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Optic foraminotomy (OF) has been recently proposed as an alternative to anterior clinoidectomy (AC) for selected types of paraclinoid aneurysms. In this study, OF and AC were compared for small superior-projecting paraclinoid aneurysms assuming visual and angiographic results as outcome measures. Indications for OF are also discussed.Data of patients who underwent surgery for a paraclinoid aneurysm in the last 10 years were collected across 3 tertiary hospitals. Small to regular-size and superior projecting aneurysms were sorted. Multiple and complex aneurysms were excluded. Records of patients who went through OF were compared with those of patients who underwent AC. Neurologic outcome was reported as a modified Rankin Scale. Aneurysm complete occlusion rate and rate of approach-related worsened vision were selected as outcome measures of efficacy and safety, respectively, of the OF versus AC. Unpaired t test and χOF and AC groups involved 18 and 25 patients, respectively. Complication rate, overall neurologic outcome, rate of approach-related worsened vision, and complete occlusion rate did not differ between the groups. The average follow-up was 51 ± 34 and 60 ± 41 months in the OF and AC groups, respectively.Compared to AC, OF did not show either a higher rate of approach-related worsened vision or a lower aneurysm complete occlusion rate. OF can be considered a valid alternative to the AC for small superior-projecting dorsal ICA wall paraclinoid aneurysms.

Extraventricular supratentorial ependymomas are rare entities. Most ependymomas are located at the infratentorial and intraventricular level, and only in a small group of cases they do not present continuity with the ventricular system. This is a case report of a patient with an atypical location of a cerebral ependymoma, which required the implementation of a complex and infrequent approach for its complete microsurgical removal.A 16-year-old male patient was referred at our department with a diagnosis of a 40 mm × 50 mm × 60 mm solid-cystic space-occupying lesion, sited between the left superior frontal-cingulate gyri. A contralateral transfalcine interhemispheric approach was selected, which achieved total resection of the tumor. The histopathological diagnosis of Grade II ependymoma was obtained according to WHO classification.The contralateral transfalcine interhemispheric approach represents a favorable surgical corridor to achieve a total resection of the tumor lesion and is favored by an adequate working angle and reduced brain manipulation.

The risks and benefits of coagulating intradural venous elements during a retrosigmoid approach for trigeminal neurovascular decompression has not been accurately established. The objectives of this study were to identify the veins that drain into the superior petrosal sinus, classify them in relation to the suprameatal tubercle, and determine the implication of their coagulation.A retrospective study of 3-dimensional surgical videos of retrosigmoid approaches for trigeminal neurovascular decompression from the Laboratory of Neurosurgical Innovations of Tucumán (LINT) digital archive was carried out. The veins encountered were classified into 3 groups: retromeatal, meatal and premeatal. The neurosurgical postoperative complication scale proposed by Landriel et al. was utilized to assess complications from venous coagulation. A grade 0 was added for patients without complications. The STATA 14 program was utilized for statistical analysis.The pontocerebellar-petrosal veins of 28 patients who underwent trigeminal decompressive surgery were analyzed. In 7 cases these were found in the retromeatal region; 100% were sacrificed. Eleven cases revealed veins within the meatal region; 90.91% were coagulated. Veins in the premeatal region were found in 14 cases; 57.14% were sacrificed. In the postoperative follow-up, 27 patients were grade 0 and 1 patient developed postoperative meningitis (grade Ib complication). No patient suffered vascular complications.The venous elements identified in trigeminal neurovascular decompressive surgery are variable. We propose classifying them into retromeatal, meatal, and premeatal groups. Retromeatal and meatal veins can be safely sacrificed for appropriate visualization of the neurovascular conflict. The premeatal venous elements should be coagulated only in justified cases.

