Transorbital neuroendoscopic surgery for treatment of sphenoid wing meningiomas extending to the cavernous sinus: clinical implications and a technical illustration.

OBJECTIVE: The aim of this study was to evaluate the efficacy and safety of transorbital neuroendoscopic surgery (TONES) in the management of sphenoid wing meningiomas (SWMs) with cavernous sinus and orbital invasion. METHODS: The authors conducted a retrospective review of 32 patients with SWMs treated at Gazi University using TONES from October 2019 to May 2023. The study includes clinical applications to elucidate the endoscopic transorbital approach. Surgical techniques focused on safe subtotal resection, aiming to minimize residual tumor volume for subsequent radiosurgery. Data were collected on patient demographics, tumor characteristics, surgical procedures, complications, and postoperative outcomes, including radiological imaging and ophthalmological evaluations. RESULTS: Surgical dissections delineated a three-phase endoscopic transorbital approach: extraorbital, intraorbital, and intracranial. In the clinical application, gross-total resection was not achieved in any patient because of planned postoperative Gamma Knife radiosurgery. The mean follow-up period was 16.3 months. Of 30 patients with preoperative proptosis, 25 experienced postoperative improvement. No new-onset extraocular muscle paresis or visual loss occurred postoperatively. The average hospital stay was 1.15 days, with minimal complications and no significant morbidity or mortality. CONCLUSIONS: Total resection of SWMs invading the cavernous sinus and orbit is associated with substantial risks, particularly cranial nerve deficits. TONES offers a minimally invasive alternative, reducing morbidity compared with transcranial approaches, and represents a significant advancement in the surgical management of SWMs, especially those extending into the cavernous sinus and orbit. The approach provides a safe, effective, and patient-centric approach, prioritizing subtotal resection to minimize neurological deficits while preparing patients for adjunctive radiosurgery. This study positions TONES as a transformative surgical technique, aligning therapeutic efficacy with neurovascular preservation and postoperative recovery.

Automatic Segmentation of Vestibular Schwannomas: A Systematic Review.

BACKGROUND: Vestibular schwannomas (VSs) are benign tumors often monitored over time, with measurement techniques for assessing growth rates subject to significant interobserver variability. Automatic segmentation of these tumors could provide a more reliable and efficient for tracking their progression, especially given the irregular shape and growth patterns of VS. METHODS: Various studies and segmentation techniques employing different Convolutional Neural Network architectures and models, such as U-Net and convolutional-attention transformer segmentation, were analyzed. Models were evaluated based on their performance across diverse datasets, and challenges, including domain shift and data sharing, were scrutinized. RESULTS: Automatic segmentation methods offer a promising alternative to conventional measurement techniques, offering potential benefits in precision and efficiency. However, these methods are not without challenges, notably the "domain shift" that occurs when models trained on specific datasets underperform when applied to different datasets. Techniques such as domain adaptation, domain generalization, and data diversity were discussed as potential solutions. CONCLUSIONS: Accurate measurement of VS growth is a complex process, with volumetric analysis currently appearing more reliable than linear measurements. Automatic segmentation, despite its challenges, offers a promising avenue for future investigation. Robust well-generalized models could potentially improve the efficiency of tracking tumor growth, thereby augmenting clinical decision-making. Further work needs to be done to develop more robust models, address the domain shift, and enable secure data sharing for wider applicability.

Endoscopic Endonasal Approach to the Orbit: A Case Series and Clinical Experience Emphasizing the Advantages of the Ipsilateral Mononostril Technique.

BACKGROUND: Lesions situated within the orbit pose significant challenges in management due to the confined space they occupy and their proximity to critical anatomical structures. The objective of our study is to assess the feasibility of the ipsilateral endoscopic endonasal approach for orbital cavernous hemangiomas and to comprehend the surgical anatomy of the orbital apex and inferomedial orbital structures. METHODS: Thirteen patients (8 women, 5 men), with ages ranging from 25 to 54 years (mean 35.2 ± 8.3 years), with orbital cavernous hemangioma who underwent surgery via the ipsilateral mononostril endoscopic endonasal approach between August 2018 and August 2023 were retrospectively evaluated. Demographic characteristics, clinical data, radiographic images, and clinical outcomes of the patients were collected from digital medical records. RESULTS: The left orbit was more commonly affected (9 left, 4 right). The average postoperative follow-up duration was 22.2 months (range: 6-50 months). Among the 13 cases of orbital cavernous hemangioma, 1 (7.7%) was located in the extraconal compartment, and 12 (92.3%) were situated in the intraconal compartment. Complete surgical resection of the tumor was successfully achieved in all patients. CONCLUSIONS: Our study highlights the potential advantages of employing a purely ipsilateral mononostril endoscopic endonasal approach for orbital surgery, particularly for accessing the orbital apex and managing medial and inferomedial orbital lesions. This technique holds promise for reducing morbidity and enhancing outcomes, especially when combined with careful patient selection, preoperative planning, and advanced endoscopic skills.

