title: Lateral transzygomatic middle fossa approach and its extensions: surgical technique and 3D anatomy.
abstract: BACKGROUND
  Various approaches to lesions involving the middle fossa and cavernous sinus (CS), with and without posterior fossa extension have been described. In the present study, we describe the surgical technique for the extradural lateral tranzygomatic middle fossa approach and its extensions, highlight relevant 3D anatomy.
  
  
  METHODS
  Simulations of the lateral transzygomatic middle fossa approach and its extensions were performed in four silicon-injected formalin fixed cadaveric heads. The step-by-step description and relevant anatomy was documented with 3D photographs.
  
  
  RESULTS
  The lateral transzygomatic middle fossa approach is particularly useful for lesions involving the middle fossa with and without CS invasion, extending to the posterior fossa and involving the clinoidal region. This approach incorporates direct lateral positioning of patient, frontotemporal craniotomy with zygomatic arch osteotomy, extradural elevation of the temporal lobe, and delamination of the outer layer of the lateral CS wall. Extradural drilling of the sphenoid wing and anterior clinoid process allows entry into the CS through the superior wall and exposure of the clinoidal segment of the ICA. Posteriorly, drilling the petrous apex allows exposure of the ventral brainstem from trigeminal to facial nerve and can be extended to the interpeduncular fossa by division of the superior petrosal sinus.
  
  
  CONCLUSIONS
  The present study illustrates 3D anatomical relationships of the lateral transzygomatic middle fossa approach with its extensions. This approach allows wide access to different topographic areas (clinoidal region and clinoidal ICA, the entire CS, and the posterior fossa from the interpeduncular fossa to the facial nerve) via a lateral trajectory. Precise knowledge of technique and anatomy is necessary to properly execute this approach.
authors.affiliation: Dardinger Skull Base Laboratory, Department of Neurological Surgery, Ohio State University Medical Center, Columbus, USA.
authors.forename: Silky
authors.initials: S
authors.lastname: Chotai
authors.affiliation: Dardinger Skull Base Laboratory, Department of Neurological Surgery, Ohio State University Medical Center, Columbus, USA; Department of Neurological Surgery, Cleveland Clinic, Cleveland, USA.
authors.forename: Varun R
authors.initials: VR
authors.lastname: Kshettry
authors.affiliation: Dardinger Skull Base Laboratory, Department of Neurological Surgery, Ohio State University Medical Center, Columbus, USA.
authors.forename: Alex
authors.initials: A
authors.lastname: Petrak
authors.affiliation: Dardinger Skull Base Laboratory, Department of Neurological Surgery, Ohio State University Medical Center, Columbus, USA. Electronic address: Mario.Ammirati@osumc.edu.
authors.forename: Mario
authors.initials: M
authors.lastname: Ammirati
mesh_terms: D002102:Cadaver; D002426:Cavernous Sinus / Q000033:anatomy & histology*; D035301:Cranial Fossa, Middle / Q000033:anatomy & histology* / Q000601:surgery; D003399:Craniotomy / Q000379:methods; D005154:Facial Nerve / Q000033:anatomy & histology / Q000601:surgery; D006801:Humans; D009915:Orbit / Q000033:anatomy & histology* / Q000601:surgery; D015050:Zygoma / Q000033:anatomy & histology* / Q000601:surgery
keywords: Middle fossa; Neurosurgery; Transzygomatic