Objective: To analyze and find risk factors associated with the development of DI using a multicenter case series via TSE. Materials and methods: Medical records of patients who underwent TSS for PA resection between 2010-2021 at three different neurosurgical centers by four experienced neurosurgeons were retrospectively analyzed. The patients were divided into two groups (DI Group or Control Group). Logistic regression analysis was conducted to identify risk factors associated with postoperative DI. Univariate logistic regression was performed to identify variables of interest, and covariates with a p-value < 0.15 were incorporated into multivariate logistic regression models to identify independently associated risk factors for DI. All statistical tests were conducted using RStudio. Results: 344 patients were included; 68% were women, the mean age was 46.5 years, and non-functioning adenomas were the most frequent (171, 49.7%). The mean tumor size was 20.3 mm. Covariates associated with postoperative DI were female gender, cavernous sinus invasion (left or bilateral), intraoperative CSF leak, endoscopic surgery, left preoperative visual field involvement, complete tumor resection, Knosp score of 2 and 4, and macroadenomas. Age was associated with a lower OR for postoperative DI. Multivariable model showed female gender (OR 3.34 CI 1.50-7.99, p=0.004) and intraoperative CSF leak (OR 3.25 CI 1.25-8.85, p=0.017) were found to be independently associated with higher OR of developing postoperative DI. Age was not shown to be a protective factor for DI (OR 0.97; CI: 0.94-1.00; p=0.038). Conclusions: The independent risk factors for the development of DI were female patients and intraoperative CSF leak.

Purpose To assess the rate, timing of diagnosis, and repairing strategies of vascular injuries in thoracic and lumbar spine surgery as their relationship to the approach. Methods PubMed, Medline, and Embase databases were utilized for a comprehensive literature search based on keywords and mesh terms to find articles reporting iatrogenic vascular injury during thoracic and lumbar spine surgery. English articles published in the last ten years were selected. The search was refined based on best match and relevance. Results Fifty-six articles were eligible, for a cumulative volume of 261 lesions. Vascular injuries occurred in 82% of instrumented procedures and in 59% during anterior approaches. The common iliac vein (CIV) was the most involved vessel, injured in 49% of anterior lumbar approaches. Common iliac artery, CIV, and aorta were affected in 40%, 28%, and 28% of posterior approaches, respectively. Segmental arteries were injured in 68% of lateral approaches. Direct vessel laceration occurred in 81% of cases and recognized intraoperatively in 39% of cases. Conclusions Incidence of iatrogenic vascular injuries during thoracic and lumbar spine surgery is low but associated with an overall mortality rate up to 65%, of which less than 1% for anterior approaches and more than 50% for posterior ones. Anterior approaches for instrumented procedures are at risk of direct avulsion of CIV. Posterior instrumented fusions are at risk for injuries of iliac vessels and aorta. Lateral routes are frequently associated with lesions of segmental vessels. Suture repair and endovascular techniques are useful in the management of these severe complications.

Background Carotid–ophthalmic aneurysms arise from the internal carotid artery between the distal dural ring and the origin of the posterior communicating artery. The surgical treatment of these aneurysms usually requires anterior clinoidectomy. However, this procedure is not without complications. In the present report, we have described optic nerve mobilization after optic foraminotomy as an alternative to anterior clinoidectomy to clip superior carotid–ophthalmic aneurysms. Methods We have reported the cases of 3 patients with superior carotid–ophthalmic aneurysms who had undergone surgical clipping. Instead of an anterior clinoidectomy, the optic nerve was mobilized after performing optic foraminotomy. The optic canal was carefully unroofed with a 3-mm, high-speed, diamond drill under constant cold saline irrigation to avoid thermal damage to the optic nerve. After incision of the falciform ligament and optic sheath, the optic nerve was gently mobilized with a No. 6 Penfield dissector, facilitating aneurysmal neck exposure and clipping through a widened opticocarotid triangle. Results The postoperative course was uneventful for all 3 patients, without any added visual defect. Optic nerve mobilization allowed us to safely widen the opticocarotid triangle and dissect the aneurysm off the optic nerve, without the need for clinoidectomy. This alternative technique permitted, not only early decompression of the optic nerve, but also dissection of the arachnoid between the inferior surface of the optic nerve and the superior surface of the ophthalmic–carotid artery and aneurysm dome. Conclusions Optic nerve mobilization after optic foraminotomy proved to be a safe and relatively easy technique for exposing and treating superior carotid–ophthalmic aneurysms.