Beyond human in neurosurgical exams: ChatGPT's success in the Turkish neurosurgical society proficiency board exams.

Chat Generative Pre-Trained Transformer (ChatGPT) is a sophisticated natural language model that employs advanced deep learning techniques and is trained on extensive datasets to produce responses akin to human conversation for user inputs. In this study, ChatGPT's success in the Turkish Neurosurgical Society Proficiency Board Exams (TNSPBE) is compared to the actual candidates who took the exam, along with identifying the types of questions it answered incorrectly, assessing the quality of its responses, and evaluating its performance based on the difficulty level of the questions. Scores of all 260 candidates were recalculated according to the exams they took and included questions in those exams for ranking purposes of this study. The average score of the candidates for a total of 523 questions is 62.02 ± 0.61 compared to ChatGPT, which was 78.77. We have concluded that in addition to ChatGPT's higher response rate, there was also a correlation with the increase in clarity regardless of the difficulty level of the questions with Clarity 1.5, 2.0, 2.5, and 3.0. In the participants, however, there is no such increase in parallel with the increase in clarity.

Cavernous Sinus capillary hemangioma: Case report and literature review.

Introduction: Capillary hemangioma of the cavernous sinus is considered a benign vascular skull base tumor. In this case report, a patient with capillary hemangioma located in the cavernous sinus who was operated on with endoscopic endonasal approach is presented. Research question: What should be considered when planning the treatment for capillary hemangiomas located in the cavernous sinus? Material and methods: The treatment approaches applied in 12 patients with a diagnosis of capillary hemangioma located in the cavernous sinus, reported in the English literature, are reviewed in this article. We presented the clinical and radiological results of the treatments. Results: Cavernous sinus capillary hemangiomas are considered benign tumors. However, surgical treatment is preferred in the foreground because of the neurological deficits due to the compression effect caused by the mass. In the case reported by Masman et al. for the first time in the literature in 2021, they provided total excision with the endoscopic endonasal approach in the patient they first diagnosed by taking a biopsy with the endoscopic endonasal approach. In our case report, we provided total excision with endoscopic endonasal transsphenoidal approach. Discussion and conclusion: Many factors should be considered when deciding on the treatment method in these patients. Although radiotherapy is quite effective in the treatment of capillary hemangioma, surgery should be preferred, especially in symptomatic patients. In patients who cannot undergo surgery, radiotherapy is very valuable, although the long-term results are not yet known.

Spontaneous improvement in syringomyelia in a patient with Chiari 1 malformation: illustrative case.

BACKGROUND: "Chiari malformation" refers to a spectrum of hindbrain abnormalities characterized by impaired cerebrospinal fluid circulation through the foramen magnum. Syringomyelia is frequently found in patients with Chiari malformation type 1. Although many theories have suggested how cerebrospinal fluid enters and makes the cystic cavity in the spinal cord, the pathogenesis of syringomyelia remains controversial. This report documents a case with spontaneous resolution of syringomyelia followed up by 3-year serial magnetic resonance imaging (MRI). These kinds of cases support a more conservative approach. OBSERVATIONS: A 59-year-old female presented to the authors' clinic in June 2019 with a history of Chiari malformation type 1. This symptomatic patient has been followed up with serial MRI. When the last MRI was performed in August 2022, compared with previous imaging, resolution of the syringomyelia was recognized. LESSONS: Because the natural evolution of mildly symptomatic/asymptomatic patients with syringes is unclear, these patients pose a treatment dilemma. Although surgical intervention is a widely accepted therapeutic method, a more conservative approach can be considered in cases with spontaneous resolution. Especially for patients without progressive symptoms, the surgical approach should not be considered as the first step. In view of relapses, follow-up with periodic neurological examinations and radiological imaging is preferrable.

