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.

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.

Effects of quercetin on chronic constriction nerve injury in an experimental rat model.

BACKGROUND: Flavonoids are popular substances in the literature, with proven effects on cardiovascular, neoplastic and neurodegenerative diseases. Antioxidant effect is the most pronounced and studied one. Among thousands of flavonoids, quercetin (QUE) is a prototype with significant antioxidant effects. This study aims to demonstrate the effects of QUE in an experimental rat model of chronic constriction injury (CCI). METHOD: A two-level study was designed with 42 adult Wistar rats that were randomly assigned to different groups. In the first part, animals in sham, control, quercetin, morphine and gabapentine groups received chronic constriction injury to their sciatic nerves and received a single dose of QUE, morphine and gabapentine. In the second part, different dose regimens of QUE were administered to different groups of animals. Pre-injury and post-injury assessments for mechanical hypersensitivity, thermal sensitivity, locomotor activity and anxiety were recorded and statistical comparisons were performed between different groups. RESULTS: Comparison of QUE with morphine and gabapentine has revealed significant effects of this agent in the current chronic constriction injury model. QUE was significantly superior to Gabapentine and morphine in terms of alleviating mechanical and thermal hypersensitivity. Additionally, pre-injury administration of QUE for 4 days demonstrated long-term effectiveness on mechanical hypersensitivity. CONCLUSIONS: This preliminary report the on effects of QUE in a chronic constriction injury model proved significant effects of the agent, which should be supplemented with different studies using different dose regimens.

Pathological evaluation of the filum terminale tissue after surgical excision.

PURPOSE: Tethered cord syndrome (TCS) is an important disease and can produce progressive neurological symptoms. Studies about the filum terminale (FT) have drawn attention to the importance of histopathological investigation of this structure. The most interesting of these subtypes is the FT that incorporates peripheral nerve fibers (PNF). Our study aimed to analyze the frequency of PNF in the FT of 40 cases diagnosed with TCS. METHODS: We performed a retrospective histopathological investigation of FT excised during surgery of patients with TCS who underwent de-tethering. Neurologic and other types of postoperative complications were also revised. RESULTS: Analysis of the samples showed six dominant histopathological subtypes in the FT: fibroadipose tissues including peripheral nerve bundles (n = 14, 37 %), fibroadipose tissue (n = 10, 25 %), fibrous or adipose tissue (n = 7, 17 %), glial tissues including peripheral nerve sections (n = 4, 10 %), and ependymal and glial tissues (n = 4, 10 %). None of the patients presented with neurologic postoperative complications. CONCLUSION: Embryologic studies revealed that it is common to encounter different histological subtypes of FT pathology. However, the presence of peripheral nerve cells in the FT is important for neurosurgical practice due to the risk of sectioning a functional structure during surgery. In our analysis, we demonstrated the high frequency of PNF in FT pathology. However, since none of the patients showed any symptoms of neurologic deterioration, we considered that these fibers were probably not functional. Our findings emphasize the importance of neuromonitoring in TCS surgery. Although we consider that most of the fibers are probably not functional, neuromonitoring after surgery may prevent serious complications.

Results of radiosurgery for trigeminal neuralgia: Ankara experience.

OBJECT: The purpose of this retrospective study is to demonstrate the effectiveness of Gamma Knife radiosurgery for essential trigeminal neuralgia (TGN) and assess the long-term outcome in a cohort from Turkey. METHODS: From 2004 to 2011, 93 cases of essential TGN were treated with single radiosurgery (RS). Female:male ratio was 45:48 and the mean age of the population was 57.06 years. Mean suffering time before treatment was 88.26 months. V2 + V3 was the most effected branch. 38.7% of the cases had no previous invasive procedures. Each case received doses ranging from 70 to 90 Gy in a target located at the pontine trigeminal root entry zone of the trigeminal nerve. Statistical analyses were performed to evaluate the outcome and factors leading to outcome status. RESULTS: The median follow-up period was 28 months. Of the cases 31.2% had poor outcome related to treatment failure after single RS session. The excellent and good outcomes were achieved in 29% and 39.8% of patients, respectively. The probability of maintaining pain relief was calculated as 67% at 36 months and 58% at 72 months. The only complication encountered was facial dysesthesia and was positive in 68.8% of patients. The presence of facial dysesthesia was significantly correlated with better outcomes. In this study, no other factor was determined to have significant influence on outcome. CONCLUSION: RS treatment for TGN is safe and effective. A multicenter, prospective, randomized controlled trial is needed to determine a guideline for better treatment protocols.

