3D simulation of aneurysm clipping: Data analysis.

Aneurysm clipping requires the proficiency of several skills, yet the traditional way of practicing them has been recently challenged. The use of simulators could be an alternative educational tool. The aim of this data analysis is to provide further evaluation of a reusable low-cost 3D printed training model we developed for aneurysm clipping [1]. The simulator was designed to replicate the bone structure, arteries and targeted aneurysms. Thirty-two neurosurgery residents performed a craniotomy and aneurysm clipping using the model and then filled out a survey. The survey was designed in two parts: a 5-point Likert scale questionnaire and three questions requiring written responses [1]. Two dimensions of the model were evaluated by the questionnaire: the face validity, assessed by 5 questions about the realism of the model, and the content validity, assessed by 6 questions regarding the usefulness of the model during the different steps of the training procedure. The three questions requiring written responses referred to the strengths and weaknesses of the simulator and a global yes/no question as to whether or not they would repeat the experience. Demographic data, experience level and survey responses of the residents were grouped in a dataset [2]. A descriptive analysis was performed for each dimension. Then, the groups were compared according to their level of expertise (Junior and Senior groups) with an independent sample t-test. A Confirmatory Factor Analysis (CFA) was estimated, using a Weighted Least Squares Mean Variance adjusted (WLSMV) which works best for the ordinal data [3]. Fitness was calculated using chi-square (χ2) test, Comparative Fit Index (CFI), Tucker-Lewis Index (TLI), and the Root Mean Square Error of Approximation (RMSEA). A non-significant χ2, CFI and TLI greater than 0.90 and RMSEA < 0.08 were considered an acceptable fit [4]. All data analysis was performed using IBM SPSS 23.0 statistical software. Data are reported as mean + standard deviation (SD). A probability p < 0.05 was considered significant. Exploratory Factor Analysis was done to explore the factorial structure of the 11-items scale in the sample, first we performed a principal components analysis. The Kaiser-Meyer-Olkin measure verified the sampling adequacy for the analysis (KMO = 0.784; Bartlett's Test of Sphericity χ2 (55) = 243.44, p < .001), indicating correlation is adequate for factor analysis. Considering Eigen values greater than 1, a two-factor solution explained 73.1% of the variance but left one item in factor 2 (Q 11). The results of this factor analysis are presented in Table 1. Confirmatory Factor Analysis, considering only the 10 items in the first factor (removing question 11 of our model), was performed. This model reached the following fit: χ2 (35) = 38.821, p > .05; CFI = 0.997; TLI = 0.996; RMSEA 0.058, without any error terms to exhibit covariance. Regarding the reliability of the questionnaire, the internal consistency was explored in the 10 items selected in the confirmatory factor analysis with an alpha coefficient (α = 0.941).

Reusable Low-Cost 3D Training Model for Aneurysm Clipping.

BACKGROUND: Aneurysm clipping requires the proficiency of several skills, yet the traditional way of practicing them has been recently challenged, especially by the growth of endovascular techniques. The use of simulators could be an alternative educational tool, but some of them are cumbersome, expensive to implement, or lacking in realism. The aim of this study is to evaluate a reusable low-cost 3-dimensional printed training model we developed for aneurysm clipping. METHODS: The simulator was designed to replicate the bone structure, arteries, and targeted aneurysms. Thirty-two neurosurgery residents performed a craniotomy and aneurysm clipping using the model and then filled out a survey. They were divided into Junior and Senior groups. Descriptive, exploratory, and confirmatory factor analysis was performed using IBM SPSS statistical software. RESULTS: The overall residents' response was positive, with high scores to face validity and content validity questions. There was no significant statistical difference between the Junior and Senior groups. The confirmatory factor and internal consistency analysis confirmed that the evaluation was highly reliable. Globally, 97% of the residents found the model was useful and would repeat the simulator experience. The financial cost is $2500 USD for implementation and only $180 USD if further training sessions are required. CONCLUSIONS: The main strengths of our training model are its highlighted realism, adaptability to trainees of different levels of expertise, sustainability, and low cost. Our data support the concept that it can be incorporated as a new training opportunity during professional specialty meetings and/or within residency academic programs.

