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Volumetría de fascículos cerebrales en población sana

Hernández, José Fernando | 2019-04

Objetivo Desde la aparición de la tractografía, al tratarse de una técnica no invasiva y que usa la ampliamente conocida resonancia magnética (RM), el estudio de la sustancia blanca se ha facilitado. A partir de eso, se han logrado grandes descubrimientos en cuanto a fascículos cerebrales involucrados en funciones cognitivas. Sin embargo, su evaluación sigue siendo subjetiva y depende de la experiencia y entrenamiento del evaluador, razón por la cual se ha limitado su aplicabilidad en la práctica clínica. En ese sentido, es conveniente parametrizar volúmenes cerebrales de sustancia blanca en población sana a través de una herramienta electrónica que se pueda reproducir y así poderlo aplicar en enfermos. Materiales y métodos Se reportan 10 sujetos sanos desde el punto de vista neurológico. Para cada sujeto, se adquirieron imágenes ponderadas por difusión y los resultados se visualizaron mediante FiberNavigator (http://scilus.github.io/ fibernavigator). Finalmente, esa misma herramienta fue utilizada para purificar los fascículos objeto de estudio y realizar el conteo de las fibras. Resultados Se obtuvieron valores de volumetría del fascículo longitudinal superior (FLS), fascículo longitudinal inferior (FLI), fascículo frontoccipital inferior (FFI), fascículo uncinado (FU) y fascículo del cíngulo (FC), identificando que no existen diferencias estadísticamente significativas entre el número de fibras que componen los fascículos cerebrales. Discusión Los resultados alcanzados de la anatomía y la direccionalidad de fibras de los fascículos cerebrales de este estudio coinciden con el resto de la evidencia publicada hasta el momento, sin encontrar diferencias en cuanto a su organización y recorrido. Conclusión Aunque esos resultados no sirven como valores de referencia para ser aplicados en pacientes con patología neurológica, brindamos información inexistente hasta el momento, con ese equipo en específico y la reproducción entre los distintos usuarios y el software.

Introducción de la geometría fractal en neurocirugía y sus posibles aplicaciones

Velasco, Alejandro | 2015-06

Las dimensiones fractales permiten caracterizar matemáticamente la irregularidad de los objetos naturales como los son las estructuras cerebrales. El objetivo es hacer una introducción de la geometría fractal aplicada a la neurocirugía. Con una nueva metodología de investigación científica basada en la geometría fractal, se encuentran en desarrollo análisis de las estructuras geométricas de las imágenes obtenidas mediante RM cerebral simple, midiendo las dimensiones fractales de estructuras como los ventrículos cerebrales, así como su ocupación en el espacio fractal de BoxCounting, determinando además la Armonía Matemática Intrínseca entre las imágenes consecutivas de las estructuras. Los resultados aún no han sido publicados y se espera tengan un valor importante especialmente en la predicción de cambios de volumen de estructuras y presión intracraneales en diferentes patologías neuroquirúrgicas como lo son la hidrocefalia, hematomas, aneurismas y tumores cerebrales. El desarrollo de nuevas medidas morfométricas para las estructuras cerebrales normales con base en geometría fractal, plantea generar medidas objetivas y reproducibles que puedan ser aplicadas en la práctica clínica.

Neuroanatomía funcional de la escala de coma de Glasgow

Ordoñez Rubiano, Edgar G. | 2019-06

Introducción: La escala de coma de Glasgow (ECG) es una escala mundialmente reconocida para la clasificación de pacientes con trauma craneoencefálico de acuerdo a su compromiso neurológico. Esta escala evalúa la apertura ocular, la respuesta verbal y la respuesta motora. La neuroanatomía funcional representa un compromiso secuencial para el descenso en el puntaje de cada uno de estos ítems. El objetivo de esta revisión es describir la anatomía del sistema reticular activador ascendente (SRAA), la anatomía funcional del lenguaje, la anatomía del tallo cerebral y de las vías motoras que representan cada ítem evaluado por la ECG. Materiales y métodos: Se hizo una revisión narrativa bibliográfica de las principales vías para cada ítem de la ECG. Resultados: Las principales vías en relación con la apertura ocular se concentran en las vías del SRAA, las vías de la respuesta verbal incluyen las vías del lenguaje y las vías que provienen del putamen y del cerebelo que regulan la emisión del lenguaje, mientras que las vías que regulan la respuesta motora principalmente se relacionan con la vía piramidal, el sistema rubroespinal y vestíbulo-espinal. Conclusiones: El descenso del puntaje en los tres ítems que evalúa la ECG se relacionan con vías específicas que predominan en los ganglios basales y en el tallo cerebral

