Optic Tract as an Upper Limit in Amygdalectomy: Microsurgical Study.

BACKGROUND: In surgeries involving resection of the amygdala, despite clear relations established with the medial, lateral, anterior, posterior, and inferior segments, the upper limit remains controversial. The optic tract (OT) has been anatomically considered as a good landmark immediately inferior to the striatopallidal region. This anatomic structure has barely been explored by microsurgical study, generating uncertainty about the exact relationship with the surrounding structures. OBJECTIVE: To describe the OT in its entire length through microsurgical study, showing its superior, inferior, medial, and lateral relationships and highlighting its value as a landmark in superior amygdala resection. METHODS: Microsurgical anatomic dissection of the OT, from its origin in the chiasm to the lateral geniculate nucleus was performed in 8 alcohol-fixed human hemispheres, showing its different segments and relations. Photographs were taken from different angles to facilitate surgical orientation. RESULTS: We performed a dissection of the OT, showing its position relative to caudate and hippocampal formations. We exposed the structures related to the OT superiorly (striatopallidal region and superior caudate fasciculus), inferiorly (head of the hippocampus, amygdala, anterior choroidal artery, perforating artery branch of the anterior choroidal artery, terminal stria, and basal vein), medially (internal capsule and midbrain), and laterally (temporal stem [uncinate and inferior fronto-occipital fascicle], anterior perforated substance, and superior caudate fasciculus). CONCLUSION: To date, there is a paucity of articles describing the anatomy of the OT from a neurosurgery perspective. In this study, we describe the microsurgical anatomic path of the OT, as a reliable upper limit landmark for amygdala resection.

Introducing a Realistic, Low-Cost Simulation Model for Clipping of Brain Aneurysms.

BACKGROUND: The current trend toward endovascular treatment of brain aneurysms may have a negative impact on young neurosurgeons who are less exposed to these lesions, thus affecting the acquisition of surgical skills in the field. Different training models have emerged to help cope with this issue, but these have specific pitfalls. Training models based on live animals or cadaveric specimens face increasing restrictions as regulations become a barrier in accessibility for everyday skills development. We introduce a novel, realistic, and inexpensive simulation model using a fresh bovine brain, and we assess its face and content validity as a training tool. METHODS: A fresh bovine brain is used to simulate microsurgical fissure dissection. Arterial and aneurysmal components are created with arteries and veins harvested from chicken thigh. A 12-item questionnaire using the Likert numeric scale (grades 1 - 5) was used to assess the validity of model in 10 surgeons. RESULTS: Ten neurosurgeons performed the simulated clipping of the aneurysm and completed a questionnaire. All surgeons surveyed responded "agree" or "strongly agree" that the simulator, and the skills trained with it, are comparable to clipping brain aneurysms. All respondents believed that this simulator could improve patient safety. CONCLUSIONS: We present a novel, realistic, and inexpensive simulation model for the clipping of brain aneurysms. This model was partially validated by the opinion of field experts. We believe this model has the potential to become a useful training tool for young neurosurgeons who have little exposure to real aneurysm cases.

Flow recovery after posterior clinoidectomy for surgical clipping of anterior choroidal aneurysm.

Inadvertent flow alterations in the parent artery during microsurgical clipping might produce postoperative ischemic complications. Intraoperative recognition of such alterations and its correction might improve operative outcomes in these patients. We present the case of a thirty-five-year-old male with an incidental small left anterior choroidal aneurysm. Microsurgical clipping induced an external compression of the anterior choroidal artery against the posterior clinoidal process which was identified in situ through surgical exploration and the loss of arterial doppler signal in the vessel. After failed attempts at clip repositioning, a posterior clinoidectomy was performed to decompress the artery. This resulted in arterial flow recovery. The aneurysm was successfully treated, and a severe ischemic complication was likely avoided. This intraoperative phenomenon has not yet been described in the literature.

