Burak Cabuk

Purpose: Despite advances in endoscopic skull base surgery, postoperative sinonasal inflammation remains poorly characterized. In particular, sphenoid sinus osteitis has received little attention, as complications after endoscopic transsphenoidal surgery (ETS) have largely been assessed in terms of mucosal pathology. This study aims to determine the incidence of sphenoid sinus osteitis after ETS, describe its clinical and radiological features, and identify associated surgical and demographic risk factors. Methods: We retrospectively reviewed patients undergoing primary ETS for sellar or parasellar tumors between September 2021 and September 2024. Osteitis was assessed on high-resolution CT using the Lee and Kennedy classification. Clinical symptoms, particularly cacosmia, and surgical approach and reconstruction techniques were analyzed as potential risk factors. Results: Among 1,443 patients, sphenoid sinus osteitis was identified in 12 cases (0.83%). All cases occurred in patients who underwent sellar reconstruction, with no osteitis observed in those without reconstruction ( p < 0.001). Regarding reconstruction techniques, the nasoseptal flap showed a borderline statistical significance ( p = 0,045). Radiologically, osteitis was Grade 1 in 50%, Grade 2 in 25%, and Grade 3 in 25% of cases. Cacosmia was the presenting symptom in 75% of affected patients ( p < 0.001). Surgical revision was required in 11 patients (91.7%), while medical treatment alone was sufficient in one case. At the 12-month follow-up, all of the patients were symptom-free; one patient required a second revision for recurrent sphenoid sinusitis at sixth months follow up. Conclusion: Sphenoid sinus osteitis represents a rare but clinically relevant bone-centered complication following ETS, distinct from conventional rhinonasal morbidity. Its exclusive association with sellar reconstruction highlights the potential role of reconstruction-related bone contact and localized inflammatory responses in its pathogenesis. Recognizing sphenoid sinus osteitis as a distinct postoperative entity may improve diagnostic accuracy and guide more targeted management of postoperative rhinonasal symptoms. Surgical revision served as the primary intervention for the patient cohort, yielding favorable outcomes characterized by complete symptomatic resolution at the 12-month follow-up.

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.

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/Objective: 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: This study aimed to develop a robotic system with autonomous functionality for holding and manipulating the endoscope in endoscopic endonasal surgery. A cost-effective prototype was created with the goal of using robotic assistance and achieving a more efficient learning curve for endoscopic surgery. METHODS: A Stewart platform–based endoscope holder and positioner robotic system, developed by the Mechatronics Engineering Department of Kocaeli University, was used in conjunction with 3D Slicer and Plus Toolkit open-source health technology software. Following initial configuration on a 3D skull model, the system was applied to a fresh-frozen cadaver. RESULTS: The robotic system and its registration process proved feasible, allowing the robot to autonomously reach predetermined anatomical points during the nasal step of the surgery. Compared with a previous study by the same authors, the surgery duration was successfully shortened. The experiment yielded positive outcomes in both the artificial skull model and the cadaver. The robotic system effectively performed the nasal stage of the surgery. The integration of a robotic surgical arm in the endoscopic endonasal approach holds the potential to enhance the learning curve through shared experiences. The robot offers assistance to surgeons during the learning phase of the endoscopic endonasal approach, aiding in the identification of anatomical landmarks through preoperative planning. CONCLUSIONS: This system may present advantages such as improved visualization, enhanced maneuverability, and reduced user fatigue compared with conventional methods. These findings show the potential of robotic assistance in endoscopic surgical techniques.

Objectives: To evaluate the performances of machine learning using semantic and radiomic features from magnetic resonance imaging data to distinguish cystic pituitary adenomas (CPA) from Rathke’s cleft cysts (RCCs). Materials and Methods: The study involved 65 patients diagnosed with either CPA or RCCs. Multiple observers independently assessed the semantic features of the tumors on the magnetic resonance images. Radiomics features were extracted from T2-weighted, T1-weighted, and T1-contrast-enhanced images. Machine learning models, including Support Vector Machines (SVM), Logistic Regression (LR), and Light Gradient Boosting (LGB), were then trained and validated using semantic features only and a combination of semantic and radiomic features. Statistical analyses were carried out to compare the performance of these various models. Results: Machine learning models that combined semantic and radiomic features achieved higher levels of accuracy than models with semantic features only. Models with combined semantic and T2-weighted radiomics features achieved the highest test accuracies (93.8%, 92.3%, and 90.8% for LR, SVM, and LGB, respectively). The SVM model combined semantic features with T2-weighted radiomics features had statistically significantly better performance than semantic features only (p = 0.019). Conclusion: Our study demonstrates the significant potential of machine learning for differentiating CPA from RCCs.

Purpose: The aim of this study is to determine and define differential magnetic resonance imaging (MRI) findings of pituitary adenomas and craniopharyngiomas. Materials and methods: This retrospective analysis was performed on MR imaging findings of 45 pituitary adenomas and 41 craniopharyngiomas with solid and cystic mixed appearance. MRI findings including shape ovoid, snowman, lobulation, chiasma compression, cavernous sinus invasion, 3rd ventricle compression, calcification, predominant type – cystic vs solid, contrast enhancement patterns – homogenous, reticular and extension were assessed. Results: Among MRI findings superiorly lobulated shape, third ventricle compression and reticular enhancement of solid parts were common in craniopharyngiomas while snowman shape, predominantly solid content, homogenous enhancement of solid parts were compatible with adenomas significantly at p <0.05 for all. Conclusion: Tumor shape and contrast enhancement patterns of solid parts seem discriminative MRI features for pituitary adenoma and craniopharyngiomas.