Comparative Analysis of Endoscopic Transorbital Approach and Extended Minipterional Approach for Sphenoid Wing Meningiomas with Osseous Involvement: Preliminary Surgical Results

Objective: Sphenoid wing meningiomas (SWMs) with osseous involvement are slow-growing benign tumors that can be cured with complete surgical resection. The majority of symptoms arise from adjacent hyperostosis and recurrences occur from inadequate resection of sphenoid bone infiltration. Sufficient resection of these tumors requires extensive surgical exposure, but recent endoscopic transorbital approach (ETOA) offers one of minimally invasive alternatives. The authors assess the feasibility of ETOA and compare the surgical outcome of ETOA and extended minipterional approach (eMPTA) for SWMs with osseous involvement.

Methods: From October 2015 to May 2019, a total of 24 patients underwent surgery for SWMs with osseous involvement. Among them, tumor resection was performed by ETOA for 11 patients (45.8%) and eMPTA for 13 patients (54.2%). The tumor characteristics, extent of resection, surgical outcome, and morbidity, and approach-related aesthetic outcome were analyzed and compared retrospectively between ETOA and eMPTA based on SWM classification.

Results: The location of SWMs was middle sphenoid ridge (group III) for 15 patients (45.8%), lateral or greater sphenoid wing (group IV) for 7 patients (29.2%), medial or lesser sphenoid wing (group I) for 3 patients (12.5%), and medial with cavernous sinus (CS) infiltration (group II) for 3 patients (12.5%). Gross total resection was achieved in 9 of 11 patients (81.8%) with ETOA and 11 of 13 patients (84.6%) with eMPTA. There were no differences in tumor classification, histology, size, consistency, peritumoral edema, and adhesion, CS lateral wall invasion, and internal carotid artery displacement between the two approaches. Surgery time, surgical bleeding, and hospital length of stay were significantly shorter with ETOA. Three patients had newly developed symptoms, such as diplopia (n = 1), ptosis (n = 1), and cerebrospinal fluid leak (n = 1) after ETOA, with full recovery later. There were two patients with vasospasm (n = 1) and ptosis (n = 1) after eMPTA. No differences could be seen in surgical morbidities between ETOA and eMPTA.

Conclusion: The preliminary surgical results suggest that ETOA can be a reasonable alternative to eMPTA for SWMs with osseous involvement. ETOA provides direct access to the sphenoid bone and resectability with a more rapid and minimally invasive exposure than eMPTA. Maximal subtotal resection with extensive sphenoid bone decompression for tumors with CS infiltration is the key to a good clinical outcome, regardless of the surgical approach.