Modelo de simulación de clipado de aneurismas cerebrales de bajo costo, validez aparente y de contenido / 1st Prize Scholarship: Low-cost brain aneurysm clipping simulation model, face and content validity

Objetivo: Presentar un modelo de entrenamiento realista en clipado microquirúrgico de aneurisma cerebral con flujo pulsátil, artificial, accesible y de bajo costo. Evaluar su validez aparente y de contenido. Introducción: La tendencia actual hacia el tratamiento endovascular de aneurismas cerebrales puede reducir la exposición de neurocirujanos jóvenes al tratamiento quirúrgico de estas lesiones durante su formación, afectando la adquisición de habilidades quirúrgicas en este campo. Presentamos un modelo de simulación fácilmente reproducible para clipado de aneurismas cerebrales verificando su validez como herramienta de entrenamiento. Material y métodos: Se utilizó cerebro bovino como alternativa al cerebro humano para simular apertura de surcos. Para la confección de aneurismas se utilizaron arteria y vena femoral de muslo de pollo. Como sistema de micro flujo se utilizó una mini bomba sumergible. Discusión: La simulación con animales vivos se considera entre los modelos más realistas para el entrenamiento en microcirugía, pero las restricciones y su costo limitan su uso, tal como ocurre con los especímenes cadavéricos humanos. Con el propósito de resolver estas dificultades, desarrollamos un modelo de bajo costo y lo usamos para similar el clipado de aneurismas cerebrales. Diez neurocirujanos experimentados utilizaron el mismo y luego completaron una encuesta para evaluar su potencial beneficio. Conclusión: Hemos presentado un nuevo modelo de simulación para el clipado microquirúrgico de aneurismas cerebrales utilizando materiales accesibles y económicos. Creemos que el mismo resulta útil y fácilmente reproducible para la práctica y el aprendizaje de la técnica microquirúrgica para neurocirujanos en formación

Objective: To show a realistic and accessible training model for cerebral aneurysm clipping with a pulsatile flow. To determine its face and content validity. Background: The current trend towards endovascular treatment of brain aneurysms may have a negative impact on young neurosurgeons who are less exposed to these lesions, thus affecting the acquisition of surgical skills in the field. We introduce an easily reproducible simulation model for clipping of cerebral aneurysms and we assess its validity as a training tool. Material and methods: A fresh bovine brain is used to simulate microsurgical fissure dissection. Arterial and aneurysmal components are created with arteries and veins harvested from chicken thigh. For the micro flow system, a submersible mini-pump was employed. Discussion: Live animal simulations are considered among the most realistic training models but restrictions and the facilities costs limit their use, just as with human cadaveric specimens. With the aim of addressing these issues, we developed a low-cost model with the use of a micro flow pump and used it for simulation of aneurysm clipping. Ten neurosurgeons performed the simulated clipping of the aneurysm and were administered a questionnaire following the procedure. Conclusion: We present a novel, realistic, inexpensive and easily reproducible simulation model for the clipping of brain aneurysms. This model was partially validated by the opinion of field experts. We believe this model has the potential of becoming a useful training tool for young neurosurgeons

Schwannoma intraparenquimatoso con calcificación focal en lóbulo temporal. Reporte de caso y revisión de literatura / Intraparenchymal schwannoma with focal calcification in the temporal lobe. Case report and literature review

Los schwannomas intraparenquimatosos son tumores con una muy baja incidencia en el sistema nervioso central. Actualmente, no se conoce su verdadero origen. Sin embargo, con el paso de los años se han descripto múltiples teorías. Son tumores que afectan principalmente a niños y adultos jóvenes. El síntoma principal es la cefalea; y se ubican principalmente en el compartimiento supratentorial. El Gold Standard para su estudio es la resonancia magnética donde suelen presentarse como lesiones hipointensas en T1, hiperintensas en T2 que captan contraste de forma homogénea. Una vez diagnosticado debe plantearse la resolución quirúrgica ya que en la mayoría de los casos representan una lesión benigna, y su exéresis completa significa la resolución de la enfermedad. El diagnóstico definitivo se obtiene mediante la anatomía patológica. A continuación, presentaremos el caso de una paciente de 46 años con antecedente de cefalea en cuyo contexto, mediante una resonancia magnética, se descubre una lesión en el lóbulo temporal siendo el diagnóstico de la misma: schwannoma intraparenquimatoso con calcificación focal

