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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.

Craniopharyngiomas are benign tumors of the sellar and parasellar region for which surgical resection remains the treatment of choice. There are many publications on the most frequent postoperative complications, but few reports on subclinical lesions affecting the arteries of the circle of Willis, despite their high morbidity and mortality rate. Trauma-induced aneurysms are infrequent, representing less than 1% of intracranial aneurysms. Iatrogenic intracranial pseudoaneurysms are a subtype of surgically induced aneurysms developed as a result of direct injury to the arterial wall or after dissection of tumors adherent to the vessel adventitia. The natural history of these lesions is not well known because their incidence is extremely low. We report two cases of postoperative aneurysms of the internal carotid artery after craniopharyngioma resection and a brief review on the management of such lesions.

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.

Objective Intracranial hemangiopericytoma (HPC) is a rare central nervous system tumor characterized by its low incidence, high rate of local recurrence and risk of metastasis. The main objectives of this paper are two: to show the results in the treatment of HPC in our institution in the last 20 years and to make a review of the literature on this topic. Methods Retrospective review that includes patients diagnosed with intracranial solitary fibrous tumor/hemangiopericytoma (TFS/HPC) that have undergone surgery from 1997 to 2017. It includes patients that had nuclear expression of STAT6 (detected by immunohistochemistry) and grade II/III histopathological diagnosis (defined by the World Health Organization in 2016). We collected demographic data, tumor characteristics, treatment and survival of these patients. Results A total of 19 patients fulfilled inclusion criteria. The median follow up was 96 months (12–230). The mortality rate was 21% (n = 4). The median follow up survival was 19.16 years. 57.9% of patients presented at least 1 tumor recurrence (n = 11) (recurrences of 6%, 67% y 90% at 1, 5 and 10 years). Five patients presented extracranial metastasis. Patients with tumors Conclusions A series of patients undergoing TFS / HPC were presented according to the new WHO criteria. Size is a predictor of survival. Currently there are no validated criteria for surgical resection in this pathology. A classification with surgical guidance would be useful.

Resumen Objetivo Los hemangiopericitomas intracraneanos (HPC) son tumores de muy baja frecuencia, alta recidiva local y riesgo de metastasis extracraneal. El objetivo del siguiente trabajo es presentar los resultados en el tratamiento de los HPC en nuestra institucion en los ultimos 20 anos y realizar una revision de la literatura del tema. Material y metodos Se realizo un estudio retrospectivo que incluyo a los pacientes con diagnostico de tumor fibroso solitario/hemangiopericitoma (TFS/HPC) intracraneanos intervenidos quirurgicamente en el periodo 1997-2017. Se incluyeron pacientes con inmunomarcacion positiva para STAT-6 y grado histologico II-III. Se recabaron datos demograficos, caracteristicas tumorales, tratamiento y sobrevida de estos pacientes. Resultados Un total de 19 pacientes cumplieron los criterios de inclusion. La mediana de seguimiento fue de 96 meses (12-230). La mortalidad fue del 21% (n = 4). El 57,9% presentaron al menos una recidiva tumoral (n = 11) (con una recurrencia del 6, del 67 y del 90% a 1, 5 y 10 anos, respectivamente). Cinco pacientes presentaron metastasis extracraneal. Tuvieron mayor sobrevida los pacientes con tumores Conclusiones Se presento una serie de pacientes operados de TFS/HPC segun los nuevos criterios de la OMS. El tamano es un factor predictor de sobrevida. Actualmente no existen criterios validados de reseccion quirurgica en esta patologia. Una clasificacion con orientacion quirurgica seria de utilidad en el futuro.

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.

Introduction: The indication of a ventriculoperitoneal shunt (VPS) is discussed in patients with idiopathic normal pressure hydrocephalus (iNPH), due to the heterogeneity of the response to treatment and the risks involved in neurosurgery. Objective: To search for clinical factors and complementary studies in order to determine predictors of a favorable response to the VPS placement in patients with iNPH. Methodology: A retrospective study of patients with probable iNPH (according to international guidelines) treated with VPS assisted in a neurological clinic from January 2014 to January 2017 was conducted. A univariate statisticalanalysis of the variables considered as possible prognostic factors was performed. Results: 58 patients were included. Women presented 3.68 times more chances of improvement after the VPS (p=0.019). Good response to the gait test was associated with better response to the VPS (p=0.024). Conclusions: Female sex and good response to the gait test could be considered as predictors of a favorable response to the VPS placement in patients with iNPH. A prospective study is necessary to achieve a homogeneous diagnostic evaluation and a more extensive longitudinal follow-up to evaluate the clinical evolution in this group of patients.