Gamma Knife radiosurgery for arteriovenous malformations in pediatric patients.

OBJECTIVE: The authors present the results of Gamma Knife stereotactic radiosurgery performed in a series of children with arteriovenous malformations (AVMs). METHODS: Between June 2005 and January 2014, 75 patients 18 years old or younger received Gamma Knife radiosurgery for AVMs. Of these, 58 patients were eligible for further analysis. The median age of the population was 12 years; 41% presented with hemorrhage, 34% with neurological insult, and 24% patients were diagnosed incidentally. The median AVM volume was 3.5 cm(3). The median radiosurgery-based AVM score (RSBAVMS) was 0.86. The median follow-up period was 32 months. RESULTS: Single session Gamma Knife radiosurgery resulted in complete AVM obliteration in 40 (68.9%) patients. There were 35 (60.3%) excellent outcome (complete obliteration with no new deficits) in this series. During the follow-up period, nine (15.51%) patients experienced new deficits and three (5.1%) patients experienced intracranial hemorrhage. The annual rate of developing new deficits and hemorrhage was calculated as 5.45 and 1.8%, respectively. Volume, gender, RSBAVMS, and nidus type factor were factors associated with excellent outcome. CONCLUSIONS: Radiosurgery was successful in majority of patients with minimal morbidity. Gamma Knife radiosurgery for AVMs can be a safe and successful method in pediatric patients.

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.

Split cord malformation: experience from a tertiary referral center.

AIM: To present clinical, radiological, and follow-up features of 34 cases with spinal split cord malformation (SCM) treated in a tertiary referral center between April 2000 and March 2012. METHODS: A total of 59 patients were treated due to SCM between April 2000 and March 2012 at the Gazi University Faculty of Medicine, Division of Pediatric Neurosurgery. Data for each patient were evaluated retrospectively, and age, sex, clinical findings, radiological findings, complications, and surgical results were recorded. Patients with a follow-up period of less than 6 months, patients harboring an open spinal dysraphism, and patients who had had their index surgery in another clinic were excluded, thus leaving a total of 34 patients for further analysis. RESULTS: There were 19 females and 15 males ranging in age from 2 months to 15 years (mean 5.04 years). In this cohort, skin stigma was the most common reason (76.5%) to seek medical care. Of the cases, 22 (64.7%) had lumbar SCM and 12 (35.3%) had thoracic SCM. There were no cervical SCM. Twenty-one (61.8%) of the cases had type 1 SCM and 13 (38.2%) had Type 2 SCM. Of the patients, 21 (61.8%) had a detectable neurological deficit at initial evaluation. There were no differences between patients with and without a neurological deficit regarding age, sex, type, and level of SCM. Overall evaluation of patients regarding their final neurological status revealed that 16 (47.1%) patients improved, 4 (11.8%) deteriorated, and 14 (41.2%) remained stable. CONCLUSIONS: In our opinion, all patients diagnosed with either type of SCM should be surgically treated to prevent further neurological deterioration. The results of this study, together with previously published data, confirm the effectiveness and safety of surgical intervention in SCM.

Effects of different surgical techniques on cephalic index and intracranial volume in isolated bilateral coronal synostosis model.

