Creation of a microsurgical neuroanatomy laboratory and virtual operating room: a preliminary study.

OBJECTIVE: A comprehensive understanding of microsurgical neuroanatomy, familiarity with the operating room environment, patient positioning in relation to the surgery, and knowledge of surgical approaches is crucial in neurosurgical education. However, challenges such as limited patient exposure, heightened patient safety concerns, a decreased availability of surgical cases during training, and difficulties in accessing cadavers and laboratories have adversely impacted this education. Three-dimensional (3D) models and augmented reality (AR) applications can be utilized to depict the cortical and white matter anatomy of the brain, create virtual models of patient surgical positions, and simulate the operating room and neuroanatomy laboratory environment. Herein, the authors, who used a single application, aimed to demonstrate the creation of 3D models of anatomical cadaver dissections, surgical approaches, patient surgical positions, and operating room and laboratory designs as alternative educational materials for neurosurgical training. METHODS: A 3D modeling application (Scaniverse) was employed to generate 3D models of cadaveric brain specimens and surgical approaches using photogrammetry. It was also used to create virtual representations of the operating room and laboratory environment, as well as the surgical positions of patients, by utilizing light detection and ranging (LiDAR) sensor technology for accurate spatial mapping. These virtual models were then presented in AR for educational purposes. RESULTS: Virtual representations in three dimensions were created to depict cadaver specimens, surgical approaches, patient surgical positions, and the operating room and laboratory environment. These models offer the flexibility of rotation and movement in various planes for improved visualization and understanding. The operating room and laboratory environment were rendered in three dimensions to create a simulation that could be navigated using AR and mixed reality technology. Realistic cadaveric models with intricate details were showcased on internet-based platforms and AR platforms for enhanced visualization and learning. CONCLUSIONS: The utilization of this cost-effective, straightforward, and readily available approach to generate 3D models has the potential to enhance neuroanatomical and neurosurgical education. These digital models can be easily stored and shared via the internet, making them accessible to neurosurgeons worldwide for educational purposes.

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.

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.

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.

The effect of antiepileptic drugs on re-myelinization of axons: Phenytoin, levetiracetam, carbamazepine, and valproic acid, used following traumatic brain injury.

OBJECTIVE: Traumatic brain injury is a major health and socioeconomic problem and the first cause of young death worldwide. For this reason, the prevention of post-traumatic brain injury and the research of new methods for it are important today. In this study, we aimed to determine whether the use of antiepileptic drugs contributed to axonal healing after traumatic brain injury. METHODS: Thirty-six Long-Evans rats, each weighing 300-350 g, were used in this study. A total of 6 groups, including the sham, control, and 4 study groups, were determined. A 1.5 mm-sized trauma was created in the biparietal area with a blunt-tipped dissector. Carbamazepine phenytoin valproic acid and levetiracetam (phenytoin: 30 mg/kg, valproic acid: 60 mg/kg, levetiracetam: 80 mg/kg, and carbamazepine: 36 mg/kg) were intraperitoneally administered to the study groups, and the control group intraperitoneally received a physiological saline solution (15 ml/kg) twice daily for 3 days. After 72 h, hemispheres of the sacrificed subjects were taken for examination in biochemistry and histology. Glutathione, malondialdehyde, and NG2 levels in the samples were determined. RESULTS: No significant difference was found in biochemical measurements. Histopathological examination revealed that the NG2 expression was more intense in the group treated with phenytoin and levetiracetam (phenytoin was partly higher) and the amount of edema decreased. The NG2 expression increased and the edema decreased, though lower in the group treated with carbamazepine and valproic acid, compared with phenytoin and levetiracetam. An increase in the NG2 expression and edema intensity were determined in the control and sham groups. CONCLUSION: Antiepileptic drug selection after traumatic brain injury is an important medical matter. Although the patient-oriented selection is essential, the study suggests that the choice of phenytoin, levetiracetam carbamazepine, and valproic acid will, respectively, have an accelerating effect for axonal healing.

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.

A Rare Entity in the Lumbar Epidural Region: T-Cell Lymphoblastic Lymphoma.

