Patricio Tagle

Cysticercosis of the central nervous system: clinical and therapeutic considerations.

In a group of forty cases of cysticercosis of the central nervous system, 59% presented with intracranial hypertension due to obstructive hydrocephalus. Ventricular or cisternal cysts, and chronic cysticercus meningitis were the most common causes of hydrocephalus. Seizures occurred in 40% of the patients, in one-half of them in association with CT-detected parenchymatous cysts. In 20% of the cases progressive mental deterioration was the main clinical feature, at times associated with hydrocephalus. CT scan provided the highest diagnostic yield, being abnormal in 90% of cases. Long term prognosis was poor, with a mortality rate of 38% over a 40-month follow-up period. The most common cause of death (60%) was meningitis. CSF shunting is the treatment of choice for hydrocephalus, irrespective of its mechanism. Surgical resection is indicated in some cases with a single superficial (cortical) or posterior fossa cyst. Supratentorial cysts carry a relatively benign prognosis.

Intracranial metastasis or meningioma? An uncommon clinical diagnostic dilemma.

BACKGROUND Cerebral metastases are the most frequent brain tumors in adults and they may occasionally present as an isolated meningeal mass, suggesting a meningioma. Because of the prognostic relevance in discriminating both tumors, we review the literature and analyze four patients in whom the diagnosis of meningioma was initially made. CASE DESCRIPTION Four cases of isolated meningeal metastases are presented and in all of them a meningioma was considered as the main preoperative diagnosis. Only one patient had a history of previous cancer. The primary tumors found after pathological testing of the lesions were thyroid carcinoma, prostate adenocarcinoma, breast adenocarcinoma, and hypernephroma. The clinical and neuroimaging features as well as the differential diagnoses are discussed. The literature regarding these forms of meningeal metastases was reviewed. CONCLUSIONS Although they are uncommon, dural metastases can be mistaken for meningiomas. Our experience in these cases has led us to consider ordinary metastases as a differential diagnosis even when a meningioma is suspected. The definitive diagnosis of a meningioma should be established only after the histopathological report has been analyzed.

A novel, inexpensive method of image coregistration for applications in image-guided surgery using augmented reality

OBJECTIVE Augmented reality (AR) is a technique in which an overlay of a virtual image to a live picture is performed to create a new image in which both original images coexist as a single image. This results in the visualization of internal structures through overlying tissues. The objective was to describe an easy, inexpensive, and successful method to coregister with AR in an image-guided surgery setting using the resources at hand. METHODS Cortical information was obtained with a volumetric acquisition of 200 0.8-mm thick, cerebral magnetic resonance imaging scans in an axial T1-weighted sequence. For the venous anatomy, a contrast phase at 7 mm/s velocity was used. This data was reconstructed in a three-dimensional fashion using MRIcro software (v. 1.37, freeware, courtesy of Chris Rorden) and was overlaid to a digital image of the cerebral cortex either pre- or intraoperatively. RESULTS Eight patients were studied. There was an adequate coregistration in seven of the patients as confirmed by intraoperative ultrasound, frame-based stereotaxy, or obvious anatomic homology between the three-dimensional magnetic resonance imaging scan virtual reconstruction and the live image obtained during surgery. AR was not possible in one case of a cerebellar lesion. CONCLUSION AR coregistration capabilities are adequate when revised by other intraoperative guidance devices. When performed with “freeware” software and conventional digital cameras, it is relatively inexpensive, which makes it a potential tool for surgical planning and noncontinuous intraoperative guidance in neurosurgery. Its largest drawbacks are the inability to function in deep-seated lesions and its lack of tracking devices, which gives it a noncontinuous coregistration nature.

Diagnóstico y tratamiento de las metástasis encefálicas

Cerebral metastasis occur in 20 to 30 percent of patients with systemic cancer and are the most common type of intracranial tumor. The median survival of untreated patients is one month with a slightly longer survival in those treated with steroids. Patients treated with whole brain radiation therapy survive between 3 to 6 months. In selected cases survival can increase to 10 to 12 months with combination of surgery and radiotherapy or stereotactic radiosurgery alone or associated to radiotherapy. Most brain metastasis arise from lung, breast and melanomas. The most important criteria for selecting patients who will benefit from surgery or stereotactic radiosurgery are a Karnofsky score of 70 or more, systemic control of the cancer and absence of leptomeningeal involvement. Surgery is indicated in patients with a single lesion located in an accessible zone and stereotactic radiosurgery is indicated for lesions up to 3 cm of diameter, and in patients with up to 3 or 4 metastasis, no matter their location. The survival benefit of chemotherapy in brain metastasis has not been demonstrated.

