title: Fluid structure interaction analysis reveals facial nerve palsy caused by vertebral-posterior inferior cerebellar artery aneurysm.
abstract: Cranial nerve palsy caused by aneurysmal compression has not been fully evaluated. The main causes of symptoms are considered to be direct mechanical compression and aneurysm pulsations. Recent studies indicate that nerve dysfunction is mainly induced by pulsation rather than by direct compression, and successful cases of endovascular surgery have been reported. We describe a patient with an unruptured vertebral artery-posterior inferior cerebellar artery (VA-PICA) aneurysm compressing the facial nerve at the root exit zone (REZ). The patient presented with peripheral facial nerve palsy but not hemifacial spasm and was successfully treated by coil embolization. To investigate the mechanisms underlying peripheral facial nerve palsy, fluid structure interaction (FSI) analysis can approximate displacement and the magnitude of aneurysmal wall motion due to hemodynamic forces. In our case, maximum mesh displacement was observed at the aneurysmal wall attached to the facial nerve inside the pons rather than the REZ, which explains the clinical manifestation of facial nerve palsy in the absence of hemifacial spasm. This preliminary report demonstrates the utility of FSI analysis for investigating cranial nerve neuropathy.
authors.affiliation: Department of Neurosurgery, The Jikei University School of Medicine, 3-25-8 Nishi-Shinbashi, Minato-ku, Tokyo 105-8461, Japan; Department of Neurosurgery, Brain Research Institute, Niigata University, 757 Asahimachi-dori 1, Chuo-ku, Niigata 951-8585, Japan. Electronic address: t.suzuki2078@gmail.com.
authors.forename: Tomoaki
authors.initials: T
authors.lastname: Suzuki
authors.affiliation: Department of Neurosurgery, The Jikei University School of Medicine, 3-25-8 Nishi-Shinbashi, Minato-ku, Tokyo 105-8461, Japan; Graduate School of Mechanical Engineering, Tokyo University of Science, 6-3-1 Niijuku, Katsushika-ku, Tokyo 125-8585, Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Takao
authors.affiliation: Graduate School of Mechanical Engineering, Tokyo University of Science, 6-3-1 Niijuku, Katsushika-ku, Tokyo 125-8585, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Suzuki
authors.affiliation: Department of Neurosurgery, The Jikei University School of Medicine, 3-25-8 Nishi-Shinbashi, Minato-ku, Tokyo 105-8461, Japan.
authors.forename: Yukinao
authors.initials: Y
authors.lastname: Kambayashi
authors.affiliation: Department of Neurosurgery, The Jikei University School of Medicine, 3-25-8 Nishi-Shinbashi, Minato-ku, Tokyo 105-8461, Japan.
authors.forename: Mitsuyoshi
authors.initials: M
authors.lastname: Watanabe
authors.affiliation: Graduate School of Mechanical Engineering, Tokyo University of Science, 6-3-1 Niijuku, Katsushika-ku, Tokyo 125-8585, Japan.
authors.forename: Sho
authors.initials: S
authors.lastname: Shinohara
authors.affiliation: Department of Neurosurgery, Brain Research Institute, Niigata University, 757 Asahimachi-dori 1, Chuo-ku, Niigata 951-8585, Japan.
authors.forename: Hidemoto
authors.initials: H
authors.lastname: Fujiwara
authors.affiliation: Department of Neurosurgery, Kuwana Hospital, 140 Koudokou, Higashi-ku, Niigata 950-0023, Japan.
authors.forename: Shinji
authors.initials: S
authors.lastname: Nakazato
authors.affiliation: Department of Neurosurgery, Kuwana Hospital, 140 Koudokou, Higashi-ku, Niigata 950-0023, Japan.
authors.forename: Masato
authors.initials: M
authors.lastname: Watanabe
authors.affiliation: Department of Neurosurgery, The Jikei University School of Medicine, 3-25-8 Nishi-Shinbashi, Minato-ku, Tokyo 105-8461, Japan; Siemens Japan K.K., Gate City Osaki West Tower 1-11-1, Osaki, Shinagawa-ku, Tokyo 141-8644, Japan.
authors.forename: Chiheb
authors.initials: C
authors.lastname: Dahmani
authors.affiliation: Department of Mechanical Engineering, Tokyo University of Science, 6-3-1 Niijuku, Katsushika-ku, Tokyo 125-8585, Japan.
authors.forename: Makoto
authors.initials: M
authors.lastname: Yamamoto
authors.affiliation: Department of Neurosurgery, Brain Research Institute, Niigata University, 757 Asahimachi-dori 1, Chuo-ku, Niigata 951-8585, Japan.
authors.forename: Yukihiko
authors.initials: Y
authors.lastname: Fujii
authors.affiliation: Department of Neurosurgery, The Jikei University School of Medicine, 3-25-8 Nishi-Shinbashi, Minato-ku, Tokyo 105-8461, Japan.
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Murayama
mesh_terms: D000465:Algorithms; D002536:Cerebral Arteries / Q000503:physiopathology*; D005154:Facial Nerve / Q000473:pathology*; D005260:Female; D019569:Hemifacial Spasm / Q000175:diagnosis* / Q000503:physiopathology; D006439:Hemodynamics; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D002532:Intracranial Aneurysm / Q000175:diagnosis* / Q000503:physiopathology; D018810:Magnetic Resonance Angiography; D008279:Magnetic Resonance Imaging; D008875:Middle Aged; D008962:Models, Theoretical; D009038:Motion; D020769:Posterior Cerebral Artery / Q000503:physiopathology; D012984:Software; D014711:Vertebral Artery / Q000473:pathology
keywords: Cerebral aneurysm; Coil embolization; Cranial nerve palsy; Facial nerve; Fluid structure interaction analysis; Vertebral artery