A fuzzy approach for feature extraction of brain tissues in Non-Contrast CT / Un enfoque difuso para la extracción de características de tejidos cerebrales en TC no contrastada

Abstract: In neuroimaging, brain tissue segmentation is a fundamental part of the techniques that seek to automate the detection of pathologies, the quantification of tissues or the evaluation of the progress of a treatment. Because of its wide availability, lower cost than other imaging techniques, fast execution and proven efficacy, Non-contrast Cerebral Computerized Tomography (NCCT) is the most used technique in emergency room for neuroradiology examination, however, most research on brain segmentation focuses on MRI due to the inherent difficulty of brain tissue segmentation in NCCT. In this work, three brain tissues were characterized: white matter, gray matter and cerebrospinal fluid in NCCT images. Feature extraction of these structures was made based on the radiological attenuation index denoted by the Hounsfield Units using fuzzy logic techniques. We evaluated the classification of each tissue in NCCT images and quantified the feature extraction technique in synthetic images from real tissues with a sensitivity of 92% and a specificity of 96% for images from cases with slice thickness of 1 mm, and 96% and 98% respectively for those of 1.5 mm, demonstrating the ability of the method as feature extractor of brain tissues.

Resumen: En neuroimagen, la segmentación de tejidos cerebrales es una parte fundamental de las técnicas que buscan automatizar la detección de patologías, la cuantificación de tejidos o la evaluación del progreso de un tratamiento. Debido a su amplia disponibilidad, menor costo que otras técnicas de imagen, rápida ejecución y eficacia probada, la tomografía computarizada cerebral sin contraste (TCNC) es la técnica mayormente utilizada en emergencias para el examen neurorradiológico, sin embargo, la dificultad inherente que representa la segmentación de los tejidos cerebrales, hace que la mayoría de las investigaciones sobre la segmentación del cerebro se centren en la resonancia magnética. En este trabajo se realizó la caracterización de tres tejidos cerebrales: sustancia blanca, sustancia gris y líquido cefalorraquídeo en imágenes TCNC. Dichas estructuras fueron caracterizadas con base en el índice de atenuación radiológica denotadas por las Unidades Hounsfield utilizando técnicas de lógica difusa. Se evaluó la caracterización de cada tejido en diversos cortes de TCNC y se cuantificó la técnica de extracción de características en imágenes sintéticas a partir de tejidos reales con una sensibilidad de 92% y una especificidad de 96% para tejidos en cortes de 1 mm de grosor y 96% y 98% para los de 1.5 mm demostrando la habilidad del método como extractor de características de los tejidos cerebrales.

La innovación curricular orientada a competencias en la Facultad de Medicina de la Universidad de Chile / Curricular innovation-oriented skills in the Faculty of Medicine of the University of Chile

This article tries to give an overview of the educational changes that have been taking place in the Faculty of Medicine, University of Chile, known as “The Process of Curricular Innovation” which is based on a competence-oriented desirable profile for its graduates. This change seeks to generate a higher quality of teaching processes considering the current needs of our society. The concepts of competences and curriculum design are reviewed here for a better understanding of the innovation process.

Factores que inciden en la participación social de los adultos mayores en actividades físico-recreativas / Factors affecting social participation of older adults in recreational physical activity

Esta investigación se enmarcó en la temática de ocupación y adulto mayor activo, con el propósito de dar respuesta a la pregunta de investigación ¿Qué factores inciden en la participación social del adulto mayor en actividades físico-recreativas?, orientándose a aquellos factores facilitadores u obstaculizadores de dicha participación. Para este objetivo realizamos entrevistas en profundidad a cuatro personas que cumplieron los criterios muestrales establecidos para el estudio, que corresponden a: adultos mayores que se reconozcan a sí mismos como activos, que participen hace al menos un año en actividades físico-recreativas, como mínimo una vez por semana en el último año. Para el análisis de datos de esta investigación cualitativa utilizamos la técnica de análisis de contenido desde el relato de los participantes, obteniendo como principales factores facilitadores de esta participación el intercambio de recursos no tangibles, la motivación, el cuerpo vivido, la trayectoria de vida, la habituación y la accesibilidad, como factores que influyen en la participación de adultos mayores. Además de los mencionados existe una variedad de factores que interactúan entre sí, determinando atrayentes relaciones inter e intra factoriales, donde identificamos aspectos transversales a las distintas temáticas abordadas en esta investigación que posibilitan la apertura de nuevas líneas de investigación para la ciencia de la ocupación y terapia ocupacional.