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.

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: 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.

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.

Background Pituicytoma is a rare neoplasm arising in the sellar region (World Health Organization grade I). Clinically, pituicytomas mimic nonfunctioning pituitary macroadenomas and are occasionally incidentally discovered at autopsy. Pituitary adenomas can occur with other sellar pathologies, and the term “collision sellar lesions” has been coined for this rare entity. There have only been a few reports of the coexistence of pituicytoma and pituitary adenoma. We present 2 cases of pituicytoma coexisting with acromegaly and Cushing disease. Case Description Case 1: A 29-year-old woman had acromegaly. The macroadenoma was partially removed in her first surgery; thus an endonasal reoperation was required for debulking and posterior radiosurgery. Pituicytoma coexisting with somatotropinoma was diagnosed on pathologic examination. Case 2: A 33-year-old woman had adrenocorticotropic hormone–dependent Cushing disease. She underwent endonasal resection. Undetectable postoperative cortisol levels provided evidence that the underlying adrenocorticotropic hormone source was successfully removed. On the basis of morphologic features and the immunohistochemical profile, pituicytoma was diagnosed on pathologic examination. Pituitary adenoma was not confirmed histologically in this patient. Conclusions Only 117 cases of pituicytoma have been reported since it was first described in 1955. Before our report, only 5 cases of patients with pituicytoma coexisting with pituitary adenoma had been described. The coexistence of these 2 entities may not just be a mere coincidence but may be due to a yet unknown pathophysiologic link or common progenitor lineage of both lesions. Association between pituicytoma and pituitary adenoma is increasingly being reported.

Background and objective The orbit is a structure of interest for many medical specialties. Surgical approaches to the orbit present significant difficulties for the general neurosurgeon. Whoever decides to practice orbital surgery must have vast anatomical knowledge of this structure. However, although many of the existing publications about orbital anatomy show the complexity of this structure in detail, they fail to facilitate their understanding. The purpose of this study was to systematise and simplify the anatomical study of the orbit from a surgical perspective, to facilitate its understanding. Materials and methods A review of the international literature on the subject was carried out, and the principle of the rule of 7 was followed for its ordering. For illustration purposes, photographs of cadaveric preparations and digital drawings were used. Results The orbits are 2 cavities located symmetrically on both sides of the nose. They have a pyramidal shape, with 4 sides, a posterior vertex, an anterior base and their axis established from the sagittal plane at a 20-degree angle. A distinctive feature of the orbit is that its elements are organised into groups of seven: 7 bones, 7 intraorbital extraocular muscles and 7 nerves. Conclusion A systematisation of the orbital anatomy was performed with clear illustrations to simplify its study. The understanding of the anatomy of the orbit is vital to classify lesions and provides a solid basis when choosing the most appropriate approach for their treatment.

Resumen Antecedentes y objetivo La orbita es una estructura de interes para diversas especialidades medicas. Los abordajes quirurgicos de la orbita presentan una dificultad significativa para el neurocirujano general. Quien decide incursionar en cirugia orbitaria debe tener un vasto conocimiento anatomico de esta estructura. Sin embargo, gran parte de las publicaciones existentes sobre anatomia de la orbita muestran detalladamente la complejidad de esta estructura, pero no logran facilitar su entendimiento. El proposito del presente trabajo es sistematizar el estudio anatomico de la orbita desde una perspectiva quirurgica, de modo sencillo, que permita facilitar su entendimiento. Materiales y metodos Se realizo una revision de la literatura mundial sobre el tema y se siguio el principio de la regla del 7 para su ordenamiento. Para ilustrar se utilizaron fotografias de preparados cadavericos y dibujos digitales. Resultados Las orbitas son 2 cavidades ubicadas simetricamente a ambos lados de la nariz. Tienen una forma piramidal, de 4 lados, con un vertice posterior, una base anterior y con su eje establecido desde el plano sagital en un angulo de 20 grados. Una caracteristica distintiva de la orbita es que sus elementos estan organizados en grupos de a 7: 7 huesos, 7 musculos extraoculares intraorbitarios y 7 nervios. Conclusion Se realizo una sistematizacion de la anatomia orbitaria con claras ilustraciones a fin de simplificar su estudio. La comprension de la anatomia de la orbita es clave para clasificar una lesion y proporciona una base solida a la hora de elegir el abordaje mas adecuado para su tratamiento.