Explorando un sistema de control de la consanguinidad vía toros de inseminación en sistemas de producción cerrados carentes de registros genealógicos / Exploring an inbreeding control system using insemination bulls in closed production systems without pedigrees / Explorando um sistema de controle da consanguinidade via touros de inseminação em sistemas de produção cerrados carentes de registros genealógicos

Resumen Si en un sistema de producción animal se sobrepasa un umbral de consanguinidad (F) promedio (en torno al 6,25%), pueden comenzar a surgir una serie de anomalías como la aparición de enfermedades autosómicas recesivas, disminución en la capacidad de respuesta inmune y en los promedios productivos y reproductivos de los rebaños, fenómeno conocido como depresión endogámica. Este problema puede verse magnificado en sistemas de producción en los que la mejora genética se realiza a través de inseminación artificial (IA) pues, en varios países, se ha informado de elevados grados de parentesco familiar entre toros de inseminación pertenecientes a una misma raza. En el presente estudio se exponen los resultados de la simulación de una estrategia para el control de la consanguinidad en rebaños productivos de la raza Aberdeen angus, basada en la gestión de registros genealógicos de toros de inseminación. Los resultados del presente estudio indican que, en teoría, es posible implementar programas de control de la consanguinidad en planteles productivos de bovinos de carne sometidos a IA, a través de una estrategia que no dependa de la existencia de registros genealógicos prediales, sino que de los registros de los toros de inseminación. Dicha estrategia dependería únicamente de la información proporcionada a los productores por parte de las empresas proveedoras de semen. Sin embargo, el método propuesto no es aplicable a criaderos de reproductores, los cuales no pueden prescindir de registros genealógicos y de un control de la consanguinidad que considere apareamientos de mínimo parentesco.

Abstract If an average consanguinity (F), threshold is exceeded (about 6.25%) in an animal production system, a series of anomalies may begin to appear, such as the appearance of autosomal recessive diseases, a decrease in the immune response capacity and in the productive and reproductive averages of the herds, a phenomenon known as inbreeding depression. This problem can be magnified in production systems in which genetic improvement is carried out through artificial insemination (IA by its acronym in Spanish), since, in several countries, high degrees of family kinship between inseminations bulls belonging to the same breed have been reported. In the present study are presented the results of the simulation of a strategy for the control of inbreeding in productive herds of the Aberdeen angus breed, based on the management of genealogical records of insemination bulls. The results of this study indicate that, in theory, it is possible to implement consanguinity control programs in productive farms of beef cattle subjected to IA, through a strategy that does not depend on the existence of farm genealogical records, but on records of insemination bulls. Said strategy would depend solely on the information provided to the producers by the semen supplying companies. However, the proposed method is not applicable to breeding farms, which cannot do without genealogical records and consanguinity control that considers pairings of minimal kinship.

Resumo Se um limiar médio de consanguinidade (F) for ultrapassado em um sistema de produção animal (em torno de 6,25%), uma série de anomalias pode começar a aparecer, como o emergência de doenças autossômicas recessivas, diminuição da capacidade de resposta imune e das médias populacionais para variáveis ​​de interesse produtivo, fenômeno conhecido como depressão endogâmica. Esse problema pode ser ampliado em sistemas de produção em que o melhoramento genético é realizado por meio de inseminação artificial (IA), pois, em vários países, tem sido relatado alto grau de parentesco familiar entre touros inseminados de uma mesma raça. No presente estudo, são apresentados os resultados da simulação de uma estratégia para o controle da endogamia em rebanhos produtivos da raça Aberdeen angus, com base no manejo de registros genealógicos de touros inseminados. Os resultados deste estudo indicam que, em teoria, é possível implementar programas de controle de consanguinidade em fazendas produtivas de bovinos de corte submetidos à IA, por meio de uma estratégia que não depende da existência de registros genealógicos da fazenda, mas de registros de touros inseminados. Essa estratégia dependeria exclusivamente das informações fornecidas aos produtores pelas empresas fornecedoras de sêmen. No entanto, o método proposto não é aplicável a fazendas de criação, que não podem prescindir de registros genealógicos intra-fazenda e controle de consanguinidade que considera pares de parentesco mínimo.

Cerebral revascularization using cadaveric vein grafts.

