2026 Proffered Presentations
S250: ANGIOGRAPHIC EPICENTER-BASED CLASSIFICATION OF PETROCLIVAL MENINGIOMAS: RATIONALE AND OUTCOMES
Nobuyuki Watanabe1; Tingting Jiang1; Arianna Fava1; Kentaro Watanabe2; Thibault Passeri1; Sébastien Froelich1; 1Lariboisière Hospital; 2Jikei University School of Medicine
Introduction: Petroclival meningiomas (PCMs) are among the most technically demanding intracranial tumors to treat, yet their definition and classification remain confusing due to transitional cases and the lack of a definitive method to determine the true tumor origin. Preoperative MRI or even intraoperative findings often fail to clearly identify the tumor origin, particularly in large PCMs with broad dural attachment. We defined the dura mater containing the primary feeding artery pedicle as angiographic epicenter (AE) for origin identification, upon which we proposed a new PCMs classification.
Methods: We retrospectively analyzed 57 cases of newly diagnosed PCMs, excluding spheno-caverno-petro-clival meningiomas, in which preoperative angiography was performed. AE locations were precisely identified using 3D reconstruction image analysis from preoperative CT, gadolinium enhanced T1WI, Cone-beam CT angiography (Figure 1). Based on AE location, PCMs were classified into four types: Clivus (CL), Posterior Cavernous (PC), Tentorial (TE), and Petrous Apex (PA) type. An AE map including all the patients with their case numbers was provided to visually show their distribution (Figure 2). Surgical videos were reviewed to evaluate the trigeminal and abducens nerve displacement. Extent of resection (EOR) was assessed using the Duke University criteria, focusing on extracavernous tumor. Radiological findings and clinical outcome were analyzed according to the AE type.
Results: The average maximum tumor diameter in cisternal portion was 4.03 cm (range 2.2–5.8 cm). AE type distribution was 10.5% CL, 31.6% PC, 33.3% TE, and 24.6% PA. The most common primary feeding arteries were: Dorsal meningeal artery (DMA) in CL type (66.7 %), Medial tentorial artery (MTA) (44.4 %) and Lateral tentorial artery (LTA) (38.9 %) in PC type, MTA in TE type (68.4 %), and DMA or Ascending pharyngeal artery (APhA) in PA type (28.6 % each). Cavernous sinus (CS) extension was observed in 34 cases (59.6 %), predominantly in PC type (94%, p < 0.001). GTR was achieved in 13 cases (22.8 %), NTR in 25 cases (43.9 %), and STR in 19 cases (33.3 %). Notably, STR was significantly more frequent in the PC type (55.6 %, p = 0.032) (Table 1). The most common postoperative cranial nerve deficit was diplopia, occurring in 21 cases (36.8 %), with a higher tendency in the PC type (p = 0.075). The AE map demonstrated the correlations between AE location and trigeminal/abducens nerve displacement (Figure 2). According to AE classification, trigeminal nerve displacement patterns were superolateral (100%) in CL, inferolateral (88.9%) in PC, and variable (inferolateral 52.6% and inferomedial 36.8%) in TE type, and superolateral (100%) in PA type.
Discussion and Conclusion: The AE allows anatomically accurate identification of PCM origin, and the AE-based classification can serve as a preoperative tool to predict nerve displacement pattern and EOR. Especially, the PC type demonstrated a significantly higher rate of STR. Tumors originating from the CS wall may pose a challenge in establishing a safe detachment plane, due to the risk of entering the CS.
