Treatment of Clival Giant Cell Tumor: A Case Report and Literature Review.

Giant cell tumors (GCTs) are locally aggressive primary bone tumors of osteoclast-like cells. Most GCTs occur within the long bones, and primary GCTs involving the clivus are extremely rare. We present the case of an 18-year-old boy with binocular horizontal diplopia with an insidious onset who was found to have a hypointense enhancing mass involving the clivus and left side dorsum sellae on magnetic resonance images. The tumor was completely resected via an endoscopic endonasal transclival approach, and histopathologic examination via immunohistochemistry indicated a GCT. The patient's left abducens nerve palsy improved slightly after surgery. Because of the rarity of GCTs, there is no consensus about the definitive treatment protocol. However, we suggest that gross total resection is the treatment of choice, and denosumab plays a critical role in patients with subtotal resection.

Central neurocytoma exhibits radial glial cell signatures with FGFR3 hypomethylation and overexpression.

We explored the genomic events underlying central neurocytoma (CN), a rare neoplasm of the central nervous system, via multiomics approaches, including whole-exome sequencing, bulk and single-nuclei RNA sequencing, and methylation sequencing. We identified FGFR3 hypomethylation leading to FGFR3 overexpression as a major event in the ontogeny of CN that affects crucial downstream events, such as aberrant PI3K-AKT activity and neuronal development pathways. Furthermore, we found similarities between CN and radial glial cells based on analyses of gene markers and CN tumor cells and postulate that CN tumorigenesis is due to dysregulation of radial glial cell differentiation into neurons. Our data demonstrate the potential role of FGFR3 as one of the leading drivers of tumorigenesis in CN.

A prospective multicenter assessor blinded pilot study using confocal laser endomicroscopy for intraoperative brain tumor diagnosis.

In this multi-center, assessor-blinded pilot study, the diagnostic efficacy of cCeLL-Ex vivo, a second-generation confocal laser endomicroscopy (CLE), was compared against the gold standard frozen section analysis for intraoperative brain tumor diagnosis. The study was conducted across three tertiary medical institutions in the Republic of Korea. Biopsy samples from newly diagnosed brain tumor patients were categorized based on location and divided for permanent section analysis, frozen section analysis, and cCeLL-Ex vivo imaging. Of the 74 samples from 55 patients, the majority were from the tumor core (74.3%). cCeLL-Ex vivo exhibited a relatively higher diagnostic accuracy (89.2%) than frozen section analysis (86.5%), with both methods showing a sensitivity of 92.2%. cCeLL-Ex vivo also demonstrated higher specificity (70% vs. 50%), positive predictive value (PPV) (95.2% vs. 92.2%), and negative predictive value (NPV) (58.3% vs. 50%). Furthermore, the time from sample preparation to diagnosis was notably shorter with cCeLL-Ex vivo (13 min 17 s) compared to frozen section analysis (28 min 28 s) (p-value < 0.005). These findings underscore cCeLL-Ex vivo's potential as a supplementary tool for intraoperative brain tumor diagnosis, with future studies anticipated to further validate its clinical utility.

Measurement of the intersiphon distance for normal skull base development and estimation of the surgical window for the endoscopic transtuberculum approach in children.

OBJECTIVE: Due to the underdeveloped skull base in children, it is crucial to predict whether a sufficient surgical window for an endoscopic endonasal approach can be achieved. This study aimed to analyze the presumed surgical window through measurement of the intersiphon distance (ISD) and the planum-sella height (PSH) on the basis of age and its correlation with the actual surgical window for the endoscopic transtuberculum approach. METHODS: Twenty patients of each age from 3 to 18 years were included as the normal skull base population. ISD and PSH were measured and compared among consecutive ages. Additionally, 42 children with craniopharyngiomas or Rathke's cleft cysts who underwent treatment via the endoscopic transtuberculum approach were included. ISD and PSH were measured on preoperative images and then correlated with the dimensions of the surgical window on postoperative CT scans. The intraoperative endoscopic view was classified as narrow, intermediate, or wide based on operative photographs or videos, and relevant clinical factors were analyzed. RESULTS: In the normal skull base population, both ISD and the estimated area of the surgical window increased with age, particularly at 8 and 11 years old. On the other hand, PSH did not show an incremental pattern with age. Among the 42 children who underwent surgery, 24 had craniopharyngioma and 18 had Rathke's cleft cysts. ISD showed the strongest correlation with the actual area of the surgical window [r(40) = 0.69, p < 0.001] rather than with age or PSH. The visual grade of the intraoperative endoscopic view was narrow in 17 patients, intermediate in 21, and wide in 4. Preoperative ISD was 14.58 ± 1.29 mm in the narrow group, 16.13 ± 2.30 mm in the intermediate group, and 18.09 ± 3.43 mm in the wide group (p < 0.01). There were no differences in terms of extent of resection (p = 0.41); however, 2 patients in the narrow group had postoperative complications. CONCLUSIONS: Normal skull base development exhibited age-related growth. However, in children with suprasellar lesions, the measurement of the ISD showed a better correlation than age for predicting the surgical window for the endoscopic transtuberculum approach. Children with a small ISD should be approached with caution due to the limited surgical window.