Establishing an acquisition and processing protocol for resting state networks with a 1.5 T scanner: A case series in a middle-income country

| 2020-06

Objective: The aim of this study was to characterize the capability of detection of the resting state networks (RSNs) with functional magnetic resonance imaging (fMRI) in healthy subjects using a 1.5T scanner in a middle-income country. Materialsandmethods:Ten subjects underwent a complete blood-oxygen-level dependent imaging (BOLD) acquisition on a 1.5T scanner. For the imaging analysis, we used the spatial independent component analysis (sICA). We designed a computer tool for 1.5 T (or above) scanners for imaging processing. We used it to separate and delineate the different components of the RSNs of the BOLD signal. The sICA was also used to differentiate the RSNs from noise artifact generated by breathing and cardiac cycles. Results: For each subject, 20 independent components (IC) were computed from the sICA (a total of 200 ICs). From these ICs, a spatial pattern consistent with RSNs was identified in 161 (80.5%). From the 161, 131 (65.5%) were fit for study. The networks that were found in all subjects were: the default mode network, the right executive control network, the medial visual network, and the cerebellar network. In 90% of the subjects, the left executive control network and the sensory/motor network were observed. The occipital visual network was present in 80% of the subjects. In 39 (19.5%) of the images, no any neural network was identified. Conclusions: Reproduction and differentiation of the most representative RSNs was achieved using a 1.5T scanner acquisitions and sICA processing of BOLD imaging in healthy subjects. Abbreviations: AAN = Arousal Network Atlas, AAn = ascending arousal network, ADC = apparent diffusion coefficient, AIC = analysis of independent component, AN = auditory network, BOLD = blood-oxygen-level dependent, CBLN = the cerebellar network, DIPY = diffusion imaging in python, DMN = default mode network, DOC = disorder of consciousness, DTI = diffusion tensor imaging, DTT = diffusion tensor tractography, DWI = diffusion weighted imaging, FA = fractional anisotropy, FC = functional connectivity, FSL = FMRIB Software Library, LECN = left executive control network, LMICs = low-to-middle income countries, LVN = lateral visual network, MoCA = Montreal Cognitive Assessment, MVN = medial visual network, ODF = orientation distribution function, OVN = occipital visual network, RECN = right executive control network, RF = reticular formation, ROI = region of interest,

Trauma intracraneal penetrante trans-orbitario: Anatomía relevante, las dinámicas del trauma y los puntos clave para el tratamiento

Ordóñez Rubiano, Edgar Gerardo | 2019-10

Las lesiones intracraneales penetrantes trans-orbitarias representan pocos casos de todos los Traumas Craneoencefálicos, sin embargo, representan del 25 al 50% de todos los traumas penetrantes craneales. Este tipo de traumas trans-orbitarios se han reportado por diferentes tipos de objetos, incluyendo objetos de metal y de madera. Muchos de estos traumas intracraneales pueden pasar desapercibidos en casos donde el material que ingresa no queda expuesto posterior al trauma y cuando no se presenta lesión neurológica que requiera examinación exhaustiva adicional con neuro-imágenes.

Endonasal endoscopic transsphenoidal resection of intrinsic third ventricular craniopharyngioma: surgical results

