PURPOSE: 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.
DESIGN: A retrospective, noncomparative, interventional case series.
STUDY POPULATION: All patients who underwent optic nerve glioma resections using 
this technique with the authors between 1994 and 2010.
PROCEDURE: 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.
MAIN OUTCOME MEASURES: 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.