Preoperative Serum Copeptin Can Predict Delayed Hyponatremia after Pituitary Surgery in the Absence of Arginine Vasopressin Deficiency.

BACKGRUOUND: Delayed postoperative hyponatremia (DPH) is the most common cause of readmission after pituitary surgery. In this study, we aimed to evaluate the cutoff values of serum copeptin and determine the optimal timing for copeptin measurement for the prediction of the occurrence of DPH in patients who undergo endoscopic transsphenoidal approach (eTSA) surgery and tumor resection. METHODS: This was a prospective observational study of 73 patients who underwent eTSA surgery for pituitary or stalk lesions. Copeptin levels were measured before surgery, 1 hour after extubation, and on postoperative days 1, 2, 7, and 90. RESULTS: Among 73 patients, 23 patients (31.5%) developed DPH. The baseline ratio of copeptin to serum sodium level showed the highest predictive performance (area under the curve [AUROC], 0.699), and its optimal cutoff to maximize Youden's index was 2.5×10-11, with a sensitivity of 91.3% and negative predictive value of 92.0%. No significant predictors were identified for patients with transient arginine vasopressin (AVP) deficiency. However, for patients without transient AVP deficiency, the copeptin-to-urine osmolarity ratio at baseline demonstrated the highest predictive performance (AUROC, 0.725). An optimal cutoff of 6.5×10-12 maximized Youden's index, with a sensitivity of 92.9% and a negative predictive value of 94.1%. CONCLUSION: The occurrence of DPH can be predicted using baseline copeptin and its ratio with serum sodium or urine osmolarity only in patients without transient AVP deficiency after pituitary surgery.

Validation of real-time inside-out tracking and depth realization technologies for augmented reality-based neuronavigation.

PURPOSE: Concomitant with the significant advances in computing technology, the utilization of augmented reality-based navigation in clinical applications is being actively researched. In this light, we developed novel object tracking and depth realization technologies to apply augmented reality-based neuronavigation to brain surgery. METHODS: We developed real-time inside-out tracking based on visual inertial odometry and a visual inertial simultaneous localization and mapping algorithm. The cube quick response marker and depth data obtained from light detection and ranging sensors are used for continuous tracking. For depth realization, order-independent transparency, clipping, and annotation and measurement functions were developed. In this study, the augmented reality model of a brain tumor patient was applied to its life-size three-dimensional (3D) printed model. RESULTS: Using real-time inside-out tracking, we confirmed that the augmented reality model remained consistent with the 3D printed patient model without flutter, regardless of the movement of the visualization device. The coordination accuracy during real-time inside-out tracking was also validated. The average movement error of the X and Y axes was 0.34 ± 0.21 and 0.04 ± 0.08 mm, respectively. Further, the application of order-independent transparency with multilayer alpha blending and filtered alpha compositing improved the perception of overlapping internal brain structures. Clipping, and annotation and measurement functions were also developed to aid depth perception and worked perfectly during real-time coordination. We named this system METAMEDIP navigation. CONCLUSIONS: The results validate the efficacy of the real-time inside-out tracking and depth realization technology. With these novel technologies developed for continuous tracking and depth perception in augmented reality environments, we are able to overcome the critical obstacles in the development of clinically applicable augmented reality neuronavigation.

Factors Limiting Complete Resection in the Subarachnoid Space in Endoscopic Surgery for Giant Pituitary Adenoma.

