The Coexistence of Carotico-Clinoid Foramen and Interclinoidal Osseous Bridge: An Anatomo-Radiological Study With Surgical Implications.

BACKGROUND AND OBJECTIVES: The coexistence of complete carotico-clinoid bridge (CCB), an ossification between the anterior (ACP) and the middle clinoid (MCP), and an interclinoidal osseous bridge (ICB), between the ACP and the posterior clinoid (PCP), represents an uncommonly reported anatomic variant. If not adequately recognized, osseous bridges may complicate open or endoscopic surgery, along with the pneumatization of the ACP, especially when performing anterior or middle clinoidectomies. METHODS: According to Preferred Reporting Items for Systematic Reviews and Meta-Analyses for Scoping Reviews guidelines, a systematic scoping review was conducted up to June 5, 2023. PubMed, Scopus, Web of Science databases, and additional citations were searched. Two hundred high-resolution noncontrast computed tomography (CT) scans (400 sides) and 41 dry skulls (82 sides) were analyzed to identify the different morphology of sellar bridges, focusing on the coexistence of complete CCF and ICB. Two embalmed latex-injected heads with coexisting CCF and ICB were dissected step-by-step to show the anatomic relationship with the surrounding structures from an endoscopic and microscopic perspective. RESULTS: A total of 19 articles were included. The review identified a complete CCF and ICB rate ranging from 4.92% to 6.3%. The analysis of 200 CT scans revealed a rate of coexistence in 4% of the cases, all encountered in White women. Two different types of interclinoid bridges were identified based on the degree of bone mineralization. Both endoscopic and macroscopic step-by-step dissections highlighted variability in morphology and consistency of the sellar bridges and the close relationship with the cavernous sinus neurovascular structures. CONCLUSION: The coexistence of CCF and ICB is an anatomic variation found in 4% of cases. Preoperative knowledge of the degree of mineralization and its relationship with surrounding structures is essential to performing safe surgery and minimizing cranial nerve and vascular injuries. Preoperative high-resolution CT scans can adequately identify these anatomic variations.

Multidisciplinary approach to anaplastic and metastatic meningioma: A case report and review of the literature.

Background: Meningiomas are slow-growing neoplasms, accounting for 20% of all primary intracranial neoplasms and 25% of all intraspinal tumors. Atypical and anaplastic meningiomas are infrequent, representing fewer than 5% of all meningiomas. Unusually, they can show aggressive behavior, and extracranial metastases are extremely rare, representing approximately 0.1% of all reported cases. Case Description: Fifty-six-year-old male patient diagnosed with atypical basal frontal meningioma with multiple resections, both endoscopic endonasal and transcranial. After hypofractionated radiosurgery, the patient showed new tumor recurrence associated to right cervical level II ganglionic metastasis. We opted for complete resection of the meningioma and reconstruction with anterior rectus abdominis muscle flap, as well as selective cervical ganglionectomy. Anatomical pathology showed neoplastic proliferation of meningothelial cells in syncytial cytoplasm, oval or spherical nuclei with slight anisocariosis and hyperchromasia, and intranuclear vacuoles, all compatible with anaplastic meningioma. Conclusion: Due to a lack of consensus on how to treat a metastatic malignant meningioma, this pathology requires a multidisciplinary approach, and treatment needs to be adapted to each particular case. Complete resection of the lesion is the primary goal, and this requires complex procedures involving endocranial as well as extracranial surgeries, which result in composite defects difficult to resolve. Microvascular free flaps are considered the gold standard in reconstructions of large skull base defects, with high success rates and few complications.