BACKGROUND: T-cell lymphoblastic lymphoma is a rare disease and an aggressive neoplasm of precursor lymphoblasts. We present a case of lumbar epidural T-cell lymphoblastic lymphoma which appeared with clinical features of epidural spinal cord compression. METHODS: A 38-year-old male patient presented with weakness in the lower extremities and newly developed urinary incontinence. His medical history included precursor T-cell acute lymphoblastic leukemia and treatment with allogeneic bone-marrow transplantation 5 years previously. Spinal magnetic resonance imaging (MRI) revealed an epidural mass lesion at L2-L4 levels and there was no sign of leukemia or lymphoma in clinical, laboratory, and radiological examinations. Surgery was planned for obtaining diagnostic material. Decompressive laminectomy and subtotal excision of the tumor were performed. RESULTS: At surgery, the tumor consisted of yellow-colored and hypovascular soft tissue fragments. It was encircling the spinal cord and spreading through the left L3 foramen. The patient underwent adjuvant chemoradiotherapy after the histopathological evaluation. At 2-month follow-up, the patient was able to walk without assistance, but the urinary incontinence was the same. At 5-month follow-up, the disease progressed, and the patient passed away because of infective endocarditis. CONCLUSION: Spinal lymphomas may display its characteristic "wrap-around" fashion in the MRI. In this report, we shared the microsurgical appearance of this fashion. As the lymphomas are chemoradiosensitive tumors, the treatment should be managed with a multidisciplinary approach.

Targeting Cancer Cell Metabolism with Metformin, Dichloroacetate and Memantine in Glioblastoma (GBM).

AIM: To investigate the effects of metformin, dichloroacetate (DCA), and memantine on T98G and U87-MG human glioblastoma (GBM) cells to target tumor cell metabolism in a multi-directional manner. MATERIAL AND METHODS: IC50 levels for metformin, DCA, metformin+DCA and memantine were determined by MTT assay in T98G and U87-MG cells in vitro. Casp3, Bcl-2, Bax, c-Myc and GSK-3B protein expressions were investigated post treatments. Fifteen GBM+ tumor tissues were assessed for Casp-3, Bcl-2, Bad, Bax for apoptotic protein expression patterns. RESULTS: Cancer cell metabolism targeting drugs metformin, DCA, metformin+DCA and memantine induced cytotoxicity in a dose-dependent manner in T98G and U87-MG cells. IC50 for memantine is found as 0.5 mM (p < 0.01) which is nearly 10 times lower concentration than that of metformin. Fifteen GBM+ tumor tissues had differential apoptotic protein expressions. CONCLUSION: Memantine exerted anti-cancer mechanism of action in T98G and U87-MG cells, however, such a mechanism requires deeper investigation for GBM treatment.

Intraoperative Magnetic Resonance Imaging Assisted Endoscopic Endonasal Resection of Clival Chordomas.

BACKGROUND: Cranial base chordomas are typically indolent and usually appear as encapsulated tumors. They slowly grow by infiltrating the bone, along with the lines of least resistance. Due to its relationship with important neurovascular structures, skull base chordoma surgery is challenging. OBJECTIVE: The usefulness of intraoperative magnetic resonance imaging (IO-MRI) in achieving the goal of surgery, is evaluated in this study. METHODS: Between March 2018 and March 2020, 42 patients were operated on for resection of skull base chordomas in our institution. All of them were operated on under IO-MRI. Patients were analyzed retrospectively for identifying common residue locations, complications and early post-operative outcomes. RESULTS: In 22 patients (52,4%) gross total resection was achieved according to the final IO-MRI. In 20 patients (47,6%) complete tumor removal was not possible because of extension to the petrous bone (8 patients), pontocerebellar angle (6 patients), prepontine cistern (4 patients), temporobasal (1 patient), cervical axis (1 patient). In 13 patients, the surgery was continued after the first IO-MRI control was performed, which showed a resectable residual tumor. 7 of these patients achieved total resection according to the second IO-MRI, in the other 6 patients all efforts were made to ensure maximal resection of the tumor as much as possible without morbidity. Repeated IO-MRI helped achieve gross total resection in 7 patients (53.8%). CONCLUSIONS: Our study proves that the use of IO-MRI is a safe method that provides the opportunity to show the degree of resection in skull base chordomas and to evaluate the volume and location of the residual tumor intraoperatively. Hence IO-MRI can improve the life expectancy of patients because it provides an opportunity for both gross total resection and maximal safe resection in cases where total resection is not possible.