Introduction: The petroclival region is among the most challenging anatomical areas to deal with in skull base surgery. Drilling of the anterior part of the petrous bone during the anterior transpetrosal approach involves the risk of injury of the cochlea, superior semicircular canal, internal carotid artery, and internal auditory canal. A thorough understanding of the microneurosurgical anatomy of this region is mandatory to execute the transpetrosal approaches, decreasing the risk of complications. The aim of this study is to describe the anatomical structures of the petroclival region, highlighting the importance of neuronavigation for safe performance of the anterior transpetrosal approach. Methods: Three adult cadaveric human heads were formalin-fixed and injected with colored silicone. They underwent an axial 1 mm slab CT scan, which was used for neuronavigation during the surgical approaches. The anterior petrosectomy was performed with the aid of neuronavigation during the drilling of the petrous bone. The surgical management of a patient harboring a petroclival meningioma, operated on using an anterior transpetrosal approach, was reported as an illustrative case. Results: The anterior petrosectomy was completed accurately with wide exposure of the surgical target without injuring the cochlea and other structures in all three cadaveric specimens. In the surgical case, no approach-related complications occurred, and a gross total resection of the tumor was achieved. Conclusions: Deep knowledge of the location and relationships of the vital elements located within the temporal bone, along with the use of neuronavigation, are the key aspects to perform the anterior transpetrosal approach safely, reducing the risk of complications.

Background Cerebrospinal fluid (CSF) fistulas are among the most clinically important and frequent complications of transsphenoidal surgery for pituitary adenomas. Between the adenoma and the CSF, a “barrier” exists that consists of ≤3 elements. These, from cephalad to caudad, are the arachnoid, dura mater (sellar diaphragm), and pituitary glandular tissue. The objective of the present study was to determine whether the presence or absence of any of these 3 anatomical elements would be associated with the development of an intraoperative CSF fistula. Methods From November 2016 to June 2018, 40 patients with pituitary adenomas underwent surgery, by transsphenoidal endonasal access, under a microscope. All procedures were filmed in 3 dimensions. The intraoperative findings and preoperative magnetic resonance images were analyzed and compared. The patients who had developed a fistula were compared against those who had not. Results In 20 patients, glandular tissue was identified between the tumor and subarachnoid space. In 13, dura mater was evident, and in 7, only the arachnoid was noted. An intraoperative CSF fistula occurred in 6 patients, all of whom had the arachnoid as the only barrier. The presence of a fistula was significantly more likely statistically for patients with an arachnoid-only barrier than for those with any other barrier composition (P Conclusions The anatomical architecture forming the roof of the pituitary fossa is an important determinant of intraoperative CSF fistula risk. When the barrier consists of only the arachnoid, the risk will be significantly greater than when the barrier contains additional elements. Preoperative magnetic resonance imaging would be useful to determine the type of the existing barrier.

A case is reported of a 19-year old patient with a supratentorial giant cavernous malformation (GCM). This was an incidental finding in the context of acute head trauma. Brain computed tomography (CT) scan and magnetic resonance imaging (MRI) revealed a giant supratentorial right mass. Surgical excision was performed, and histopathology findings were consistent with a cavernous malformation (CM). The patient had a complete neurological recovery. To our knowledge, this is the first case of a GCM in an asymptomatic patient with total surgical excision.

Surgical removal of anterior clinoidal meningiomas remains a challenge because of its complicated relationship with surrounding vascular and neural structures.1-3 This is a 39-yr-old female, with headaches, neurofibromatosis type 2, and history of 3 previous brain surgeries. The patient gave the consent to use the images and surgical video. In the imaging control, the growth of bilateral anterior clinoidal meningiomas was observed. A right pterional approach and extradural anterior clinoidectomy was performed, and a complete resection of bilateral clinoidal meningiomas was achieved obtaining a Simpson scale resection grade 1. The patient evolved without neurological deficits after the surgery, and the postoperative magnetic resonance imaging (MRI) evidenced a complete bilateral resection of the clinoidal meningiomas. Clinoidal meningiomas are the unique subset of tumors because of their close proximity to neurovascular structures and can be safely excised with minimal morbidity and mortality using microsurgical techniques.3-5 In rare cases of bilateral anterior clinoidal meningiomas such as the case presented, we recommend detailed neuroimaging analysis and consider the possibility to resect both in a single approach.