Microsurgical free flaps for skull base reconstruction following tumor resection: Available techniques and complications / Utilización de colgajos libres microvasculares para la reconstrucción de la base del cráneo secundaria a resecciones tumorales: técnicas disponibles y complicaciones

Introduction: Resection of malignant tumors located in the anterior and middle fossae of the skull base requires thorough anatomical knowledge, as well as experience regarding the possible reconstructive options to resolve the resulting defects. The anatomical and functional relevance of the region, the complexity of the defects requiring reconstruction and the potential complications that can occur, represent a true challenge for the surgical team. The goal of this study is to describe the microsurgical reconstructive techniques available, their usefulness and postoperative complications, in patients with malignant tumors involving the skull base. Materials and method: This observational, retrospective study, included all patients who underwent surgery for malignant craniofacial tumors from January 1st, 2009 to January 1st, 2019 at a University Hospital in Argentina. Only patients who required reconstruction of the resulting defect with a free flap were included. Results: Twenty-four patients required reconstruction with FF; 14 were male (58.3%) and mean age was 54.9 years. Sarcoma was the most frequent tumor histology. Free flaps used were the following: anterolateral thigh, rectus abdominis, radial, latissimus dorsi, iliac crest and fibular. Complications occurred in 6 cases and no deaths were reported in the study group. Conclusion: Free flaps are considered one of the preferable choices of treatment for large skull base defects. In spite of the complexity of the technique and the learning curve required, free flaps have shown to be safe, with a low rate of serious complications. For these patients, the surgical resolution should be performed by a multidisciplinary team. (AU)

Introducción: La resección de los tumores malignos de la base de cráneo anterior y media requieren no solo un amplio conocimiento anatómico, sino también experiencia en las posibles opciones reconstructivas factibles para resolver el defecto generado. La importancia anatómica y funcional de la región, la complejidad de los defectos a reconstruir y las posibles complicaciones que pueden desarrollar representan un verdadero desafío para el equipo quirúrgico. El objetivo del presente trabajo es exponer las posibles opciones reconstructivas microquirúrgicas, su utilidad y las complicaciones postoperatorias en pacientes con tumores malignos que comprometen la base de cráneo. Materiales y método: Se realizó un estudio observacional retrospectivo de todos los pacientes operados de tumores malignos craneofaciales en el período comprendido entre el primero de enero de 2009 al primero de enero de 2019 en un hospital universitario de Argentina. Se incluyeron solo aquellos pacientes en los que fue necesario reconstruir el defecto a través de un colgajo libre (CL). Resultados: Veinticuatro pacientes requirieron reconstrucción con CL. Catorce fueron varones (n = 14 [58,3%]) y la media de edad fue de 54,9 años. La variedad tumoral histológica más frecuente fue el sarcoma. Los tipos de CL utilizados fueron los siguientes: anterolateral de muslo, recto anterior del abdomen, radial, dorsal ancho, cresta iliaca y fibular fueron los CL utilizados. Se reportó una tasa global de complicaciones del n = 6 (25%). Un solo paciente presentó isquemia del colgajo. No hubo mortalidad asociada. Conclusión: Los CL representan una de las primeras opciones en el tratamiento en defectos grandes de la base de cráneo. A pesar de la complejidad de la técnica y la curva de aprendizaje necesaria, los CL han demostrado ser seguros con bajas tasas de complicaciones graves. La resolución quirúrgica de estos pacientes se debe realizar por un equipo multidisciplinario. (AU)

Microsurgical free flaps for skull base reconstruction following tumor resection: Available techniques and complications.

INTRODUCTION: Resection of malignant tumors located in the anterior and middle fossae of the skull base requires thorough anatomical knowledge, as well as experience regarding the possible reconstructive options to resolve the resulting defects. The anatomical and functional relevance of the region, the complexity of the defects requiring reconstruction and the potential complications that can occur, represent a true challenge for the surgical team. The goal of this study is to describe the microsurgical reconstructive techniques available, their usefulness and postoperative complications, in patients with malignant tumors involving the skull base. MATERIALS AND METHOD: This observational, retrospective study, included all patients who underwent surgery for malignant craniofacial tumors from January 1st, 2009 to January 1st, 2019 at a University Hospital in Argentina. Only patients who required reconstruction of the resulting defect with a free flap were included. RESULTS: Twenty-four patients required reconstruction with FF; 14 were male (58.3%) and mean age was 54.9 years. Sarcoma was the most frequent tumor histology. Free flaps used were the following: anterolateral thigh, rectus abdominis, radial, latissimus dorsi, iliac crest and fibular. Complications occurred in 6 cases and no deaths were reported in the study group. CONCLUSION: Free flaps are considered one of the preferable choices of treatment for large skull base defects. In spite of the complexity of the technique and the learning curve required, free flaps have shown to be safe, with a low rate of serious complications. For these patients, the surgical resolution should be performed by a multidisciplinary team.

