Background/Objectives: Giant pituitary adenomas (GPAs) pose significant surgical challenges due to their large size, parasellar/suprasellar extensions, and proximity to critical neurovascular structures. Although the endoscopic endonasal approach (EEA) is preferred for pituitary tumors, achieving gross total resection (GTR) in GPAs remains difficult. Additional transcranial approaches may improve resection rates while minimizing morbidity. This study evaluates the impact of endoscopic and combined surgical approaches on resection outcomes using a classification system previously defined in GPA patients treated over the past year. Methods: Among 517 pituitary adenomas treated in our clinic between September 2023 and September 2024, 49 GPA patients underwent endoscopic endonasal, transcranial, or combined surgery. Their medical records and surgical videos were retrospectively reviewed. Data included demographics, symptoms, imaging, surgical details, and follow-up outcomes. Tumor resection rates were analyzed based on the “landmark-based classification”, considering radiological and pathological features and surgical approach. Results: The mean age was 45.5 years (female/male: 14/35). Zone distribution was 8 (Zone 1), 21 (Zone 2), and 20 (Zone 3). GTR was achieved in 34.6%, near-total resection in 36.7%, and subtotal resection in 28.5%. Endoscopic surgery was performed in 41 patients, combined surgery in 7, and a transcranial approach in 1. Complications included diabetes insipidus (9/49), cerebrospinal fluid leakage (2/49), apoplexy (2/49), hypocortisolism (3/49), epidural hematoma (1/49), and epistaxis (1/49). Conclusions: While EEA is effective for Zone 1 and 2 GPAs, Zone 3 tumors often require combined or transcranial approaches for better resection. A multimodal strategy optimizes tumor removal while minimizing morbidity. Individualized surgical planning based on tumor classification is crucial for improving outcomes.

BACKGROUND AND OBJECTIVES: Endoscopic endonasal surgery (EES) is the preferred approach for treating sellar and parasellar lesions due to its panoramic view and detailed anatomical definition. This study aims to review major arterial injuries during EES, a rare but critical complication associated with high mortality and morbidity rates. METHODS: A retrospective analysis was conducted, including 15 patients from 5640 EES procedures performed between August 1997 and February 2024 at in our center/Department of Neurosurgery. The study focuses on perioperative and postoperative management strategies, highlighting the use of oxidized regenerated cellulose (Surgicel®)/gelatin-thrombin matrix (Floseal®) and multidisciplinary collaboration to achieve hemostasis. RESULTS: The incidence of major arterial injury was 0.2%, with a mean patient age of 38.4 years and a female-to-male ratio of 10:5. The most common tumors were adenomas (n = 7) and chordomas (n = 5). The most commonly bleeding arteries in 6 patients each are the cavernous segment of the internal carotid artery and the paraclival carotid artery. Low-flow bleeding was observed in 10 of our patients, while high-flow bleeding was seen in 5 patients, 4 of whom were recurrent cases (P < .05). In 3 patients with high-flow bleeding from segments of the carotid artery, digital subtraction angiography was performed for stent placement or coil embolization, while in 1 patient with high-flow bleeding, digital subtraction angiography was used for monitoring cerebral blood flow. One of our patients died of a myocardial infarction at the 14th month of follow-up and 1 of our patients developed left-hemiparesis. CONCLUSION: The study underscores the importance of preoperative planning, surgical expertise, and multidisciplinary teamwork in managing major arterial injuries during EES. The authors advocate for the development of standardized treatment algorithms to improve outcomes in these patients. The findings contribute to the limited literature on managing internal carotid artery injuries in EES, emphasizing the need for ongoing research and algorithm development.

Objective: Paraspinal schwannomas arise from the dorsal nerve root. Symptoms of schwannomas may depend on their locations and sizes. This case was presented by a female patient with a dorsalgia for 10 years. She had not any specific symptoms but pain and a thick spot on the neck (cervical area). Paraspinal schwannomas involve the dorsal nerve roots, affecting people in the fourth and fifth decades of life. Paraspinal schwannomas are frequently asymptomatic and diagnosed incidentally on imaging of the spine. Total excision is mostly possible and the recurrence rate is low.