Among the posterolateral corridors to the ventral foramen magnum (FM), the transcondylar fossa (supracondylar transjugular tubercle) approach (TCFA) is indicated for lesions lying anteriorly to the dentate ligament and above the jugular foramen and hypoglossal canal.1-13 It involves the drilling of the condylar fossa, namely the exocranial surface of the jugular tubercle. Despite the anatomic variability of the condyle and posterior condylar emissary vein,14,15 they are important landmarks for the TCFA. The extradural jugular tuberculectomy has no risk of iatrogenic mechanical instability compared with the transcondylar approach. This 2-dimensional operative video (Video 1) aims to show the key technical aspects of the TCFA through the case description of an anterolateral FM meningioma. A 35-year-old male patient with a left anterolateral FM meningioma underwent TCFA in a semisitting position. Drilling of the condylar fossa led to an extradural resection of the jugular tubercle. Posterior condylar emissary veins connecting the sigmoid sinus/jugular bulb with the vertebral venous plexus marked the lateral limit of the approach. Through a suprahypoglossal working corridor, the meningioma was debulked and dissected. Postoperative magnetic resonance imaging confirmed complete resection of the tumor, and the patient was discharged neurologically intact on the third postoperative day. TCFA is a valuable technical option for selected anterolateral FM meningiomas. The perfect knowledge and intraoperative use of specific anatomic landmarks are critical to safely perform the TCFA while maximizing the exposure of the surgical target and decreasing the risk of postoperative mechanical instability of the craniovertebral junction.

The foramen magnum is a complex region with diverse pathologies of intra and extradural location; the first includes mainly meningiomas and neurinomas, while the second corresponds to chordomas and bone tumors. Together, these pathologies are very rare. Foramen magnum meningiomas (FMM) represent 1.8–3.2% of all meningiomas. In most of the cases, FMMs are intradural lesions, and most of them are anterior or lateral. The surgical treatment of anterior and lateral FMM can be performed safely and effectively. To achieve this, it is necessary to possess the following: good anatomical knowledge of the region, exposing the suboccipital triangle and the vertebral artery using the nuchal lines as references, perform a retrocondylar approach on lateral tumors and transcondylar approach in anterior tumors and experience in microsurgery. This chapter will highlight the anatomical and surgical nuances of approaching foramen magnum tumors.

According to reports from the literature,1,2 depending on the location where cavernomas appear, range from the very common locations to unusual. Cavernous malformations arising from the optic nerve and chiasm are rare, with only few cases reported to date.3-5 We present a case of a 28-yr-old man who suddenly started with sever visual loss in the right eye and homonymous lateral hemianopia in the left eye. Because of the acute symptomatology, a brain MRI was immediately performed in order to diagnose the etiology. The MRI showed a chiasmatic mass with right extension, heterogeneous on T1 and T2 sequences, without enhancement after gadolinium. The surgery was carried out a week after the diagnosis. A right pterional transsylvian approach was performed and the cavernoma was resected with microsurgical maneuvers, preserving the optic nerve fibers, chiasm, and optic tract. The patient evolved favorably, improving the visual deficit in the postoperative period as can be observed in the postoperative visual field study 7 mo after the surgery. The patient signed an informed consent for the procedure and agreed with the use of his images and surgical video for research and academic purposes. Our surgical case emphasizes the importance of a prompt diagnosis and surgery for chiasmatic cavernomas3 associated to visual loss, providing early decompression of the optic apparatus and improvement of the visual field defects after surgery.