The first case of glioma detected by an artificial intelligence algorithm running on real-time data in neurosurgery: illustrative case.

BACKGROUND: The aim of this paper is to report one of the significant applications of artificial intelligence (AI) and how it affects everyday clinical practice in neurosurgery. The authors present a case in which a patient was diagnosed via an AI algorithm during ongoing magnetic resonance imaging (MRI). According to this algorithm, the corresponding physicians were immediately warned, and the patient received prompt appropriate treatment. OBSERVATIONS: A 46-year-old female presenting with nonspecific headache was admitted to undergo MRI. Scanning revealed an intraparenchymal mass that was detected by an AI algorithm running on real-time patient data while the patient was still in the MRI scanner. The day after MRI, a stereotactic biopsy was performed. The pathology report confirmed an isocitrate dehydrogenase wild-type diffuse glioma. The patient was referred to the oncology department for evaluation and immediate treatment. LESSONS: This is the first report of a glioma diagnosed by an AI algorithm and a subsequent prompt operation in the literature-the first of many and an example of how AI will enhance clinical practice.

The possible relation between temporal muscle mass and glioblastoma multiforme prognosis via sarcopenia perspective.

BACKGROUND: The optimal sarcopenia measurement method in patients with a diagnosis of glioblastoma multiforme (GBM) is unknown. It has been found that temporal muscle thickness (TMT) may reflect sarcopenia and be associated with survival, but the relationship between temporal muscle area (TMA) and GBM prognosis has never been evaluated before. The primary outcome of the study was to evaluate the relationship between TMA/TMT and overall survival (OS) time in newly diagnosed GBM patients. METHODS: The data of patients who presented at the university hospital between January 2009 and January 2019 with a confirmed diagnosis of glioblastoma multiforme at the time of diagnosis were analyzed retrospectively. Temporal muscle thickness and TMA were measured retrospectively from preoperative MRIs of patients diagnosed with GBM. Due to the small number of patients and the failure to determine a cut-off value with acceptable sensitivity and specificity using ROC analysis, the median values were chosen as the cut-off value. The patients were basically divided into two according to their median TMT (6.6 mm) or TMA (452 mm2 ) values, and survival analysis was performed with the Kaplan-Meier analysis. RESULTS: The median TMT value was 6.6 mm, and the median TMA value was 452 mm2 . The median overall survival (OS) was calculated as 25.8 months in patients with TMT < 6.6 mm, and 15.8 months in patients with TMT ≥ 6.6 mm (p = 0.29). The median overall survival (OS) of patients with TMA < 452mm2 was 26.3 months, and the group with TMA ≥ 452mm2 was 14.6 months (p = 0.06). The median disease-free survival was 18.3 months (%95 CI: 13.2-23.4) in patients with TMT < 6.6mm, while mDFS was 10.9 (%95 CI: 8.0-13.8) months in patients with TMT ≥ 6.6mm (p = 0.21). The median disease-free survival was found to be 21.0 months (%95 CI: 15.8-26.1) in patients with TMA < 452 mm2 and 10.5 months (%95 CI: 7.8-13.2) in patients with TMA ≥ 452 mm2 (p = 0.018). DISCUSSION: No association could be demonstrated between TMT or TMA and OS of GBM patients. In addition, the median DFS was found to be longer in patients with low TMA. There is an unmet need to determine the optimal method of sarcopenia in GBM patients.

Arterial Supply of the Basal Ganglia: A Fiber Dissection Study.

