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Abstract Tumor-associated microglia and blood-derived macrophages (TAMs) play a central role in modulating the immune suppressive microenvironment in glioma. Here, we show that GPNMB is predominantly expressed by TAMs in human glioblastoma multiforme and the murine RCAS-PDGFb high grade glioma model. Loss of GPNMB in the in vivo tumor microenvironment results in significantly smaller tumor volumes and generates a pro-inflammatory innate and adaptive immune cell microenvironment. The impact of host-derived GPNMB on tumor growth was confirmed in two distinct murine glioma cell lines in organotypic brain slices from GPNMB-KO and control mice. Using published data bases of human glioma, the elevated levels in TAMs could be confirmed and the GPNMB expression correlated with a poorer survival.

Introduction: The integration of augmented reality (AR) in spine surgery marks a significant advancement, enhancing surgical precision and patient outcomes. AR provides immersive, three-dimensional visualizations of anatomical structures, facilitating meticulous planning and execution of spine surgeries. This technology not only improves spatial understanding and real-time navigation during procedures but also aims to reduce surgical invasiveness and operative times. Despite its potential, challenges such as model accuracy, user interface design, and the learning curve for new technology must be addressed. AR’s application extends beyond the operating room, offering valuable tools for medical education and improving patient communication and satisfaction. Material and methods: A literature review was conducted by searching PubMed and Scopus databases using keywords related to augmented reality in spine surgery, covering publications from January 2020 to January 2024. Results: In total, 319 articles were identified through the initial search of the databases. After screening titles and abstracts, 11 articles in total were included in the qualitative synthesis. Conclusion: Augmented reality (AR) is becoming a transformative force in spine surgery, enhancing precision, education, and outcomes despite hurdles like technical limitations and integration challenges. AR’s immersive visualizations and educational innovations, coupled with its potential synergy with AI and machine learning, indicate a bright future for surgical care. Despite the existing obstacles, AR’s impact on improving surgical accuracy and safety marks a significant leap forward in patient treatment and care.

Background: The sciatic nerve (SN) is the widest nerve of the human body that exits the pelvis through the greater sciatic foramen, usually below the piriformis muscle (PM), and descends between the greater trochanter of the femur and ischial tuberosity of the pelvis to the knee. The aim of this paper is to examine and identify the SN variations in relation to the PM, its prevalence, pattern, and course. Methods: A prospective-descriptive cross-sectional study was carried out to determine the frequency of anatomical variations in the exit of the SN in relation with the PM in 20 anatomical bodies (corpses) of both genders, in equal numbers. Results: The dissection of 40 SNs in corpses of both sexes in equal numbers showed that the SN exited inferior to the PM in 37 lower limbs (92.5%); between the fascicles of the PM and inferior to the PM in two lower limbs (5%); and in one thigh, between the fascicles of the PM and superior to the PM (2.5%). Our study reported that the SN divides in its terminal branches more commonly in the proximal part of the popliteal fossa in 55% of cases, in the gluteal region in 35% of cases, and in the middle third of the thigh in 10% of cases. Conclusions: Anatomical variations of the SN in relation to the PM are challenging for the diagnostic and therapeutic procedure in many clinical and surgical cases. Rapid recognition of the SN changes makes surgical approaches more accurate and effective. Our study confirmed that the SN exits the pelvis most commonly below the PM, although some anatomical variations may occur.

In subarachnoid hemorrhage following traumatic brain injury (TBI), the high intracisternal pressure drives the cerebrospinal fluid into the brain parenchyma, causing cerebral edema. Basal cisternostomy involves opening the basal cisterns to atmospheric pressure and draining cerebrospinal fluid in an attempt to reverse the edema. We describe a case of basal cisternostomy combined with decompressive craniectomy. A 35-year-old man with severe TBI following a road vehicle accident presented with acute subdural hematoma, Glasgow coma scale score of 6, fixed pupils and no corneal response. Opening of the basal cisterns and placement of a temporary cisternal drain led to immediate relaxation of the brain. The patient had a Glasgow coma scale score of 15 on postoperative day 6 and was discharged on day 10. We think basal cisternostomy is a feasible and effective procedure that should be considered in the management of TBI.