Neurovascular procedures along the interhemispheric fissure harbor unique features differentiating them from those arteriovenous malformations (AVMs) located at the lateral surface of the brain.1-4 The aim of this 3-dimensional operative video is to present a microsurgical resection of an AVM in a subparacentral location, operated through an interhemispheric contralateral transfalcine approach.1,3,5 This is a case of a 29-yr-old female, with headaches and history of seizures. The patient presented an interhemispheric bleeding 6 mo before the surgery. The magnetic resonance imaging (MRI) showed a vascular lesion located on the medial surface of the right hemisphere at the confluence between the cingulate sulcus and its ascending sulcus. In the cerebral angiography, a right medial AVM was observed, receiving afference from the right anterior cerebral artery and draining to the superior longitudinal sinus. The patient signed an informed consent for the procedure and agreed with the use of her images and surgical video for research and academic purposes. The patient was in a supine position, and a left interhemispheric contralateral transfalcine approach was performed,1-3 a circumferential dissection of the nidus, and, finally, the AVM was resected in one piece. The patient evolved without neurological deficits after the surgery. The postoperative MRI and angiography showed a complete resection of the AVM. In the case presented, to avoid exposing the drainage vein first and to use the gravity of the exposure, the contralateral transfalcine interhemispheric approach was used,1,2 which finally accomplished the proposed objectives.

The meningo-orbital band (MOB) is the most superficial dural band that tethers the fronto-temporal dura to the periorbita. It is usually encountered when performing a pterional or fronto-temporo-sphenoidal approach, and it disrupts surgical access to deeper regions. Our objective was to perform a detailed anatomy study and a stepwise method to successfully detach the MOB using cadaveric specimens. We used six formalin-fixed, silicone-injected cadaveric heads. On each side, we performed a pterional approach plus mini-peeling of the anterior third of the middle fossa and/or extradural anterior clinoidectomy. We also applied this technique in three clinical cases to prove its safety and efficacy. The detachment of the MOB consists in four steps, 1) detachment of the temporal and frontal dura, 2) cutting of the MOB, 3) exposure and drilling of the anterior clinoid process, and 4) pealing of the lateral wall of the cavernous sinus. Using clinical cases, we explain how to adapt the technique depending on the localization of the lesion. The detachment of the MOB is the key to safely expose the cavernous sinus and the anterior clinoid process. The authors proposed a step-by-step method for the safe and effective detachment of the MOB. It is recommended, particularly to less experienced neurosurgeons that are starting with skull base surgery, and also to experts that want to expand their knowledge.

AIM To analyze the effectiveness of fat and fibrin glue to prevent postoperative cerebrospinal fluid (CSF) leak in pituitary surgery. MATERIAL AND METHODS Two hundred and eleven patients affected by pituitary adenoma entered this study. Patients that underwent a microscopic transsphenoidal approach between January 2013 and April 2019 were included. All the patients that developed intraoperative CSF leak were treated with fat and fibrin glue. The presence or absence of postoperative CSF leak was considered as a parameter to test the effectiveness of the intraoperative reconstruction technique used. RESULTS Postoperative CSF leak was observed in 5 patients (2.4%). Among patients with an intraoperative low- grade CSF leak (1 or 2), 97.9% did not develop a postoperative CSF leak. In contrast, those who presented an intraoperative CSF leak of grade 3, had a worse prognosis. CONCLUSION Fat and fibrin glue is currently an effective method in the treatment of low-grade intraoperative CSF leak. In case of intraoperative CSF leak of grade 3, it should be used combined with the nasoseptal flap technique to obtain a safer reconstruction.

Background The sellar barrier concept reflects the association between the components of the roof of the pituitary fossa and the risk of intraoperative cerebrospinal fluid (CSF) leak in the surgery of pituitary adenomas. We based our concept in previous reports on the microsurgical anatomy of the pituitary fossa's superior wall. However, proof of the usefulness of this concept in endoscopic approaches is yet missing. The aim of this study was to describe the endoscopic anatomy of the sellar barrier and its subtypes in a laboratory setting and to provide evidence of its clinical usefulness. Methods We provided anatomical models in six fresh-frozen head and neck specimens. We performed an endoscopic endonasal approach and recreated a pathological model of each possible subtype of sellar barrier. To demonstrate the usefulness of this model in clinical practice, we conducted a prospective study including all patients with pituitary adenoma operated by an endoscopic approach between June and July 2019. Results We successfully recreated the models for each subtype of sellar barrier. When analyzing the clinical cases, we found that intraoperatively, 73.69% (14) had a strong sellar barrier; 21.05% (4) had mixed sellar barrier, and 5.26% (1) had weak sellar barrier. We recorded one case of intraoperative CSF leak in a patient with a weak sellar barrier by magnetic resonance imaging. Conclusion We described the endoscopic anatomy of the sellar barrier and we recreated the three subtypes in anatomical models. We also identified these subtypes in a series of clinical cases, proving its clinical usefulness.

