title: Combined transcranial-orbital approach for resection of optic nerve gliomas:  a clinical and anatomical study.
abstract: OBJECTIVE
  To describe a combined transcranial-orbital approach for en bloc resection of optic nerve gliomas with preservation of the annulus of Zinn that minimizes recurrence and prevents postoperative paralytic ptosis.
  
  
  METHODS
  
  
  
  METHODS
  A retrospective, noncomparative, interventional case series.
  
  
  METHODS
  All patients who underwent optic nerve glioma resections using this technique with the authors between 1994 and 2010.
  
  
  METHODS
  A transcranial-orbital approach is used to resect the intracranial segment of the optic nerve glioma from 2 mm anterior to the chiasm to the posterior extent of annulus of Zinn. The proximal transected edge of the nerve is examined intraoperatively for tumor margin clearance. Through a superior orbitotomy exposure, the entire retrobulbar segment of the tumor is transected from the globe to the annulus of Zinn. A simulation of the procedure in a cadaver and en bloc resection of the orbital apex are performed to demonstrate the subdural plane of dissection within the annulus of Zinn.
  
  
  METHODS
  Postoperative outcome measures include: health of the ipsilateral globe, paralytic ptosis, postoperative complications, and tumor recurrence.
  
  
  RESULTS
  Eleven patients underwent resection of optic nerve gliomas using this technique. No patients had tumor recurrence or developed postoperative paralytic ptosis.
  
  
  CONCLUSIONS
  The combined transcranial-orbital approach with preservation of the annulus of Zinn is a safe and effective way to remove optic nerve gliomas and ensure tumor clearance while avoiding paralytic ptosis.
authors.affiliation: Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami, Miller School of Medicine, Miami, Florida 33136, USA.
authors.forename: Erin M
authors.initials: EM
authors.lastname: Shriver
authors.forename: John
authors.initials: J
authors.lastname: Ragheb
authors.forename: David T
authors.initials: DT
authors.lastname: Tse
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D003399:Craniotomy; D005260:Female; D006801:Humans; D007223:Infant; D008279:Magnetic Resonance Imaging; D008297:Male; D009364:Neoplasm Recurrence, Local; D013508:Ophthalmologic Surgical Procedures; D020339:Optic Nerve Glioma / Q000175:diagnosis / Q000601:surgery*; D019574:Optic Nerve Neoplasms / Q000175:diagnosis / Q000601:surgery*; D009915:Orbit / Q000601:surgery*; D011183:Postoperative Complications; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome; D014792:Visual Acuity / Q000502:physiology; D055815:Young Adult