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Introduction: Orbital surgery has always been disputed among specialists, mainly neurosurgeons, otorhinolaryngologists, maxillofacial surgeons and ophthalmologists. The orbit is a borderland between intra- and extracranial compartments; Krönlein's lateral orbitotomy and the orbitozygomatic infratemporal approach are the historical milestones of modern orbital-cranial surgery. Research question: Since its first implementation, endoscopy has significantly impacted neurosurgery, changing perspectives and approaches to the skull base. Since its first application in 2009, transorbital endoscopic surgery opened the way for new surgical scenario, previously feasible only with extensive tissue dissection. Material and methods: A PRISMA based literature search was performed to select the most relevant papers on the topic. Results: Here, we provide a narrative review on the current state and future trends in endoscopic orbital surgery. Discussion and conclusion: This manuscript is a joint effort of the EANS frontiers committee in orbital tumors and the EANS skull base section.

Introduction: Central to neurosurgical care, neurosurgical education is particularly needed in low- and middle-income countries (LMICs), where opportunities for neurosurgical training are limited due to social and economic constraints and an inadequate workforce. The present paper aims (1) to evaluate the validity and usability of a cadaver-free hybrid system in the context of LMICs and (2) to report their learning needs and whether the courses meet those needs via a comprehensive survey., Methods: From April to November 2021, a non-profit initiative consisting of a series of innovative cadaver-free courses based on virtual and practical training was organized. This project emerged from a collaboration between the Young Neurosurgeons Forum of the World Federation of Neurological Societies (WFNS), the NIHR Global Health Research Group on Neurotrauma, and UpSurgeOn, an Italian hi-tech company specialized in simulation technologies, creator of the UpSurgeOn Box, a hyper-realistic simulator of cranial approaches fused with augmented reality. Over that period, 11 cadaver-free courses were held in LMICs using remote hands-on Box simulators., Results: One hundred sixty-eight participants completed an online survey after course completion of the course. The anatomical accuracy of simulators was overall rated high by the participant. The simulator provided a challenging but manageable learning curve, and 86% of participants found the Box to be very intuitive to use. When asked if the sequence of mental training (app), hybrid training (Augmented Reality), and manual training (the Box) was an effective method of training to fill the gap between theoretical knowledge and practice on a real patient/cadaver, 83% of participants agreed. Overall, the hands-on activities on the simulators have been satisfactory, as well as the integration between physical and digital simulation., Conclusions: This project demonstrated that a cadaver-free hybrid (virtual/hands-on) training system could potentially participate in accelerating the learning curve of neurosurgical residents, especially in the setting of limited training possibilities such as LMICs, which were only worsened during the COVID-19 pandemic., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Background: Two statistical models have been established to evaluate characteristics associated with postoperative motor outcome in patients with glioma associated to the motor cortex (M1) or the corticospinal tract (CST). One model is based on a clinicoradiological prognostic sum score (PrS) while the other one relies on navigated transcranial magnetic stimulation (nTMS) and diffusion-tensor-imaging (DTI) tractography. The objective was to compare the models regarding their prognostic value for postoperative motor outcome and extent of resection (EOR) with the aim of developing a combined, improved model., Methods: We retrospectively analyzed a consecutive prospective cohort of patients who underwent resection for motor associated glioma between 2008 and 2020, and received a preoperative nTMS motor mapping with nTMS-based diffusion tensor imaging tractography. The primary outcomes were the EOR and the motor outcome (on the day of discharge and 3 months postoperatively according to the British Medical Research Council (BMRC) grading). For the nTMS model, the infiltration of M1, tumor-tract distance (TTD), resting motor threshold (RMT) and fractional anisotropy (FA) were assesed. For the PrS score (ranging from 1 to 8, lower scores indicating a higher risk), we assessed tumor margins, volume, presence of cysts, contrast agent enhancement, MRI index (grading white matter infiltration), preoperative seizures or sensorimotor deficits., Results: Two hundred and three patients with a median age of 50 years (range: 20-81 years) were analyzed of whom 145 patients (71.4%) received a GTR. The rate of transient new motor deficits was 24.1% and of permanent new motor deficits 18.8%. The nTMS model demonstrated a good discrimination ability for the short-term motor outcome at day 7 of discharge (AUC = 0.79, 95 %CI: 0.72-0.86) and the long-term motor outcome after 3 months (AUC = 0.79, 95 %CI: 0.71-0.87). The PrS score was not capable to predict the postoperative motor outcome in this cohort but was moderately associated with the EOR (AUC = 0.64; CI 0.55-0.72). An improved, combined model was calculated to predict the EOR more accurately (AUC = 0.74, 95 %CI: 0.65-0.83)., Conclusion: The nTMS model was superior to the clinicoradiological PrS model for potentially predicting the motor outcome. A combined, improved model was calculated to estimate the EOR. Thus, patient counseling and surgical planning in patients with motor-associated tumors should be performed using functional nTMS data combined with tractography., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 The Authors. Published by Elsevier Inc. All rights reserved.)