OBJECTIVES: Giant pituitary adenomas (>4 cm, GPAs) have presented great challenges to surgeons because the residual tumor in the subarachnoid space can cause hemorrhage or vessel injury following apoplexy. This study aimed to investigate the factors limiting surgical success in endoscopic skull base surgery (ESS) for GPAs. METHODS: ESS was performed on 67 consecutive patients with GPAs from 2010 to 2020. We retrospectively analyzed the clinical and radiologic features and surgical outcomes. Correlations between the tumor characteristics and extent of resection were statistically presented with odds ratios (ORs). RESULTS: Preoperative visual and hormonal impairments were present in 59 (88.1%) and 55 patients (82.1%), respectively. Gross total resection (GTR) was achieved in 58.2% of patients, and the tumor remained on the lateral side of the subarachnoid space or the cavernous sinus when complete resection failed. The tumor volume, maximal diameter, multilobulated shape, cavernous sinus invasion, posterior fossa extension, and extent of suprasellar lateral extension of tumors were significantly correlated with incomplete resection. In tumors with subarachnoid lateral extension, greater distances from the medial wall of the proximal cavernous internal carotid artery to the most lateral tumor significantly increased the risk of incomplete resection for the suprasellar lateral portion of the tumor, with an OR of 1.21. CONCLUSIONS: Considerable surgical planning in ESS for GPAs is crucial for complete resection and patient safety. We elucidated that lateral extension of tumors in the subarachnoid space hindered the surgical success of the suprasellar portion of the tumor.

Survival and Malignant Transformation of Pineal Parenchymal Tumors: A 30-Year Retrospective Analysis in a Single-Institution.

BACKGROUND: This study aims to elucidate clinical features, therapeutic strategies, and prognosis of pineal parenchymal tumors (PPT) by analyzing a 30-year dataset of a single institution. METHODS: We reviewed data from 43 patients diagnosed with PPT at Seoul National University Hospital between 1990 and 2020. We performed survival analyses and assessed prognostic factors. RESULTS: The cohort included 10 patients with pineocytoma (PC), 13 with pineal parenchymal tumor of intermediate differentiation (PPTID), and 20 with pineoblastoma (PB). Most patients presented with hydrocephalus at diagnosis. Most patients underwent an endoscopic third ventriculostomy and biopsy, with some undergoing additional resection after diagnosis confirmation. Radiotherapy was administered with a high prevalence of gamma knife radiosurgery for PC and PPTID, and craniospinal irradiation for PB. Chemotherapy was essential in the treatment of grade 3 PPTID and PB. The 5-year progression-free survival rates for PC, grade 2 PPTID, grade 3 PPTID, and PB were 100%, 83.3%, 0%, and 40%, respectively, and the 5-year overall survival rates were 100%, 100%, 40%, and 55%, respectively. High-grade tumor histology was associated with lower survival rates. Significant prognostic factors varied among tumor types, with World Health Organization (WHO) grade and leptomeningeal seeding (LMS) for PPTID, and the extent of resection and LMS for PB. Three patients experienced malignant transformations. CONCLUSION: This study underscores the prognostic significance of WHO grades in PPT. It is necessary to provide specific treatment according to tumor grade. Grade 3 PPTID showed a poor prognosis. Potential LMS and malignant transformations necessitate aggressive multimodal treatment and close-interval screening.

Surgical indication of pediatric Rathke's cleft cyst based on a 20-year retrospective cohort.