BACKGROUND: Bilateral coronal synostosis (brachycephaly) is the most common single-suture synostosis that may lead to functional deficits such as mental retardation. This increases the importance of volume gain during surgery. This study was designed to understand the differences in volume gain, cranial index (CI), and aesthetic outcomes when additional osteotomies or rotations are applied on the frontoparietal segment. METHODS: Acrylic brachycephaly models were prepared. Frontoparietal osteotomy was standard in all models. Frontoparietal segment was fixed: to the same position in surgical control model, after 1.2-cm advancement in advancement model, after 180-degree rotation without advancement in rotation model, after 180-degree rotation plus a horizontal osteotomy and 1.2-cm advancement in rotation plus angled advancement model, and after a horizontal osteotomy without rotation and 1.2-cm advancement and in angled advancement model. RESULTS: Intracranial volume changes (in milliliters) and CIs were as follows between groups: control group, 828/94.1; surgical control group, 830/93.8; advancement model, 900/84.5; rotation model, 834/89.1; rotation plus angled advancement model, 897/82.7; angled advancement model, 902/81.8. CONCLUSIONS: Advancement of the frontoparietal segment is the keystone of surgery in brachycephaly treatment. Making an additional horizontal osteotomy can angle this segment and may supply additional volume gain. Rotation of the frontoparietal segment does not provide additional volume or CI gain but increase better aesthetic outcomes.

Intraventricular dysembryoplastic neuroepithelial tumour: case report.

Dysembryoplastic neuroepithelial tumour (DNT) is located in the cerebral cortex with very few exceptions. In this article, an extremely rare case of intraventricular DNT originating from the septum pellucidum is reported. A 25-year-old woman presented with 5-month history of headache. Cranial magnetic resonance imaging (MRI) scans revealed a mass in the right lateral and third ventricle which was hypointense on T1-weighted image, and hyperintense on T2-weighted images. No contrast enhancement was detected. The lesion was excised totally using a transcallosal-transventricular approach. Immunohistochemical examination revealed DNT. The patient was discharged without any neurological deficits. Intraventricular DNT presents with symptoms of increased intracranial pressure rather than seizures. Distinguishing DNT from other intraventricular tumours is essential as DNT is characterized by benign clinical course and does not require adjuvant therapy.

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.

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.

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.

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.

Anti-apoptotic and neuroprotective effects of α-lipoic acid on spinal cord ischemia-reperfusion injury in rabbits.

PURPOSE: Radical oxygen species produced after injury counteracts antioxidant activity and frequently causes severe oxidative stress for the tissues. Alpha-lipoic acid is a powerful metabolic antioxidant with immunomodulatory effects which provides neuroprotection. The aim of this study is to investigate the neuroprotective and anti-apoptotic effects of alpha-lipoic acid on spinal cord ischemia-reperfusion. METHODS: Twenty-four adult, male, New Zealand rabbits were divided into sham (n = 8), control (n = 8), and treatment groups (n = 8). The abdominal aorta was clamped for 30 min by an aneurysm clip, approximately 1 cm below the renal artery and 1 cm above the iliac bifurcation in control and treatment groups. Only laparotomy was performed in the sham group. Twenty-five cubic centimeters of saline in control group and 100 mg/kg lipoic acid were administered intraperitoneally in the treatment group after closure of the incision. The animals were killed 48 h later. Spinal cord segments between L2 and S1 were harvested for analysis. Levels of nitric oxide, glutathione, malondialdehyde, advanced oxidation protein products, and superoxide dismutase were analyzed as markers of oxidative stress and inflammation. Caspase-3 activity was analyzed to detect the effect of lipoic acid on apoptosis. RESULTS: In all measured parameters of oxidative stress, administration of lipoic acid significantly demonstrated favorable effects. Both plasma and tissue levels of nitric oxide, glutathione, malondialdehyde, and advanced oxidation protein products significantly changed in favor of antioxidant activity. There was no significant difference between the plasma superoxide dismutase levels of the groups. Histopathological evaluation of the tissues also demonstrated significant decrease in cellular degeneration and infiltration parameters after lipoic acid administration. However, lipoic acid has no effect on caspase-3 activity. CONCLUSIONS: Although further studies considering different dose regimens and time intervals are required, the results of the present study prove that alpha-lipoic acid has favorable effects on experimental spinal cord ischemia-reperfusion injury.