Primary optic nerve sheath meningiomas: a follow-up study.

Area of Science:

• Ophthalmology
• Neurosurgery
• Oncology

Background:

• Optic nerve sheath meningiomas (ONSM) present complex management challenges.
• Current treatment options include surgery, radiotherapy, and observation, with no universally agreed-upon approach.

Purpose of the Study:

• To present a follow-up study on optic nerve sheath meningiomas.
• To evaluate treatment modalities based on a novel classification system for ONSMs.

Main Methods:

• Retrospective analysis of 90 patients with ONSM treated between 1991 and 2008.
• Patients received surgery only, radiation only, or a combination of both, with a small group under observation.
• Follow-up ranged from 6 to 220 months (median 45.8 months).

Main Results:

• A classification system was developed: Type 1 (intraorbital), Type 2 (intracanalicular/intrafissural), and Type 3 (intraorbital and intracranial).
• Tumor extension patterns included through the optic canal (Type 2a) and involvement of the chiasm or contralateral side (Type 3a/3b).
• Visual acuity was not significantly affected by surgery but worsened with longer preoperative symptoms and follow-up; radiotherapy improved or preserved vision in 20/23 cases.

Conclusions:

• Vision loss in ONSM is often a progressive, time-dependent process.
• Radiotherapy is recommended for intraorbital ONSMs.
• Surgery, including optic canal decompression and intracranial resection, is preferred for tumors with intracanalicular and intracranial extension.