Transnasal Endoscopic Optic Decompression as the Initial Management of Primary Optic Nerve Sheath Meningiomas

Background The management of optic nerve sheath meningiomas (ONSMs) in patients with signs of optic nerve compression remains a matter of controversy. Stereotactic radiotherapy is currently the modality of choice in the management of these tumors. Surgical decompressions through traditional techniques that involve even minor tumor resection have been associated with a risk of significant morbidity. Transnasal endoscopic optic nerve decompression (EOND) offers a direct route to the orbit and orbital apex, providing a minimally invasive alternative to traditional decompressive paradigms. Herein, we present our experience with EOND in the management of primary ONSMs.

Objective To assess the efficacy of EOND as the initial management of symptomatic patients with primary ONSM.

Methods Patients with ONSMs without a history of radiotherapy who underwent EOND were retrospectively reviewed. Postoperative imaging, duration of follow-up, and visual outcomes (i.e., visual acuity and visual field) obtained at the last ophthalmology visit were assessed.

Results Four women ranging in age from 25 to 63 years (mean = 40) with ONSMs and treated with EOND were identified. All patients displayed subjective and objective baseline signs of vision loss. In addition, baseline proptosis, diplopia, optic nerve atrophy, and ocular pain were identified, if present. In none of the cases, the optic nerve sheath was breached, and following EOND, all patients deferred treatment with adjuvant radiotherapy.

At a mean postoperative follow-up of 14 months, all patients were clinically stable without evidence of disease progression on imaging and physical examination. At last ophthalmologic visit, three of four patients (75%) showed objective improvements from baseline visual acuity and visual field. The remaining patient had presented with baseline signs of optic nerve atrophy. Significant improvements from baseline proptosis and diplopia were confirmed in one of two patients (50%) and one of two (50%) patients, respectively. Flattening of the ipsilateral medial rectus muscle was identified intraoperatively in a single patient who showed no improvement from baseline diplopia. Resolution of ocular pain occurred in four out of four patients (100%). A reduction of postoperative tumor volume was confirmed in one of four patients, while tumor size remained stable in the remaining cases (75%).

Conclusion These results suggest that EOND is a viable minimally invasive alternative to traditional paradigms in the treatment of carefully selected cases of ONSMs. EOND allows for early stabilization of symptoms and the potential improvement of compressive neuropathy signs. Further studies are warranted to determine its long-term efficacy and its role in a stepwise progression of management.