Intraparenchymal schwannomas have a very low incidence in the central nervous system. Currently, its true origin is not known, however, over the years, multiple theories have been described. This pathology mainly affects children and young adults. The main symptom is headache; and usually it is located in the supratentorial compartment. The Gold Standard is MRI where they usually present as hypointense lesions in T1, hyperintense in T2 that capture contrast in a homogeneous way. Once diagnosed, surgical resolution should be considered, since in most cases they represent a benign lesion, and their complete excision means resolution of the disease. The definitive diagnosis is obtained by pathological anatomy. We present a case of a 46-year-old patient with history of headache, its magnetic resonance revealed an extra axial lesion in the temporal lobe with considerable surrounding edema, the diagnosis was Intraparenchymal schwannoma with focal calcification in the temporal lobe

Intra- and extradural anterior clinoidectomy: anatomy review and surgical technique step by step.

PURPOSE: The complex relations of the paraclinoid area make the surgical management of the pathology of this region a challenge. The anterior clinoid process (ACP) is an anatomical landmark that hinders the visualization and manipulation of the surrounding neurovascular structures, hence in certain surgical interventions might be necessary to remove it. We reviewed the anatomical relationships that involve the paraclinoid area and detailed the step-by-step techniques of intra and extradural clinoidectomy in cadaveric specimens. MATERIALS AND METHODS: A literature review was done describing the most relevant anatomic relationships regarding the anterior clinoid process. Extradural and intradural clinoidectomy techniques were performed in six dry bone heads and in ten previously injected cadaverous specimens with colored latex (Sanan et al. in Neurosurgery 45:1267-1274, 1999) and each step of the procedure was recorded using photographic material. Finally, an analysis of the anatomical exposure achieved in each of the techniques used was performed. RESULTS: The main advantage of the intradural clinoidectomy technique is the direct visualization of the neurovascular structures adjacent to the ACP when drilling, at the same time, opening the Sylvian fissure will allow the direct visualization of the ACP variants. The main advantage offered by the extradural technique is that the dura protects adjacent eloquent structures while drilling. Among the disadvantages, it is noted that the same dura that would protect the underlying structures also prevents the direct visualization of these neurovascular structures adjacent to the ACP. CONCLUSION: We reviewed the anatomy of the paraclinoid area and made a step-by-step description of the technique of the anterior clinoidectomy in its intra- and extradural variants in cadaveric preparations for a better understanding.

Novel Simulation Model with Pulsatile Flow System for Microvascular Training, Research, and Improving Patient Surgical Outcomes.

BACKGROUND: Simulation allows surgical trainees to acquire surgical skills in a safe environment. With the aim of reducing the use of animal experimentation, different alternative nonliving models have been pursued. However, one of the main disadvantages of these nonliving models has been the absence of arterial flow, pulsation, and the ability to integrate both during a procedure on a blood vessel. In the present report, we have introduced a microvascular surgery simulation training model that uses a fiscally responsible and replicable pulsatile flow system. METHODS: We connected 30 human placentas to a pulsatile flow system and used them to simulate aneurysm clipping and vascular anastomosis. RESULTS: The presence of the pulsatile flow system allowed for the simulation of a hydrodynamic mechanism similar to that found in real life. In the aneurysm simulation, the arterial flow could be evaluated before and after clipping the aneurysm using a Doppler ultrasound system. When practicing anastomosis, the use of the pulsatile flow system allowed us to assess the vascular flow through the anastomosis, with verification using the Doppler ultrasound system. Leaks were manifested as "blood" pulsatile ejections and were more frequent at the beginning of the surgical practice, showing a learning curve. CONCLUSIONS: We have provided a step-by-step guide for the assembly of a replicable and inexpensive pulsatile flow system and its use in placentas for the simulation of, and training in, performing different types of anastomoses and intracranial aneurysms surgery.