BACKGROUND: Use of cadaveric cryopreserved saphenous vein grafts (CSVGs) has been described for peripheral vascular and coronary revascularization. The aim of this study is to recognize CSVGs as a potential alternative to autologous conduits for extracranial-intracranial (EC-IC) bypass in patients without available or suitable saphenous vein graft or radial artery. We report the short-term patency rate of CSVGs in EC-IC bypass. METHODS: We present our preliminary experience in 10 patients using CSVG for cerebral revascularization. Data regarding operative indications, patient demographics, and bypass patency were collected. RESULTS: The average age was 56 years old with equal sex distribution. The indications for the procedure were giant aneurysms in 7 patients, medically refractory vertebrobasilar ischemia in 2, and a skull base tumor in 1. ABO/Rh blood group compatible CSVG was used in each case. Postoperative angiography demonstrated patency in all cases. Quantitative magnetic resonance angiography was performed in 8 patients, demonstrating a mean bypass flow of 109 mL/min +/- 19 mL/min (mean +/- SE). CONCLUSIONS: Use of CSVG for EC-IC bypass has not previously been reported. In our series, the short-term patency rate was 100%, better than that found in cardiac and peripheral vascular series, possibly because of the higher flow in EC-IC bypasses. Our preliminary experience suggests that CSVGs may be an option in patients without available autologous conduits, although longer follow-up is needed to assess long-term patency.

Is an angiographically obliterated aneurysm always secure?

OBJECTIVE: Conventional cerebral angiography is the standard examination used to confirm aneurysm obliteration. Intraoperative indocyanine green (ICG) video angiography has recently been introduced as a valuable tool that is comparable to catheter intraoperative angiography. Intraoperative imaging evaluation is especially useful when complex aneurysm features are present, making direct clipping challenging. The aim of these angiographic evaluations is to assess parent vessel patency and to confirm lesion obliteration. However, there have been recent reports of growth or even rupture of angiographically obliterated aneurysms. CLINICAL PRESENTATION: We report two patients in whom ICG video angiography falsely indicated that a clipped aneurysm was secure. INTERVENTION: Both patients underwent direct clipping of unruptured aneurysms. ICG video angiography was performed, showing absence of residual filling of the sac. After incising the aneurysm dome, slow but significant dye extravasation was demonstrated. In the first patient, this occurred as a result of incomplete clipping of a wide aneurysm neck that was difficult to visualize; in the second patient, it occurred as a result of atheroma at the neck not allowing complete closure of the clip blades. This finding prompted clip readjustment and placement of an additional reinforcing clip in the two patients, respectively. CONCLUSION: We demonstrate false indication of aneurysm obliteration by intraoperative video angiographic evaluation using ICG. It is possible that this limitation would also apply to catheter angiography. If certainty of complete exclusion of the aneurysm through opening the dome is not achieved, long-term follow-up angiographic evaluation would be strongly advised.

Resección de lesiones cerebrales con asistencia de mapeo cortical intraoperatorio / Intraoperative cortical mapping in surgery for brain lesions

Introducción: Se ha demostrado que la resección extensa de tumores intracraneanos intra-axiales malignos mejora la sobrevida. Esto no siempre es posible dada la eventual ubicación de estos tumores en o cercanos a áreas elocuentes, como corteza motora primaria o de lenguaje. En estas circunstancias, el desafío es evitar secuelas neurológicas. Uno de los métodos para disminuir dicho riesgo es el mapeo cortical intraoperatorio (MCI). El presente trabajo describe la técnica de mapeo cortical intraoperatorio de áreas elocuentes, al igual que su factibilidad y complementariedad con otras técnicas de localización tumoral. Método: Se analizan 7 pacientes operados, portadores de lesiones cercanas a áreas elocuentes. Se utilizó neuronavegación y MCI (estimulación directa de corteza y registro de potenciales evocados somatosensoriales). Se analizó la localización, tamaño y tipo de la lesión, grado de resección y estado neurológico pre y postoperatorio. Resultados: En todos los pacientes el MCI fue efectivo en localizar corteza motora primaria. Hubo 6 pacientes en los que se pudo resecar el área tumoral no asociada a funcionalidad, logrando en 5 de ellos resección completa o superior al 90 por ciento. En un paciente la lesión correspondió a una malformación arteriovenosa profunda ubicada en corteza motora primaria en que el MCI permitió una vía de abordaje por corteza no elocuente para su resección completa. No hubo déficit neurológico agregado postoperatorio con seguimiento de 12 meses. Conclusión: El MCI es útil y localiza en forma efectiva, simple y reproducible áreas de corteza funcional, haciendo posible realizar resecciones extensas de tumores en áreas elocuentes. Esta técnica es complementaria a otros métodos de ubicación anatómica y fisiológica pudiendo contribuir a una cirugía más segura y efectiva.