Background: An appreciation for complex three-dimensional relationships in neuroanatomy forms a fundamental tenet of neurosurgical education. The value of experience in the cadaver lab is indisputable; however, it is expensive and often inaccessible. The wide availability of 3D technologies has opened new possibilities, although scientific inaccuracy has hitherto limited their use., Objective: In the present study, we aim to describe a novel, literature-based process of scientific 3D modeling for the creation of neuroanatomical models adapted for mobile technology., Methods: A systematic literature review regarding current resources in neuroanatomy education was performed according to PRISMA guidelines. The composition of the team and the workflow behind the 3D Head Atlas app are also described., Results: A total of 101 manuscripts were reviewed, and 24 included. Cadaveric dissections improve the learning process, although high costs limit their availability. Digital advancements have partially overcome the limitations of dissection, and have been associated with improved knowledge retention. Nevertheless, 3D models are often inaccurate, poorly adapted to mobile hardware, and expensive. Recent technological advances provide a new way to widely disseminate complex 3D models, with a revolutionary impact on learning. The approach behind the 3D Head Atlas app, based on the synergistic work of scientific and development teams, facilitates the creation of interactive 3D scientific material with high accuracy and wide accessibility., Conclusion: The study of neuroanatomy is intimately related to the evolution of digital technology. Traditional methods (i.e. cadaveric dissections) have undisputed value but high costs. High-fidelity 3D scenarios and mobile devices may revolutionize learning if based on a sound evidence-based approach., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Background: Acquisition of neurosurgical anatomy knowledge requires the progressive construction of a 3-dimensional (3D) mental image from the study of 2-dimensional pictures. Tridimensional neuroimaging modeling and 3D pictures and videos have facilitated a better understanding of intricate brain anatomy. One of the main limitations of these methods however is that the user is unable to freely change his or her own point of view of the observed structures. The objective of this paper was to develop a 3D reconstruction method to facilitate learning and teaching of neurosurgery., Methods: We developed a 3D reconstruction method by using 3D photogrammetry to convert intraoperative images into a fully explorable 3D textured model. We also developed a mobile application to navigate the virtual scenario by using the gyroscopic technology of mobile devices to simulate the different movements of the surgical microscope. We named this process 3D virtual intraoperative reconstruction (VIR)., Results: We report the detailed methodology for picture acquisition, 3D reconstruction, and visualization with some surgical examples since the first applications in 2015. We also demonstrate how these navigable models can be used to buildup hybrid images derived by the fusion of 3D intraoperative scenarios with neuroimaging-derived 3D models., Conclusions: 3D VIR is a digital reconstruction method developed with the goal of facilitating the teaching and learning of neurosurgical anatomy by allowing the user to directly explore a surgical field and anatomic structures. The result is an interactive navigable 3D textured model for the analysis of the surgical approach and regional anatomy and for reconstruction of hybrid 3D scenarios., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Objective: To evaluate the feasibility of transcranial sonography in patients harboring polymethylmethacrylate cranioplasties (PMMA-CP) and explore whether this material is a valid sonic window to explore intracerebral structures., Methods: In 6 patients, we performed transcranial sonography (TCS), using the PMMA-CP as sonic window. To test the reliability of ultrasound images, we collected several quantitative and qualitative measurements of intracranial structures and compared these sonographic images with standard computed tomography (CT) scan images., Results: We found that PMMA-CP is a very good sonic window and allowed us to obtain very good quality echographic images of intracranial structures, as shown by the comparison of measurements with CT scan, which were very reliable. The main drawback was related to the shape (i.e., the curvature) of the cranial