Home Program for Acquisition and Maintenance of Microsurgical Skills During the Coronavirus Disease 2019 Outbreak.

BACKGROUND: During the current global crisis unleashed by the severe acute respiratory syndrome coronavirus 2 outbreak, surgical departments have considerably reduced the amount of elective surgeries. This decrease leads to less time in the surgical room to develop and improve the surgical skills of residents. In this study, we developed a training program to obtain and maintain microsurgical skills at home, using a smartphone camera and low-cost materials, affordable for everyone. METHODS: Using a smartphone camera as a magnification device, 6 participants performed 5 exercises (coloring grids, grouping colors, unraveling of a gauze, knots with suture threads, and tower of Hanoi), both with the dominant and with the nondominant hand, for 4 weeks. We compared performance at the beginning and at the end of the training process. Each participant filled out an anonymous survey. RESULTS: When we compared the performance at the beginning and at the end of the training process, we found significant improvements (P = 0.05) with the dominant as well as the nondominant hand in all the exercises. All participants were satisfied or very satisfied with the definition of the objectives of the training process, material availability, the exercises performed, the choice of the time to train, and general satisfaction with the training program. CONCLUSIONS: We developed a microsurgical skills training program to be performed at home, which can be easily reproduced. It allows residents to improve manual coordination skills and is regarded as a feasible adjunct for ongoing training for surgical residents.

Aneurisma gigante de Arteria Cerebral Media: Trapping y By-Pass / Giant Aneurysm of the Middle Cerebral Artery: Trapping and By-Pass

Objetivo: Presentar la resolución quirúrgica de un aneurisma gigante de arteria cerebral media mediante técnica de Trapping y By-Pass. Introducción: La tasa de mortalidad a 5 años de pacientes con aneurismas gigantes es del 80%. Debido a su cuello ancho en ocasiones el clipado directo no es posible, requiriendo realizar Trapping del aneurisma seguido de revascularización mediante By-Pass. Material y Método: Se analizaron datos de historia clínica, imágenes complementarias pre y postquirúrgicas, así como imágenes de video intraoperatorias de un paciente portador de aneurisma gigante de arteria cerebral media intervenido en nuestro centro. Resultados: Mediante abordaje Pterional se localizó arteria temporal superficial y sus ramos. Luego de una cuidadosa disección del saco aneurismático se intentó el clipado primario, debido a su cuello ancho, aterosclerosis asociada y trombo intrasacular, el flujo en la rama temporal de arteria cerebral media era comprometido por el clip. Se decidió la oclusión del aneurisma mediante técnica de trapping y, en mismo tiempo quirúrgico, realización de By Pass extra-intracraneano de arteria temporal superficial a rama temporal de arteria cerebral media. A su vez se secciono el aneurisma y se removió el trombo contenido en su interior, logrando disminuir el efecto de masa ejercido por el mismo. Se corroboro permeabilidad intraquirurgica mediante Doppler y en el postoperatorio alejado mediante angiotomografía con reconstrucción 3D. El paciente evoluciono sin complicaciones asociadas con un Rankin modificado de 1. Conclusión: Se presentó resolución quirúrgica de aneurisma gigante de arteria cerebral media mediante técnica de Trapping seguida de By-Pass extra-intra craneano temporo-silviano

