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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.

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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

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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.

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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

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BACKGROUND: Minimally invasive spine surgeries (MISS) are currently used for a wide variety of intradural spinal pathologies. Although MISS techniques have brought great benefits, primary dural closure can prove a challenge due to the narrow corridor of the tubular retractor systems. OBJECTIVE: To present the surgical technique we developed for dural closure using an extracorporeal knot that is simple and reproducible. METHODS: We describe the use of an extracorporeal knot for primary dural closure in MISS surgeries using standard instrumental. We illustrate this operative technique with figures and its application in a surgical case with images and demonstration video2. RESULTS: Using our surgical technique, a watertight dural closure with separated knots was performed without specific instruments. CONCLUSION: The use of extracorporeal knots facilitates primary dural closure in MISS surgeries.

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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.

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Ex situ management is an important conservation tool that allows the preservation of biological diversity outside natural habitats while supporting survival in the wild. Captive breeding followed by re-introduction is a possible approach for endangered species conservation and preservation of genetic variability. The Cayman Turtle Centre Ltd was established in 1968 to market green turtle (Chelonia mydas) meat and other products and replenish wild populations, thought to be locally extirpated, through captive breeding. We evaluated the effects of this re-introduction programmme using molecular markers (13 microsatellites, 800-bp D-loop and simple tandem repeat mitochondrial DNA sequences) from captive breeders (N = 257) and wild nesting females (N = 57) (sampling period: 2013-2015). We divided the captive breeders into three groups: founders (from the original stock), and then two subdivisions of F1 individuals corresponding to two different management strategies, cohort 1995 ("C1995") and multicohort F1 ("MCF1"). Loss of genetic variability and increased relatedness was observed in the captive stock over time. We found no significant differences in diversity among captive and wild groups, and similar or higher levels of haplotype variability when compared to other natural populations. Using parentage and sibship assignment, we determined that 90% of the wild individuals were related to the captive stock. Our results suggest a strong impact of the re-introduction programmme on the present recovery of the wild green turtle population nesting in the Cayman Islands. Moreover, genetic relatedness analyses of captive populations are necessary to improve future management actions to maintain genetic diversity in the long term and avoid inbreeding depression.

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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.

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Objetivo: Las cirugías espinales mínimamente invasivas (MISS) son actualmente utilizadas para una gran variedad de patologías espinales intradurales. Aunque las técnicas MISS han demostrado estar asociadas a grandes beneficios, el cierre dural primario puede constituir un desafío debido al estrecho corredor que ofrecen los sistemas retractores tubulares. El objetivo es describir una técnica de cierre dural primario en cirugías MISS. Métodos: Describimos la utilización de nudos extracorpóreos en el cierre primario de duramadre en cirugías espinales MISS con la utilización de instrumental estándar y presentamos un video demostrativo. Resultados: Se logró un cierre dural hermético con puntos separados, facilitados por la utilización de nudos extracorpóreos y sin la utilización de instrumental especializado. Conclusión: La utilización de nudos extracorpóreos facilita el cierre dural primario en cirugías MISS.

Objective: Minimally-invasive spinal surgery (MISS) is currently used for a wide variety of intradural spinal pathologies. Although MISS techniques have proven to be of great benefit, primary dural closure might be a challenge, due to the narrow corridor of tubular retractor systems. Methods: We describe employing an extracorporeal knot for primary dural closure during MISS, using standard instrumentation. We also illustrate this technique with a demonstration video. Results: Watertight dural closure with separated extracorporeal knots was performed, all without specialized instruments. Conclusion: The use of extracorporeal knots facilitates primary dural closure after MISS.

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Objetivo: analizar en forma prospectiva la viabilidad de una neurorrafia mediante técnicas microquirúrgicas, en un modelo experimental con diferentes grados crecientes de pérdida de tejido nervioso periférico. Introducción: Para reparar un nervio periférico que tiene pérdida de tejido, clásicamente este defecto se suple por un injerto autólogo. Sin embargo, se produce comorbilidad en el sitio dador y sus resultados siempre son inferiores a la sutura directa sin tensión. Existe una opción para evitar el uso de injertos cuando el defecto es escaso, colocando puntos epineurales distales (PED) a la neurorrafia, eliminando así la tensión en dicha unión. Materiales y métodos: Se utilizaron 40 ratas Wistar, dividiéndose aleatoriamente en 4 grupos. Bajo anestesia general se abordó al nervio ciático y se efectuó sección trasversal y sutura simple con nylon 10.0 al grupo A (control). Se realizó exéresis de 2 mm de nervio al grupo B, de 4 mm al grupo C y de 6 mm al grupo D; para luego realizar PED. Se realizaron determinaciones de índice de función ciático (análisis de las huellas), velocidad de conducción (electrofisiología) e índice de regeneración (histopatología) para evaluar la viabilidad de la neurorrafia. Se confrontaron los diferentes grupos planteados con ANOVA, considerando significativo un valor de p < 0.05. Conclusiones:La neurorrafia simple no evidencia diferencias estadísticamente significativas con la reparación de 2mm de pérdida de tejido mediante PED en la rata Wistar.

Objective: To analyze, in a prospective way, the viability of a neurorraphy by a microsurgical technique, in an experimental model with different increasing grades of peripheral nerve tissue loss.Introduction: In order to repair a peripheral nerve that has experienced some grade of substance loss, autologous grafts have been used by most neurosurgeons. However, comorbidities in the donor site are produced, and the results obtained are always inferior compared to the ones achieved by using a direct suture without tension. There is an option to avoid using grafts when the defect is scarce, which is the confection of distal epineural sutures (DES) to the neurorraphy, discarding any tension in this junction site.Materials and methods: We have used 40 Wistar rats, randomly separated into 4 groups. In ‘Group A’, under complete anesthesia, the sciatic nerve was dissected and transversely sectioned and then sutured with a 10.0 nylon suture. Furthermore we made a 2 mm extirpation in ‘Group B’, a 4 mm one in ‘Group C’ and a 6 mm one in ‘Group C’, in order to perform a DES technique. Our group also ran a sciatic nerve function test (footprint analysis), conduction speed (by electrophysiology), and even determined the nerve regeneration index (histopathology) to estimate the viability of the neurorraphy. The different groups were confronted with ANOVA, considering a value of p<0.05 as statistically significative.Conclusions: Simple neurorraphy exposed no statistically significative differences in comparison to the reparation of a 2 mm tissue loss with DES technique, in the Wistar rat model.

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