title: Extended Endoscopic Endonasal Approach to the Third Ventricle: Multimodal Anatomical Study with Surgical Implications.
abstract: BACKGROUND
  A certain interest for the extended endoscopic endonasal approach for the management of sellar-suprasellar lesions extending inside the third ventricle has been growing in recent years. The aim of this anatomical study was to evaluate the possibilities in terms of exposure and access to the different areas of the third ventricle, with the endoscopic endonasal technique, as compared with the microscopic or endoscopic view provided via different transcranial approaches. The advantages and limitations of both surgical pathways were analyzed.
  
  
  METHODS
  Ten human cadaver heads were dissected. In order to standardize the comparison between the endonasal and the transcranial routes, the third ventricle cavity has been divided into four areas by means of two ideal planes, one passing through the optic chiasm and the interthalamic commissure and one passing through the posterior edge of the foramen of Monro and the interthalamic commissure. Accordingly, two anterior (infundibular and foraminal) and two posterior (mesencephalic and tectal) areas have been defined.
  
  
  RESULTS
  The endoscopic endonasal approach allows for exploration and surgical maneuverability, especially in the anterior areas of the third ventricle. In the infundibular and foraminal areas the surgical maneuverability seems to be better as compared with that obtained inside the mesencephalic region, while via the endonasal route the tectal area could not be reached. In particular, the infundibular area can be explored either passing through the lamina terminalis or via the tuber cinereum; this latter trajectory enables visualization of the foramina of Monro and the floor of the third ventricle up to the pineal recess.
  
  
  CONCLUSIONS
  This anatomical study shows that the lamina terminalis and, above all, the tuber cinereum represent two safe entry points defining possible surgical corridors to be considered for the extended endoscopic endonasal approach to the third ventricle.
authors.affiliation: Division of Neurosurgery, Department of Neurosciences, Reproductive and Odontostomatological Sciences, Università degli Studi di Napoli Federico II, Naples, Italy. Electronic address: lcavallo@unina.it.
authors.forename: Luigi Maria
authors.initials: LM
authors.lastname: Cavallo
authors.affiliation: Division of Neurosurgery, Department of Neurosciences, Reproductive and Odontostomatological Sciences, Università degli Studi di Napoli Federico II, Naples, Italy.
authors.forename: Alberto
authors.initials: A
authors.lastname: Di Somma
authors.affiliation: Department of Neuroscience, G. Rummo Hospital, Neurosurgery Operative Unit, Benevento, Italy.
authors.forename: Matteo
authors.initials: M
authors.lastname: de Notaris
authors.affiliation: Laboratory of Surgical Neuroanatomy (LSNA), Faculty of Medicine, Universitat de Barcelona, Barcelona, Spain.
authors.forename: Alberto
authors.initials: A
authors.lastname: Prats-Galino
authors.affiliation: Department of Neurosurgery, Emsey Hospital, Pendik, Istanbul, Turkey.
authors.forename: Salih
authors.initials: S
authors.lastname: Aydin
authors.affiliation: Department of Neuroscience, G. Rummo Hospital, Neurosurgery Operative Unit, Benevento, Italy.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Catapano
authors.affiliation: Division of Neurosurgery, Department of Neurosciences, Reproductive and Odontostomatological Sciences, Università degli Studi di Napoli Federico II, Naples, Italy.
authors.forename: Domenico
authors.initials: D
authors.lastname: Solari
authors.affiliation: Division of Neurosurgery, Department of Neurosciences, Reproductive and Odontostomatological Sciences, Università degli Studi di Napoli Federico II, Naples, Italy.
authors.forename: Oreste
authors.initials: O
authors.lastname: de Divitiis
authors.affiliation: Division of Neurosurgery, Department of Neurosciences, Reproductive and Odontostomatological Sciences, Università degli Studi di Napoli Federico II, Naples, Italy.
authors.forename: Teresa
authors.initials: T
authors.lastname: Somma
authors.affiliation: Division of Neurosurgery, Department of Neurosciences, Reproductive and Odontostomatological Sciences, Università degli Studi di Napoli Federico II, Naples, Italy.
authors.forename: Paolo
authors.initials: P
authors.lastname: Cappabianca
mesh_terms: D002102:Cadaver; D004210:Dissection; D006801:Humans; D008866:Microsurgery; D009296:Nasal Cavity; D057605:Natural Orifice Endoscopic Surgery; D044583:Neuroendoscopy / Q000379:methods*; D020542:Third Ventricle / Q000473:pathology* / Q000601:surgery*
keywords: Craniopharyngiomas; Endoscopic transsphenoidal surgery; Extended endoscopic endonasal approach; Lamina terminalis; Neuroendoscopy; Third ventricle; Third ventricle anatomy