This research was part of the issue of occupation and active older adult, setting a goal to answer the research question: what factors influence the social participation of the elderly, specifically in recreational physical activity?, aiming specifically those factors that emerge as facilitators or impede participation. To achieve this objective, in-depth interviews were conducted to four people who met the criteria established for the study sample, corresponding to: older adult who recognize themselves as active, involved at least a year in recreational physical activity, and as at least once a week in the last year. This exploratory qualitative used the technique of content analysis from the account of participants, having as main findings of this participation facilitating factors, where the most significant relate to: exchange of intangible resources, motivation, lived body, path of life, habituation and accessibility, which relate primarily to factors relating to that person, being a powerful accessibility elderly external prism that influences their involvement in such activities. In addition there was a variety of factors that interact with each other attractive determining relationships within and between categories, which identified issues which cut across the different themes addressed in this research. Finally, note that the nature of this study enables the opening of new lines of research that may contribute to the occupation science and occupational therapy.

Validación del cuestionario de calidad de vida ConQol, en niños chilenos portadores de cardiopatías congénitas / Validation of quality of life questionnaire ConQol for Chilean children with congenital heart diseases

Background: ConQoL questionnaire assesses health related quality of life among children with congenital heart diseases. It has a version for children aged 8 to 11 years and anotherfor children aged 12 to 16years. Aim: To validate ConQol questionnaire for Chilean children with a congenital heart disease. Material and Methods: Using a multicentric cross sectional design, 334 children from four hospitals (54% males), were surveyed. Among them 45% were aged 8 to 11 years and 55%, 12 to 16 years. The study involved three stages: cross cultural adjustment of the original questionnaire, pre-test study, and estimation of its psychometric properties. Content, construct and criterion validity and internal consistency with Cronbach's alpha, were assessed. Results: The version for children aged 8 to 11 years and comprised by three domains (symptoms, activity and relationships), obtained and α ≥ 0.60. In the questionnaire for children aged 12 to 16years, there is one more domain called coping, which obtained an α of 0.53, that was different to the other three domains that obtained an α > 0.70. The correlation between Health Quality of Life and Perception of Health Quality of Life was statistically significant for both groups. The association between Health Quality ofLife and health capability was only significant among children aged 12 to 16years (p < 0.01). Conclusions: The adapted ConQol questionnaire matched properly with the original one. The adapted questionnaire is valid and reliable to assess Health Quality ofLife among Chilean children with congenital heart diseases.

Genotipificación y resistencia antibacteriana de cepas de Campylobacter spp aisladas en niños y en aves de corral / Genotyping and antibacterial resistance of Campylobacter spp strains isolated in children and in free range poultry

Poultry is a main reservoir and source of human infection in campylobacteriosis. Three hundred and forty one stool samples (291 human, 50 avian) were analyzed. In the human group, 220 samples were collected from children with acute diarrheal disease (183 inpatients, 37 outpatients) and 71 from healthy children. Erythromycin and ciprofloxacin agar dilution MIC tests, Penner serotyping and RAPD-PCR genotyping were performed on 23 strains isolated. C. jejuni was reported only in patients with acute diarrhea (5.4 percent inpatients, 2.2 percent outpatients). Campylobacter prevalence in poultry was 34 percent. Cross-resistance to nalidixic acid and ciprofloxacin was found in 33.3 percent of human samples and 11.8 percent of animal samples. Human samples could not be typed using the Penner method. F serotype was the most expressed in poultry. We obtained a total of 14 genotypes (4 / 5 human and 10/15 avian). In conclusion, the predominant species in poultry and humans was C. jejuni, a significant amount of quinolone-resistant human and avian samples were obtained, and avian genotypes and serotypes were not found in human samples. The latter would mean that another source of infection could exist; therefore other reservoirs must be studied.

