title: Microsurgical Approaches to the Ambient Cistern Region: An Anatomic and Qualitative Study.
abstract: OBJECTIVE
  We used microscopy to conduct qualitative and quantitative analysis of 4 surgical approaches commonly used in the surgery of the ambient cistern: infratentorial supracerebellar (SC), occipital interhemispheric, subtemporal (ST), and transchoroidal (TC). In addition, we performed a parahippocampal gyrus resection in the ST context.
  
  
  METHODS
  Each approach was performed in 3 cadaveric heads (6 sides). After the microscopic anatomic dissection, the parahippocampal gyrus was resected through an ST approach. The qualitative analysis was based on anatomic observation and the quantitative analysis was based on the linear exposure of vascular structures and the area of exposure of the ambient cistern region.
  
  
  RESULTS
  The ST approach provided good exposure of the inferior portion of the cistern and of the proximal segments of the posterior cerebral artery. After the resection of the parahippocampal gyrus, the area of exposure improved in all components, especially the superior area. A TC approach provided the best exposure of the superior area compared with the other approaches. The posterolateral approaches (SC/occipital interhemispheric) to the ambient cistern region provided similar exposure of anatomic structures. There was a significant difference (P < 0.05) in linear exposure of the posterior cerebral artery when comparing the ST/TC and ST/SC approaches.
  
  
  CONCLUSIONS
  This study has demonstrated that surgical approaches expose dissimilarly the different regions of the ambient cistern and an approach should be selected based on the specific need of anatomic exposure.
authors.affiliation: Department of Neurology, Discipline of Neurosurgery, University of São Paulo Medical School (FMUSP), São Paulo, Brazil.
authors.forename: Eberval Gadelha
authors.initials: EG
authors.lastname: Figueiredo
authors.affiliation: Department of Neurology, Discipline of Neurosurgery, University of São Paulo Medical School (FMUSP), São Paulo, Brazil.
authors.forename: André
authors.initials: A
authors.lastname: Beer-Furlan
authors.affiliation: Department of Medicine, Discipline of Neurosurgery, State University of Ponta Grossa, Ponta Grossa, Brazil. Electronic address: leonardowelling@yahoo.com.br.
authors.forename: Leonardo C
authors.initials: LC
authors.lastname: Welling
authors.affiliation: Department of Neurology, Discipline of Neurosurgery, University of São Paulo Medical School (FMUSP), São Paulo, Brazil.
authors.forename: Eduardo C
authors.initials: EC
authors.lastname: Ribas
authors.affiliation: Department of Medicine, Discipline of Neurosurgery, State University of Ponta Grossa, Ponta Grossa, Brazil.
authors.forename: Marcelo
authors.initials: M
authors.lastname: Schafranski
authors.affiliation: Department of Neurosurgery, Barrow Neurological Institute, Phoenix, Arizona, USA.
authors.forename: Neil
authors.initials: N
authors.lastname: Crawford
authors.affiliation: Department of Neurology, Discipline of Neurosurgery, University of São Paulo Medical School (FMUSP), São Paulo, Brazil.
authors.forename: Manoel J
authors.initials: MJ
authors.lastname: Teixeira
authors.affiliation: Department of Neurosurgery, University of Florida, Gainesville, Florida, USA.
authors.forename: Albert L
authors.initials: AL
authors.lastname: Rhoton
authors.affiliation: Department of Neurosurgery, Barrow Neurological Institute, Phoenix, Arizona, USA.
authors.forename: Robert F
authors.initials: RF
authors.lastname: Spetzler
authors.affiliation: Department of Neurosurgery, Barrow Neurological Institute, Phoenix, Arizona, USA.
authors.forename: Mark C
authors.initials: MC
authors.lastname: Preul
mesh_terms: D001099:Arachnoid / Q000033:anatomy & histology / Q000601:surgery; D002102:Cadaver; D002550:Cerebral Veins / Q000033:anatomy & histology / Q000601:surgery; D006801:Humans; D008636:Mesencephalon / Q000033:anatomy & histology* / Q000601:surgery*; D008866:Microsurgery / Q000379:methods*; D019635:Neurosurgical Procedures / Q000379:methods*; D020534:Parahippocampal Gyrus / Q000033:anatomy & histology / Q000601:surgery; D020769:Posterior Cerebral Artery / Q000033:anatomy & histology / Q000601:surgery; D013346:Subarachnoid Space / Q000601:surgery
keywords: Ambient cistern; Anatomy; Approach; Microneurosurgery; Microsurgery; Surgical Approaches