title: Classification of sphenoid sinus pneumatization: relevance for endoscopic skull base surgery.
abstract: OBJECTIVE
  The goal of this study was to present a classification based on the degree of pneumatization of the sphenoid sinus in the coronal plane that can be used to instruct preoperative planning for endoscopic endonasal surgery (EES).
  
  
  METHODS
  Observational anatomical study.
  
  
  METHODS
  The geometry of sphenoid sinus pneumatization was characterized (n = 204 hemisinus) on high-resolution computed tomography scans, and its associations with the location of the foramen rotundum (FR) and the vidian canal (VC) were measured. Based on these findings, we propose a simple classification of pneumatization of the sphenoid sinus relevant for EES.
  
  
  RESULTS
  The lateral recess of the sphenoid sinus was pneumatized lateral to the FR in the coronal plane in 54% of patients. The distance separating the FR and the VC correlated strongly with the depth of the lateral recess. Based on these findings, we propose three types of pneumatization: type I, where the pneumatization extends from the midline to the medial edge of the VC (25%); type II, where the pneumatization reaches the medial edge of the FR (39%); and type III, where the pneumatization extends beyond the medial border of the FR (37%).
  
  
  CONCLUSIONS
  The proposed sphenoid sinus pneumatization classification in the coronal plane is simple and reproducible. It predicts the distance between vidian and maxillary nerve, determines the size of the surgical window to access the middle cranial fossa transnasally, and instructs on the potential risk to neurovascular structures during surgery.
authors.affiliation: Department of Otolaryngology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, U.S.A.
authors.forename: Alec
authors.initials: A
authors.lastname: Vaezi
authors.forename: Eugenio
authors.initials: E
authors.lastname: Cardenas
authors.forename: Carlos
authors.initials: C
authors.lastname: Pinheiro-Neto
authors.forename: Alessandro
authors.initials: A
authors.lastname: Paluzzi
authors.forename: Barton F
authors.initials: BF
authors.lastname: Branstetter
authors.forename: Paul A
authors.initials: PA
authors.lastname: Gardner
authors.forename: Carl H
authors.initials: CH
authors.lastname: Snyderman
authors.forename: Juan C
authors.initials: JC
authors.lastname: Fernandez-Miranda
mesh_terms: D002102:Cadaver; D035301:Cranial Fossa, Middle / Q000000981:diagnostic imaging; D004724:Endoscopy / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D019291:Skull Base / Q000000981:diagnostic imaging* / Q000601:surgery; D013101:Sphenoid Sinus / Q000000981:diagnostic imaging* / Q000601:surgery; D015524:Sphenoid Sinusitis / Q000145:classification* / Q000000981:diagnostic imaging / Q000601:surgery; D014057:Tomography, X-Ray Computed
keywords: Endoscopic endonasal approach; foramen rotundum; middle cranial fossa; pneumatization; radiological classification; sphenoid sinus; vidian canal; vidian nerve