order to evaluate the clinical response and promptly assess side-effects. Conclusions: The expert opinion report on ANT-DBS provides scientific and strategic advice on patient selection, stimulation strategies, management of side effects and insufficient clinical response and presents recommendations for outcome evaluation. Although current evidence is too low for definite practical guidelines, this EP report could support clinicians in adopting the therapy. Funding: Please list any funding that was received in support of this abstract.: All authors received speaker honoraria by Medtronic Inc. The face-to-face meeting was held in the European Medtronic Headquarter in Tolochenaz, Switzerland, upon invitation by Medtronic.
