[Vertebral fixation with a transpedicular approach. Relevance of anatomical and imaging studies]. / Fijación vertebral por vía transpedicular. Importancia de los estudios anatómicos y de imagen.

The number of patients with spine conditions has grown exponentially in recent years leading to an increase in the number of cases requiring surgical treatment. Currently vertebral fusion surgery with a transpedicular approach represents the most commonly used technique to treat any type of vertebral disorder. The morphometric characteristics of vertebrae, particularly the pedicle, determine the size of pedicular implants, including width and length, as well as the shape and direction of the screw and its ideal angulation at the time of introduction. Knowing these characteristics is important to prevent injuring important adjacent structures and to decrease the postoperative complication rate. In recent decades numerous studies on the morphometric characteristics of the vertebral pedicle have been conducted in different populations to determine its real dimensions by means of direct measurement and imaging methods. These studies have concluded that there are significant differences in these measurements among the different ethnic groups, races, genders, ages and the vertebral regions studied. This paper analyzes the different morphometric studies of the pedicle and all the other vertebral elements studied in Mexico and the rest of the world and explain the importance of their knowledge and surgical application for the correct development of vertebral fusion surgery with a transpedicular approach.

Copula-based regression models for a bivariate mixed discrete and continuous outcome.

This paper is concerned with regression models for correlated mixed discrete and continuous outcomes constructed using copulas. Our approach entails specifying marginal regression models for the outcomes, and combining them via a copula to form a joint model. Specifically, we propose marginal regression models (e.g. generalized linear models) to link the outcomes' marginal means to covariates. To account for associations between outcomes, we adopt the Gaussian copula to indirectly specify their joint distributions. Our approach has two advantages over current methods: one, regression parameters in models for both outcomes are marginally meaningful, and two, the association is 'margin-free', in the sense that it is characterized by the copula alone. By assuming a latent variable framework to describe discrete outcomes, the copula used still uniquely determines the joint distribution. In addition, association measures between outcomes can be interpreted in the usual way. We report results of simulations concerning the bias and efficiency of two likelihood-based estimation methods for the model. Finally, we illustrate the model using data on burn injuries.

Association between idiopathic achalasia and IL23R gene.

BACKGROUND: Idiopathic achalasia is a primary esophageal motor disorder of unknown etiology. Different evidences have been reported in support of achalasia as the result of an autoimmune and inflammatory process leading to neuronal cell loss. According to this, idiopathic achalasia has been significantly associated with specific alleles of the human leukocyte antigen system class II, although few reports studying association with other loci can be found in the literature. Recent studies have shown association of a non-synonymous polymorphism within the IL23R gene with different chronic inflammatory disorders, including Barrett's esophagus. The purpose of this study was to assess whether the IL23R coding variant Arg381Gln polymorphism is involved in susceptibility to idiopathic achalasia. METHODS: We performed a case-control study including 262 patients with idiopathic achalasia and 802 healthy subjects, all of them white Spaniards. Achalasia patients were diagnosed on the basis of clinical, radiographic, endoscopic, and manometric criteria. All samples were genotyped for the IL23R Arg381Gln polymorphism using TaqMan technology. KEY RESULTS: The minor allele of the Arg381Gln polymorphism was significantly increased in patients compared with healthy controls (OR = 1.46, 95% CI = 1.01-2.11, P = 0.036). This association seems to be specific to male patients with disease onset after 40 years (OR = 2.33, 95% CI = 1.29-4.16, P = 0.002). CONCLUSIONS & INFERENCES: Our results suggest a role of IL23R in idiopathic achalasia predisposition and extend the evidence of the general influence of this gene in autoimmune and inflammatory diseases.

A likelihood approach to estimating sensitivity and specificity for binocular data: application in ophthalmology.

Binocular data typically arise in ophthalmology where pairs of eyes are evaluated, through some diagnostic procedure, for the presence of certain diseases or pathologies. Treating eyes as independent and adopting the usual approach in estimating the sensitivity and specificity of a diagnostic test ignores the correlation between eyes. This may consequently yield incorrect estimates, especially of the standard errors. The paper proposes a likelihood-based method of accounting for the correlations between eyes and estimating sensitivity and specificity using a model for binocular or paired binary outcomes. Estimation of model parameters via maximum likelihood is outlined and approximate tests are provided. The efficiency of the estimates is assessed in a simulation study. An extension of the methodology to the case of several diagnostic tests, or the same test measured on several occasions, which arises in multi-reader studies, is given. A further extension to the case of multiple diseases is outlined as well. Data from a study on diabetic retinopathy are analysed to illustrate the methodology.

[Health needs of the diabetic user of primary care]. / Necesidades en salud del diabético usuario del primer nivel de atención.

OBJECTIVE: To determine the extent and importance of unmet health needs of type 2 diabetic patients seen at primary care services. MATERIAL AND METHODS: A cross-sectional study was conducted in 1999, among rural and urban patients of the Mexican Institute of Social Security, in Nuevo Leon, Mexico. The study population consisted of 256 subjects selected at random, diagnosed with type-II diabetes for at least two years. Data were obtained by interview and complemented with medical charts and provider interviews. Five health areas and four health determinants were evaluated, through Mexican Official Standards and American Diabetes Association standards of medical care for diabetic patients. Analysis consisted of descriptive statistics and estimation of z scores. RESULTS: Health needs were met in 49% of cases. A lower mean of health need satisfaction was found in rural regions as compared to urban regions (36.8% vs. 53.3%, p < .01). Nutrition was the most affected health area (z score = -6), followed by the physical exercise (z score = -1), the metabolic health area (z score = +1), the non-smoking health area (z score = +2), the prevention and early detection of complications health area (z score = +2), and the cognitive health area (z score = +3). The health determinant with the highest requirement corresponded to utilization (z score = -5), followed by resource availability (z score = -4), perceived health need (z score = +4), and access barriers (z score = +6). CONCLUSIONS: Health need measurement allows evaluating the effectiveness of existing interventions, in addition to identifying areas with higher unmet health needs. These findings facilitate analysis and decision-making to devise specific health policies and actions directed at improving the quality of care for diabetic patients. The English version of this paper is available at: http://www.insp.mx/salud/index.html

Of helping relationships: a concept paper.

As professionals engaged in the practice of nursing, our involvement with people in different situations provides us many opportunities to be of significant help to them. People are often motivated to enhance themselves. It is the aim of this paper to present a concept in helping relationships that may assist nurses towards a positive direction in helping other people, whether sick or well to improve themselves, to achieve growth, realize their potentials and/or limit their disabilities.