Hemicraniectomía endonasal por estesioneuroblastoma: informe de un caso / Endonasal hemicraniectomy by esthesioneuroblastoma: report of a case

El estesioneuroblastoma es una neoplasia maligna que se origina del epitelio olfatorio. El tratamiento se establece de acuerdo con su extensión y el grado histológico de atipia y puede incluir cirugía, cirugía más radioterapia o más radioquimioterapia. Se han utilizado diferentes abordajes quirúrgicos que incluyeron incisiones faciales y craneotomía pero, con la mayor experiencia adquirida en cirugía endoscópica de senos paranasales y el trabajo en equipo con el neurocirujano, se han desarrollado técnicas endonasales que posibilitan realizar resecciones oncológicas en pacientes seleccionados, con menos morbilidad, internación breve y sin comprometer el control local de la enfermedad. Describimos el caso clínico de una paciente con un estesioneuroblastoma con invasión intracraneal, que fue tratada con éxito mediante una hemicraniectomía endonasal preservando el bulbo olfatorio contralateral. (AU)

Esthesioneuroblastoma is a malignant neoplasm that originates from the olfactory epithelium. Treatment is established according to its extension and the histological degree of atypia and may include surgery, surgery more radiotherapy or more chemoradiation therapy. Different surgical approaches have been used, including facial incisions and craniotomy, but with the greater experience acquired with endoscopic sinus surgery and teamwork with the neurosurgeon, endonasal techniques have been developed that make it possible to perform oncological resections in selected patients, with less morbidity, brief hospitalization and without compromising local control of the disease. We describe the clinical case of a patient with an esthesioneuroblastoma with intracranial invasion who was successfully treated by endonasal hemicraniectomy preserving the contralateral olfactory bulb. (AU)

Minimally Invasive Drainage of Intracerebral Hemorrhage. A South American Experience with the MISTIE Procedure.

BACKGROUND: Intracerebral hemorrhage (ICH) is the second most common subtype of stroke but is associated with greater rates of disability or mortality. One of the factors of a poor prognosis is large hematoma volume. The MISTIE III trial with the aim of decreasing clot size showed that the greater the ICH reduction, the higher likelihood of lower mortality without a net increase in the proportion of patients with severe disability. Our aim is to describe our experience with treating selective patients with ICH per the MISTIE trial protocol in a university hospital in Argentina during 4 years. METHODS: A retrospective analysis was performed of consecutive patients with ICH treated at a single university tertiary-care center from 2017 to 2021 with the MISTIE protocol. RESULTS: We deployed this procedure in 7 patients with a median age of 61 years, median National Institutes of Health Stroke Scale score of 14, an ICH volume of 35 mL and median ICH score of 2. Five of 7 patients achieved the target goal of hematoma reduction; 4 of the patients had a total independence level and 1 needed minimal help at 12 months after discharge. Five patients had a good functional outcome (modified Rankin Scale score 0-3 and extended Glasgow Outcome Scale score 4-8) and 2 patients had died but neither because of consequences of thrombolysis of the intracerebral hemorrhage. We did not find bleeding complications during catheter placement, alteplase infusion, or after catheter removal. CONCLUSIONS: The procedure can be carried out safely in Latin American centers that have experience in managing neurocritical patients.

Surgical Management of a Superior Orbital Fissure Cavernous Hemangioma.

Background: 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. Objective: Describe a case of a SOF CSH and review of literature. Material and Methods: 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. Results: Gross total resection was accomplished. No recurrences were observed 2 years after surgery. Conclusion: 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.