Objetivo: Presentar nuestra experiencia en el tratamiento quirúrgico de los meningiomas espinales. Material y métodos: Estudio descriptivo retrospectivo que incluye a 24 pacientes operados de meningiomas espinales durante el período Julio de 2009 a Diciembre de 2016. Se analizaron datos epidemiológicos, antecedentes personales, sintomatología preoperatoria, características radiológicas, hallazgos intraoperatorios, grado de resección, descripción histológica y evolución post operatoria. Resultados: Se operaron 24 pacientes siendo 83% de sexo femenino. En cuanto a la localización, 79% fueron dorsales, 17% cervicales y 4% lumbares. La anatomía patológica reveló meningiomas grado I (OMS) en todos los casos. En el 63% se abordó la lesión por hemilaminectomía, logrando en éstas un grado de resección satisfactorio (Simpson 2). El 66% de los pacientes presentaron mejoría clínica post operatoria, 30% sin cambios significativos y solo un caso (4%) de empeoramiento. El periodo de seguimiento promedio fue de 14,9 meses. Conclusión: La cirugía continúa siendo el tratamiento de elección en los meningiomas espinales. El abordaje por hemilaminectomía es una opción útil en lesiones con base de implantación lateral. Lesiones predominantemente ventrales, con componente cálcico y alteraciones motoras preoperatorias suelen presentar mayor complejidad quirúrgica y peor evolución.

Background Primary central nervous system lymphomas (PCNSL) are infrequent. The traditional treatment of choice is chemotherapy. Complete resections have generally not been recommended, because of the risk of permanent central nervous system deficits with no proven improvement in survival. The aim of the current study was to compare survival among patients with PCNSL who underwent biopsy versus surgical resection. Methods A retrospective study was conducted on 50 patients with a confirmed diagnosis of PCNSL treated at our center from January 1994 to July 2015. Results Patients in the resection group exhibited significantly longer median survival time, relative to the biopsy group, surviving a median 31 months versus 14.5 months; p = 0.016. Conclusions In our series, patients who had surgical resection of their tumor survived a median 16.5 months longer than patients who underwent biopsy alone. RESUMO Introducción Los linfomas primarios del sistema nervioso central (LPSNC) son infrecuentes. Tradicionalmente el tratamiento de elección es la quimioterapia. Existe un paradigma de no indicar resección, por el riesgo de déficit neurológico sin aumento de la sobrevida. El objetivo del presente estudio es comparar la sobrevida de pacientes con LPSNC sometidos a biopsia versus resección. Métodos Estudio retrospectivo que incluye 50 pacientes con diagnóstico confirmado de LPSNC tratados en nuestra Institución desde enero de 1994 hasta julio de 2015. Resultados Los pacientes del “grupo resección” mostraron una sobrevida media significativamente mayor respecto a los del “grupo biopsia”; 31 meses versus 14,5 meses respectivamente, p = 0,016. Conclusiones En nuestra serie, los pacientes que con resección quirúrgica de su tumor tuvieron una sobrevida media de 16,5 meses superior que los pacientes biopsiados.

The orbitomeningeal or meningo-orbital band (MOB) has been described as the most superficial dural band responsible for tethering the frontotemporal basal dura to the periorbita.1,2 The MBO usually interferes with the surgical approach to the most profound areas of the anterior and middle skull base. It is known that there are no cranial nerves on the lateral surface of the superior orbital fissure; therefore, the neurosurgeon can cut the MOB without causing any neurological deficit and, at the same time, achieving fully exposure of the anterior clinoid process1-4 and/or the lateral wall of the cavernous sinus.5 The purpose of this video is to describe the microsurgical anatomy of the MOB and illustrate the technique for its detachment, accompanied by 2 illustrative cases. To achieve this, we use 3-dimensional recordings of 2 cadaveric specimens' dissections performed by the senior author. Case 1: 58-yr-old female with left blindness. Magnetic resonance imaging (MRI) shows an anterior and middle skull base lesion with orbital compression. Case 2: 32-yr-old male presenting with headache and trigeminal neuralgia. The MRI revealed an hourglass-shaped lesion in the posterior and middle fossa. Both patients signed an informed consent and agree with the use of their images for research purposes. We used a step-by-step approach for an adequate and secure dissection of the MOB highlighting the anatomic structures involved in the process. This approach allows safe and adequate access to the deeper structures of the anterior and middle skull base.

