title: The Extended Lateral Supraorbital Approach and Extradural Anterior Clinoidectomy Through a Frontopterio-Orbital Window: Technical Note and Pilot Surgical Series.
abstract: BACKGROUND
  Lateral approaches to treat anterior cranial fossa lesions have evolved since the first frontotemporal approach described by Dandy in 1918. We describe a less invasive approach to perform extradural anterior clinoidectomy through a lateral supraorbital (LSO) approach for anterior circulation aneurysms and anterolateral skull base lesions.
  
  
  METHODS
  The extended LSO approach involves performing a standard lateral supraorbital craniotomy followed by drilling of the sphenoid wing and lateral wall of the orbit through the frontal bony opening of the LSO approach, without any temporal extension of the craniotomy. This creates a frontopterio-orbital window exposing the periorbita; superior, medial, and anterior aspect of the temporal dura mater; and superior orbital fissure. After unroofing the superior orbital fissure, the meningo-orbital fold is cut, and the temporal dura mater is peeled from the lateral wall of the cavernous sinus to expose the anterior clinoid process allowing a standard opening of the optic canal and anterior clinoidectomy.
  
  
  RESULTS
  The extended LSO approach and extradural anterior clinoidectomy allowed access to 4 sphenoid wing/anterior clinoidal meningiomas, 5 anterior circulation aneurysms, 2 temporomesial lesions, and 1 orbital/cavernous sinus abscess. Postoperatively, 2 patients had transient hemiparesis, 2 patients had transient third nerve palsy, and 1 patient had minimal visual field deterioration. All patients had a modified Rankin Scale score ≤1 at 8-week follow-up.
  
  
  CONCLUSIONS
  The extended LSO approach opens a new route (frontopterio-orbital window) to perform extradural anterior clinoidectomy safely and increases surgical exposure, angles, and operability of a less invasive keyhole craniotomy (LSO approach) to treat anterior cranial fossa lesions.
authors.affiliation: Division of Neurosurgery, Department of Surgery, Toronto Western Hospital, University Health Network, Toronto, Ontario, Canada; Department of Surgery, University of Toronto, Toronto, Ontario, Canada; Department of Neurosurgery, Helsinki University Hospital, Helsinki, Finland. Electronic address: hugoandrade2@yahoo.es.
authors.forename: Hugo
authors.initials: H
authors.lastname: Andrade-Barazarte
authors.affiliation: Division of Neurosurgery, Geneva University Hospitals and University of Geneva, Geneva, Switzerland.
authors.forename: Max
authors.initials: M
authors.lastname: Jägersberg
authors.affiliation: Division of Neurosurgery, Department of Surgery, Toronto Western Hospital, University Health Network, Toronto, Ontario, Canada; Department of Surgery, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Sirajeddin
authors.initials: S
authors.lastname: Belkhair
authors.affiliation: Division of Neurosurgery, Department of Surgery, Toronto Western Hospital, University Health Network, Toronto, Ontario, Canada; Department of Surgery, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Rachel
authors.initials: R
authors.lastname: Tymianski
authors.affiliation: Division of Neurosurgery, Department of Surgery, Toronto Western Hospital, University Health Network, Toronto, Ontario, Canada; Department of Surgery, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Mazda K
authors.initials: MK
authors.lastname: Turel
authors.affiliation: Division of Neurosurgery, Geneva University Hospitals and University of Geneva, Geneva, Switzerland.
authors.forename: Karl
authors.initials: K
authors.lastname: Schaller
authors.affiliation: Department of Neurosurgery, Helsinki University Hospital, Helsinki, Finland.
authors.forename: Juha A
authors.initials: JA
authors.lastname: Hernesniemi
authors.affiliation: Division of Neurosurgery, Department of Surgery, Toronto Western Hospital, University Health Network, Toronto, Ontario, Canada; Department of Surgery, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Michael
authors.initials: M
authors.lastname: Tymianski
authors.affiliation: Division of Neurosurgery, Department of Surgery, Toronto Western Hospital, University Health Network, Toronto, Ontario, Canada; Department of Surgery, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Ivan
authors.initials: I
authors.lastname: Radovanovic
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001254:Astrocytoma / Q000000981:diagnostic imaging / Q000601:surgery; D001932:Brain Neoplasms / Q000000981:diagnostic imaging / Q000601:surgery; D035262:Cranial Fossa, Anterior / Q000000981:diagnostic imaging / Q000601:surgery*; D003399:Craniotomy / Q000379:methods*; D005260:Female; D006801:Humans; D002532:Intracranial Aneurysm / Q000000981:diagnostic imaging / Q000601:surgery; D008297:Male; D008579:Meningioma / Q000000981:diagnostic imaging / Q000601:surgery; D008875:Middle Aged; D010865:Pilot Projects; D012189:Retrospective Studies; D013345:Subarachnoid Hemorrhage / Q000000981:diagnostic imaging / Q000601:surgery; D055815:Young Adult
keywords: Anterior cranial fossa; Extradural anterior clinoidectomy; Intracranial aneurysm; Lateral supraorbital approach; Tumor