Background: Endoscopic endonasal approach (EEA) has become a well- established approach for skull base pathologies, providing a minimally invasive corridor to access various lesions. While the technique has been extensively studied for common skull base tumors, data on extremely rare pathologies remain limited. Our study aims to present our experience with rare skull base lesions managed via the endoscopic endonasal approach, highlighting the challenges associated with preoperative diagnosis, intraoperative decision-making, and surgical strategy modifications. Methods: A retrospective analysis was conducted on patients who underwent endoscopic endonasal surgery at the tertiary center up to January 2025. Among 6,225 endoscopic endonasal procedures performed, 41 patients with exceptionally rare skull base pathologies were identified. Each tumor type was separately evaluated for differences in resection rates, complication rates, and recurrence patterns. Results: These included 6 pituitary pituicytomas, 5 plasmacytomas, 5 xanthogranulomas, 4 granular cell tumors, 3 giant cell tumors and others. Gross total resection was achieved in 68% of cases, with subtotal resection in vascular or malignant tumors. Intraoperative challenges included unexpected vascularity and fibrotic adhesions. Postoperative CSF leakage occurred in 7%, and recurrence was observed in 17%, mostly in malignant or partially resected tumors. No intraoperative mortality was recorded. Tailored adjuvant treatments ensured durable disease control in most patients. Conclusions: Even in highly experienced centers, rare skull base pathologies pose unique diagnostic and surgical challenges. The discrepancy between preoperative and intraoperative findings often necessitates real-time strategic adaptations. In these rare cases, for optimizing patient outcomes requires a comprehensive understanding of skull base anatomy, flexibility in surgical planning, readiness for sudden strategy modifications, and a multidisciplinary approach.

Background/Objectives The aim of this study was to induce demyelination in rats by placing a balloon catheter applying pressure under the optic chiasm using a stereotaxic device, and subsequently examine the effects of myricetin, a neuroprotective agent, on the demyelination/remyelination processes using electron microscopy. Methods A total of 40 adult male Wistar albino rats were used to establish an experimental model of optic chiasm compression via stereotaxic placement of a neuroballoon catheter. Animals were divided into four groups: control, demyelination, remyelination, and myricetin treatment. After catheter-induced compression, demyelination and remyelination processes were evaluated. Myricetin was administered intraperitoneally in the treatment group. Optic chiasm tissues were harvested and analyzed histopathological and ultrastructurally using electron and light microscopy. Statistical analyses were performed using chi-square tests, with p< 0.05 considered significant. Results When the demyelination and remyelination groups were compared with the control group, severe degeneration accompanied by Wallerian degeneration was observed, along with demyelination in axons, vacuolization in oligodendrocytes, and dark axonal degeneration. Compared to the other groups, the myricetin group showed a reduction in dark degeneration, axonal demyelination, and degeneration. Conclusions This study represents another example of experimental models of demyelination resulting from optic chiasm compression, which are rare in the literature. Myricetin has been shown to have positive effects on remyelination and may guide subsequent studies. Furthermore, this experimental model may allow the investigation of the demyelination and remyelination effects of different agents in the optic chiasm.

AIM: To demonstrated demyelination and remyelination of the optic nerve histologically by electron microscopy in an experimental model similar to the compression of pituitary adenomas on the optic chiasm.MATERIAL and METHODS: The rats were fixed to a stereotaxic device under deep anesthesia, and a balloon catheter was placed under the optic chiasm through a burr hole which was in front of the bregma in accordance with the brain atlas of rats. The animals were divided into five groups (n=8): control, mild compression demyelination, severe compression demyelination, mild compression remyelination, severe compression remyelination. The fine structures of the tissues obtained were evaluated using electron microscopy.RESULTS: We found a significant difference in the severity of degeneration when comparing group 1 with group 5 (p<0.001); there was no degeneration in group 1 rats and severe degeneration in all of the group 5 rats. Oligodendrocytes were found in all rats in group 1 and none of the rats in no group 2. The nuclei were preserved in the group 1 rats but damaged in all of the group 5 rats. There were no lymphocytes or erythrocytes in group 1 and all positives in group 5. CONCLUSION: This technique, which induced degeneration without causing damage to the optic nerve with toxic or chemical agents, revealed Wallerian degeneration similar to tumoral compression. After compression relief, the optic nerve remyelination process can be better understood, particularly for sellar lesions. In our opinion, this model may guide future experiments to identify protocols to induce and accelerate remyelination.