Safety margin for the preservation of the nasoseptal artery during trans-nasal endoscopic approach.

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. 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 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.

Surgical management of atypical trigeminal neuralgia secondary to tentorial meningioma: 2D video.

Background: Tentorial meningiomas (TM) are complex entities with distinguished clinical, radiological and surgical considerations. They comprise approximately 3 - 6% of all intracranial meningiomas1. TM have been classified in 5 subgroups according to the modified Yasargil's classification, based on their location 2 and 3. Those located at the free margin of the tentorium are still challenging for neurosurgeons, with high morbidity and mortality. Atypical trigeminal neuralgia (ATN) is a type of trigeminal neuralgia that is identified by the constancy of symptoms. They experience less intense pain, but a constant dull aching or burning pain, and it is frequently misdiagnosed. Although it is well known that typical trigeminal (TN) neuralgia responds very well to medical treatment and are related with posterior fossa tumors, ATN is less likely. In this video we demonstrate the microsurgical resection of group 1 tentorial meningioma in the treatment of atypical trigeminal neuralgia. Case Description: A previously healthy 63-year-old female came to our service complaining of long lasting, intermittent, right facial pain for two years. On neurological examination, the patient had hypoesthesia in the territory of maxillae (V2) branch of the right trigeminal nerve. She had no other complaints on the physical examination. Initial treatment with carbamazepine and pregabalin was performed, however, it could not be further increased because of the maximal doses and side effects. Radiological investigation was carried out with cranial computed tomography (CT) and magnetic resonance image (MRI), which showed a high signal density mass lesion in the free margin of the tentorium, with extension to the right cerebello pontine angle (CPA), compressing the trigeminal nerve, that exhibited homogeneous contrast enhancement, suggestive of tentorial meningioma. Given the size, the location of the mass, and no response to the medical treatment, microsurgical resection was performed. Conclusion: The postoperative period was excellent, without any neurological deficit. The patient consented with publication of her images and videos.

[Collision sellar lesions: pituitary adenoma and Rathke cleft cyst]. / Lesiones sincrónicas selares: adenoma hipofisario y quiste de la bolsa de Rathke.

Rathke's cleft cyst (RCC) are a slow-growing, benign, cystic lesions that arises from the remnants of the primitive ectoderm and Rathke's pouch. They present a common origin with pituitary adenomas (PA), however, the concomitant presentation of a PA and a RCC rarely occur. We present a case of a 41-year-old female with Cushing's disease. Magnetic resonance imaging (MRI) showed two synchronic lesions in the sellar region. An endoscopic transnasal approach was performed, with complete excision of both. The histological studies revealed an ACTH secreting PA and a RCC. The patient presented clinical and endocrinological remission six months after surgery. With the presence of cystic lesion at the sellar region, and the concomitant finding of a pituitary adenoma, RCC should be considered.

El quiste de la bolsa de Rathke (QBR) es una entidad benigna de crecimiento lento que proviene del remanente del ectodermo primitivo. Presenta un origen común con los adenomas hipofisarios (AH), sin embargo, la presentación sincrónica de un AH y un QBR es infrecuente. Presentamos el caso de una mujer de 41 años con enfermedad de Cushing. Se realizó resonancia magnética con el hallazgo de dos lesiones en región selar. Se hizo un abordaje transnasal endoscópico, con exéresis completa de ambas. El informe de anatomía patológica reveló un AH corticotropo y un QBR. Tuvo una remisión clínica analítica endocrinológica a los seis meses postquirúrgicos. Ante el hallazgo de una imagen quística a nivel selar concomitante con un adenoma hipofisario, debe ser considerada la posibilidad diagnóstica de un QBR.

