title: Efficacy of the transtemporal approach with awake brain mapping to reach the dominant posteromedial temporal lesions.
abstract: Surgeries for lesions in the dominant hippocampal and parahippocampal gyrus involving the posteromedial temporal regions are challenging to perform because they are located close to Wernicke's area; white matter fibers related with language; the optic radiations; and critical neurovascular structures. We performed a transtemporal approach with awake functional mapping for lesions affecting the dominant posteromedial temporal regions. The aim of this study was to assess the feasibility, safety, and efficacy of awake craniotomy for these lesions.
  
  
  
  We retrospectively reviewed four consecutive patients with tumors or cavernous angiomas located in the left hippocampal and parahippocampal gyrus, which further extended to the posteromedial temporal regions, who underwent awake surgery between December 2014 and January 2016.
  
  
  
  Four patients with lesions associated with the left hippocampal and parahippocampal gyrus, including the posteromedial temporal area, who underwent awake surgery were registered in the study. In all four patients, cortical and subcortical eloquent areas were identified via direct electrical stimulation. This allowed determination of the optimal surgical route to the angioma or tumor, even in the language-dominant hippocampal and parahippocampal gyrus. In particular, this approach enabled access to the upper part of posteromedial temporal lesions, while protecting the subcortical language-related fibers, such as the superior longitudinal fasciculus.
  
  
  
  This study revealed that awake brain mapping can enable the safe resection of dominant posteromedial temporal lesions, while protecting cortical and subcortical eloquent areas. Furthermore, our experience with four patients demonstrates the feasibility, safety, and efficacy of awake surgery for these lesions.
authors.affiliation: Department of Neurosurgery, Nagoya University School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya, 466-8550, Japan.
authors.forename: Kentaro
authors.initials: K
authors.lastname: Iijima
authors.affiliation: Department of Neurosurgery, Nagoya University School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya, 466-8550, Japan. kmotomura@med.nagoya-u.ac.jp.
authors.forename: Kazuya
authors.initials: K
authors.lastname: Motomura
authors.affiliation: Department of Neurosurgery, Nagoya University School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya, 466-8550, Japan.
authors.forename: Lushun
authors.initials: L
authors.lastname: Chalise
authors.affiliation: Department of Neurosurgery, Nagoya University School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya, 466-8550, Japan.
authors.forename: Masaki
authors.initials: M
authors.lastname: Hirano
authors.affiliation: Department of Neurosurgery, Nagoya University School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya, 466-8550, Japan.
authors.forename: Atsushi
authors.initials: A
authors.lastname: Natsume
authors.affiliation: Department of Neurosurgery, Nagoya University School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya, 466-8550, Japan.
authors.forename: Toshihiko
authors.initials: T
authors.lastname: Wakabayashi
mesh_terms: D000328:Adult; D001931:Brain Mapping / Q000379:methods*; D001932:Brain Neoplasms / Q000601:surgery*; D004558:Electric Stimulation / Q000379:methods*; D005260:Female; D007839:Functional Laterality / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D019635:Neurosurgical Procedures / Q000379:methods*; D020534:Parahippocampal Gyrus / Q000601:surgery*; D012189:Retrospective Studies; D013702:Temporal Lobe / Q000601:surgery*; D014851:Wakefulness
keywords: Awake surgery; Cortical and subcortical mapping; Dominant posteromedial temporal lesions