OBJECTIVE: Rathke's cleft cyst (RCC) is the most commonly encountered pituitary incidentaloma in children. Because RCC is not frequently diagnosed in children, there are few reports on pediatric RCCs. The natural course of the disease and appropriate treatments are still obscure. The present study aimed to elucidate the natural history and surgical indications of RCCs in children. METHODS: The authors retrospectively reviewed the clinical presentations, imaging features, ophthalmological evaluations, endocrine evaluations, and surgical outcomes of pediatric RCCs at a single institution from January 2000 to October 2022. Clinical outcomes between the surgery and observation groups were compared. RESULTS: Among 93 patients, there were 41 patients in the surgery group and 52 patients in the observation group. The mean age at diagnosis was 10.9 years, and the mean follow-up period was 5.6 years. Headache fully or partially improved after surgery (86.2%), but the rate of improvement was not different from that of the observation group (70.0%). Ophthalmological abnormalities were effectively improved by surgical treatment (93.3%). Both the improvement and deterioration rates of endocrine abnormalities were significantly higher in the surgery group (p = 0.026 and p < 0.001, respectively), but the deterioration rate (43.9%) was higher than the improvement rate (14.6%). In the surgery group, the recurrence rate was 17.1% and the reoperation rate was 4.9%. Compared with total cyst wall resection, cyst fenestration with partial wall resection was associated with a higher recurrence rate (26.9%, p = 0.035) but a lower rate of endocrine abnormalities (30.8%, p = 0.049). CONCLUSIONS: Pediatric RCCs of ≥ 10 mm in size were analyzed. Ophthalmological abnormalities are the major surgical indications for pediatric RCCs. Headache and partial endocrine abnormalities may be improved with surgery, but they are not absolute indications for surgery. Cyst fenestration with partial wall resection via an endoscopic endonasal approach is the most recommended surgical method. Follow-up is essential to monitor for the occurrence of visual field defects and the recurrence of cysts.

Changes of Resection Goal After Using 3-Dimensional Printing Brain Tumor Model for Presurgical Planning.

BACKGROUND: Conventional 2-Dimensional magnetic resonance imaging-based neuronavigation systems can improve the maximal safe resection in brain tumor surgery but can be unintuitive. A 3-Dimensional (3D)-printed brain tumor model allows for a more intuitive and stereoscopic understanding of brain tumors and adjacent neurovascular structures. This study aimed to identify the clinical efficacy of a 3D-printed brain tumor model in presurgical planning by focusing on differences in the extent of resection (EOR). METHODS: Thirty two neurosurgeons (14 faculty members, 11 fellows, 7 residents) randomly selected the two 3D-printed brain tumor models from the 10 manufactured models and performed presurgical planning following a standardized questionnaire. To compare the 2-Dimensional magnetic resonance imaging-based planning results with the 3D-printed model-based planning results, we analyzed the changing patterns and characteristics of the EOR. RESULTS: Of 64 randomly generated cases, the resection goal changed in 12 cases (18.8%). When the tumor was located intra-axially, the surgical posture required a prone position, and when the neurosurgeon was dexterous in surgery, there was a higher rate of EOR changes. 3D-printed models 2, 4, and 10, which all represented tumors in the posterior of the brain, had high rates of changing EOR. CONCLUSIONS: A 3D-printed brain tumor model could be utilized in presurgical planning to effectively determine the EOR.

Obesity mechanism after hypothalamic damage: Cohort analysis of neuroimaging, psychological, cognitive, and clinical phenotyping data.

Objective: The hypothalamus regulates energy homeostasis, and its damage results in severe obesity. We aimed to investigate the multifaceted characteristics of hypothalamic obesity. Methods: We performed multidimensional analyses of brain structure/function and psychological and behavioral phenotypes in 29 patients with hypothalamic damage (HD) (craniopharyngioma) and 31 controls (non-functional pituitary adenoma). Patients underwent structural and functional magnetic resonance imaging and completed self-reports and cognitive tasks. Results: Patients with HD showed significantly higher postoperative weight gain than controls. The HD group also showed significant hypothalamic damage and lower neural activation in the left caudate nucleus in response to food images. The HD group had significantly higher food inattention, lower satiety, and higher restrained eating behavior. Within the HD group, higher restrained eating behavior was significantly associated with lower activation in the bilateral fusiform gyrus. Conclusion: These results suggest that hypothalamic damage contributes to weight gain by altering the brain response, attention, satiety, and eating behaviors. The present study proposes novel neuro-psycho-behavioral mechanisms targeted for patients with hypothalamic obesity.

Serum and hair steroid profiles in patients with nonfunctioning pituitary adenoma undergoing surgery: A prospective observational study.