BACKGROUND: The basal ganglia, a group of subcortical nuclei located deep in the insular cortex, are responsible for many functions such as motor learning, emotion, and behavior control. Nowadays, because it has been shown that deep brain stimulation and insular tumor surgery can be performed by endovascular treatment, the importance of the vascular anatomy of the basal ganglia is being increasingly recognized. OBJECTIVE: To explain the arterial blood supply of the basal ganglia using white matter dissection. METHODS: The Klingler protocol was used to prepare 12 silicone-injected human hemispheres. The dissections were performed from lateral to medial with the fiber dissection technique to preserve arteries. RESULTS: The globus pallidus blood supply came from the medial lenticulostriate, lateral lenticulostriate, and anterior choroidal arteries; the substantia nigra and subthalamic nucleus were supplied by the branches of posterior cerebral artery; the putamen was supplied by the lateral and medial lenticulostriate arteries; and the caudate nucleus was supplied by the lateral lenticulostriate and medial lenticulostriate arteries and the recurrent artery of Heubner. CONCLUSION: Knowledge of the detailed anatomy of the basal ganglia and its vascular supply is essential for avoiding postoperative ischemic complications in surgeries related to the insula. In addition, knowledge of this anatomy and vascular relationship opens the doors to endovascular deep brain stimulation treatment. This study provides a 3-dimensional understanding of the blood supply to the basal ganglia by examining it using the fiber dissection technique. Further studies could use advanced imaging modalities to explore the vascular relationships with critical structures in the brain.

Endonasal endoscopic approach for sellar metastatic pathologies: a national observation.

PURPOSE: Sellar metastases are rare lesions. Recent improvements in diagnosis and treatment strategies have prolonged survival but increased the probability of metastatic tumors. Evaluation with clinical symptomatology and meticulous laboratory examination is crucial. We present our multicenter national study on sellar metastases to evaluate and underline the main clinical, endocrine, and radiological considerations regarding the diagnosis and endonasal endoscopic management of such rare lesions. METHODS: A medical literature-based retrospective study was planned across 13 neurosurgical centers in Turkey, where a data survey was conducted to collect information regarding sellar metastases surgically treated using the endoscopic endonasal approach, including clinical presentation, radiographic features, primary tumor origin, histopathological confirmation, time to metastasis, treatment, and patient outcomes. RESULTS: Between 2010 and 2020, 54 patients (22 women [40.7%] and 32 men [59.3%]) who underwent surgery with the endonasal endoscopic approach and had pathologically proven sellar metastases (overall incidence, 0.54%) were included. Of the patients, 59.3% had no known malignancy and presented with new-onset symptoms, 79.6% reported headache, 51.9% complained of some degree of visual deficits, and 50% had cranial nerve symptoms. Tissue biopsy was performed in 7.4% of the patients, whereas gross or subtotal resection was achieved in the remaining patients. CONCLUSION: To our knowledge, this is the largest series of patients surgically treated with the endonasal endoscopic approach for sellar metastases. For these patients, the treatment focus should be on management modalities for increasing quality of life instead radical treatment options with survival benefit.

Retrospective Review of Surgical Site Infections after Endoscopic Endonasal Sellar and Parasellar Surgery: Multicenter Quality Data from the North American Skull Base Society.

Introduction Transnasal access to the anterior skull base provides a minimally invasive approach for sellar and parasellar masses compared with its open counterparts. The unique microbiome of the sinonasal mucosa provides distinct challenges not encountered with other cranial approaches. The use of antibiotics in these cases has not been standardized, and data remain scarce regarding infectious outcomes. Methods We conducted a multicenter retrospective analysis of shared quality data points for the endoscopic endonasal approach (EEA) for pituitary adenomas, along with other sellar and parasellar region masses that were included by participating institutions. Patient and operative characteristics, perioperative and postoperative antibiotic regimens and their durations, intraoperative and postoperative cerebrospinal fluid leak, and onset of postoperative meningitis and sinusitis were compared. Results Fifteen institutions participated and provided 6 consecutive months' worth of case data. Five hundred ninety-three cases were included in the study, of which 564 were pituitary adenomectomies. The incidences of postoperative meningitis and sinusitis were low (0.67 and 2.87% for all pathologies, respectively; 0.35% meningitis for pituitary adenomas) and did not correlate with any specific antibiotic regimen. Immunocompromised status posed an increased odds of meningitis in pituitary adenomectomies (28.6, 95% confidence interval [1.72-474.4]). Conclusions The results show no clear benefit to postoperative antimicrobial use in EEA, with further larger studies needed.

Microsurgical anatomy and insular connectivity of the cerebral opercula.