Objective: To present the surgical resolution of a giant aneurysm of the middle cerebral artery using Trapping and By-Pass technique. Introduction: The 5-year mortality rate of patients with giant aneurysms is 80%. Due to its wide neck, sometimes-direct clipping is not possible, requiring trapping of the aneu-rysm followed by bypass revascularization. Material and Method: Clinical history data and intraoperative video images of a pa-tient with a giant aneurysm of the middle cerebral artery were analyzed. Results: The superficial temporal artery and its branches were identified through a Pterional approach. After careful aneurysm dissection, primary clipping was attempted, but the flow in the temporal branch of the middle cerebral artery was compromised. Due to its wide neck, associated atherosclerosis and intrasaccular thrombus, an Extra-intracranial bypass was performed from superficial temporal artery to temporal branch of middle cerebral artery, followed by trapping technique of the aneurysm. Then the aneu-rysm was sectioned and the thrombus contained inside was removed, decreasing the mass effect exerted by it. A Doppler probe was used to corroborate bypass permeability, as well as 3D reconstruction angiotomography during the postoperative period. The pa-tient was discharged without associated complications and a modified Rankin scale of 1. Conclusion: Surgical resolution of a giant middle cerebral artery aneurysm was present-ed by Trapping technique followed by extra-intra-cranial temporo-Silvian bypass

Utilidad de las Escalas de Gradación en el Tratamiento Quirúrgico de Malformaciones Arteriovenosas Cerebrales / Usefulness of the Gradation Scales in the Surgical Treatment of Cerebral Arteriovenous Malformations

Introducción: Las malformaciones arteriovenosas (MAVs) cerebrales comprenden una compleja patología responsable de hasta el 38% de las hemorragias en pacientes de entre 15-45 años, acarreando cada episodio de sangrado un 25-50% de morbilidad y un 10-20% de mortalidad. La decisión terapéutica en un paciente con una MAV debe tener en cuenta la comparación entre los riesgos propios de la intervención y los de la historia natural de esta enfermedad. Objetivo: Evaluar la utilidad de predecir riesgo quirúrgico de diferentes escalas de gradación de MAV cerebrales según nuestra experiencia en una serie de casos. Material y Métodos: Se realizó un análisis bibliográfico de escalas de gradación de riesgo quirúrgico de MAV cerebrales utilizando como motor de búsqueda Pubmed incluyendo como palabras clave "malformación arteriovenosa cerebral" y "escala de gradación" (brain arteriovenous and malformation grading scale). Se analizaron de forma retrospectiva aquellos pacientes intervenidos quirúrgicamente por MAV en este hospital público, se las clasificó acorde a las escalas analizadas y se compararon los resultados obtenidos con los previstos en ellas. Resultados: Se analizaron 90 pacientes intervenidos quirúrgicamente por MAV, sin tratamiento coadyuvante. De forma retrospectiva se los agrupó acorde a las escalas de Spetzler Martin (SM), Spetzler-Ponce (SP) y suplementaria de Lawton. Las MAV grado 3 se subclasificaron según las escalas de Lawton y de de Oliveira. Considerando buenos resultados aquellos con Rankin modificado (mRs) igual o menor a 2. Con un rango de seguimiento de 12 a 48 meses, encontramos buenos resultados en el 100% de MAV SM grado 1, 91.7% de las grado 2, 80% en grado 3 y 42.9% en grado 4. Utilizando la escala SP, 93.7% de buenos resultados en tipo A, 80% en tipo B y 42.9% en tipo C. Subclasifican-do las MAV SM 3 acorde a las escalas de de Oliveira y Lawton, 84% de buenos resultados en el tipo 3A, 71.3% en las 3B, 92% en MAV tipo 3-, 72.1% en el tipo 3+, 60% en tipo 3. Utilizando la escala suplementaria de Lawton combinada con SM, buen resultado en 100% grados II y III, 85,7% grado IV, 87,6 grado V, 80% grado VI, 75% grado VII y 66,6% grado VIII. Conclusión: Reafirmamos en esta serie, la utilidad de estimar riesgo quirúrgico con las escalas SM, SP, y la subclasificación de las MAV grado 3 propuesta por Lawton. Y principalmente el utilizar la escala suplementaria de Lawton-Young al considerar el tratamiento quirúrgico de los pacientes con MAV que sangraron.

