Classification and Management of Pontecerebellar-Petrosal Bridging Veins.

OBJECTIVES: 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. METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.

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.

Manejo preoperatorio de los adenomas hipofisarios. Lo que un residente de neurocirugía debe conocer / Preoperative management of pituitary adenomas. What a neurosurgery resident should know

Las lesiones selares son una patología con una incidencia de 3,2 a 4 / 100,000 y una prevalencia de 78 a 94 / 100,000. Un 10% son incidentalomas en la población adulta. Se cree que su prevalencia en el orden mundial actualmente va en aumento.En relación a las manifestaciones clínicas, cabe destacar que es una de las pocas enfermedades que pueden manifestarse tanto por signos y síntomas neurológicos (por ejemplo: hemianopsia bitemporal, síndrome de hipertensión endocraneana debido a hidrocefalia, entre otros), como también por síndromes endocrinológicos (por ejemplo: síndrome de Cushing, acromegalia, amenorrea-galactorrea, infertilidad).Todo paciente debe presentar un estudio clínico-radiológico completo, lo que permitirá un correcto diagnóstico y categorización del mismo.El objetivo del presente trabajo es proporcionar al neurocirujano en formación los conceptos claves que servirán de sustento para el manejo preoperatorio de un paciente con adenoma hipofisario.

Sellar lesions are a pathology with an incidence of 3.2 to 4 / 100.000 and a prevalence of 78 to 94 / 100.000. Normally, 10% of them are incidentalomas and adult patients are in the highest risk group. Because it ́s prevalence in the world is currently increasing, it is of extremely importance to study and understand this pathology. In relation to the clinical manifestations, it should be noted that it is one of the few diseases that can manifest through neurological signs and symptoms like bitemporal hemianopsia, endocranial hypertension syndrome due to hydrocephalus, as well as endocrinological syndromes like Cushing's, acromegaly, amenorrhea-galactorrhea and infertility. One of the most important things to notice is that the treatment success in this pathology comes with the correct diagnosis and characterization of it, for what all patients should have a complete clinical-radiological evaluation.In this study, we establish a guide with concepts and key tools to support the medical personal during a pre-surgical preparation of patients with pituitary adenoma.

Posición semisentada en neurocirugía. Nota técnica y presentación de casos ilustrativos / Semi-sitting position in neurosurgery. Technical note and illustrative case presentation

Introducción: En las últimas décadas el uso de la posición sentada ha disminuido en frecuencia a causa de 2 complicaciones mayores: el embolismo aéreo venoso y la hipotensión intraoperatoria. Sin embargo es innegable que la posición sentada ofrece una serie de ventajas al neurocirujano, el anestesiólogo y al electrofisiólogo. Materiales y métodos: Estudio retrospectivo de pacientes operados en dos instituciones de Tucumán, entre enero de 2015 y diciembre de 2019. Resultados: Se operaron un total de 119 pacientes en posición sentada por vía posterior. Conclusión: Se presentó la técnica de posición semisentada paso a paso y consejos específicos. Se ilustró la utilidad de la misma mediante la presentación de casos representativos

Introduction: In the last decades, the use of the sitting position has been abandoned due to 2 major complications: venous air embolism and intraoperative hypotension. However, it is undeniable that the sitting position offers a series of advantages to the neurosurgeon, the anesthesiologist and the electrophysiologist. Materials and methods: Retrospective study of patients operated at two institutions in Tucumán, between January 2015 and December 2019. Results: A total of 119 patients were operated in a sitting position and posterior approach. Conclusion: The sitting position technique was presented step by step in detail, with the key steps and a series of tricks. The usefulness of the position was illustrated by presenting representative cases

Conflicto neurovascular trigeminal: ¿Cuál es el factor predictor más confiable? / Trigeminal neurovascular conflict: What is the most reliable predictor?

Introducción: La Academia Americana de Neurología propone que, para que un paciente sea candidato a descompresiva neurovascular trigeminal (DNV), se debe demostrar la presencia de contacto neurovascular a través de la resonancia magnética (RM). Sin embargo, recientes estudios han demostrado que la sensibilidad de la RM para diagnosticar un conflicto neurovascular (CNV) es muy variable. Estos conceptos antagónicos ubican al neurocirujano ante un verdadero dilema a la hora de tomar decisiones. El objetivo del presente estudio es evaluar la utilidad de la clínica y la RM como factor predictor de un verdadero CNV. Materiales y Métodos: Estudio analítico retrospectivo que incluye a 81 pacientes a los que se les realizó una DNV por neuralgia trigeminal (NT), desde enero de 2013 hasta abril de 2019, en la provincia de Tucumán. Resultados: Al considerar la serie completa: A) Un total de 65 pacientes cursaron con NT Típicas; de estos, 64 (98,5%) presentaron CNV durante la cirugía y B) De las 16 Atípicas, ninguna presentó CNV en el intraoperatorio. Al considerar los pacientes con NT primaria: A) un 98% de los pacientes con clínica de NT típica presentaran CNV en el intraoperatorio y B) hubo un grupo de pacientes donde se evidencio un CNV en el intraoperatorio pero en su RM preoperatoria no se objetivo el mismo (n=15), el valor predictivo negativo de la RM fue sólo un 6%. Conclusión: La clínica del paciente es más efectiva que la RM para decidir si realizar o no una cirugía de DNV.

Introduction: The American Academy of Neurology proposes that, for a patient to be a candidate for trigeminal neurovascular decompression (NVD), the presence of neurovascular contact must be demonstrated through magnetic resonance imaging (MRI). However, recent studies have shown that the sensitivity of MRI to diagnose a neurovascular conflict (NVC) is highly variable. These antagonistic concepts put, the neurosurgeon, in a real dilemma when making decisions about this entity. The aim of this study is to evaluate the usefulness of clinical and MRI as a predictor of a real NVC. Methods: This is a retrospective analytical study including 81 patients undergoing NVD to treat trigeminal neuralgia (TN), from January 2013 to April 2019, in Tucumán. Results: When considering the complete series: A) Of the total of 65 patients who had typical TN, 64 (98.5%) presented NVC during surgery and B) Of the 16 atypical TN, none of then presented NVC during the surgery. When considering patients with primary TN: A) 98% of the patients with typical NT presented a NVC during surgery and B) there was a group of patients where NVC was evidenced during surgery but it wasn`t noticed during the preoperative MRI (n=15), the negative predictive value of the MRI was only 6%. Conclusion: The patient's clinic is more effective than the MRI deciging whether or not to perform NVD surgery.