Las aves de consumo constituyen uno de los principales reservorios y fuente de infección humana de la campilo-bacteriosis. Se analizaron 341 muestras de deposiciones, 291 humanas y 50 aviares. De las muestras, 220 de niños con síndrome diarreico agudo-SDA (183 hospitalizados y 37 consultantes ambulatorios) y 71 niños sanos. A las 23 cepas obtenidas se les realizó CIM por dilución en agar a eritromicina y ciprofloxacina, serotipificación de Penner y genotipiicación por RAPD-PCR. Se encontró Campylobacterjejuni sólo en pacientes con SDA, de ellos 5,4 por ciento ambulatorios y 2,2 por ciento hospitalizados. En aves, la prevalencia de Campylobacter spp., fue de 34 por ciento. Hubo resistencia cruzada a ácido nalidixico y ciprofloxacina en 33,3 por ciento cepas de origen humano y 11,8 por ciento animal. Las cepas humanas fueron no tipiicables por el método de Penner. Predominó entre las aves el serotipo F. Se obtuvo un total de 14 genotipos (4/5 humanos y 10/15 aviares). En conclusión, la especie predominante en aves de corral y en humanos fue C. jejuni, existiendo una alta prevalencia de cepas de origen humano y aviar resistentes a quinolonas. Los genotipos y serotipos aviares no fueron encontrados en cepas de origen humano, lo que indica que podría existir otra fuente de infección, por lo que se requiere estudiar otros reservorios.

La profesión docente / The teaching profession

This article focuses on understanding teaching activities, especially in the feld of health science, as a set of tasks and actions that teachers undertake when transforming scientifc knowledge into curriculum contents and actions. There are several ways to address this issue. Some authors identify specifc roles and qualities of teachers structured as variables and dimensions. Others use the term competences, applied as skills, aptitudes or abilities to do something very well or duly intervene in a certain matter. The term competence, although not yet clearly defined, is used in this work because it is widely used in Health Sciences education. Some defnitions are reviewed. Teacher’s competences in the following areas recognized: those related to specifc professional skills, in contents organization, in learning skills, in new information and communication technologies, in evaluation and in social and ethical areas of educational practices.

Polimorfismos del gen del receptor de vitamina D y riesgo de fractura de cadera en la mujer adulta mayor de la Región del Bío Bío / Vitamin D receptor gene polymorphisms and risk of hip fracture in Chilean elderly women

Background: Osteoporotic hip fractures are devastating events in older women. There is a genetic modulation of bone phenotypic parameters including bone density (BMD) and bone fragility fractures. Vitamin D receptor (VDR) gene polymorphisms explain a small part of the genetic influence on BMD, whereas their effect on fractures remains uncertain. Aim: To examine the contributions of VDR genotypes to the susceptibility to hip fracture in elderly Chilean women. Patients and methods: We recruited 126 women (67 with fractures and 59 without) from Bio-Bio Region, Chile, aged 65 to 94 years. Genotyping for Bsm-l, Apa-1, Taq-1 and Fok-1 VDR polymorphisms was performed using polymerase chain reaction methods. All hip fractures were confirmed by X-ray. Results: The alíele frequencies were 0.49 for B, 0.57 for A, 0.60 for T and 0.65 for F in the Bsm-l, Apa-1, Taq-1 and Fok-1 polymorphisms respectively. The prevalence of these VDR gene polymorphisms in women with fractures were 16 percent BB, 69 percent Bb, 15 percent bb for Bsm-l; 30 percent AA, 46 percent Aa, 14 percent aa for Apa-1; 17 percent TT, 34 Tt, 8 percent tt for Taq-1 and 43 percentFF, 41 percent Ff, 16 percent ff for Fok-1. All VDR genotype frequencies did not differ from Hardy- Weinberg expectations. Alíele or genotype frequencies did not differ between women with or without fractures. These results did not change when analysis was adjusted by age weight, height or gynecologic history. Conclusions: The genotype frequencies of the VDR polymorphisms are in accordance with the frequencies of other Hispanic and Caucasian populations. Our results suggest that VDR polymorphisms are not associated with the risk of hip fracture in older women of this Region of Southern Chile.