Introduction: Brain arteriovenous malformations (AVM) are a complex disease responsible for up to 38% of hemorrhages in patients between 15-45 years old, carrying every bleeding episode a 25-50% risk of morbidity and a 10-20% of mortality. The therapeutic decision in a patient with an AVM needs to consider both the risks of the intervention and the risks of the natural evolution of the disease. Objective: To assess the effectiveness of different AVM grading scales in predicting surgical risks according to our experience in a case series. Material and Method: a literature review of the AVM grading scales was made, through Pubmed including as key words "brain arteriovenous malformations" and "grading scale". A retrospective analysis was made of patients with AVM who were operated in our institution, they were classified according to the scales and their results were compared. Results: 90 patients were operated in our institution with AVM. Retrospectively, they were classified according to the Spetzler-Martin (SM), Spetzler-Ponce (SP), Lawton supplementary, and the sub-classifications in AVM grade 3, from Lawton and de Oliveira. Good outcome were considered when modified Rankin Scale (mRs) was equal or less than 2. The follow-up ranged from 12-48 months, having good outcome in 100% of AVM SM grade I, 91,7% grade II, 80% in grade III and 42,9% in grade IV. Using the SP scale, 93,7% of good outcome in grade A, 80% in grade B and 42,9% in grade C. In the sub-classification of AVM SM 3, we found 84% of good outcome in type 3A de Oliveira and 71,3% in type 3B. According to the Lawton scale, good outcome were found in 92% in type 3-, 72,1% in type 3+ and 60% in type 3. Using Lawton supplementary scale combined with SM, there were 100% of good outcome in grades II and III, 85,7% in grade IV, 87,6% in grade V, 80% in grade VI, 75% in grade VII, 66,6% in grade VIII. Conclusion: In our series, we reaffirm the effectiveness to predict surgical risk of the following scales: SM, SP and the Lawton's sub-classification of AVM grade 3. Specially, the use of the supplementary Lawton-Young scale in the surgical treatment of bleeding AVMs.

[Usefulness of Gradation Scales in the Surgical Treatment of Cerebral Arteriovenous Malformations]. / Utilidad de las Escalas de Gradación en el Tratamiento Quirúrgico de Malformaciones Arteriovenosas Cerebrales.

INTRODUCTION: Brain arteriovenous malformations (AVM) are a complex disease responsible for up to 38% of hemorrhages in patients between 15-45 years old, carrying every bleeding episode a 25-50% risk of morbidity and a 10-20% of mortality. The therapeutic decision in a patient with an AVM needs to consider both the risks of the intervention and the risks of the natural evolution of the disease. OBJECTIVE: To assess the effectiveness of different AVM grading scales in predicting surgical risks according to our experience in a case serie. MATERIAL AND METHOD: A literature review of the AVM grading scales was made, through Pubmed including as key words "brain arteriovenous malformations" and "grading scale". A retrospective analysis was made of patients with AVM who were operated in our institution, they were classified according to the scales and their results were compared. RESULTS: 90 patients were operated in our institution with AVM. Retrospectively, they were classified according to the Spetzler-Martin (SM), Spetzler-Ponce (SP), Lawton supplementary, and the sub-classifications in AVM grade 3, from Lawton and de Oliveira. Good outcome were considered when modified Rankin Scale (mRs) was equal or less than 2. The follow-up ranged from 12-48 months, having good outcome in 100% of AVM SM grade I, 91,7% grade II, 80% in grade III and 42,9% in grade IV. Using the SP scale, 93,7% of good outcome in grade A, 80% in grade B and 42,9% in grade C. In the sub-classification of AVM SM 3, we found 84% of good outcome in type 3A de Oliveira and 71,3% in type 3B. According to the Lawton scale, good outcome were found in 92% in type 3-, 72,1% in type 3+ and 60% in type 3. Using Lawton supplementary scale combined with SM, there were 100% of good outcome in grades II and III, 85,7% in grade IV, 87,6% in grade V, 80% in grade VI, 75% in grade VII, 66,6% in grade VIII. CONCLUSION: In our serie, we reaffirm the effectiveness to predict surgical risk of the following scales: SM, SP and the Lawton's sub-classification of AVM grade 3. Specially, the use of the supplementary Lawton-Young scale in the surgical treatment of bleeding AVMs.