2025 Poster Presentations
P356: INDICATIONS AND OUTCOMES OF ENDOSCOPIC ENDONASAL APPROACHES FOR TRIGEMINAL SCHWANNOMA BASED ON TUMOR CHARACTERISTICS: A MULTICENTER CASE SERIES STUDY OF 20 CASES
Abdulaziz Almusa1; Won jae Lee2; Ho Jun Seol2; Yong Hwy Kim3; Young Hoon Kim4; Doo-sik Kong2; 1Prince Sultan Medical Military City, Samsung Medical Center; 2Samsung Medical Center, Sungkyunkwan University; 3Seoul National University College of Medicine; 4Asan Medical Center
Introduction: Trigeminal schwannomas are rare tumors. It can Involve various components of the trigeminal nerve throughout its course. Hence requiring complex surgical Approaches. Initially cranial Approaches were the mainstay, then Endoscopic Skullbase Approaches were developed to be a valuable alternative. Endoscopic Endonasal Approaches (EEA) and Transorbital Approaches can both be used to tackle this pathology. However, there is a need to further define the indication for the suitability of each approach based on specific tumor characteristics.
Methods: multicenter case series from three tertiary centers Samsung Medical Center, Seoul National University Center, and Asan Medical Center. A total number of 20 cases were included. Analysis was done on tumor characteristics including: modified Samii Classification, Extracranial extension, Internal Carotid Artery displacement pattern, and Sphenoid Sinus Pneumatization pattern. Outcome measures were Gross total or near total resection (GNTR).
Results: 20 cases were analyzed. D3 was the most common type 7 (35%). Gross or Near Total Resection (GNTR) was achieved in 15 cases (70%). An additional Transorbital Approach was performed prior to EEA in 3 cases (15%). Regarding Tumor characteristics, 13 cases had Extracranial Extension(65%), 9 cases had ICA displacement(45%). In the absence of all 3 factors (Extracranial extension, lateral ICA Displacement, and sphenoid sinus pneumatization) GNTR decreased significantly to 29%. GNTR was 100 % in the presence of 1 and 3 factors and 86% in cases with 2 factors present. In the latter group Only one case out of seven had incomplete resection due to extensive bleeding from tumor and resulting potential risk to underlying neurovascular structures.
Conclusion: Endoscopic Endonasal Approaches can be considered as a valid option for Trigeminal Schwannomas. However, based on our series in the absence of extracranial extension, medial ICA displacement and lack of sphenoid sinus pneumatization. The chances of GNTR were markedly decreased and a an Endoscopic Transorbital Approach should be considered.