BACKGROUND: The coronavirus disease 2019 (COVID-19) pandemic has exerted a significant impact on health care workers. Recent studies have reported the detrimental effects of the pandemic on neurosurgery residents in North America, Asia, and Italy. However, the impact of the pandemic on neurosurgical training in Latin America and Spain has not yet been reported. In the present report, we describe effects of COVID-19 on training and working conditions of neurosurgery residents in these countries. METHODS: An electronic survey with 33 questions was sent to neurosurgery residents between September 7, 2020 and October 7, 2020. Statistical analysis was made in SPSS version 25. RESULTS: A total of 293 neurosurgery residents responded. The median age was 29.47 ± 2.6 years, and 79% (n = 231) were male. Of respondents, 36.5% (n = 107) were residents training from Mexico; 42% surveyed reported COVID symptoms and 2 (0.7%) received intensive care unit care; 61.4% of residents had been tested for COVID and 21.5% had a positive result; 84% of the respondents mentioned persisted with the same workload (≥70 hours per week) during the pandemic. Most residents from Mexico were assigned to management of patients with COVID compared with the rest of the countries (88% vs. 68.3%; P < 0.001), mainly in medical care (65.4% vs. 40.9%; P < 0.001), mechanical ventilators (16.8% vs. 5.9%; P = 0.003), and neurologic surgeries (94% vs. 83%; P = 0.006). CONCLUSIONS: Our results offer a first glimpse of the changes imposed by the COVID-19 pandemic on neurosurgical work and training in Latin America and Spain, where health systems rely strongly on a resident workforce.

Cavernous sinus hemangiomas (CSHs) are intracranial extradural benign, well-demarcated neoplasms arising within dural sinuses. The orbital apex and superior orbital fissure (SOF) are common locations for these lesions. Because of the complex anatomy of this area and potential morbidity, SOF CSH surgical management is challenging.Describe a case of a SOF CSH and review of literature.We present the case of a 44-year-old female with a 2-month history of right eye visual disturbances. A contrast-enhanced magnetic resonance imaging showed a right orbital apex nodular formation. A pterional craniotomy with a middle fossa mini peeling was performed.Gross total resection was accomplished. No recurrences were observed 2 years after surgery.SOF CSH should be included in a differential diagnosis in cases of space-occupying orbital apex lesions with atypical features. Surgery is the gold standard treatment. Radiosurgery is a valid option for tumor remnants.

Antecedentes: El conocimiento profundo de la anatomía microquirúrgica del lóbulo de la ínsula es crucial para operar pacientes con tumores en esta región. El objetivo de la segunda parte de este estudio es correlacionar la anatomía microquirúrgica con casos ilustrativos retirados de nuestra casuística de 35 pacientes en los cuales fueron realizados 44 cirugías de tumores en relación con el lóbulo de la ínsula. Métodos: A lo largo de marzo de 2007 y agosto de 2014, 44 microcirugías fueron realizadas en 35 pacientes portadores de tumores insulares y los hallazgos de las cirugías y mapeo cerebral se correlacionaron con la anatomía microquirúrgica. Resultados: De una serie de 44 pacientes con tumores de la ínsula, la mayoría de los casos eran gliomas de bajo grado de malignidad (29 casos). El inicio de los síntomas en 34 pacientes fue epilepsia, siendo esta refractaria al tratamiento medicamentoso en 12 casos. El grado de resección fue subtotal o total en la mayoría de los casos de la serie. La mejoría en la calidad de vida (epilepsia, etc.) estuvo presente en más de la mitad de los pacientes. El dé cit neurológico permanente estuvo presente en tres pacientes. Conclusión: En los tumores insulares, es tan importante el conocimiento profundo de la anatomía, como el saber utilizar e interpretar en tiempo real las observaciones de la monitorización neuro siológica intraoperatoria.