Meningiomas de fosa posterior: nomenclatura con orientación anatomo-quirúrgica y presentación de casos ilustrativos / Posterior fossa meningiomas: nomenclature with anatomical-surgical orientation and presentation of illustrative cases

Introducción: Los meningiomas de la fosa posterior representan el 20% de todos los meningiomas intracraneales. Cada subtipo tiene una base de implantación, abordaje quirúrgico y morbimortalidad postoperatoria muchas veces diferente. Advertimos que en reuniones científicas y publicaciones no se sigue una forma de clasificar uniforme, sencilla y clara con orientación netamente quirúrgica. Esto genera que el neurocirujano en formación no cuente con herramientas suficientes para la toma de decisiones. Objetivos: Proponer una clasificación sencilla de los meningiomas de la fosa posterior con un fundamento anatomo-quirúrgico y presentar casos ilustrativos de cada subtipo. Materiales y métodos: Se estableció una nomenclatura considerando reportes previos, el criterio anatómico y la experiencia quirúrgica de los autores. Se presentaron casos revisando las historias clínicas y los archivos de imágenes correspondientes a cada subtipo de la clasificación. Resultados: Representamos a la fosa posterior como un compartimento con 3 anillos: el superior se divide en medial, lateral-anterior y lateral-posterior; el medio se divide en 6 variantes: clivales puros, esfeno-petro-clivales, petrosos anteriores, petrosos posteriores y de la convexidad suboccipital medial y lateral; el inferior se divide en anterior, lateral derecho, lateral izquierdo y posterior. Conclusión: Los meningiomas del anillo superior pueden resolverse mediante una vía suboccipital medial o lateral; los del anillo medio tienen un espectro de opciones más diverso; los del anillo inferior -siguiendo el esquema de división en cuadrantes de un reloj- pueden resolverse por medio de un abordaje suboccipital medial o extremolatera

Introduction: Posterior fossa meningiomas represent 20% of all meningiomas, being each location associated with a specific approach, morbidity and mortality. The actual classifications are focus on the dural attachment, without associating the anatomical with the surgical aspects, useful to the young neurosurgeons for decision making. Objectives: To propose a classification of the posterior fossa meningiomas with an anatomical-surgical view including the presentation of cases. Materials and Methods: A nomenclature was established concerning previous reports, the anatomical criteria and the surgical experience of the authors. Cases were presented by reviewing the medical records corresponding to each subtype of the proposed classification. Results: We represent the posterior fossa as a 3 rings compartment: the upper one is divided into medial, anterior-lateral and posterior-lateral; the middle ring is divided into 6 variants: pure clival, spheno-petro-clival, anterior petrosal, posterior petrosal, and medial and lateral suboccipital convexity; the lower ring is divided into anterior, right lateral, left lateral, and posterior. Conclusion: Superior ring meningiomas can be resolved by a medial or lateral suboccipital approach; middle ring meningiomas have a more diverse spectrum of options; while meningiomas of the inferior ring - following the scheme of division into quadrants of a clock - can be resolved by means of a medial or extreme-lateral suboccipital approach.

Lesiones sincrónicas selares: adenoma hipofisario y quiste de la bolsa de Rathke / Collision sellar lesions: pituitary adenoma and Rathke cleft cyst

Resumen El quiste de la bolsa de Rathke (QBR) es una entidad benigna de crecimiento lento que proviene del remanente del ectodermo primitivo. Presenta un origen común con los adenomas hipofisarios (AH), sin embargo, la presentación sincrónica de un AH y un QBR es infrecuente. Presentamos el caso de una mujer de 41 años con enfermedad de Cushing. Se realizó resonancia magnética con el hallazgo de dos lesiones en región selar. Se hizo un abordaje transnasal endoscópico, con exéresis completa de ambas. El informe de anatomía patológica reveló un AH corticotropo y un QBR. Tuvo una remisión clínica analítica endocrinológica a los seis meses postquirúrgicos. Ante el hallazgo de una imagen quística a nivel selar concomitante con un adenoma hipofisario, debe ser considerada la posibilidad diagnóstica de un QBR.

