title: Anterior nuclear deep brain stimulation guided by concordant hippocampal recording.
abstract: OBJECTIVE
  Anterior nuclear (AN) stimulation has been reported to reduce the frequency of seizures, in some cases dramatically; however, it has not been approved by the US Food and Drug Administration. The anterior nucleus is difficult to target because of its sequestered location, partially surrounded by the ventricle. It has traditionally been targeted by using transventricular or lateral transcortical routes. Here, the authors report a novel approach to targeting the anterior nucleus and neurophysiologically confirming effective stimulation of the target, namely evoked potentials in the hippocampus.
  
  
  METHODS
  Bilateral AN 3389 electrodes were placed in a novel trajectory followed by bilateral hippocampal 3391 electrodes from a posterior trajectory. Each patient was implanted bilaterally with a Medtronic Activa PC+S device under an investigational device exemption approval. Placement was confirmed with CT. AN stimulation-induced hippocampal evoked potentials were measured to functionally confirm placement in the anterior nucleus.
  
  
  RESULTS
  Two patients had implantations by way of a novel AN trajectory with concomitant hippocampal electrodes. There were no lead misplacements. Postoperative stimulation of the anterior nucleus with a PC+S device elicited evoked potentials in the hippocampus. Thus far, both patients have reported a > 50% improvement in seizure frequency.
  
  
  CONCLUSIONS
  Placing AN electrodes posteriorly may provide a safer trajectory than that used for traditionally placed AN electrodes. In addition, with a novel battery that is capable of electroencephalographic recording, evoked potentials can be used to functionally assess the Papez circuit. This treatment paradigm may offer increased AN stimulation efficacy for medically intractable epilepsy by assessing functional placement more effectively and thus far has proven safe.
authors.affiliation: Departments of 1Neurosurgery and.
authors.forename: Jamie J
authors.initials: JJ
authors.lastname: Van Gompel
authors.affiliation: 2Neurology, Mayo Clinic, Rochester, Minnesota.
authors.forename: Bryan T
authors.initials: BT
authors.lastname: Klassen
authors.affiliation: 2Neurology, Mayo Clinic, Rochester, Minnesota.
authors.forename: Gregory A
authors.initials: GA
authors.lastname: Worrell
authors.affiliation: Departments of 1Neurosurgery and.
authors.forename: Kendall H
authors.initials: KH
authors.lastname: Lee
authors.affiliation: 2Neurology, Mayo Clinic, Rochester, Minnesota.
authors.forename: Cheolsu
authors.initials: C
authors.lastname: Shin
authors.affiliation: 2Neurology, Mayo Clinic, Rochester, Minnesota.
authors.forename: Cong Zhi
authors.initials: CZ
authors.lastname: Zhao
authors.affiliation: Departments of 1Neurosurgery and.
authors.forename: Desmond A
authors.initials: DA
authors.lastname: Brown
authors.affiliation: Departments of 1Neurosurgery and.
authors.forename: Steven J
authors.initials: SJ
authors.lastname: Goerss
authors.affiliation: Departments of 1Neurosurgery and.
authors.forename: Bruce A
authors.initials: BA
authors.lastname: Kall
authors.affiliation: 2Neurology, Mayo Clinic, Rochester, Minnesota.
authors.forename: Matt
authors.initials: M
authors.lastname: Stead
mesh_terms: D000328:Adult; D020643:Anterior Thalamic Nuclei / Q000502:physiology*; D046690:Deep Brain Stimulation / Q000379:methods*; D004567:Electrodes, Implanted; D004828:Epilepsies, Partial / Q000628:therapy*; D005260:Female; D006624:Hippocampus / Q000503:physiopathology*; D006801:Humans; D008297:Male
keywords: AC = anterior commissure; AN = anterior nuclear; DBS = deep brain stimulation; EEG = electroencephalographic; MMT = mammillothalamic tract; MNI = Montreal Neurological Institute; PC = posterior commissure; SANTE = Stimulation of the Anterior Nucleus of the Thalamus for Epilepsy; anterior nucleus; epilepsy; hippocampus; neuromodulation