Antecedentes: El lóbulo de la ínsula, o ínsula, se encuentra oculto en la super cie lateral del cerebro. La ínsula está localizada profundamente en el surco lateral o cisura silviana, recubierta por los opérculos frontal, parietal y temporal. Estudiar la compleja anatomía del lóbulo de la ínsula, una de las regiones de mayor complejidad quirúrgica del cerebro humano, y su correlación anatómica con casos quirúrgicos. Métodos: En la primera parte de este estudio presentamos los resultados de nuestras disecciones microquirúrgicas en fotografías 2 D y 3D; en la segunda parte de nuestro trabajo, la correlación anatómica con una serie de 44 cirugías en pacientes con tumores de la ínsula, principalmente gliomas, operados entre 2007 y 2014. Resultados: Extenso conjunto de bras subcorticales, incluyendo el fascículo uncinado, fronto-occipital inferior y el fascículo arcuato, conectan la ínsula a las regiones vecinas. Varias estructuras anatómicas responsables por dé cits neurológicos severos están íntimamente relacionadas con la cirugía de la ínsula, tales como lesiones de la arteria cerebral Media, cápsula interna, áreas del lenguaje en el hemisferio dominante y arterias lenticuloestriadas. Conclusión: El entrenamiento en laboratorio de neuroanatomía, estudio de material impreso en 3D, el conocimiento sobre neuro siología intra-operatoria y el uso de armamento neuroquirúrgico moderno son factores que in uencian en los resultados quirúrgicos.

Background The temporal muscle (TM) needs to be dissected and reflected downward in some anterolateral cranial approaches, and failing to preserve its integrity could have severe functional and cosmetic consequences. Most articles focus on techniques to prevent vascular injury during retrograde dissection or techniques to preserve the facial nerve; however, information on how to take care of the muscle during hook retraction is limited. We presented an anatomic study of vascularization of the TM, and we established safe areas for muscular hook retraction. Methods We dissected 16 TMs in 8 cadaveric heads. The TM was reflected downward, and we measured the distance between the anterior branch of the posterior deep temporal artery (PDTA) and the frontozygomatic suture and the distance between the posterior branch of the PDTA and the external auditory meatus projection. Results The average distance between the anterior branch of the PDTA and the frontozygomatic suture was 19.5 mm (range, 14–26 mm). The average distance between the posterior branch of the PDTA and the external auditory canal was 37.1 mm (range, 31–43 mm). We established 2 safe zones for hook placement: an anterior safe zone 14 mm posterior to the frontozygomatic suture and a posterior safe zone 30 mm anterior to the external auditory meatus. Conclusions We delimited 2 safe zones for hook placement during TM retraction aiming to avoid direct vascular damage in anterolateral cranial approaches.

Background: The type of sellar barrier observed between a pituitary tumor and cerebrospinal fluid (CSF) on preoperative magnetic resonance imaging (MRI) may predict intraoperative CSF leak during endonasal pituitary surgery. This is the first multicentric prospective cohort trial to study the sellar barrier concept and CSF leak rate during endoscopic pituitary surgery. Methods: This multi-center, international study enrolled patients operated for pituitary adenomas via fully endoscopic endonasal surgery over a period of 4 months. The independent variable was the subtype of sellar barrier observed on preoperative MRI (strong, mixed or weak); the dependent variable was the presence of an intraoperative CSF leak. The primary goal was to determine the association between a particular type of sellar barrier and the risk of intraoperative CSF leak. Appropriate statistical methods were then applied for data analysis. Results: Over the study period, 310 patients underwent endoscopic endonasal surgery for pituitary tumor. Preoperative imaging revealed a weak sellar barrier in 73 (23.55%), a mixed sellar barrier in 75 (24.19%), and a strong sellar barrier in 162 (52.26%) patients. The overall rate of intraoperative CSF leak among all patients was 69 (22.26%). A strong sellar-type barrier was associated with significantly reduced rate of intraoperative CSF leak (RR = 0.08; 95% CI 0.03–0.19; p < 0.0001), while a weak sellar barrier associated with higher rates of CSF leak (RR = 8.54; 95% CI 5.4–13.5; p < 0.0001). Conclusions: The preoperative MRI of pituitary patients can suggest intraoperative CSF leak rates, utilizing the concept of the sellar barrier. Patients with a weak sellar barrier carry a higher risk for an intraoperative CSF leak, whereas a strong sellar barrier on MRI seems to mitigate intraoperative CSF leak. We propose that preoperatively assessment of the sellar barrier can prepare surgeons for intraoperative CSF leak repair.