Perforación estercorácea secundario a enfermedad inflamatoría intestinal colitis ulcerativa: a propósito de un caso / Estercorácea perforation secondary to inflammatory bowel disease ulcerative colitis: a purpose of a case

La perforación estercorácea es una entidad poco frecuente, es el resultado de las necrosis isquémica del colon causado por varias entidades clínicas como las de origen traumático causado principalmente por colonoscopia o restosigmoidoscopia, por enfermedad divertícular generalmente de origen de malformaciones, las de tipo vascular como el síndrome de Ehrles Danlos tipo IV, debido a la rotura de las arterias principales del colon, las de origen inflamatorio como la colitis ulcerativa y las de origen idiopático. Su forma de presentación no es característica, por lo general el dolor es el síntoma más constante aunque no es más relevante en pacientes jóvenes tratados con glucocorticoides.

Comportamiento clínico de los tumores cardíacos desde el feto hasta el adulto: serie multicéntrica de 38 pacientes / Cardiac tumors in children and adults: A retrospective study

Background: Cardiac tumors are very uncommon at all ages. There are important clinical differences between children and adults in the behavior of these tumors. Aim: To compare the behavior of primary and secondary cardiac tumors, from fetal age to adults. Patients and Method: Multicentric retrospective analysis of 38 children and adults with cardiac tumors, evaluated with echocardiography between January 1995 and August 2001. Medical records, echocardiographic and radiological examinations, surgical protocols and pathologic examinations were reviewed. Follow-up was obtained through data on medical records or calling patients by telephone. Results: Tumors were diagnosed in 38 patients (13 children and 25 adults), from a total of 31.800 echocardiograms. In children the diagnosis was made by fetal, transthoracic or transesophageal echocardiography in 23.6 percent and 8 percent of cases, respectively. Eighty five percent were primary (10 benign and 1 malignant) and 15 percent, secondary tumors. Fifty four percent were rhabdomyomas and 75 percent regressed spontaneously. Seventy seven percent were symptomatic and 31 percent were treated with surgery. During a follow up of 44±35 months, 31 percent of patients died. In adults, 76 percent of tumors were diagnosed by transthoracic and 20 percent by transesophageal echocardiography. Seventy six percent were primary (18 benign and 1 malignant) and 24 percent secondary tumors. Fifty six percent were myxomas. Ninety two percent were symptomatic and 84 percent were treated surgically. Twenty percent of patients died in the early postoperative period. No adult patients had a follow-up. Conclusions: Rhabdomyomas were solely found in children. In adults, myxomas are the predominat cardiac tumors. Primary and metastasic malignant tumors are observed both in children and in adults.

Astrocitoma pilocítico: ¿su comportamiento es siempre benigno?: a propósito de un caso / Pilocytic astrocytoma: its behavior is always benign?:a purpose of a case

Lactante mayor femenina de 15 meses de edad, con clínica de dificultad para la marcha, paresia de hemicuerpo derecho, desviación de la comisura labial hacia lado izquierdo, ptosis palpebral parcial ipsilateral. En la Resonancia Magnética Computarizada de cráneo con contraste reporta lesión ocupante de espacio intraxial temporo-parietal de aspecto quistico, con masa mural compatible con ASTROCITOMA PILOCITICO, corroborado con estudios histopatológico. En el presente trabajo se destaca que los astrocitomas pilocíticos aparecen con mayor frecuencia en la infancia y cuya ubicación predilectoria se encuentra a nivel del Cerebelo, sin embargo nuestro caso clínico presenta una ubicación a nivel supratentorial, siendo esta mas frecuente en los adultos que en los infantes, por lo que no se correlaciona con las estadísticas establecidas a nivel mundial y de diversos estudios realizados para los tumores primarios benignos, específicamente, el astrocitoma pilocítico, por tal motivo quisimos traer a colación el presente estudio.

