Combined transcranial-orbital approach for resection of optic nerve gliomas: A clinical and anatomical study

Abstract

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. Methods: 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.© 2012 The American Society of Ophthalmic Plastic and Reconstructive Surgery, Inc.