INTRODUCTION Most of the versatility of the pterional approach depends on a series of variations progressively reported by several groups, but little emphasized over the years. The present study condenses the technical notes which the authors adopted in their practice to maximize the surgical freedom of the pterional approach, at once lessening the approach-related complication rate. METHODS Data of a series of patients who underwent a pterional approach between January 2011 and May 2021 were retrospectively reviewed focusing on the technical variations compared to the original Yaşargil’s description. The anatomical rationale, technique, and advantages were outlined and validated through the appraisal of functional and cosmetic complications. RESULTS 994 patients were reviewed. Head extension was avoided in the case of anterior clinoidectomy. A single double-layered galea-pericranium flap was used for duraplasty. The submuscular technique, with compulsive preservation of deep temporal fascia and deep temporal arteries, was preferred for temporalis muscle dissection. McCarty keyhole was never used, thus avoiding exposing the orbit if unnecessary. Widening of the superior orbital fissure and thinning of the orbital roof allowed to significantly increase the working area. The average follow-up was 7.2 years. The overall rate of functional and cosmetic complications was 2.1. DISCUSSION In the authors' experience, the gradual adoption of technical variations related to the patient's positioning, soft tissue dissection, bony work, dura opening, and reconstruction allowed to enhance the versatility of the pterional approach concurrently decreasing the risk of functional and cosmetic complications.

Background: Endoscopic third ventriculostomy (ETV) is currently used as a treatment for different types of hydrocephalus. However, the anatomical endoscopic variants of the third ventricle floor (3VF), as well as their surgical implications, have been underrated. The anatomic variations of the 3VF can influence the technique and the success rate of the ETV. The purpose of this article is to describe the anatomical variations of 3VF, assess their incidence, and discuss the implications for ETV. Methods: Intraoperative videos of 216 patients who underwent ETV between January 2012 and February 2020 at Hospital Infantil Universitario de San José, Bogotá, Colombia were reviewed. One hundred and eighty patients who met the criteria to demonstrate the type of 3VF were selected. Results: 3VF types were classified as follows: (1) Thinned, (2) thickened, (3) partially erased, (4) globular or herniated, and (5) narrowed. Conclusion: Knowledge of anatomical variations of the 3VF is paramount for ETV and it influences the success rate of the procedure.

In certain cases, the closing force of a single vascular clip is not sufficient for complete aneurysmal occlusion, and the use of multiple clips, or clip stacking, is required. Many stacking techniques have been described in the literature, such as in tandem stacking and overstacking. However, these may not be feasible during procedures with limited exposure or narrow corridors. Clip reinforcement with a second high-pressure booster clip, also known as the piggyback technique, is an alternative for these cases along with anatomically complex aneurysms or aneurysms demonstrating atypical morphological features. Although this technique has been cited as a potential resource for certain aneurysms, descriptions of its characteristics and advantages are scarce. The purpose of this technical note was to discuss our experience with the piggyback clipping technique and use of a booster clip for a partially embolized and recanalized saccular posterior communicating artery aneurysm in a 50 year-old patient.

Background: Cisternostomy is a surgical technique thought of and developed as an option for severe brain trauma treatment. It demands a particular knowledge and skill to microsurgically approach basal cisterns and effectively manipulate their contents. To perform this procedure safely, the anatomy and pathophysiology must be clearly understood. Methods: Detailed microscopic dissection and anatomical review were done, after a detailed reading of facts and recent publications about cisternostomy. Cisternal pathways and landmark planning are described and augmented using a new method to show de arachnoid borders. Finally, a brief discussion is written as a synopsis. Results: Cisternostomy requires thorough microscopic knowledge and microsurgical skills. This paper intends to provide information to understand better the anatomy related, thus, easing the learning curve. The technique used to show arachnoid borders, complementing cadaveric and surgical images, was useful for this purpose. Conclusion: To perform this procedure safely, it is mandatory to handle microscopic details of cistern anatomy. Reaching a core cistern is necessary to assure effectiveness. This procedure needs, as well, surgical step-by-step landmark planning and performing. Cisternostomy could be a life-saving procedure and a new powerful tool for severe brain trauma treatment. Evidence is being collected to support its indications.