Abstract Rathke's cleft cyst (RCC) are a slow-growing, benign, cystic lesions that arises from the remnants of the primitive ectoderm and Rathke's pouch. They present a common origin with pituitary adenomas (PA), however, the concomitant presentation of a PA and a RCC rarely occur. We present a case of a 41-year-old female with Cushing's disease. Magnetic resonance imaging (MRI) showed two synchronic lesions in the sellar region. An endoscopic transnasal approach was performed, with complete excision of both. The histological studies revealed an ACTH secreting PA and a RCC. The patient presented clinical and endocrinological remission six months after surgery. With the presence of cystic lesion at the sellar region, and the concomitant finding of a pituitary adenoma, RCC should be considered.

Morphologic Variations in the Circle of Willis as a Risk Factor for Aneurysm Rupture in the Anterior and Posterior Communicating Arteries.

BACKGROUND: Intracranial aneurysms are acquired abnormal vascular dilations. The most dangerous complication of a cerebral aneurysm is its rupture, with a high rate of mortality. This study aimed to determine whether there is an association between anatomic variations in the circle of Willis and ruptured aneurysms in the anterior and posterior communicating arteries. METHODS: A cross-sectional study of adult patients with a diagnosis of intracranial aneurysm was carried out between March 2015 and March 2019. The patients were divided into groups of ruptured or unruptured aneurysm in the anterior and posterior communicating arteries. RESULTS: A total of 132 patients with anterior and posterior communicating artery aneurysms were included. The presence of anatomic variation in the circle of Willis presented a statistically significant association with ruptured aneurysms (odds ratio [OR], 2.28; 95% confidence interval [CI], 1.11-4.65; P = 0.024). There was a statistically significant difference between the presence of nonspherical aneurysm and rupture (OR, 6.9; 95% CI, 3.12-15.48; P < 0.0001). Multivariate logistic regression observed smoking (OR, 2.4; 95% CI, 1.01-5.9; P = 0.4), anterior complex variations (OR, 2.68; 95% CI, 1.01-7.18; P < 0.04), and nonspherical morphology (OR, 4.7; 95% CI, 1.93-11.45; P = 0.001) presented a statistically significant association with the rupture. CONCLUSIONS: Our results suggest that the studied variations of the circle of Willis and nonspherical morphology, in addition to playing a role in the development of cerebral aneurysms, may contribute to their rupture.

Morphometric analysis of posterior cranial fossa and surgical implications.

BACKGROUND: Posterior cranial fossa (PCF) is an important area in terms of anatomy and surgery. It is a common site of many neoplastic, vascular, and degenerative lesions. Craniovertebral surgeries require special attention regarding detailed information about the morphology and morphometry of this region. The aim of this study was to analyze the morphometric characteristics of PCF and distances between the inner base of the skull. MATERIALS AND METHODS: An observational, retrospective cross-sectional study was made. Fifty-five dry human skulls of unknown sex were measured ascertained using digital Vernier caliper with 0.01 mm precision. RESULTS: The morphometric analysis of the mean length and width of the FM was 34.51 mm and 29.85 mm, respectively. We found a significant difference (P < 0.05) among the distance between the posterior tip of occipital condyle and basion of the right and left sides. CONCLUSION: According to our observations, the present study yielded detailed morphometry of the PCF and neurovascular relationship. It can facilitate successful instrumentation and minimize neurovascular injuries. Furthermore, it provides safe and suitable data for guiding neurosurgical procedures. The major limitation of this study was the lack of knowledge regarding the age and gender of the participants whose skull base was studied.