Introduction: Extensive resection for malignant intraaxial intracranial tumors has been demonstrated to improve survival. This is not always possible due to potential tumor location in or next to eloquent brain regions, like primary motor cortex or speech areas. In this case, avoiding neurological deficits is challenging. One of the tools for minimizing that risk is intraoperative cortical mapping (ICM). This report describes the ICM technique of eloquent brain regions, feasibility and complementariness with other methods for tumor localization. Methods: Seven patients with brain lesions near eloquent regions operated on were analyzed. Frameless stereotaxis (neuronavigation) and intraoperative cortical mapping (direct cortical stimulation and monitoring of somatosensory evoked potentials) were used. The location, size, type of lesion, amount of resection, pre and postoperative neurological status were studied. Results: ICM was effective in localizing primary motor cortex in all patients. In 6 patients the tumor area without functionality was removed, achieving complete or greater than 90 percent resection in 5 of them. In one patient the lesion was a deep arteriovenous malformation located below the primary motor cortex. In this case ICM made feasible an approach from non-eloquent cortex to achieve total resection. No new postoperative deficit was found in a 12 month follow-up period. Conclusion: ICM is useful and localize functional cortical regions effectively, simply and reliably, making possible to perform extensive tumor resections in eloquent regions. This technique is complementary to other tools for anatomical or physiological localization and could contribute to a safer and more effective surgery.

[Chronic subdural hematoma: a disease of elderly people]. / Hematoma subdural crónico: una enfermedad del adulto mayor.

BACKGROUND: The lack of specificity and heterogeneity of the clinical picture of chronic subdural hematoma, hampers its diagnosis. AIM: To report the experience of a Neurosurgical Service in chronic subdural hematoma. PATIENTS AND METHODS: One hundred patients (77 male, mean age 77 +/- 13 years) with chronic subdural hematoma were analyzed. RESULTS: The main clinical presentations were mental status changes (50%) and progressive focal neurological deficit (46%). Five cases presented as a transient neurological deficit. All patients were treated with burr hole drainage. Thirteen had recurrence of the hematoma and they were reoperated. The surgical mortality was 3%. Eighty seven patients were followed for a mean of 66 months. Eighty one of these had a complete recovery, 6 had permanent neurological deficit and 2 of these were unable to care for themselves. Bad prognosis was associated with the absence of a previous trauma to explain the hematoma and symptoms of dementia as the clinical presentation. CONCLUSIONS: Most patients with chronic subdural hematoma treated with burr hole drainage have a good outcome.

Quistes sinoviales de columna lumbar: una causa de compresión radicular / Synovial cysts of the lumbar spine: a cause of radicular compression

Los quistes sinoviales (QS) de columna lumbar son lesiones infrecuentes pero deben considerarse frente a casos de compresión radicular. Existe controversia acerca de su patogenia y se describen múltiples opciones terapéuticas. Se presenta una serie clínica retrospectiva de siete pacientes tratados en un período de ocho años. En general fueron pacientes mayores de 60 años, con un cuadro de dolor radicular unilateral, que se presentó 3 meses antes del diagnótico. Sólo dos pacientes tuvieron déficit de la raíz correspodiente. Todos los QS se localizaron en el nivel L4-L5, realizándose hemilaminectomía y resección total del quiste. Seis casos tuvieron desaparición completa del dolor. Un paciente presentó sólo alivio moderado, constatándose espondilolistesis, por lo que fue sometido posteriormente a una fusión vertebral, mejorando su sintomatología. La cirugía es un tratamiento seguro y eficaz para la resolución de esta patología. La literatura acerca de esta importante patología fue revisada

Trauma espinal penetrante por arma de fuego / Gunshot spinal cord injury

El traumatismo raquimedular (TRM) penetrante por arma de fuego es una patología cada vez más prevalente, relevante y de un alto costo social y económico, por el grado de invalidez que genera en población generalmente joven. El tratamiento óptimo ha sido debatido ampliamente, estando sólo parcialmente establecido el rol de los antibióticos, corticoides y cirugía. Se presenta un caso clínico, con lesión incompleta a nivel de cauda equina, en el cual se realizó tratamiento quirúrgico con resultado final satisfactorio y se revisa la bibliografía correspondiente