Objectives: Variations in the morphological anatomy of the median nerve such as formation, distribution, and communication have been well documented. All these variations should be taken into account when practicing any surgical approach for the treatment of injuries affecting the median nerve. Furthermore, they are of the utmost importance for interpretation of the clinical presentation. Methods: The objective of this investigation was to determine the anatomical variations in the formation of the median nerve in cadavers at the Forensic Pathology department in Central Clinical Hospital of the Academy of Sciences of the Russian Federation between January 2022 and April 2022. A descriptive, cross-sectional, and prospective information source study was conducted on 42 anatomical bodies (corpses) and 84 brachial plexuses. Results: After analyzing the results obtained in this investigation, we concluded that the median nerve presented variation in its formation in 22.6% of the investigated cases. These variations were more common in males (81.8%) than females (18.2%). The anatomical variation was unilateral in 7.1% and bilateral in 19% of all anatomical bodies examined. Conclusions: The median nerve presented a great number of variations in its formation in roughly 23% of the anatomical bodies, with male being the predominant gender. Furthermore, the most frequent region of formation was the axillary region (92.9%). For clinicians, it is important to remember these variations during surgical procedures in this area and during brachial plexus block.

BackgroundAnterior cervical discectomy and fusion (ACDF) is an often performed procedure in spine neurosurgery. These are often performed using an operating microscope (OM) for better illumination and visualization. But its use is limited to the surgeon and the assistant. There is difficulty in maneuvering long surgical instruments due to the limited space available. Exoscope (EX) has been used as an alternative to microscopes and endoscopes. We used an EX in patients undergoing ACDF for cervical spondylotic myelopathy.MethodsA prospective comparative trial was conducted to test the safety and usability of a low-cost EX compared to a conventional surgical binocular OM in ACDF. Twenty-six patients with degenerative cervical myelopathy symptoms were operated by ACDF assisted by the EX and OM between December 2021 and June 2022. The authors collected and compared data on operative time, intraoperative hemorrhage, hospital admission, and complications in the two groups.ResultsThere were no statistically significant differences between the two groups in mean operative time, hospital stay, or postoperative complications. The average intraoperative blood loss was significantly more in the OM group. There were no surgical complications related to the use of the EX or OM. The comfort level, preoperative setup and intraoperative adjustment of position and angle of the EX were rated higher than the OM group. The image quality, depth perception, and illumination were rated as inferior to that of the OM. The low-cost EX was rated to be superior to that of the OM with regard to education and training purposes.ConclusionOur study showed that the low-cost EX appears to be a safe and effective alternative for OM-assisted ACDF with great comfort and ergonomics and serves as an essential tool for education and training purposes. However, some limitations of our EX included slightly inferior image quality and illumination when compared with the OM.

Background and Objectives: Neurosurgery has been underrepresented in the medical school curriculum. Advances in augmented reality and 3D printing have opened the way for early practical training through simulations. We assessed the usability of the UpSurgeOn simulation-based training model and report first experiences from a hands-on neurosurgery course for medical students. Materials and Methods: We organized a two-day microneurosurgery simulation course tailored to medical students. On day one, three neurosurgeons demonstrated anatomical explorations with the help of life-like physical simulators (BrainBox, UpSurgeOn). The surgical field was projected onto large high-definition screens by a robotic-assisted exoscope (RoboticScope, BHS Technologies). On day two, the students were equipped with microsurgical instruments to explore the surgical anatomy of the pterional, temporal and endoscopic retrosigmoid approaches. With the help of the RoboticScope, they simulated five clipping procedures using the Aneurysm BrainBox. All medical students filled out a digital Likert-scale-based questionnaire to evaluate their experiences. Results: Sixteen medical students participated in the course. No medical students had previous experience with UpSurgeOn. All participants agreed that the app helped develop anatomical orientation. They unanimously agreed that this model should be part of residency training. Fourteen out of sixteen students felt that the course solidified their decision to pursue neurosurgery. The same fourteen students rated their learning experience as totally positive, and the remaining two rated it as rather positive. Conclusions: The UpSurgeOn educational app and cadaver-free models were perceived as usable and effective tools for the hands-on neuroanatomy and neurosurgery teaching of medical students. Comparative studies may help measure the long-term benefits of UpSurgeOn-assisted teaching over conventional resources.