flap, which hindered the ultrasound probe from correctly adhering to the scalp., Conclusions: Although limited by the restricted number of cases, this preliminary experience represents the first available data about the serial use of TCS using PMMA-CP as window. These results open the path to the routine use of TCS to longitudinally control patients already harboring PMMA-CP. More, we here discuss its potential role in globally reducing the number of follow-up CT and magnetic resonance imaging scans required in different type of patients and pathologies., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Purpose: The practical management of cavernous angioma located within eloquent brain area before, during and after surgical resection is poorly documented. We assessed the practical pre-operative, intra-operative, and post-operative management of cavernous angioma located within eloquent brain area., Method: An online survey composed of 61 items was sent to 26 centers to establish a multicenter international retrospective cohort of adult patients who underwent a surgical resection as the first-line treatment of a supratentorial cavernous angioma located within or close to eloquent brain area., Results: 272 patients from 19 centers (mean 13.6 ± 16.7 per center) from eight countries were included. The pre-operative management varied significantly between centers and countries regarding the pre-operative functional assessment, the pre-operative epileptological assessment, the first given antiepileptic drug, and the time to surgery. The intra-operative environment varied significantly between centers and countries regarding the use of imaging systems, the use of functional mapping with direct electrostimulations, the extent of resection of the hemosiderin rim, the realization of a post-operative functional assessment, and the time to post-operative functional assessment. The present survey found a post-operative improvement, as compared to pre-operative evaluations, of the functional status, the ability to work, and the seizure control., Conclusions: We observed a variety of practice between centers and countries regarding the management of cavernous angioma located within eloquent regions. Multicentric prospective studies are required to solve relevant questions regarding the management of cavernous angioma-related seizures, the timing of surgery, and the optimal extent of hemosiderin rim resection., (Copyright © 2019 British Epilepsy Association. Published by Elsevier Ltd. All rights reserved.)

Objective: Three-dimensional (3D), high-definition (HD) endoscopy has been recently introduced in neurosurgery, and its value has been discussed extensively in endonasal skull base surgery. Because there has been no reported clinical series on the use of a recent 3D-HD ventriculoscope, the aim of this study was to describe our initial experience with this novel device., Methods: Patients consecutively operated on from June 2016 to June 2018 with a 3D-HD ventriculoscope were prospectively collected. The system is a 6-mm, 0-degree optic with a 105-degree field of view, with a central working channel of 2.2-mm diameter and 2 side channels of 1.3-mm diameter. Patients' demographic data, preoperative symptoms, and neurologic status; neuroradiologic data; type of surgery; operative time; intraoperative and postoperative complications, and follow-up data were prospectively recorded and retrospectively reviewed., Results: Twenty-four patients (age range: 3-84 years) underwent 25 procedures including endoscopic third ventriculocisternostomy, biopsy, and cyst fenestration. The technical goal of surgery was obtained in all patients. There were no intraoperative complications, expect for 1 intraoperative epileptic seizure. Postoperative complications included asymptomatic subdural collections in 2 patients, infection, and delayed endoscopic third ventriculocisternostomy closure in 1 patient each. Relative limits of the system are its size and the availability of only a 0-degree optic. Image quality appeared satisfactory in all procedures. The lack of a dedicated introducer was resolved, exploiting a vascular "peel-away" system., Conclusions: 3D-HD technology seems to provide potential advantages in ventricular surgery. This initial experience is promising but must be confirmed by larger series., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Objective: In this prospective study, we assessed the utility of a novel prognostic score (PS) in guiding the surgical strategy of patients with sensorimotor area gliomas., Patients