2026 Poster Presentations
P127: SURGICAL STRATEGIES TO AVOID COMPLICATIONS IN LARGE ANTERIOR CLINOIDAL MENINGIOMAS INVOLVING THE INTERNAL CAROTID ARTERY
Takafumi Mitsuhara; Hiroki Takahashi; Masaaki Takeda; Nobutaka Horie; Hiroshima University Hospital
Objectives: This study aimed to discuss the surgical strategy for large clinoidal meningiomas involving the internal carotid artery (ICA) and its perforating branches.
Background: Anterior clinoidal meningiomas remain a challenging pathology because of their intimate relationship with vital neurovascular structures. Preoperative visual status, symptom duration, lesion size, and adherence to the ICA and its branches have been shown to be significant determinants of postoperative outcomes, and there is still a risk of serious complications in the case of a large or huge lesion with major vessel encasement.
Methods: Our experience with large meningiomas involving the ICA will be classified using the Al-Mefty classification, and treatment strategies for each classification will be discussed based on preoperative symptoms, preoperative imaging, and surgical findings of the patients.
Results: Seven patients with large clinoidal meningiomas involving the ICA were retrospectively treated between 2020 and 2024 at the Department of Neurosurgery, Hiroshima University Hospital, Hiroshima, Japan. Four female patients, with a median age of 71 years, had large to giant tumors with a median diameter of 47 mm. According to the Al-Mefty classification, three cases were classified as Group I, two as Group II, and two as Group III. Three patients achieved GTR, and four achieved STR. Cases infiltrating the cavernous sinus or the optic canal to the orbital apex were limited to STR alone. Postoperative asymptomatic perforator infarction occurred in two cases. Oculomotor nerve hypofunction persisted as a sequela in one case. With an infraclinoid origin (Al-Mefty group I) with or without cavernous sinus invasion, some tumors were directly adhered to the adventitia of the carotid artery in the absence of an intervening arachnoid membrane. Surgical strategies require early optic nerve decompression and preservation of important vessels and perforating branches. When we had difficulty removing the tumor while sparing the perforating branch, determining whether the arachnoid remained around the perforating arteries was critical to the success of the surgery, and sometimes the decision to allow the tumor to remain was necessary. 3D-DSA and high-resolution MRI fusion images were used to identify the ICA perforating branches within the tumor. With large tumor involving the ICA and middle cerebral artery, it was better to proceed with surgery as a ”pincer” operation from both the central and peripheral sites.
Conclusions: Anterior clinoidal meningiomas remain a challenge for neurosurgeons. The main factors determining the quality of resection and postoperative complications seem to be the intimate relationship between the tumor and vessel adventitia and cavernous sinus invasion when the tumor involves the ICA and perforating branches. In Group I, tumors originating from the undersurface of the anterior clinoid process and infiltrating the vascular adventitia, perforating branches were embedded within the tumor. Dissecting the tumor from these perforating branches carries a high risk of infarction. In Group III, tumors infiltrating the optic nerve sheath may lead to visual function deterioration during resection; therefore, limiting management to decompression is appropriate.