Forbes, Jonathan A. | 2018-05

OBJECTIVE Intrinsic third ventricular craniopharyngiomas (IVCs) have been reported by some authors to “pose the greatest surgical challenge” of all craniopharyngiomas (CPAs). A variety of open microsurgical approaches have historically been used for resection of these tumors. Despite increased utilization of the endoscopic endonasal approach (EEA) for resection of CPAs in recent years, many authors continue to recommend against use of the EEA for resection of IVCs. In this paper, the authors present the largest series to date utilizing the EEA to remove IVCs. METHODS The authors reviewed a prospectively acquired database of the EEA for resection of IVCs over 14 years at Weill Cornell Medical College, NewYork-Presbyterian Hospital. Preoperative MR images were examined independently by two neurosurgeons and a neuroradiologist to identify IVCs. Pre- and postoperative endocrinological, ophthalmological, radiographic, and other morbidities were determined from retrospective chart review and volumetric radiographic analysis. RESULTS Between January 2006 and August 2017, 10 patients (4 men, 6 women) ranging in age from 26 to 67 years old, underwent resection of an IVC utilizing the EEA. Preoperative endocrinopathy was present in 70% and visual deterioration in 60%. Gross-total resection (GTR) was achieved in 9 (90%) of 10 patients, with achievement of near-total (98%) resection in the remaining patient. Pathology was papillary in 30%. Closure incorporated a “gasket-seal” technique with nasoseptal flap coverage and either lumbar drainage (9 patients) or a ventricular drain (1 patient). Postoperatively, complete anterior and posterior pituitary insufficiency was present in 90% and 70% of patients, respectively. In 4 patients with normal vision prior to surgery, 3 had stable vision following tumor resection. One patient noted a new, incongruous, left inferior homonymous quadrantanopsia postoperatively. In the 6 patients who presented with compromised vision, 2 reported stable vision following surgery. Each of the remaining 4 patients noted significant improvement in vision after tumor resection, with complete restoration of normal vision in 1 patient. Aside from the single case (10%) of visual deterioration referenced above, there were no instances of postoperative neurological decline. Postoperative CSF leakage occurred in 1 morbidly obese patient who required reoperation for revision of closure. After a mean follow-up of 46.8 months (range 4–131 months), tumor recurrence was observed in 2 patients (20%), one of whom was treated with radiation and the other with chemotherapy. Both of these patients had previously undergone GTR of the IVC. CONCLUSIONS The 10 patients described in this report represent the largest number of patients with IVC treated using EEA for resection to date. EEA for resection of IVC is a safe and efficacious operative strategy that should be considered a surgical option in the treatment of this challenging subset of tumors.

Preserve or sacrifice the stalk? Endocrinological outcomes, extent of resection, and recurrence rates following endoscopic endonasal resection of craniopharyngiomas

Ordóñez Rubiano, Edgar G. | 2018-11

OBJECTIVE Gross-total resection (GTR) of craniopharyngiomas (CPs) is potentially curative and is often the goal of surgery, but endocrinopathy generally results if the stalk is sacrificed. In some cases, GTR can be attempted while still preserving the stalk; however, stalk manipulation or devascularization may cause endocrinopathy and this strategy risks leaving behind small tumor remnants that can recur. METHODS A retrospective review of a prospective cohort of patients who underwent initial resection of CP using the endoscopic endonasal approach over a period of 12 years at Weill Cornell Medical College, NewYork-Presbyterian Hospital, was performed. Postresection integrity of the stalk was retrospectively assessed using operative notes, videos, and postoperative MRI. Tumors were classified based on location into type I (sellar), type II (sellar-suprasellar), and type III (purely suprasellar). Pre- and postoperative endocrine function, tumor location, body mass index, rate of GTR, radiation therapy, and complications were reviewed. RESULTS A total of 54 patients who had undergone endoscopic endonasal procedures for first-time resection of CP were identified. The stalk was preserved in 33 (61%) and sacrificed in 21 (39%) patients. GTR was achieved in 24 patients (73%) with stalk preservation and 21 patients (100%) with stalk sacrifice (p = 0.007). Stalk-preservation surgery achieved GTR and maintained completely normal pituitary function in only 4 (12%) of 33 patients. Permanent postoperative diabetes insipidus was present in 16 patients (49%) with stalk preservation and in 20 patients (95%) following stalk sacrifice (p = 0.002). In the stalk-preservation group, rates of progression and radiation were higher with intentional subtotal resection or near-total resection compared to GTR (67% vs 0%, p < 0.001, and 100% vs 12.5%, p < 0.001, respectively). However, for the subgroup of patients in whom GTR was achieved, stalk preservation did not lead to significantly higher rates of recurrence (12.5%) compared with those in whom it was sacrificed (5%, p = 0.61), and stalk preservation prevented anterior pituitary insufficiency in 33% and diabetes insipidus in 50%. CONCLUSIONS While the decision to preserve the stalk reduces the rate of postoperative endocrinopathy by roughly 50%, nevertheless significant dysfunction of the anterior and posterior pituitary often ensues. The decision to preserve the stalk does not guarantee preserved endocrine function and comes with a higher risk of progression and need for adjuvant therapy. Nevertheless, to reduce postoperative endocrinopathy attempts should be made to preserve the stalk if GTR can be achieved.