OBJECTIVE: Radiological, anatomical, and electrophysiological studies have shown the insula and cerebral opercula to have extremely high functionality. Because of this complexity, interventions in this region cause higher morbidity compared to those in other areas of the brain. In most early studies of the insula and white matter pathways, insular dissection was begun after the opercula were removed. In this study, the authors examined the insula and deep white matter pathways to evaluate the insula as a whole with the surrounding opercula. METHODS: Twenty formalin-fixed adult cerebral hemispheres were studied using fiber microdissection techniques and examination of sectional anatomy. Dissections were performed from lateral to medial, medial to lateral, inferior to superior, and superior to inferior. A silicone brain model was used to show the normal gyral anatomy. Sections and fibers found at every stage of dissection were photographed with a professional camera. MRI tractography studies were used to aid understanding of the dissections. RESULTS: The relationships between the insula and cerebral opercula were investigated in detail through multiple dissections and sections. The relationship of the extreme and external capsules with the surrounding opercula and the fronto-occipital fasciculus with the fronto-orbital operculum was demonstrated. These findings were correlated with the tractography studies. Fibers of the extreme capsule connect the medial aspect of the opercula with the insula through the peri-insular sulcus. Medial to lateral dissections were followed with the removal of the central core structures, and in the last step, the medial surface of the cerebral opercula was evaluated in detail. CONCLUSIONS: This anatomical study clarifies our understanding of the insula and cerebral opercula, which have complex anatomical and functional networks. This study also brings a new perspective to the connection of the insula and cerebral opercula via the extreme and external capsules.

Prediction of IDH Mutation Status in High-grade Gliomas Using DWI and High T1-weight DSC-MRI.

RATIONALE AND OBJECTIVES: We aimed to evaluate the diagnostic performance of diffusion-weighted imaging (DWI) and dynamic susceptibility contrast-enhanced (DSC) magnetic resonance imaging (MRI) parameters in the noninvasive prediction of the isocitrate dehydrogenase (IDH) mutation status in high-grade gliomas (HGGs). MATERIALS AND METHODS: A total of 58 patients with histopathologically proved HGGs were included in this retrospective study. All patients underwent multiparametric MRI on 3-T, including DSC-MRI and DWI before surgery. The mean apparent diffusion coefficient (ADC), relative maximum cerebral blood volume (rCBV), and percentage signal recovery (PSR) of the tumor core were measured and compared depending on the IDH mutation status and tumor grade. The Mann-Whitney U test was used to detect statistically significant differences in parameters between IDH-mutant-type (IDH-m-type) and IDH-wild-type (IDH-w-type) HGGs. Receiver operating characteristic curve (ROC) analysis was performed to evaluate the diagnostic performance. RESULTS: The rCBV was significantly higher, and the PSR value was significantly lower in IDH-w-type tumors than in the IDH-m group (p = 0.002 and <0.001, respectively).The ADC value in IDH-w-type tumors was significantly lower compared with the one in IDH-m types (p = 0.023), but remarkable overlaps were found between the groups. The PSR showed the best diagnostic performance with an AUC of 0.938 and with an accuracy rate of 0.87 at the optimal cutoff value of 86.85. The combination of the PSR and the rCBV for the identification of the IDH mutation status increased the discrimination ability at the AUC level of 0.955. In terms of each tumor grade, the PSR and rCBV showed significant differences between the IDH-m and IDH-w groups (p ≤0.001). CONCLUSION: The rCBV and PSR from DSC-MRI may be feasible noninvasive imaging parameters for predicting the IDH mutation status in HGGs. The standardization of the imaging protocol is indispensable to the utility of DSC perfusion MRI in wider clinical usage.

Utilizing Deep Convolutional Generative Adversarial Networks for Automatic Segmentation of Gliomas: An Artificial Intelligence Study.

AIM: To describe a deep convolutional generative adversarial networks (DCGAN) model which learns normal brain MRI from normal subjects than finds distortions such as a glioma from a test subject while performing a segmentation at the same time. MATERIAL AND METHODS: MRIs of 300 healthy subjects were employed as training set. Additionally, test data were consisting anonymized T2-weigted MRIs of 27 healthy subjects and 27 HGG patients. Consecutive axial T2-weigted MRI slices of every subject were extracted and resized to 364x448 pixel resolution. The generative model produced random normal synthetic images and used these images for calculating residual loss to measure visual similarity between input MRIs and generated MRIs. RESULTS: The model correctly detected anomalies on 24 of 27 HGG patients? MRIs and marked them as abnormal. Besides, 25 of 27 healthy subjects? MRIs in the test dataset detected correctly as healthy MRI. The accuracy, precision, recall, and AUC were 0.907, 0.892, 0.923, and 0.907, respectively. CONCLUSION: Our proposed model demonstrates acceptable results can be achieved only by training with normal subject MRIs via using DCGAN model. This model is unique because it learns only from normal MRIs and it is able to find any abnormality which is different than the normal pattern.