BACKGROUND The introduction of the nasoseptal flap for the reconstruction of extended endoscopic approaches decreased the incidence of postoperative fistula. In order to preserve the septal vascular pedicles, many have started to prepare the flap systematically, prior to the opening of the sphenoid rostrum. OBJECTIVE The aim of this study is to obtain an average measure of the location of the posterior septal artery using the upper edge of the choana as a landmark. METHODS Ten cadaveric heads, fixed with formaldehyde and injected with colored silicone, were studied. The course, branching pattern and dominance of the branches of the posterior septal artery were recognized, as well as the distance in of its superior and lower branches respect to the medial upper edge of the choana. RESULTS In all cases, the posterior septal artery enters as an only vessel through the sphenopalatine foramen. In its sphenoid segment, over the sphenoid rostrum, the posterior septal artery divides into its upper and lower branches, in most cases, laterally to the sphenoid ostium (70%, n=14). The lower branch was dominant in 60% of the cases (n=12). Regarding the mean distance in millimeters from the medial upper edge of the choana to the superior branch, it was 14.45 +/- 0.4102 (18-11.5) and, to the lower branch, 10.9 +/- 0.4682 (14-7). CONCLUSIONS A rostrum opening up to 15 mm over the upper edge of the choana is safe to avoid vascular complications, and to be able to prepare a viable nasoseptal flap only if it is necessary.

The far lateral approach is an inferolateral extension of the lateral suboccipital approach. Designed for clipping of the aneurysms of the vertebrobasilar junction and proximal segments of the posterior inferior cerebellar artery, it became over the years a workhorse approach for ventral foramen magnum meningiomas and other intradural lesions located anterior to the dentate ligament. This article summarizes the technical key aspects of the far lateral approach and transcondylar, supracondylar, and paracondylar extension.

Background: Aneurysms of the A1 segment of the anterior cerebral artery (ACA) are rare and have characteristics differentiating them from other intracranial aneurysms. Their microsurgical management is challenging and requires different strategies. In this article, we review the surgical anatomy of the A1 segment of the ACA with cadaveric dissections and describe the microsurgical management of complex A1 aneurysms with illustrative cases. Methods: A right pterional craniotomy and Sylvian dissection were performed on a formalin-fixed and silicone-injected cadaver head to depict the key anatomic structures and surgical corridors for microsurgical clipping of A1 segment aneurysms. The microneurosurgical management of ruptured and unruptured aneurysms of the A1 segment of the ACA is described with case illustrations. Results: The A1 segment of the ACA can be subdivided into proximal, middle, and distal subsegments, the former having abundant perforating branches. Both patients treated with microsurgical clipping had excellent and durable outcomes and postoperative cerebral angiograms showed complete aneurysm occlusion. Conclusion: Small A1 aneurysms may require early treatment as their rupture risk appears to be higher. A1 aneurysms are usually embedded in perforators, especially those arising from the proximal A1 subsegment, and require careful distal to proximal microdissection and strategic placement of the aneurysm clip blades. The approach, arachnoid dissection, and angles of attack are carefully planned after accounting for the aneurysm dome projection, precise location of the aneurysm neck and perforators, and the presence or absence of subarachnoid hemorrhage.

The cranio-orbito-zygomatic (COZ) approach consists of an extension of the pterional approach characterized by the removal of the superolateral part of the orbital rim and zygoma. This key step tremendously increases the angular exposure to some deep targets and overall surgical freedom to the lesion. In this article we review the technical variations of the COZ approach, mainly focusing on the differential quantitative effects coming from the orbital osteotomy compared to the zygomatic one.

