The use of a three-dimensional endoscope for different skull base tumors: results of a preliminary extended endonasal surgical series.

BACKGROUND: The evolution of skull base surgery over the past decade has been influenced by advancement in visualization technology. Recently, as a result of such improvements, three-dimensional (3-D) scopes have been widely used during endoscopic endonasal approaches. In the present study, we describe the use of 3-D stereoscopic endoscope for the treatment of a variety of skull base lesions. METHODS: From January 2010 to June 2015, a 3-D endoscopic endonasal approach (4 and 4.9 mm, 0°, and 30° rigid endoscopes) was performed in 70 patients with the following lesions: 42 large extrasellar pituitary macroadenomas, seven tuberculum sellae meningiomas, seven clivus chordomas, five craniopharyngiomas, three fibrous dysplasia of the clivus, three sinonasal malignancies, one orbital lymphangioma, one trigeminal neurinoma, one primary suprasellar lymphoma. RESULTS: Total tumor removal was obtained in 50 patients (71.4 %) while in 14 (20 %), subtotal removal was possible in six (8.6 %) only partial removal was achieved. Overall complications included diabetes insipidus in eight patients (11.4 %), hypopituitarism in seven patients (10 %), CSF leak in five patients (7.1 %), cranial nerve injury in two patients (2.8 %), panhypopituitarism in two patients (2.8 %), meningitis in one (1.4 %) and one postoperative central retinal artery occlusion (1.4 %). There was no mortality in the series. The mean follow-up time was 39 months (range, 6-72 months). CONCLUSIONS: In our experience, the 3-D endoscope represents a critical development in visualization, thus enabling improved hand-eye coordination and depth perception, which are mandatory for the management of complex intradural neurovascular structures during tumor removal surgery.

Diagnosis of breast cancer using Bayesian networks: a case study.

We evaluate the effectiveness of seven Bayesian network classifiers as potential tools for the diagnosis of breast cancer using two real-world databases containing fine-needle aspiration of the breast lesion cases collected by a single observer and multiple observers, respectively. The results show a certain ingredient of subjectivity implicitly contained in these data: we get an average accuracy of 93.04% for the former and 83.31% for the latter. These findings suggest that observers see different things when looking at the samples in the microscope; a situation that significantly diminishes the performance of these classifiers in diagnosing such a disease.

How good is crude MDL for solving the bias-variance dilemma? An empirical investigation based on Bayesian networks.

The bias-variance dilemma is a well-known and important problem in Machine Learning. It basically relates the generalization capability (goodness of fit) of a learning method to its corresponding complexity. When we have enough data at hand, it is possible to use these data in such a way so as to minimize overfitting (the risk of selecting a complex model that generalizes poorly). Unfortunately, there are many situations where we simply do not have this required amount of data. Thus, we need to find methods capable of efficiently exploiting the available data while avoiding overfitting. Different metrics have been proposed to achieve this goal: the Minimum Description Length principle (MDL), Akaike's Information Criterion (AIC) and Bayesian Information Criterion (BIC), among others. In this paper, we focus on crude MDL and empirically evaluate its performance in selecting models with a good balance between goodness of fit and complexity: the so-called bias-variance dilemma, decomposition or tradeoff. Although the graphical interaction between these dimensions (bias and variance) is ubiquitous in the Machine Learning literature, few works present experimental evidence to recover such interaction. In our experiments, we argue that the resulting graphs allow us to gain insights that are difficult to unveil otherwise: that crude MDL naturally selects balanced models in terms of bias-variance, which not necessarily need be the gold-standard ones. We carry out these experiments using a specific model: a Bayesian network. In spite of these motivating results, we also should not overlook three other components that may significantly affect the final model selection: the search procedure, the noise rate and the sample size.

Depressed skull fracture in Ping Pong: elevation with Medeva extractor.

INTRODUCTION: The bones of the skull of the newborn and nursing infants, in general, possess great malleability. For this reason, the depressed fractures occurring at this age are called "Ping Pong" or "Green Stick" fractures. The treatment of these fractures is surgical according to different authors, although some of these fractures that happen in childbirth can elevate themselves spontaneously. TECHNIQUE: A breast milk extractor trade mark "MEDEVA" was used for the procedure in newborns with a depression larger than 2 cm in diameter. Minimal aspiration was performed while observing the elevation through the transparent breast milk extractor MEDEVA until the depression elevated without leaving any trace. DISCUSSION: The aspiration procedure was satisfactory and curative in the five children treated. The fracture was successfully elevated and the skull returned to its normal position and configuration without complications for the patients. CONCLUSION: Finally, it has been demonstrated that this procedure is simple, inexpensive, and avoids surgical intervention.

Derivacion ventriculo - vesicular - biliar. Una opcion de tratamiento en la hidrocefalia / Ventricle - gallblader shunt: an option in the treatment of hydrocephalus

Introduccion: en el año 1958, Smith, Moretz y Pritchard, derivaron el LCR (fluido cerebroespinal) a la vesicula biliar en 10 pacientes hidrocefalicos, las derivaciones fueron desde el espacio subaracnoideo lumbar en pacientes con hidrocefalia comunicante y desde el ventriculo lateral en aquellos con hidrocefalia obstructiva. La principal funcion de la vesicula biliar en la composicion de la bilis, es absorber agua y electrolitos inorganicos por tanto no tiene problemas en la absorcion del LCR. Material y metodos: Se realizo el proceder en 3 pacientes que fueron operados de Hidrocefalia en multiples ocasiones y en los cuales no fue posible la derivacion de LCR al peritoneo ni a las cavidades cardiacas. Se establece en los mismos una derivacion ventriculo vesicula biliar en la composicion de la bilis, es absorber agua y electrolitos inorganicos por tanto no tiene problemas en la absorcion del LCR. Material y metodos: se realizo el proceder en 3 pacientes que fueron operados de Hidrocefalia en multiples ocasiones y en los cuales no fue posible la derivacion de LCR al peritoneo ni a las cavidades cardiacas. Se establece en los mismos una derivacion ventriculo vesicula biliar plenamente funcional. Se utilizo la tecnica quirurgica de Yarsagaray modificada por nosotros. Conclusion: Los 3 pacientes evolucionaron bien sin ninguna complicacion y 2 de ellos llevan 3 años de operados sin disfuncion de su sistema derivativo. Se demostro la eficacia de este metodo de tratamiento, dando una solucion a la Hidrocefalia de estos pacientes y mostrando los mismos una evolucion favorable