title: Endoscopic endonasal anatomy and approaches to the anterior skull base: a neurosurgeon's viewpoint.
abstract: OBJECTIVE
  The objective of this study was to review the endoscopic anatomy of the anterior skull base, defining the pitfalls of endoscopic endonasal approaches to this region. Recently, these approaches are gaining popularity among neurosurgeons, and the details of the endoscopic anatomy and approaches are highlighted from the neurosurgeons' point of view, correlated with demonstrative cases.
  
  
  METHODS
  Twelve fresh adult cadavers were studied (n = 12). We used Karl Storz 0 and 30 degrees, 4 mm, 18- and 30-cm rod lens rigid endoscope in our dissections. After preparation of the cadaveric specimens, we approached the anterior skull base by the extended endoscopic endonasal approach.
  
  
  RESULTS
  After resection of the superior portion of the nasal septum, bilateral middle and superior turbinates, and bilateral anterior and posterior ethmoidal cells, we could obtain full exposure of the anterior skull base. The distance between optic canal and the posterior ethmoidal artery ranged from 8 to 16 mm (mean, 11.08 mm), and the distance between posterior ethmoidal artery and the anterior ethmoidal artery ranged from 10 to 17 mm (mean, 13 mm). After resecting the anterior skull base bony structure and the dura between the 2 medial orbital walls, we could visualize the olfactory nerves, interhemispheric sulcus, and gyri recti. With dissecting the interhemispheric sulcus, we could expose the first (A1) and second (A2) segments of the anterior cerebral artery, anterior communicating artery, and Heubner arteries.
  
  
  CONCLUSIONS
  This study showed that extended endoscopic endonasal approaches are sufficient in providing wide exposure of the bony structures, and the extradural and intradural components of the anterior skull base and the neighboring structures providing more controlled manipulation of pathologic lesions. These approaches need specific skill and learning curve to achieve more minimally invasive interventions and less postoperative complications.
authors.affiliation: Department of Neurosurgery, Cerrahpasa Medical Faculty, Istanbul University, Istanbul, Turkey.
authors.forename: Bashar
authors.initials: B
authors.lastname: Abuzayed
authors.forename: Necmettin
authors.initials: N
authors.lastname: Tanriover
authors.forename: Nurperi
authors.initials: N
authors.lastname: Gazioglu
authors.forename: Galip Zihni
authors.initials: GZ
authors.lastname: Sanus
authors.forename: Fatma
authors.initials: F
authors.lastname: Ozlen
authors.forename: Huseyin
authors.initials: H
authors.lastname: Biceroglu
authors.forename: Ali Metin
authors.initials: AM
authors.lastname: Kafadar
authors.forename: Berna Senel
authors.initials: BS
authors.lastname: Eraslan
authors.forename: Ziya
authors.initials: Z
authors.lastname: Akar
mesh_terms: D000328:Adult; D020771:Anterior Cerebral Artery / Q000033:anatomy & histology; D001158:Arteries / Q000033:anatomy & histology; D002102:Cadaver; D002559:Cerebrospinal Fluid Rhinorrhea / Q000601:surgery; D054022:Cerebrum / Q000033:anatomy & histology; D002941:Circle of Willis / Q000033:anatomy & histology; D004210:Dissection / Q000295:instrumentation / Q000379:methods; D004388:Dura Mater / Q000601:surgery; D019723:Endoscopes; D004724:Endoscopy / Q000379:methods*; D005004:Ethmoid Bone / Q000098:blood supply / Q000601:surgery; D005260:Female; D015718:Fibrin Tissue Adhesive / Q000627:therapeutic use; D005500:Follow-Up Studies; D005625:Frontal Lobe / Q000033:anatomy & histology; D006801:Humans; D008297:Male; D008875:Middle Aged; D009300:Nasal Septum / Q000601:surgery; D019635:Neurosurgical Procedures / Q000379:methods*; D009832:Olfactory Nerve / Q000033:anatomy & histology; D009915:Orbit / Q000601:surgery; D019651:Plastic Surgery Procedures / Q000379:methods; D019291:Skull Base / Q000033:anatomy & histology / Q000601:surgery*; D014014:Tissue Adhesives / Q000627:therapeutic use; D014420:Turbinates / Q000601:surgery
chemical_list: D015718:Fibrin Tissue Adhesive; D014014:Tissue Adhesives