Stereoscopy has been demonstrated to be a useful method of education in the field of anatomy because it allows users to see, in a simulation, the anatomical structures in their actual volume and depth.Cadaveric specimens preserved under formaldehyde using the Thiel and Klinger techniques have been dissected and photographed in the medical school anatomy laboratory (University Miguel Hernández) for the past 10 years. The photographic material and technique required to capture and project stereoscopic photographs have been described in different fields of surgical neuroanatomy. We used the results from a survey completed by the participants of different training courses to evaluate the utility of the 3-dimensional (3D) method.A large database of photographs taken of different anatomical regions and approaches of neurosurgical interest was obtained. We have presented some examples in the form of pairs of photographs in 2-dimensional (2D) format, with explanatory labels, paired with the corresponding 3D photograph in anaglyph format. The survey showed that the lectures that had included 3D photographs were significantly better accepted than the lectures with conventional 2D photographs.The teaching of basic, academic, and clinical neuroanatomy through the projection of stereoscopic photographs can be useful. The methods of image capture and stereoscopic projection in neuroanatomy, once combined with the necessary theoretical and practical knowledge, can be reproduced at other centers of neuroanatomy teaching.

The pterional approach is a workhorse in neurosurgery, to the point where perfect knowledge of its execution is essential in neurosurgical daily practice. The pterional transsylvian corridor is used to treat aneurysms involving anterior circulation, basilar apex, the proximal segment of the superior cerebellar and posterior cerebral artery, arteriovenous malformations and cavernous hemangiomas of the basal forebrain, anterior and middle skull base tumors, gliomas of the frontal, parietal, and temporal opercula, insula, mediobasal temporal region, cerebral peduncles, interpeduncular fossa, and also orbital lesions. We herein overview the core technique and variations of the pterional approach aimed at broadening surgical freedom and decreasing the risk of approach-related complications.

Introduction Intracranial aneurysms (IAs) are devastating cerebrovascular diseases with multifactorial etiology. The role of inflammation is indisputable, and interleukins are pivotal in supporting local inflammatory pathways and endothelial dysfunction at the aneurysm wall. In the light of insufficient evidence reported in the literature, this meta-analysis was aimed to investigate the genetic linkage between IL-1β (rs16944) -511CT polymorphisms and IAs susceptibility. Methods A comprehensive online literature review was completed using the PubMed/Medline and Web of Science databases in accordance with the PRISMA guidelines. "Interleukin-1β," "IL-1β," "polymorphism," "intracranial aneurysm," and "subarachnoid hemorrhage" were the main keywords. Only human case-control studies, published from 2005 to 2021, written in English or translated, were screened. In the statistical analysis, we applied the fixed- and random-effect models, according to the level of heterogeneity, to assess the odds ratios (ORs) and 95% confidence intervals (CIs). RevMan 5.0 software was used for the statistics. Results Only 4 studies were eligible, with a total of 2070 patients, 1050 of which were assigned to the study group. Combined results showed a statistically significant association between the risk of IAs and -511CC (OR=0.79, 95% CI [0.65-0.95], p=0.01), and CT (OR=0.69, 95% CI [0.58-0.82], p0.0001; OR=0.71, 95% CI [0.55-0.93], p=0.01) allele variations, both in the fixed- and random- models. No correlation was identified for the -511TT genotype (p=0.42; p=0.78). All the texts showed a low level of publication bias. Conclusion The present meta-analysis proved a potential role of IL-1β -511CC/CT genotypes in the pathogenesis of IAs. Additional studies are imperative to explain the underlying neuroimmune mechanisms, also allowing tailoring the potential inflammatory-target therapies for IAs.