Cerebral spinal fluid (CSF) leak is a significant complication in pituitary surgery, increasing both patient morbidity and mortality. In a recent publication, Campero et al. observed worse postoperative prognosis and increased risk of intraoperative CSF leak in patients with reduced sellar barrier thickness. The objective of this study was to analyze the association between sellar barrier thickness and intraoperative CSF leak in older individuals. A retrospective review was conducted of 44 transsphenoidal surgery resections for pituitary adenomas, 24 microscopic and 20 purely endoscopic procedures. Presence of intraoperative CSF fistula was significantly greater in patients with weak sellar barrier (thickness under 1 mm), compared to strong sellar barrier (52.94% vs 3.70% p 0.0001, respectively). Application of this novel concept may help improve surgical technique selection as well as predict risk of intraoperative CSF leak and need for eventual use of flaps for reconstruction.

Introducción: La colocación de un shunt ventrículo-peritoneal, a pesar de considerarse un procedimiento de baja complejidad, puede devenir en una serie de complicaciones. Nuestro equipo quirúrgico desarrolló e implementó a partir de junio de 2016 un nuevo protocolo. El objetivo del presente trabajo es: describir e ilustrar paso a paso la técnica quirúrgica utilizada y demostrar que el uso del “nuevo protocolo” disminuye significativamente las complicaciones asociadas al procedimiento. Material y métodos: Desde junio de 2014 a noviembre de 2017 se intervinieron 184 pacientes en relación a sistemas de derivación de LCR. Se realizó un estudio retrospectivo que incluyó los pacientes con colocación primaria de shunt ventrículo-peritoneal (n=114). El seguimiento promedio fue de 14,2 meses (rango 6-38). Para el análisis estadístico se dividió a la muestra en 2 grupos: “protocolo previo” (n=59) y “nuevo protocolo” (n=55). Para describir la técnica quirúrgica se utilizó el archivo fotográfico y los partes quirúrgicos. Resultados: Se describió la técnica quirúrgica en 7 fases. La cantidad de pacientes con alguna complicación fue significativamente menor luego de implementar el “nuevo protocolo” (20% versus 39% respectivamente; p=0,04). En el grupo “nuevo protocolo” no se registró infección alguna asociada a shunt. Conclusión: Se presentó e ilustró, de manera clara y detallada, la técnica de colocación de shunt ventrículo-peritoneal en 7 fases. Esta técnica, junto a una serie de normas, constituyen un “nuevo protocolo”. La aplicación de éste disminuyó significativamente las complicaciones asociadas al procedimiento. La tasa de infección “cero” no es una utopía.

Background Pituitary adenomas (PA) are usually benign neoplasms. Chiari I malformation (CIM) is an uncommon finding. Isolated cases associating functional PA and CIM have been reported. The concomitant presence of a nonfunctional PA and a CIM has not yet been described in the literature. Case Description We present the case of a 35-year-old patient whose symptoms were compatible with CIM. Magnetic resonance imaging of the brain, with and without contrast material, confirmed the CIM and incidentally encountered a PA. The patient was treated initially for her PA through an endoscopic endonasal approach with complete tumor resection, confirming a nonfunctional PA. Posterior fossa decompression was successfully accomplished 3 months later. The patient has been followed up for 5 years and has been free of symptoms, with no recurrence of her PA. This represents the first reported case of a nonfunctional PA with a concomitant CIM. Conclusion This is the first reported case of a concomitant CIM and a nonfunctional PA. We discuss our successful management and conduct a systematic review of the literature to provide the most up-to-date guidance on managing these singular cases with concomitant pathologic conditions.