Stereotactic radiosurgery for cerebral cavernous malformation: comparison of hemorrhage rates before and after stereotactic radiosurgery.

OBJECTIVE: Cerebral cavernous malformation (CM) is an angiographically occult vascular pathology. Although microsurgery is the gold standard treatment to control the symptoms of CM, resection carries high risk in some situations, especially eloquent areas. The objective was to evaluate annual hemorrhage rates (AHRs) before and after stereotactic radiosurgery (SRS) treatment of cerebral CM in different locations. METHODS: A total of 195 patients (119 women and 76 men) with CM treated at the Gazi University Gamma Knife Center between April 2005 and June 2017 were analyzed. The mean ± SD follow-up period was 67.4 ± 31.1 months (range 12 days to 170 months). AHR before SRS, AHR after SRS, morbidity associated with radiation, seizure control rate after SRS, lesion volume, coexistence with developmental venous anomaly, and SRS treatment parameters were analyzed, with evaluation of radiological data and clinical charts performed retrospectively. The seizure control rate was assessed using the Engel outcome scale. RESULTS: The AHR before SRS was 15.3%. Application of SRS to these patients significantly reduced the AHR rates to 2.6% during the first 2 years after treatment and to 1.4% thereafter. Favorable seizure control (Engel class I and II) after radiosurgery was achieved in 23 patients (88.5%) with epilepsy. Radiation-related temporary complications occurred in 15.4% of patients, and permanent morbidity occurred in 4.6%. CONCLUSIONS: SRS is a safe and effective treatment modality for reducing the hemorrhage risk of CM. The authors suggest that SRS should be considered for the treatment of patients with CM, high surgical risks, and hemorrhage history, instead of a using a wait-and-see policy.

Do We Need Intraoperative Magnetic Resonance Imaging in All Endoscopic Endonasal Pituitary Adenoma Surgery Cases? A Retrospective Study.

There are previous reports investigating effectiveness of intraoperative magnetic resonance imaging (IO-MRI) in pituitary adenoma surgery but there is no clear data in the literature recommending when there is no need of intraoperative scan. This retrospective analysis was based on determining which patients does not need any IO-MRI scan following endoscopic endonasal pituitary adenoma surgery. Patients with functional or non-functional pituitary adenomas that were operated via endoscopic endonasal approach (EEA) between June 2017 and May 2019 were enrolled. Patients younger than 18 years old, patients who did not underwent IO-MRI procedure or not operated via EEA were excluded from the study. Hence, this study is designed to clarify if IO-MRI is useful in both functional and non-functional pituitary adenomas, functional adenomas did not split into subgroups. A total of 200 patients treated with pituitary adenoma were included. In Knosp Grade 0 - 2 group, primary surgeon's opinion and IO-MRI findings were compatible in 150 patients (98.6%). In Knosp Grade 3 - 4 correct prediction were performed in 32 (66.6%) patients. When incorrectly predicted Knosp Grade 3 - 4 patients (n = 16) was analyzed, in 13 patients there were still residual tumor in cavernous sinus and in 3 patients there were no residual tumor. Fisher's exact test showed there is a statistically significant difference of correct prediction between two different Knosp Grade groups (two-tailed P < 0.0001). Eighteen patients had a residual tumor extending to the suprasellar and parasellar regions which second most common site for residual tumor. Our findings demonstrate that there is no need of IO-MRI scan while operating adenomas limited in the sellae and not invading the cavernous sinus. However, we strongly recommend IO-MRI if there is any suprasellar and parasellar extension and/or cavernous sinus invasion.

Stereotactic Radiosurgery after Subtotal Resection of Critically-Located Grade I Meningioma: A Single-Center Experience and Review of Literature.