Cavernoma Paraventricular / Paraventricular Cavernoma

Introducción: Los cavernomas representan el 5 al 13% de las malformaciones cerebrales y suelen tener una localización supratentorial. Clínicamente pueden permanecer asintomáticos o presentar síntomas neurológicos progresivos. Para estos últimos, así como los que presentan hemorragia recurrente, la resección quirúrgica es el tratamiento de elección. Sin embargo, para aquellos que presentan una localización profunda es menester estudiar la relación que existe entre la lesión y las estructuras cerebrales adyacentes. La tractografía (DTI) y las técnicas de navegación intraoperatoria son herramientas fundamentales para planificar y guiar el abordaje a la lesión y realizar un mapeo de las vías de proyección, asociación y comisurales, permitiendo un acceso seguro mediante corticotomías pequeñas y mínima retracción del parénquima cerebral. Objetivo: Describir la técnica quirúrgica guiada por neuronavegación para la resección de un cavernoma frontal derecho profundo yuxtaventricular a través de una pequeña corticotomía. Caso: Paciente de sexo masculino de 20 años de edad, deportista profesional, con parestesias miembro superior izquierdo y cefalea severa. Resonancia magnética evidencia lesión heterogénea en T1 y T2 y presencia de un halo de hemosiderina, compatible con cavernoma a nivel del techo del cuerpo en el ventrículo lateral derecho. Mide 28 mm x 31 mm x 28 mm en sus diámetros transversal, dorso-ventral y rostro-caudal. Tractografía evidencia lesión en íntima relación con el tracto corticoespinal en su recorrido por la corona radiada. Resultados: Exéresis completa de la lesión. El paciente evolucionó sin déficit neurológico y fue dado de alta a las 72 horas del postoperatorio. Conclusión: El uso de la tractografía y de la navegación intraoperatorio, permite abordar lesiones profundas, en contacto con áreas elocuentes, mediante corticotomías pequeñas con mínima retracción cerebral

Introduction: Cavernous malformation represents among 5 to 13% of brain vascular malformations, most of them have a supratentorial location. Clinically they can remain asymptomatic or present with neurological symptoms. In cavernomas with recurrent hemorrhage, located in safe areas, surgical resection is the treatment of choice. However, for those which have a deep yuxta-ventricular localization it is necessary to know the relationship between the lesion and eloquent cerebral structures. Fiber tractography and intraoperative navigation systems are essentials tools to plan and guide the surgical approach and make a mapping of the projection, association and commissural fibers in order to have a safe access to the lesion. Objective: To describe the surgical technique using neuronavigation for the resection of a right frontal yuxta-ventricular cavernous malformation through a minimal approach. Case: A 20-year-old man, professional athlete with left arm paresthesia and severe headache. Magnetic resonance shows a heterogeneous lesion in T1 and T2 with a hemosiderin in the roof of the right lateral ventricle, compatible with a cavernous malformation. Its size was 28 mm x 31mm x 28 mm in the transversal, dorsoventral and rostrocaudal diameter. The fiber tractography shows an intimate relationship with the corticospinal tract on its path through the corona radiata. Results: Complete resection of the lesion. The patient evolved without a neurological deficit and was discharged 72 hours later. Conclusion: The fiber tractography and the intraoperative navigation system allow the deep lesions approach, especially for those who have an intimal relationship with eloquent ́s areas, using minimally corticotomy with less parenchymal retraction.

Relationship between the posterior septal artery and the upper edge of the choana.

BACKGROUND: The pedicled nasoseptal flap has been a key element in advancing the endoscopic transnasal approach (ETA) for the treatment of skull base lesions from the anterior cranial fossa to the occipitocervical junction. To preserve vascular supply, an anatomical knowledge of the location of the posterior septal artery (PSA) is essential. The objective of this work is to establish the relationship between PSA and the superior edge of the choana to define a safety margin during the opening of the sphenoidal rostrum preserving PSA. METHODS: One hundred and eighty angiotomographies of the brain were assessed. The sphenopalatine artery (SPA) was evaluated in the pterygopalatine fossa and PSA at its entrance into the nasal cavity and on the sphenoidal rostrum. RESULTS: PSA was found in all 3 tomographic planes (axial, coronal and sagittal) in 100 patients (200 PSAs). Thirty-five were male and 65 were females. Average age was 62 years with a range of 19-90 years. Total average distance between PSA and the superior edge of the choana was 8.5 mm with a range of 2.5-18 (12.45 90th percentile). CONCLUSION: Although the distance between the choanal edge and PSA is 8.5 mm on average, due to its variability, a distance of at least 12.45 mm for the opening of the sphenoidal sinus in the ETA approach should be considered as a safety margin.