Resectability of spheno-orbital meningiomas: surgical outcome in 93 cases and a proposed clinically relevant anatomical classification

OBJECTIVE Resection is the foundation of spheno-orbital meningioma (SOM) treatment, but the confluence of critical neurovascular structures traversing the cranium and orbit and the unforgiving nature of orbital injury make resection of the tumor’s orbital components challenging. Large series detailing surgical outcomes are rarely reported, and a surgical framework is needed. This study examined the feasibility of resection of SOMs with an involved orbit. The authors classified SOMs based on the relative orbital involvement to determine tumor resectability, with the goals of improving proptosis and functional visual outcome and avoiding new deficit. METHODS A retrospective chart review identified patients with surgically treated SOMs with a minimum 1-year follow-up at an academic center from 2002 to 2023. Imaging and clinical presentations and outcomes are reported, and a clinically relevant grading system is proposed based on imaging findings of orbital hyperostosis (grade 1), periorbital involvement (grade 2), intraorbital involvement without (grade 3a) or with (grade 3b) rectus muscle invasion, or involvement of the orbital apex or optic nerve (grade 4). RESULTS Among 93 included patients (71% female), the mean age at surgery was 54.8 years. The most common presentations were proptosis (74.2%), visual decline (57.0%), and cranial neuropathies (30.1%). Gross-total resection of the orbital contents was achieved in 88.5%, 50.0%, 16.7%, and 24.1% of grade 1–4 tumors, respectively; it was less likely in grade 3 or 4 tumors (OR 0.06, 95% CI 0.019–0.190; p < 0.001), unless it was for oncological removal in a patient with no functional vision. Resection led to stable or improved vision in most patients across all grades (96.2%, 100%, 83.3%, and 93.1% in grade 1–4 tumors, respectively). Proptosis was less pronounced in grade 1 tumors, and the degree of proptosis was statistically more likely to improve with pronounced proptosis in higher-grade tumors (Δexophthalmos index 0.04, 0.14, 0.11, and 0.15 in grade 1–4 tumors, respectively). Overall surgical, visual, and ophthalmological morbidities were similar across all grades, and there were no deaths. CONCLUSIONS This study introduces a grading system for SOMs and validates its utility through the assessment of surgical outcomes of a large patient cohort. This grading system allows for a better understanding of visual risks associated with surgery and facilitates comparisons across clinical studies. This may guide clinical management discussions and future research of this complex pathology.