AIM: To analyze the results of stereotactic radiosurgery in 295 patients with residual Grade I meningiomas located at parasellar region, petroclival region, cerebellopontine angle and parasagittal region. MATERIAL AND METHODS: A total of 295 patients with Grade 1 residual Meningiomas (197 women, 98 men), who were treated by adjuvant radiosurgery in Gazi University Gamma Knife Center between 2004-2015 were analyzed. WHO Grade 2 and 3 meningiomas were not included in our study. Minimum radiological follow-up was 24 months. The median follow-up was 54 months. The tumor volume, location, treatment dose, morbidity, progression free survival and tumor control rate were analyzed. RESULTS: The median tumor volume was 5.2 cm3 (0.04-39.7), median age was 50 (20-80), median dose was 14 Gy and tumor control rate was 94.5% (stationary in 85.0%, volume reduction in 9.5%). Increase in tumor volume was seen in 16 patients (5.5%) and re-operation was performed in 5 of them (1.6%). Stereotactic radiosurgery was performed again for 8 patients (2.7%).The location of the tumors was as follows: 39.3% parasellar region, 20% cerebellopontine angle, 13.6% petroclival and 27.1% was parasagittal, falcine or convexity. Major morbidities were detected in 6 (2%) patients. Minor morbidities were detected in 18 (6.1%) patients. CONCLUSION: Stereotactic radiosurgery is an effective and safe treatment modality for residual Grade I meningiomas.

Interhemispheric Precuneus Retrosplenial Transfalcine Approach for Falcotentorial Meningiomas: Anatomic Study and Clinical Series.

BACKGROUND: Falcotentorial meningiomas are surgically challenging. Currently accepted approaches include occipital interhemispheric and supracerebellar infratentorial approaches, which have documented drawbacks. OBJECTIVE: To propose an alternative approach to the posterior tentorial incisural space, the interhemispheric precuneus retrosplenial transfalcine approach (IPRTA). METHODS: A total of 6 colored-silicone-injected adult cadaveric heads were dissected. We measured the interval between bridging veins and studied computed tomography venography scans of 20 subjects to confirm the feasibility of the IPRTA. Bony landmarks, the region's bridging veins, and the anterior and posterior borders of the approach were identified. The surgical corridor widths (veins' interval) and lengths were compared between alternative midline approaches. We also reviewed 4 consecutive clinical cases using this approach. RESULTS: The IPRTA provides the shortest distance to the anterior and posterior limits of the posterior tentorial incisura. Moreover, it is the only approach that provides direct visualization of the anterior and posterior limits of falcotentorial junction meningiomas. In all specimens and patients, a minimum 30-mm interval between the anterior and posterior parietal veins was found in at least one of the hemispheres. Tumor removal was successful in all 4 patients but resulted in mild paresthesia in the lower extremities of 2 patients and temporary foot drop in 1 patient. CONCLUSION: The IPRTA offers the shortest and most direct corridor for falcotentorial meningiomas and provides excellent visualization of most of the critical structures in the region. Detailed preoperative evaluation of the deep and superficial venous structures is recommended.

Subdural Hematoma Evacuation via Rigid Endoscopy System: A Cadaveric Study.

ABSTRACT: The utilization of endoscope-assisted surgery is becoming a more common modality for the surgical treatment of subdural collections. Considering the inflexible construction of the rigid endoscope, it's not clear where to perform the optimal craniotomy. Twenty four craniotomies (3 cm diameter) were performed in 8 hemicrania. The craniotomies were placed 1 cm front and behind the coronal suture and to the point where the parietal bone was the most convex. The craniotomies in the anterior (C1) and posterior (C2) of the coronal suture were in the mid pupillary line, while the posterior craniotomy (C3) was just lateral to the midpupillary line. At first, subdural distances measured, and then the distances from the craniotomy to the anterior, posterior, medial, and lateral directions in which endoscope could reach the farthest without the damage to the parenchyma were measured. The subdural distance was significantly deeper in C3 than C1 (P = 0.001); however, there was no difference between C3 and C2 (P = 0.312). The distance that could be reached with C3 was higher than C1 in anterior, posterior, lateral, and medial directions (P ≤0.001, 0.037, <0.001, and <0.001, respectively). The distance that could be reached with C3 was higher than C2 in anterior, posterior, lateral, and medial directions (P < 0.001, 0.02, 0.01 and <0.001, respectively). In subdural hematomas, especially that covers all surface of the hemisphere, the most suitable craniotomy is the posteriorly placed craniotomy to reach the most extended projection in anteroposterior line of the hematoma.