Extreme Lateral Supracerebellar Infratentorial Approach for Petroclival Meningioma with an Ophthalmic Artery Originating from the Middle Meningeal Artery: Illustrative Case

Petroclival meningiomas are traditionally resected via the combined transpetrosal approach. However, rare anatomical variants, such as the ophthalmic artery originating from the middle meningeal artery, preclude the combined transpetrosal approach due to the risk of permanent blindness from middle meningeal artery sacrifice. We present a 46-year-old woman with a left petroclival meningioma (Upper Clivus type) and trigeminal neuralgia, in whom preoperative angiography revealed an ophthalmic artery arising from the middle meningeal artery (incidence -1.45%) and a non-dominant left transverse sinus. To preserve visual function, the extreme lateral supracerebellar infratentorial approach was employed. By ligating the non-dominant transverse sinus and incising the tentorium laterally under exoscopic visualization, a wide corridor to the superior petroclival region was achieved while preserving the middle meningeal artery. Subtotal resection was performed; firm tumor adherence to the lateral midbrain, proximal superior cerebellar artery perforators, and posterior cerebral artery precluded complete removal. Postoperatively, transient right hemiparesis and oculomotor palsy resolved within 3 months. Histopathology confirmed a world health organization grade 1 meningothelial meningioma (mitotic count: 1/10 high-power fields) with preserved MTAP expression and retained H3K27me3 staining. Despite benign histology, the MIB-1 index of 3%-5% correlated with tumor progression at 13 months, which was managed with stereotactic radiosurgery; the patient remains neurologically stable at 3 years. The extreme lateral supracerebellar infratentorial approach is a viable alternative for petroclival meningiomas when standard corridors are precluded by vascular anomalies, though its limitations, including restricted access to the middle cranial fossa and the required microsurgical expertise, must be recognized. Detailed preoperative vascular screening is essential for optimal approach selection.