INTRODUCTION: Three-dimensional (3D) imaging and videos are a very useful tool in the neurosurgical training, although unfortunately the 3D systems available have a very high cost. The objective of this study is to describe a novel and low-cost 3D microsurgical video system. METHODS: To obtain the 3D videos we use a surgical microscope, 2 video adapters, 2 cameras, and an HDMI cable. A video editor program is used for processing the videos. For the projection we use a computer with PowerPoint (Microsoft, Inc, Redmond, WA) software, a video splitter, DVI cables, 2 projectors, 2 polarization filters, and a "silver screen" with polarized glasses. RESULTS: By using 2 equal cameras and video adaptors in each beam splitter port it was possible for us to obtain 2 videos that were equivalent to the images received by both surgeon's eyes. Using the video signal of both cameras during processing resulted in a 3D stereoscopic recording with Final Cut (Apple, Inc, Cupertino, CA) software. The polarized 3D format provided the best projection conditions. It does not alter the original colors of the videos and its prolonged visualization was more comfortable. The main advantage of this method is the ability to show in a realistic way the spatial relationships and the depth of the structures captured with the microscope. CONCLUSIONS: This paper presents in a clear and detailed way how to create and use a low-cost 3D surgical video system.

Background: The use of the recent concept of sellar barrier revealed that a specific group of patients were difficult to categorize. For this reason, we propose to add a new subtype: the mixed sellar barrier. The aim of this work was to define the new mixed barrier subtype and analyze this in a series of operated patients. Methods: A retrospective study was carried out. From January to December 2018, 72 patients with pituitary adenomas underwent surgery by transsphenoidal approach. Patients with more than 1 surgery were excluded. Each patient's magnetic resonance imaging (MRI) was analyzed and classified using the following criteria: strong barrier (>1 mm), weak barrier (1 mm in another part). Results: Mixed sellar barrier is the coexistence of 2 types of sellar barrier (strong and weak). The presence of a mixed sellar barrier on MRI was associated with the presence of a mixed sellar barrier intraoperatively (P < 0.0001). By using the new MRI classification that includes the mixed sellar barrier, we found a stronger statistically significant association regarding the risk of cerebrospinal fluid leak (for the extreme categories; i.e., strong and weak) compared to the original work. Conclusions: The new mixed sellar barrier subtype was precisely defined and illustrated. The correlation between MRI and intraoperative findings for this new subtype has been demonstrated in this study. A prospective study with a larger series of patients is required for validation.

Intracranial trigeminal schwannomas are rare tumors.1-4 The aim of this 3-dimensional operative video is to present a double stage complete removal of a dumbbell-shaped trigeminal schwannoma. This is a 25-yr-old male with headaches, diplopia, and facial pain. The MRI shows a big tumor located at the level of the cerebellopontine angle, petroclival region, and middle fossa. Because of the size of the tumor and its growth within the cerebellopontine angle, we decided to operate the patient in two stages. For the first surgery, the patient was in a semi-sitting position, and a retrosigmoid approach was performed. The second surgery was performed 2 mo after the first operation in a supine position for a pretemporal transzygomatic approach. The pathological study was reported as a schwannoma, and the histological findings were spindle cell lesion with a storiform pattern and histiocytes. The patient evolved without neurological deficit after the surgeries, and the postoperative MRI shows a complete resection of the tumor. The patient gave the consent to use the images and surgical video. Preoperative imaging plays an important role in diagnosis and surgical planning.3-6 For these cases of trigeminal schwannomas with a large extension in the posterior fossa and middle fossa, we believe that the most prudent thing is to perform the surgery in 2 stages.3.

Sellar arachnoidocele is a term used to define the herniation of the subarachnoid space to the sella. 1 This is a rare radiologic finding that, in most cases, does not require treatment. 2 , 3 , 4 , 5 When symptoms appear, the term empty sella syndrome is used. Two varieties exist: primary and secondary empty sella syndrome. 2 The aim of this 3-dimensional operative video ( Video 1 ) is to demonstrate the extradural microsurgical remodeling of the sellar fossa with autologous bone in 2 cases of primary empty sella syndrome. Both patients signed an informed consent for the procedures and agree with the use of their images for research purposes. In both cases, magnetic resonance imaging scans showed herniation of the subarachnoid space into the pituitary fossa and an anchor-like silhouette on coronal view. Patients evolved favorably, improving their visual deficit after the surgery, as can be observed in the postoperative visual field study. If surgery is indicated due to visual loss, the procedure is known as chiasmapexy. Recently, Guinto et al 3 described a technique for chiasmapexy. Our team considers this procedure to be useful, technically simple, and low cost. Being autologous, rejection possibilities are almost null. This 3D video serves as a complement to illustrate the technique.