Patients who undergo transsphenoidal surgery (TSS) experience perioperative hormonal changes, but there are few studies on the perioperative changes of serum and hair steroid profiles. This study investigated the perioperative changes in steroid metabolic signatures in patients with nonfunctioning pituitary adenoma (NFPA) who underwent transsphenoidal surgery (TSS). A total of 55 participants who underwent TSS for NFPA at a single center between July 2017 and October 2018 were enrolled. Fifteen serum steroids and their metabolic ratios were profiled using gas chromatography-mass spectrometry (GC-MS) before and 1 day, 1 week, and 3 months after TSS. Five steroids from hair samples collected 1 day and 3 months after TSS were also quantitatively compared. Serum cortisol and its A-ring reductive metabolites, as well as 6ß-hydroxycortisol, increased dramatically 1 day after TSS and then gradually decreased. Seven serum steroids, including adrenal androgens and mineralocorticoids, and hair cortisone levels were significantly lower in patients with preoperative adrenocorticotropic hormone (ACTH) deficiency (N = 7) than in those without ACTH deficiency (N = 48). Serum levels of dehydroepiandrosterone (DHEA) levels 1 week after TSS predicted ACTH deficiency 3 months after TSS, with 100 % sensitivity and 86 % specificity. A significant positive correlation between the preoperative serum and hair DHEA levels (r = 0.356, P = 0.008) was observed. These findings suggest that the levels of DHEA in both the serum and hair could be an early marker of ACTH deficiency after TSS. In addition, hair cortisone may be a useful preoperative indicator of chronic ACTH deficiency.

Fully Automated MRI Segmentation and Volumetric Measurement of Intracranial Meningioma Using Deep Learning.

BACKGROUND: Accurate and rapid measurement of the MRI volume of meningiomas is essential in clinical practice to determine the growth rate of the tumor. Imperfect automation and disappointing performance for small meningiomas of previous automated volumetric tools limit their use in routine clinical practice. PURPOSE: To develop and validate a computational model for fully automated meningioma segmentation and volume measurement on contrast-enhanced MRI scans using deep learning. STUDY TYPE: Retrospective. POPULATION: A total of 659 intracranial meningioma patients (median age, 59.0 years; interquartile range: 53.0-66.0 years) including 554 women and 105 men. FIELD STRENGTH/SEQUENCE: The 1.0 T, 1.5 T, and 3.0 T; three-dimensional, T1 -weighted gradient-echo imaging with contrast enhancement. ASSESSMENT: The tumors were manually segmented by two neurosurgeons, H.K. and C.-K.P., with 10 and 26 years of clinical experience, respectively, for use as the ground truth. Deep learning models based on U-Net and nnU-Net were trained using 459 subjects and tested for 100 patients from a single institution (internal validation set [IVS]) and 100 patients from other 24 institutions (external validation set [EVS]), respectively. The performance of each model was evaluated with the Sørensen-Dice similarity coefficient (DSC) compared with the ground truth. STATISTICAL TESTS: According to the normality of the data distribution verified by the Shapiro-Wilk test, variables with three or more categories were compared by the Kruskal-Wallis test with Dunn's post hoc analysis. RESULTS: A two-dimensional (2D) nnU-Net showed the highest median DSCs of 0.922 and 0.893 for the IVS and EVS, respectively. The nnU-Nets achieved superior performance in meningioma segmentation than the U-Nets. The DSCs of the 2D nnU-Net for small meningiomas less than 1 cm3 were 0.769 and 0.780 with the IVS and EVS, respectively. DATA CONCLUSION: A fully automated and accurate volumetric measurement tool for meningioma with clinically applicable performance for small meningioma using nnU-Net was developed. EVIDENCE LEVEL: 3 TECHNICAL EFFICACY: Stage 2.

Endoscopic biopsy of pineal tumors: two burr hole trans-foramen of Monro approach and endonasal trans-tuber cinereum approach.

INTRODUCTION: The pineal region is a challenging area for neurosurgeons due to its innate anatomical features, such as its deep location, surrounding large draining veins, and adjacent critical neural structures. DISCUSSION: There is a high proportion of malignant tumors in the pineal gland, especially in children, and they are frequently accompanied by obstructive hydrocephalus. These cases require that surgical procedures can make a pathological diagnosis to guide further treatment strategies and immediately resolve increased intracranial pressure. Simultaneous endoscopic third ventriculostomy and biopsy have been regarded as the first-line surgical intervention before establishing a definite treatment plan. However, it is not always successful because various factors affect the surgical procedures, such as the location and extent of the tumor, degree of ventriculomegaly, location and size of the massa intermedia, and size of the foramen of Monro. CONCLUSION: Here, we briefly reviewed the points to be considered in endoscopic biopsy of pineal tumors and introduced an alternative surgical procedure, the endoscopic endonasal trans-tuber cinereum approach, to surmount the anatomical hurdles.