Endoscopic endonasal resection of epidermoid cysts involving the ventral cranial base

Forbes, Jonathan A. | 2018-06-08

OBJECTIVE Epidermoid cysts (ECs) commonly extend to involve the ventral cisterns of the cranial base. When present, symptoms arise due to progressive mass effect on the brainstem and adjacent cranial nerves. Historically, a variety of open microsurgical approaches have been used for resection of ECs in this intricate region. In recent years, the endoscopic endonasal approach (EEA) has been proposed as an alternative corridor that avoids crossing the plane of the cranial nerves. To date, there is a paucity of data in the literature regarding the safety and efficacy of the EEA in the treatment of ECs of the ventral cranial base. METHODS The authors reviewed a prospectively acquired database of EEAs for resection of ECs over 8 years at Weill Cornell, NewYork-Presbyterian Hospital. All procedures were performed by the senior authors. Standardized clinical and radiological parameters were assessed before and after surgery. Statistical tests were used to determine the impact of previous surgery and tumor volume on extent of resection and recurrence as well as the method of closure on rate of CSF leak. RESULTS Between January 2009 and February 2017, 7 patients (4 males and 3 females; age range 16–70 years) underwent a total of 8 surgeries for EC resection utilizing the EEA. Transplanum and transclival extensions were performed in 3 and 5 patients, respectively. Methods of closure incorporated a gasket seal in 6 of 8 procedures and a nasoseptal flap in 7 of 8 procedures. Gross-total resection (GTR) was achieved in 43% of patients, and near-total resection (> 95%) was obtained in another 43%. Complications included diabetes insipidus (n = 2), postoperative CSF leak (n = 2), transient third cranial nerve palsy (n = 1), and epistaxis (n = 1). With a mean follow-up of 43.5 months, recurrence has been observed in 2 of 7 patients. In 1 case, reoperation for recurrence was required 71 months following the initial surgery. Use of the gasket-seal technique with nasoseptal flap coverage significantly correlated with the absence of postoperative CSF leakage (p = 0.018). GTR was achieved in 25% of the patients who had prior surgeries and in 50% of patients without previous resections. The mean volume of cysts in which GTR was achieved (4.3 ± 1.8 cm3) was smaller than that in which subtotal or near-total resection was achieved (12.2 ± 11 cm3, p = 0.134). CONCLUSIONS The EEA for resection of ECs of the ventral cranial base is a safe and effective operative strategy that avoids crossing the plane of the cranial nerves. In the authors’ experience, gasket-seal closure with nasoseptal flap coverage has been associated with a decreased risk of postoperative CSF leakage.

Inyecciones perineurales selectivas lumbares con fluoroscopio: anatomía y técnica quirúrgica para el manejo del dolor radicular

Ordónez, Javier | 2020-06-30

El dolor radicular representa uno motivo de consulta frecuente en medicina. La persistencia del dolor después de un manejo farmacológico y de rehabilitación con terapia física adecuados representa una indicación para el manejo percutáneo con inyecciones perineurales. Este manuscrito presenta una revisión de la anatomía relevante, de las características radiológicas, de los puntos de referencia y de la técnica quirúrgica de las inyecciones perineurales trans-foraminales selectivas lumbares para manejo de dolor radicular.

Fractal characterization of normal cerebral ventricles in t2-wheigthed magnetic resonance imaging

Velasco, Alejandro | 2017-10

Introduction: The fractal geometry describes adequately the irregularity of the natural objects such as the cerebral ventricles, which are irregular structures that can be characterized through the Box-Counting method. Objective: This research aims to develop a new methodology of geometric characterization of the cerebral ventricles, based on the fractal geometry for the analysis of normal cerebral ventricles. Methods: Based on the Box-Counting method, the fractal dimensions of the both lateral ventricles of a normal adult were obtained. Sequential cephalic-caudal 4mm axial slices were acquired on T2-WI, and the differences and similarities of the lateral ventricles were established using the Ventricular Intrinsic Mathematical Harmony. Results: The fractal dimension of the left lateral ventricle had values between 1.0641 and 1,3599, and in the right lateral ventricle had values between 0.8931 and 1.3219. Conclusion: A new morphometric measure of the cerebral ventricles was developed based on the fractal geometry for its use as an objective and reproducible measure.