Abstract Microglia are the primary immune-competent cells of the central nervous system (CNS) and sense both pathogen- and host-derived factors through several receptor systems including the Toll-like receptor (TLR) family. Although TLR5 has previously been implicated in different CNS disorders including neurodegenerative diseases, its mode of action in the brain remained largely unexplored. We sought to determine the expression and functional consequences of TLR5 activation in the CNS. Quantitative real-time PCR and immunocytochemical analysis revealed that microglia is the major CNS cell type that constitutively expresses TLR5. Using Tlr5 −/− mice and inhibitory TLR5 antibody we found that activation of TLR5 in microglial cells by its agonist flagellin, a principal protein component of bacterial flagella, triggers their release of distinct inflammatory molecules, regulates chemotaxis, and increases their phagocytic activity. Furthermore, while TLR5 activation does not affect tumor growth in an ex vivo GL261 glioma mouse model, it triggers microglial accumulation and neuronal apoptosis in the cerebral cortex in vivo. TLR5-mediated microglial function involves the PI3K/Akt/mammalian target of rapamycin complex 1 (mTORC1) pathway, as specific inhibitors of this signaling pathway abolish microglial activation. Taken together, our findings establish TLR5 as a modulator of microglial function and indicate its contribution to inflammatory and injurious processes in the CNS.

Background: Because nearly 23,000 more neurosurgeons are needed globally to address 5 million essential neurosurgical cases that go untreated each year, there is an increasing interest in task-shifting and task-sharing (TS/S), delegating neurosurgical tasks to nonspecialists, particularly in low- and middle-income countries (LMICs). This global survey aimed to provide a cross-sectional understanding of the prevalence and structure of current neurosurgical TS/S practices in LMICs. Methods: The survey was distributed to a convenience sample of individuals providing neurosurgical care in LMICs with a Web-based survey link via electronic mailing lists of continental societies and various neurosurgical groups, conference announcements, e-mailing lists, and social media platforms. Country-level data were analyzed by descriptive statistics. Results: The survey yielded 127 responses from 47 LMICs; 20 countries (42.6%) reported ongoing TS/S. Most TS/S procedures involved emergency interventions, the top 3 being burr holes, craniotomy for hematoma evacuation, and external ventricular drain. Most (65.0%) believed that their Ministry of Health does not endorse TS/S (24.0% unsure), and only 11% believed that TS/S training was structured. There were few opportunities for TS/S providers to continue medical education (11.6%) or maintenance of certification (9.4%, or receive remuneration (4.2%). Conclusions: TS/S is ongoing in many LMICs without substantial structure or oversight, which is concerning for patient safety. These data invite future clinical outcomes studies to assess effectiveness and discussions on policy recommendations such as standardized curricula, certification protocols, specialist oversight, and referral networks to increase the level of TS/S care and to continue to increase the specialist workforce. Key words: Capacity, Global health, Global neurosurgery, LMIC, Task-sharing, Task-shifting, Workforce

Summary: Microglia express Toll-like receptors (TLRs) that sense pathogen- and host-derived factors, including single-stranded RNA. In the brain, let-7 microRNA (miRNA) family members are abundantly expressed, and some have recently been shown to serve as TLR7 ligands. We investigated whether let-7 miRNA family members differentially control microglia biology in health and disease. We found that a subset of let-7 miRNA family members function as signaling molecules to induce microglial release of inflammatory cytokines, modulate antigen presentation, and attenuate cell migration in a TLR7-dependent manner. The capability of the let-7 miRNAs to control microglial function is sequence specific, mapping to a let-7 UUGU motif. In human and murine glioblastoma/glioma, let-7 miRNAs are differentially expressed and reduce murine GL261 glioma growth in the same sequence-specific fashion through microglial TLR7. Taken together, these data establish let-7 miRNAs as key TLR7 signaling activators that serve to regulate the diverse functions of microglia in health and glioma. : Buonfiglioli et al. elucidate the role of let-7 miRNAs acting as Toll-like receptor (TLR) ligands in the brain. Select let-7 miRNAs function as signaling molecules to modulate diverse microglial functions and glioma growth through TLR7. These data establish let-7 miRNAs as TLR7 signaling activators of microglia in health and glioma. Keywords: glioblastoma, lethal-7, microglia, microRNA, Toll-like receptor 7