Serum copeptin levels at day two after pituitary surgery and ratio to baseline predict postoperative central diabetes insipidus.

PURPOSE: Central diabetes insipidus is a complication that may occur after pituitary surgery and has been difficult to predict. This study aimed to identify the cutoff levels of serum copeptin and its optimal timing for predicting the occurrence of central diabetes insipidus in patients who underwent transsphenoidal surgery. METHODS: This was a prospective observational study of patients who underwent transsphenoidal surgery for pituitary gland or stalk lesions. Copeptin levels were measured before surgery, 1 h after extubation, and on postoperative days 1, 2, 7, and 90. RESULTS: Among 73 patients, 14 (19.2%) and 13 (17.8%) patients developed transient and permanent central diabetes insipidus, respectively. There was no significant difference in copeptin levels before surgery and 1 h after extubation; copeptin levels on postoperative days 1, 2, 7, and 90 were significantly lower in patients with permanent central diabetes insipidus than in those without central diabetes insipidus. Copeptin measurement on postoperative day 2 exhibited the highest performance for predicting permanent central diabetes insipidus among postoperative days 1, 2, and 7 (area under the curve [95% confidence interval] = 0.754 [0.632-0.876]). Serum copeptin level at postoperative day 2(< 3.1 pmol/L) showed a sensitivity of 92.3% and a negative predictive value of 97.1%. The ratio of copeptin at postoperative day 2 to baseline (< 0.94) presented a sensitivity of 84.6% and a negative predictive value of 94.9%. The copeptin levels > 3.4 and 7.5 pmol/L at postoperative day 2 and 7 may have ruled out the occurrence of CDI with a negative predictive value of 100%. CONCLUSION: The copeptin level at postoperative day 2 and its ratio to baseline can predict the occurrence of permanent central diabetes insipidus after pituitary surgery.

A Novel Missense PRKAR1A Variant Causes Carney Complex.

The Carney complex (CNC) is an autosomal dominant disorder characterized by endocrine and nonendocrine tumors. Loss-of-function variants of protein kinase A regulatory subunit 1 alpha (PRKAR1A) are common causes of CNC. Here, we present the case of a patient with CNC with a novel PRKAR1A missense variant. A 21-year-old woman was diagnosed with CNC secondary to acromegaly and adrenal Cushing syndrome. Genetic analysis revealed a novel missense heterozygous variant of PRKAR1A (c.176A>T). Her relatives, suspected of having CNC, also carried the same variant. RNA analysis revealed that this variant led to nonsense-mediated mRNA decay. In vitro functional analysis of the variant confirmed its role in increasing protein kinase A activity and cyclic adenosine monophosphate levels. This study broadens our understanding of the genetic spectrum of CNC. We suggest that PRKAR1A genetic testing and counseling be recommended for patients with CNC and their families.

The telomere maintenance mechanism spectrum and its dynamics in gliomas.

BACKGROUND: The activation of the telomere maintenance mechanism (TMM) is one of the critical drivers of cancer cell immortality. In gliomas, TERT expression and TERT promoter mutation are considered to reliably indicate telomerase activation, while ATRX mutation and/or loss indicates an alternative lengthening of telomeres (ALT). However, these relationships have not been extensively validated in tumor tissues. METHODS: Telomerase repeated amplification protocol (TRAP) and C-circle assays were used to profile and characterize the TMM cross-sectionally (n = 412) and temporally (n = 133) across glioma samples. WES, RNA-seq, and NanoString analyses were performed to identify and validate the genetic characteristics of the TMM groups. RESULTS: We show through the direct measurement of telomerase activity and ALT in a large set of glioma samples that the TMM in glioma cannot be defined solely by the combination of telomerase activity and ALT, regardless of TERT expression, TERT promoter mutation, and ATRX loss. Moreover, we observed that a considerable proportion of gliomas lacked both telomerase activity and ALT. This telomerase activation-negative and ALT negative group exhibited evidence of slow growth potential. By analyzing a set of longitudinal samples from a separate cohort of glioma patients, we discovered that the TMM is not fixed and can change with glioma progression. CONCLUSIONS: This study suggests that the TMM is dynamic and reflects the plasticity and oncogenicity of tumor cells. Direct measurement of telomerase enzyme activity and evidence of ALT should be considered when defining TMM. An accurate understanding of the TMM in glioma is expected to provide important information for establishing cancer management strategies.

