title: Surgical anatomy of anterior and retrofacial approaches to sinus tympani.
abstract: OBJECTIVE
  To define anatomic parameters indicating or limiting the use of anterior and retrofacial accesses to sinus tympani (ST).
  
  
  METHODS
  Anatomic study (30 temporal bones).
  
  
  METHODS
  The profundity of the ST, the distance between the sigmoid sinus and facial nerve (SS-F), the distance from posterior semicircular canal to the facial nerve, and the capacity of adequate visualization of the ST.
  
  
  RESULTS
  Sinus tympani depth was significantly smaller (<or=0.83 mm) when visualization was possible by anterior approach. Measurements of SS-F greater than 10 mm and ST profundity greater than 1 mm indicated accessibility of posterior approach.
  
  
  CONCLUSIONS
  Posterior extension of ST and the relation SS-F were the most important measures when the surgical accessibility of the ST was envisaged. Sinus tympani can be accessed through an anterior approach when the depth is less than 1 mm or by means of a posterior access when profundity is 1 mm or greater and the relation of SS-F is 10 mm or greater.
authors.affiliation: Federal University of São Paulo (UNIFESP), Brazil.
authors.forename: Carlos Eduardo
authors.initials: CE
authors.lastname: Cesário de Abreu
authors.forename: Oswaldo Laércio
authors.initials: OL
authors.lastname: Mendonça Cruz
mesh_terms: D005154:Facial Nerve / Q000033:anatomy & histology*; D006801:Humans; D013506:Otologic Surgical Procedures / Q000379:methods*; D012665:Semicircular Canals / Q000033:anatomy & histology / Q000601:surgery; D013701:Temporal Bone / Q000033:anatomy & histology / Q000601:surgery*; D014432:Tympanic Membrane / Q000033:anatomy & histology* / Q000601:surgery*