Speakers

Characteristic of optic canal invasion in 31 consecutive cases with tuberculum sellae meningioma
1110 13:50-14:00
AASNS / AANS Joint Session "Spetzler Symposium"/305
Objectives: Optic canal invasion by tuberculum sellae meningiomas (TSMs) has been reported, but the characteristics of invasion remain unclear. This study was performed to clarify the incidence and characteristics of optic canal invasion by TSM and to determine whether optic canal invasion could be predicted preoperatively by magnetic resonance imaging (MRI). Methods: 31 patients with TSM underwent tumor resection in our institute. In all cases, the optic canal was explored to identify any tumor invasion. We classified the characteristics of optic canal invasion from intraoperative findings. Invasion was classified into four types: type 1: no invasion; type 2: secondary invasion; type 3: partial wall invasion (two subtypes); and type 4: invasion into the supero-medial-inferior walls of the optic canal. Results: Thirty of 31 cases showed optic canal invasion. Of these 30 cases, 9 (30 %) showed bilateral optic canal invasion. The most common finding was type 1 (23 sides). Among cases with optic canal invasion (39 sides), type 4 was the most common pattern (17 sides), followed by type 3-infero-medial (13 sides), type 2 (5 sides), and type 3-supero-medial (4 sides). Blinded prediction of tumor invasion was accurate in 61 % of cases, but characteristics of tumor invasion were undeterminable from preoperative MRI. Conclusions: Optic canal invasion was frequently seen in our consecutive series of TSM, characteristics of which were unpredictable preoperatively. Neurosurgeons should be aware of the high incidence and variety of optic canal invasion in planning strategies for TSM treatment.

Surgical implementation and efficacy of endoscopic endonasal extradural posterior clinoidectomy
1109 13:30-13:40
AASNS & WANS Joint Seminar/305
Objective: The endoscopic endonasal approach (EEA) for skull base tumors has become an important topic in recent years, but its use, merits, and demerits are still being debated. Herein, the authors describe the nuances and efficacy of the endoscopic endonasal extradural posterior clinoidectomy for maximal tumor exposure. Methods: The surgical technique included extradural posterior clinoidectomy following lateral retraction of the paraclival internal carotid artery and extradural pituitary transposition. In cases with prominent posterior clinoid process, a midline sellar dura cut was added to facilitate extradural exposure. Forty-four consecutive patients, in whom this technique was performed at Osaka City University Hospital, were reviewed. The pathology included 19 craniopharyngiomas, 7 chordomas, 6 meningiomas, 6 pituitary adenomas, 4 chondrosarcomas, and 2 miscellaneous. Utilization and effectiveness of this approach were further demonstrated with neuroimaging. Results: Extradural posterior clinoidectomies were successfully applied in all patients without permanent neurovascular injury and with better maneuverability and greater resection rate of the tumors. Four patients experienced transient postoperative abducens nerve paresis, and 1 patient experienced transient postoperative oculomotor nerve paresis; however, the patients with deficits recovered within 3 months. On radiological examination, the surgical field was 2.2 times wider in cases with bilateral posterior clinoidectomy than in cases without posterior clinoidectomy. Conclusions: The extended EEA with extradural posterior clinoidectomy creates an extra working space and allows adequate accessibility with safe surgical maneuverability to remove tumors that extend behind the posterior clinoid and dorsum sellae.

Surgery of pediatric craniopharyngiomas
1109 14:00-14:10
Video Session/304B
Pediatric craniopharyngiomas necessitate careful selection of the surgical approach, which may involve endonasal surgery and/or craniotomy techniques, depending on the tumor's size, location, and relationship to surrounding structures. These tumors have the potential for lifelong morbidity, impacting not only the patients but also their families due to their tendency for local recurrence. They typically present as large cystic tumors with solid components, which influences the choice of surgical technique for optimal resection; however, they are often well-encapsulated, facilitating surgical removal. Our surgical strategy aims for nearly complete resection of the tumor. In this video session, we will present representative cases illustrating radical surgical resection achieved through staged surgeries as well as simultaneous approaches utilizing both endonasal and transcranial techniques.