Anaesthetic Management in Successive Spinal Surgeries During Pregnancy and Postpartum.

In this case report, we present a parturient with spinal tumour who required neurosurgery before and after caesarean delivery under general anaesthesia. A 25-year-old woman at 30 weeks of gestation and suffering from bilateral lower-limb weakness and sensory deficit due to spinal tumour underwent emergent laminectomy and decompression surgery under general anaesthesia. In this case, total intravenous anaesthesia was used. Two weeks later, the patient underwent emergent caesarean delivery under general anaesthesia due to preterm labour and gave birth to a healthy new-born. Meanwhile, pathological exam revealed soft tissue sarcoma requiring re-operation for gross total excision in the postpartum Week 4, which was followed by multisession chemoradiotherapy. The patient survived for 3 years, that is, until generalised systemic and neural metastasis. General anaesthesia management in surgeries before and after caesarean delivery in patients with spinal tumours is of utmost importance in providing optimal maternal, foetal and neonatal safety using a multidisciplinary team approach.

A Novel Deep Learning Algorithm for the Automatic Detection of High-Grade Gliomas on T2-Weighted Magnetic Resonance Images: A Preliminary Machine Learning Study.

AIM: To propose a convolutional neural network (CNN) for the automatic detection of high-grade gliomas (HGGs) on T2-weighted magnetic resonance imaging (MRI) scans. MATERIAL AND METHODS: A total of 3580 images obtained from 179 individuals were used for training and validation. After random rotation and vertical flip, training data was augmented by factor of 10 in each iteration. In order to increase data processing time, every single image converted into a Jpeg image which has a resolution of 320x320. Accuracy, precision and recall rates were calculated after training of the algorithm. RESULTS: Following training, CNN achieved acceptable performance ratios of 0.854 to 0.944 for accuracy, 0.812 to 0.980 for precision and 0.738 to 0.907 for recall. Also, CNN was able to detect HGG cases even though there is no apparent mass lesion in the given image. CONCLUSION: Our preliminary findings demonstrate; currently proposed CNN model achieves acceptable performance results for the automatic detection of HGGs on T2-weighted images.

Protection from spinal cord ischemia-reperfusion damage with alpha-lipoic acid preconditioning in an animal model.

BACKGROUND: This study aims to investigate whether preconditioning with alpha-lipoic acid has any protective effect in neuronal damage in an experimental spinal cord ischemia-reperfusion injury model. METHODS: Eighteen adult male New Zealand rabbits (2.4-3.5 kg) were equally divided into sham, control and treatment groups. The abdominal aorta was occluded for 30 min proximally 1 cm below the renal artery and distally 1 cm above the bifurcation using aneurysm clips in control and treatment groups. Treatment group received intraperitoneal 100 mg/kg lipoic acid 20 min before aortic cross-clamping. The animals were sacrificed 48 hours after the operation and spinal cord segments between L2 and L5 were removed for biochemical and histopathological analysis. Levels of glutathione, malondialdehyde, total nitrate/nitrite, advanced oxidation protein products, catalase, superoxide dismutase, and glutathione peroxidase were examined in spinal cord. RESULTS: Preconditioning with alpha-lipoic acid demonstrated significantly favorable effects in all measured parameters of oxidative stress. Histopathological evaluation of the tissues also demonstrated significantly decreased neuronal degeneration, axonal damage, and microglial and astrocytic infiltration in the treatment group compared to the control group. CONCLUSION: The results of this study indicate that alpha-lipoic acid administration before aortic cross-clamping has significant neuroprotective effect on spinal cord injury in rabbits.