Microvascular Decompression for a Patient with a Glossopharyngeal Neuralgia: A Technical Note

Ordoñez Rubiano, Edgar Gerardo | 2017-07-20

The glossopharyngeal neuralgia (GPN) constitutes approximately 0.2-1.3% of all facial pain syndromes. The GPN is a syndrome of neuropathic pain characterized by paroxysmal pain episodes localized in the posterior tongue, tonsil, throat, or external ear canal. The first-line treatment is pharmacological. Patients who are refractory to medical therapy can be treated surgically with microvascular decompression (MVD) or sectioning the IX nerve and the upper rootlets of the X nerve. We aim to describe the technical nuances of MVD of the IX cranial nerve with a targeted inferior mini-craniotomy in a patient with a neurovascular compression.

Reconstruction of the Ascending Reticular Activating System with Diffusion Tensor Tractography in Patients with a Disorder of Consciousness after Traumatic Brain Injury

Ordoñez Rubiano, Edgar Gerardo | 2017-09-17

Giant aneurysms have been treated with endovascular approaches like general, balloon-assisted and stent-assisted coiling, and flow diverter stent-assisted techniques. Few cases have been reported to be treated with both normal and large coils. Despite the mass effect, an adequate revascularization has been reported. An initial use of these coils is being reported in the current study. This is a case which has been successfully treated using a stent-assisted coiling with both small and large coils i.e., Penumbra Coil 400 (Penumbra, Inc., Alameda, California).

Stent-assisted Embolization of a Giant Aneurysm of the Middle Cerebral Artery Using Small and Large Coils (Penumbra Coil 400)

Ordóñez Rubiano, Edgar Gerardo | 2016-08-31

Giant aneurysms have been treated with endovascular approaches like general, balloon-assisted and stentassisted coiling, and flow diverter stent-assisted techniques. Few cases have been reported to be treated with both normal and large coils. Despite the mass effect, an adequate revascularization has been reported. An initial use of these coils is being reported in the current study. This is a case which has been successfully treated using a stent-assisted coiling with both small and large coils i.e., Penumbra Coil 400 (Penumbra, Inc., Alameda, California).

Trauma intracraneal penetrante trans-orbitario: anatomía relevante, las dinámicas del trauma y los puntos clave para el tratamiento

Ordóñez Rubiano, Edgar Gerardo | 2019-10-01

Las lesiones intracraneales penetrantes trans-orbitarias representan pocos casos de todos los Traumas Cráneo encefálicos, sin embargo, representan del 25 al 50% de todos los traumas penetrantes craneales. Este tipo de traumas trans-orbitarios se han reportado por diferentes tipos de objetos, incluyendo objetos de metal y de madera. Muchos de estos traumas intracraneales pueden pasar desapercibidos en casos donde el material que ingresa no queda expuesto posterior al trauma y cuando no se presenta lesión neurológica que requiera examinación exhaustiva adicional con neuro-imágenes.

Embriología del sistema ventricular cerebral

Ordóñez Rubiano, Edgar Gerardo | 2019-10-01

El Sistema Ventricular Cerebral se desarrolla de forma paralela al resto del Sistema Nervioso Central, facilitando la circulación del Líquido Cefalorraquídeo, desde su separación del líquido amniótico a nivel embrionario. Este desarrollo es necesario para entender correctamente la anatomía ventricular y facilitar el abordaje para patologías intraventriculares. El objetivo de esta revisión es reconocer los puntos más importantes en la embriología ventricular para facilitar el aprendizaje de la anatomía quirúrgica ventricular

Anatomía ventricular para tercer ventriculostomía endoscópica

Ordóñez Rubiano, Edgar Gerardo | 2017

El conocimiento de la anatomía de las estructuras cerebrales en relación con los ventrículos cerebrales representa la capacidad para poder respetarlas durante una tercer ventriculostomía endoscópica (TVE), lo cual es indispensable para evitar complicaciones relacionadas al procedimiento. El propósito de este trabajo es hacer una revisión sobre la anatomía ventricular endoscópica, tomas ventriculares y vías de acceso para hacer una TVE. Se revisaron los puntos relevantes de la técnica quirúrgica y de la anatomía ventricular en nuestra experiencia institucional con el fin de hacer una descripción gráfica de la anatomía ventricular endoscópica para fenestración del piso del tercer ventrículo. Se mostrarán imágenes y videos relacionados con este abordaje.