Development of 3-dimensional printed simulation surgical training models for endoscopic endonasal and transorbital surgery.

Background: Endoscopic skull base surgery (ESBS) is complex, requiring methodical and unremitting surgical training. Herein, we describe the development and evaluation of a novel three-dimensional (3D) printed simulation model for ESBS. We further validate the efficacy of this model as educational support in neurosurgical training. Methods: A patient-specific 3D printed simulation model using living human imaging data was established and evaluated in a task-based hands-on dissection program. Endoscopic endonasal and transorbital procedures were simulated on the model by neurosurgeons and otorhinolaryngology surgeons of varying experience. All procedures were recorded using a high-definition camera coupled with digital video recorder system. The participants were asked to complete a post-procedure questionnaire to validate the efficacy of the model. Results: Fourteen experts and 22 trainees participated in simulations, and the 32 participants completed the post-procedure survey. The anatomical realism was scored as 4.0/5.0. The participants rated the model as helpful in hand-eye coordination training (4.7/5.0) and improving surgical skills (4.6/5.0) for ESBS. All participants believed that the model was useful as educational support for trainees (4.7 [ ± 0.5]). However, the color (3.6/5.0) and soft tissue feedback parameters (2.8/5) scored low. Conclusion: This study shows that high-resolution 3D printed skull base models for ESBS can be generated with high anatomical accuracy and acceptable haptic feedback. The simulation program of ESBS using this model may be supplemental or provide an alternative training platform to cadaveric dissection.

Advances in Pituitary Surgery.

Pituitary surgery has advanced considerably in recent years with the exploration and development of various endoscopic approaches and techniques. Different endoscopic skull base approaches are being applied to access sellar tumors in different locations. Moreover, extracapsular dissection and cavernous sinus exploration have enabled gross total resection of sellar tumors where it could not have been achieved in the past. Techniques for skull base reconstruction have also progressed, allowing surgeons to remove larger and more complicated tumors than before. This review article discusses different endoscopic skull base approaches, surgical techniques for removing pituitary adenomas, and reconstruction methods for repairing postoperative low-flow and high-flow cerebrospinal fluid leakage.

Complications of Endoscopic Skull Base Surgery for Sellar and Parasellar Tumors in Pediatric Population; Neurosurgical Perspectives.

Background: Advances in surgical techniques based on in-depth anatomical knowledge of the skull base have broadened the indications for endoscopic skull base surgery (ESS) with the advantage of wide and direct surgical exposure while minimizing invasiveness. However, the low incidence of the indicated diseases and narrow surgical corridors in children have limited the popularization of ESS. In addition, surgical complications and preventive interventions are not yet well known. Therefore, we retrospectively investigated the complications and prevention methods of ESS in children with a comprehensive review. Methods: We retrospectively analyzed the medical records of pediatric patients who underwent ESS for sellar and parasellar tumors at Seoul National University Children's Hospital from July 2010 to December 2020. Visual and endocrine status, extent of resection, complications, and recurrences were investigated depending on the pathology of the tumor. In addition, a comprehensive literature review regarding the complications of pediatric ESS was performed. Results: A total of 98 patients were enrolled. The median age of the patients was 12 years, and 52 patients were male. Preoperative visual disturbance was found in 53 patients, anterior pituitary function deficit in 69, and diabetes insipidus in 32. Gross total resection was attempted in 67 patients and achieved in 62 (93%). Biopsy and cyst fenestration were the goals of surgery in 26 patients, and all were achieved as planned. Regarding outcomes, visual disturbance worsened in two patients (2%), endocrine status was aggravated in 34 (35%) patients, and new-onset diabetes insipidus occurred in 27 (41%) patients. The overall surgical complication rate (other than aggravation of visual or endocrine status) was 17%. Postoperative meningitis (12%) was the most common complication, followed by cerebrospinal fluid leakage (2%), vasospasm, hemorrhage and infarction. By pathological diagnosis, craniopharyngioma had the highest complication rate of 29%. All but one patient with postoperative hemorrhage showed no permanent deficits. Conclusion: ESS in children is feasible and relatively safe. More attention and different postoperative management protocols are required in children to avoid complications, especially in craniopharyngiomas. However, the complications can be mostly managed conservatively without permanent neurologic deficits.