Limbus lumbar and sacral vertebral fractures

Abstract e evaluated the fractures of the lumbar and sacral vertebral limbus by disc impingement at the peripheral ring apophysis in 23 adults associated with trauma in 16 of them. Lumbalgia, radicular pain and narrow canal symptoms are the presenting forms of this underdiagnosed pathology. CT is the best method of examination, while plain roentgenograms and MR are usually negative. Accurate diagnosis and surgical technique with larger exposure are needed to resect the fractured fragments and protruded disc material for decompressing the roots and the dural sac. Our results were very good on the majority of cases. [Neurol Res 2002; 24: 139-144]

Conflicto de interés: una reflexión impostergable. Panel del comité editorial

Con motivo de incorporar la declaracion de conflicto de interes en nuestra revista, el comite editorial presenta un Panel sobre el tema. En este, se define conflicto de interes en terminos generales y editoriales, asi como se analizan otros escenarios de la practica medica con potenciales conflictos de intereses. Se evalua el sentido de las declaraciones explicitas de conflicto de interes, como expresion de preventiva transparencia, clave del control comunitario del problema. Finalmente se evaluan casos y ejemplos de subnotificacion de intereses y el impacto del conocimiento de los conflictos de intereses en los usuarios de la informacion biomedica. De la informacion presentada en el panel es posible concluir que: el conflicto de interes existe, el aludirlo es inevitable, el pensar controlarlo con facilidad es ingenuo. El generar instrumentos que sirvan para transparentar relaciones y vinculos que son naturales en nuestro quehacer, es necesario. Muchos de los que declaran sus conflictos de interes tienen vinculos sanos. En un escenario de declaraciones explicitas los vinculos no declarados por ese solo hecho resultan potencialmente sospechosos. El acuerdo y consenso conceptual en un tema tarda en cambiar conductas, pero el paso inicial es impostergable. La responsabilidad de pensar en el sesgo, como manera sistematica de analisis de un articulo, es una responsabilidad indelegable, incluso en aquellos articulos que cuentan con gran soporte corporativo profesional o de sociedades cientificas. Finalmente el abstraerse de las pautas del International Committee of Medical Journal Editors, es editorialmente imprudente e insular.

Quistes sinoviales de columna lumbar: una causa de compresión radicular

Los quistes sinoviales (QS) de columna lumbar son lesiones infrecuentes pero deben considerarse frente a casos de compresion radicular. Existe controversia acerca de su patogenia y se describen multiples opciones terapeuticas. Se presenta una serie clinica retrospectiva de siete pacientes tratados en un periodo de ocho anos. En general fueron pacientes mayores de 60 anos, con un cuadro de dolor radicular unilateral, que se presento 3 meses antes del diagnostico. Solo dos pacientes tuvieron deficit de la raiz correspondiente. Todos los QS se localizaron en el nivel L4-L5, realizandose hemilaminectomia y reseccion total del quiste. Seis casos tuvieron desaparicion completa del dolor. Un paciente presento solo alivio moderado, constatandose espondilolistesis, por lo que fue sometido posteriormente a una fusion vertebral, mejorando su sintomatologia. La cirugia es un tratamiento seguro y eficaz para la resolucion de esta patologia. La literatura acerca de esta importante patologia fue revisada

Trombosis carotidea en el lactante

INTRODUCTION. Los Accidentes Vasculares En-falicos (A. V. E.) oclusivos del adulto tienenuna frecuencia alta, habiendose discutido exten-samente su etiopatogenia, cuadro clinico y trata-miento. Conocido es tambien el papel que juegaen ellos la oclusion (total o parcial) de la arteriacarotida a nivel del cuello. (7-8).Problema aparte, lo constituyen los A. V. E.oclusivos en el nino, los cuales son poco conocidosy estudiados, quedando a menudo la etiologia pococlara.Ademas de la escasa frecuencia con que se des-criben estos casos, mas excepcional aim resulta elcompromise de la arteria carotida a nivel del cue-llo, a diferencia del adulto.Nuestro proposito es el presentar a un lactan-te, con una trombosis de carotida cervical y exten-dernos en algunas consideraciones a proposito dela etiologia de estas oclusiones, considerando queno hemos encontrado referencias nacionales so-bre el tema.

History of the Neurosurgery Department of Pontificia Universidad Catolica, Santiago, Chile

Pontificia Universidad Católica de Chiles medical school was founded in 1929. An interest in neurosurgical development arose in the minds of the Dean, Dr. Cristobal Espíldora, and the Chief of Surgery, Dr. Rodolfo Rencoret, in 1946. They encouraged and supported Dr. J. Ricardo Olivares to specialize in Neurosurgery with Professor H. Olivecrona in Stockholm, Sweden. The first neurosurgical procedure in the Hospital Clínico de la Universidad Católica was performed in 1950. Since then, intensive efforts have been made to develop neurosurgery and its science. As a result, it is now a center capable of achieving high-quality standards in vascular, oncologic, and endoscopic neurosurgery; stereotactic and radiosurgery; complex spine surgery; pediatric neurosurgery; and epilepsy surgery. This article tells the story of a university hospital neurosurgery service in a country at the southern end of the world and how it became one of the most important neurosurgical centers in Chile and South America.

Resección de lesiones cerebrales con asistencia de mapeo cortical intraoperatorio

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 defi cits 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% 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 defi cit 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.