and Methods: Form December 2012 to April 2016, we collected data from patients diagnosed with brain gliomas in the sensorimotor area. All the patients had intraoperatively confirmed contiguity or continuity with sensorimotor cortical and subcortical structures. Several clinical and radiological factors were analyzed to generate a PS for each patient (range 1-8). The end-points included the extent of resection (EOR) and neurological outcome (modified Rankin Score; mRS). We assessed the predictive power of the PS using different analyses. Crosstabs analyses and Fisher's exact test (Fet) were used to evaluate the possible predictive parameters, and for the classification of positive or negative outcomes for the chosen proxies; the significance threshold was set at p<0.05., Results: Using independent t-tests, we compared the mRS at different time points (pre, post, and at 6 months) for 2 subgroups from the total sample using a cut-off PS value of 4. For the EOR, a PS value of ≥5 was predictive of successful outcome, a value of 4 indicated an uncertain outcome, and a value of ≤3 predicted a worse outcome., Conclusions: This PS value can be easily used in clinical settings to help predict the functional outcome and EOR in sensorimotor area tumors. Integration with information from fMRI, DTI, and TMS, along with MRI spectroscopy could further enhance the value of this PS., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Objectives: To estimate the prevalence rate of silent cranial and intracranial lesions in a series of Ollier-Maffucci patients., Patients and Methods: Cerebral MRI was routinely performed in Ollier-Maffucci patients followed-up in our tertiary centers. Patients with previous history of skull base or intracranial tumors were excluded from the study. Clinical and radiological datas were retrospectively collected. The occurrence rate and nature of abnormal cerebral MRIs were determined., Results: Twelve patients were included. A glioma-looking lesion was found in one patient (8%), while skull base lesions were evidenced in 3 others (25%). A regular MRI follow-up was recommended for each patient, with a time interval varying between 1year and 3years depending on the likelihood of tumoral evolutivity, as infered from the MRI findings., Conclusion: All in all, the high rate of intracranial and skull base lesions with a malignant potential warrants to include cerebral MRI in the routine follow-up of Ollier-Maffucci patients., (Copyright © 2017. Published by Elsevier B.V.)

Objective: To analyze the efficacy and safety of cortical and subcortical electrical stimulation CSES and awake surgery to approach purely subcortical tumors in highly functional locations, particularly in guiding the choice of the best transcortical path., Patients and Methods: Prospective analysis of the surgical, neurological, and radiological outcome of patients harboring supratentorial, subcortically located brain tumors or vascular malformations who are operated on through awake surgery and CSES. Functional magnetic resonance (fMRI; either sensory-motor or language, based on the location) was performed in order to confirm the proximity to functional cortical areas. Major white matter tracts were investigated by MRI diffusion tensor fiber tracking (DTI-ft). The Rankin modified score was chosen to express the pre and postoperative functional neurological status. Immediate postoperative MRI was used to evaluate the extent of resection., Results: Seventeen patients were selected. The main distance of the tumors from the cortical surface was 18.2mm (range 9-48 mm). Neuronavigation was used to show the most direct route to the tumor (transsulcal or transgyral), but CSES was fundamental to adapt the surgical corridor to the functional topography both cortically and subcortically. If the transgyral route was chosen, CSES helped to detect a non-eloquent area. When a transsulcal route was preferred, CSES documented the presence or absence of function in the deep sulcus. The transient postoperative morbidity was 76.4%, but at last follow-up (range 4-20 months), all the patients regained preoperative status and 2 improved. Postoperative MRI demonstrated complete resection in all cases., Conclusions: Approaching purely subcortical tumors requires microsurgical skills, but in eloquent areas, functional topography monitoring is mandatory to allow safe surgery. CSES in an awake patient is a method that produces very good results in terms of resection and neurological outcome., (Copyright © 2013 Elsevier B.V. All rights reserved.)