Background: Focal cortical dysplasias (FCD) cause a subgroup of malformations of cortical development that has been closely linked to cause drug intractable epilepsy. Attaining adequate and safe resection of the dysplastic lesion has proved to be a viable option to archive meaningful seizure control. Of the three types of FCD (types I, II, and III), type I has the least detectable architectural and radiological abnormalities. This makes it challenging (preoperatively and intraoperatively) to achieve adequate resection. Intraoperatively, ultrasound navigation has proven an effective tool during the resection of these lesions. We evaluate our institutional experience in surgical management of FCD type I using intraoperative ultrasound (IoUS). Methods: Our work is a retrospective and descriptive study, where we analyzed patients diagnosed with refractory epilepsy who underwent IoUS-guided epileptogenic tissue resection. The surgical cases analyzed were from January 2015 to June 2020 at the Federal Center of Neurosurgery, Tyumen, only patients with histological confirmation of postoperative CDF type I were included in the study. Results: Of the 11 patients with histologically diagnosed FCD type I, 81.8% of the patients postoperatively had a significant reduction in seizure frequency (Engel outcome I-II). Conclusion: IoUS is a critical tool for detecting and delineating FCD type I lesions, which is necessary for effective post-epilepsy surgery results.

Background: Most neurosurgical photographs are limited to two-dimensional (2D), in this sense, most teaching and learning of neuroanatomical structures occur without an appreciation of depth. The objective of this article is to describe a simple technique for obtaining right and left 2D endoscopic images with manual angulation of the optic. Methods: The implementation of a three-dimensional (3D) endoscopic image technique is reported. We first describe the background and core principles related to the methods employed. Photographs are taken demonstrating the principles and also during an endoscopic endonasal approach, illustrating the technique. Later, we divide our process into two sections containing explanations, illustrations, and descriptions. Results: The results of taking a photograph with an endoscope and its assembly to a 3D image has been divided into two parts: Photo acquisition and image processing. Conclusion: We conclude that the proposed method is successful in producing 3D endoscopic images.

Background: Presurgical three-dimensional (3D) reconstructions allow spatial localization of cerebral lesions and their relationship with adjacent anatomical structures for optimal surgical resolution. The purpose of the present article is to present a method of virtual preoperative planning aiming to enhance 3D comprehension of neurosurgical pathologies using free DICOM image viewers. Case Description: We describe the virtual presurgical planning of a 61-year-old female presenting a cerebral tumor. 3D reconstructions were created with the “Horos®” Digital Imaging and Communications in Medicine viewer, utilizing images obtained from contrast-enhanced brain magnetic resonance imaging and computed tomography. The tumor and adjacent relevant structures were identified and delimited. A sequential virtual simulation of the surgical stages for the approach was performed with the identification of local gyral and vascular patterns of the cerebral surface for posterior intraoperative recognition. Through virtual simulation, an optimal approach was gained. Accurate localization and complete removal of the lesion were achieved during the surgical procedure. Virtual presurgical planning with open-source software can be utilized for supratentorial pathologies in both urgent and elective cases. Virtual recognition of vascular and cerebral gyral patterns is helpful reference points for intraoperative localization of lesions lacking cortical expression, allowing less invasive corticotomies. Conclusion: Digital manipulation of cerebral structures can increase anatomical comprehension of neurosurgical lesions to be treated. 3D interpretation of neurosurgical pathologies and adjacent anatomical structures is essential for developing an effective and safe surgical approach. The described technique is a feasible and accessible option for presurgical planning.

Background: During aneurysm microsurgery, the aneurysmal sac is excluded from circulation by placing one or more clips at the base of the aneurysm. In some cases of complex aneurysms or subarachnoid hemorrhage history, transient clipping before definitive clipping is necessary. The closing force of the transient clip is less than the permanent clip; however, it is sufficient to stop circulation to the aneurysmal sac. The aim of the following work is to analyze and describe histological changes caused by transient and permanent clipping of the abdominal aorta in Wistar-type rats, to study the correlation between the closing force of the clip and the time, it remains on the vascular tissue structures. Methods: Six groups were formed, with 10 rats each, whereby temporary clipping of the abdominal aorta was performed with subsequent sampling of the site where the vascular clip was placed. The groups were: control and temporary clipping with: 2, 5, 10, and 15 and permanent clipping with 5 min. Results: Resection samples of the 3 μm thick aorta were obtained through the routine histological technique and special histochemical techniques (Masson’s Trichrome and orcein) from the six groups. Transmural changes were found from Group II–VI. Conclusion: There is a vascular histological effect after both transient and permanent clipping. The sum of time and strength of the clip induce vascular changes visible at 5 min.