Effects of positive end-expiratory pressure on intracranial pressure during pneumoperitoneum and Trendelenburg position in a porcine mode

Background/aim: This study was undertaken to evaluate the effects of positive end-expiratory pressure (PEEP) levels on intracranial pressure (ICP) and cerebral perfusion pressure (CPP) and to determine the appropriate PEEP level during steep Trendelenburg position combined with pneumoperitoneum.Materials and methods: Ten pigs were included in this study. Pneumoperitoneum and Trendelenburg position were maintained and PEEP titration was initiated. Arterial pressure, heart rate, arterial blood gas, ICP, and CPP were recorded at the following time points: baseline (T0), 30 min after positioning and pneumoperitoneum (T1), PEEP 5 (T2), PEEP 10 (T3), PEEP 15 (T4), and PEEP 20 (T5).Results: MAP significantly increased at T1 compared to T0 and decreased at T4 and T5 compared to T1. ICP was 9.5 mmHg and CPP was 69.3 mmHg at T0. CO2 insufflation and steep Trendelenburg position did not cause any significant difference in ICP and CPP. ICP increased and CPP decreased significantly at T4 and T5 compared to both T0 and T1. PaO2 and PaO2/FiO2 decreased significantly at T1 and T2 compared to T0, while both increased significantly at T3, T4, and T5 compared to T1.Conclusion: PEEP of 10 cmH2O was effective for providing oxygenation while preserving hemodynamic stability, ICP, and CPP in this model.

Endovascular Treatment of Intracranial Anterior Circulation Aneurysms with Flow Diverters: A Single Centre Experience with mid and long-term results.

AIM: We report our experience with flow diverter devices in the treatment of intracranial aneurysms arising from anterior circulation with mid and long-term follow-up. MATERIAL AND METHODS: 78 aneurysms in 61 patients (range 25-81 years, 13 male, 48 female) were treated with flow diverter devices. 40 (51,3%) aneurysms were treated with pipeline embolization device (PED), 24 (30,8%) aneurysms were treated with SILK stent, 12(15,4%) aneurysms were treated with flow redirection endoluminal device (FRED) and two aneurysms were treated with P64 Flow Modulation Device (P64). Angiographic follow-up data at six month and one yea were recorded and the occlusion degrees of aneurysms were evaluated according to the scale which was formed by Kamran et al. RESULTS: At six month follow-up, complete occlusion (grade 4) rate was 60,8% and at one year increased to 74,3%. Statistical analysis revealed significant difference (p=0,002) between six month and one year follow-up results but there was no significant association (p=0,531, p=1,000) between aneurysm occlusion rate and aneurysm diameter. Two patient (3,2%) died due to hemorrhagic complication. CONCLUSION: Endovascular treatment of intracranial anterior circulation aneurysms with flow diverters is a safe and effective treatment option. A high rate of stable occlusion is achieved at long term follow-up.

The Effect of Hydrogen Sulphide on Experimental Cerebral Vasospasm.

AIM: Cerebral vasospasm is the primary cause of morbidity and mortality after subarachnoid hemorrhage (SAH). Hydrogen Sulfide (H < sub > 2 < /sub > S), a gaseous neurotransmitter, is produced in many tissues including the central nervous system (CNS). The vasodilatatory effect of H2S has been shown in the CNS; however, its role in cerebral vasospasm has not been investigated before. MATERIAL AND METHODS: The rats were divided into 8 groups: control, SAH, sodium hydrosulphide (NaHS), propargylglycine (PPG), aminooxy acetic acid (AOAA), SAH+NaHS, SAH+PPG, and SAH+AOAA. After establishing experimental SAH, the basilar artery and brain stem were harvested at 24th hours. The diameter and wall thickness of basilar artery were measured. Production of H2S was assessed by showing the activity of cystathionine ?-synthase (CBS) and cystathionine ?-lyase enzymes (CSE). RESULTS: NaHS treatment significantly reduced vasospasm at 24 hours following SAH. This vasodilatatory effect was correlated with the CSE expression in basilar artery. CSE and CBS enzyme expressions were significantly lower in brain stem and basilar artery in PPG and AOAA-treated groups. PPG and AOAA treatments exerted a vasoconstrictive effect in the basilar artery. There were statistically significant differences between NaHS, PPG and AOAA groups, in terms of basilar artery luminal diameter. CONCLUSION: H < sub > 2 < /sub > S may have a therapeutic potential in the treatment of vasospasm with its vasodilatator activity.