Características reproductivas de las mujeres consultantes en servicios de urgencia general de la VIII Región / Reproductive history of women consulting in emergency services in a southern region of Chile

Background: The occurrence and timing of menstrual and reproductive events such as menarche, regularity of menses, births, maternal breastfeeding and menopause play an important role in a woman's life. Aim: To study the variability of reproductive live from menarche to menopause in different age groups in Chilean Caucasian and Mapuche aborigine females in a southern location of Chile. Subjects and Methods: A questionnaire about reproductive history was answered by 502 women consulting in six general emergency rooms of different public hospitals of the 8th region of Chile, between May and September 2002. Results: The median age at menarche was 12.8 years among adolescents and 13.7 years among older women (p <0.001). Fecundity rate was 5.2, 3.9 and 1.8 among older women, adults and young adults, respectively. Forty seven percent of adolescent had at least one child. The median age for natural menopause was 47 years. Eighty one percent of older women and 65% of adult women had given breastfeeding for more than six months. No statistical differences in reproductive characteristics were observed between Chilean Caucasians and Mapuche aborigines. Conclusions: Among these women, the age of menarche in younger women is similar to that of women from industrialized countries. Fecundity has been progressively decreasing. Menopause tends to occur sooner than in other geographical regions, probably due to the high number of surgical sterilizations in our population. Adolescent pregnancy still is a problem.

Reemplazo valvular mitral y aórtico en niños: resultados durante la última década con prótesis de última generación / Mitral and aortic valve replacement in children: last decade results with latest generation prothesis

Antecedentes: El reemplazo valvular mitral (RVM) y aórtico (RVA) es poco frecuente en pacientes pediátricos y las series publicadas reportan elevada morbi-mortalidad. Objetivo: Evaluar los resultados a mediano plazo en niños sometidos a RVM y RVA durante los últimos diez años, con el fin de determinar morbimortalidad y calidad de vida. Método: Análisis retrospectivo de 26 niños consecutivos (mediana de edad 5,6 años) sometidos a RVM y RVA, entre marzo 1992 y junio 2003. Diecisiete presentaban patología mitral y once aórtica. Resultados: Se realizaron 26 operaciones implantando 28 prótesis (26 mecánicas y 2 biológicas). Tres pacientes (12 por ciento) fallecieron durante el primer mes. La mediana de seguimiento fue de 6,2 años. Tres pacientes con RVM fallecieron alejadamente por causa no atribuible al reemplazo valvular con una sobrevida actuarial de 87 por ciento. Tres pacientes requirieron reoperación. Todos realizan actividades adecuadas a su edad, restringiéndose los deportes de contacto. Conclusión: Los resultados a mediano plazo del reemplazo valvular en niños con valvulopatía grave son satisfactorios.

Enfermedad de von Willebrand como manifestación clínica inhabitual del hipotiroidismo primario: Caso clínico / Acquired von Willebrand disease as an unusual manifestation of primary hypothyroidism: Report of two cases

Patients with hypothyroidism may have a minor increase in their bleeding tendency, causing easy bruising and menorrhagia. There is a positive correlation between factor VIII coagulant activity and thyroxin serum levels. Thus, patients with hypothyroidism have an acquired coagulation defect that is reversible with thyroxin supplementation. We report two sisters, aged 13 and 11 years, who met the criteria for von Willebrand's disease at the age of eight. Both sisters had a primary hypothyroidism due to Hashimoto's thyroiditis, diagnosed three years later. Thyroid hormone replacement normalized von Willebrand factor, factor VIII, and the bleeding diathesis disappeared. Acquired von Willebrand's disease is an unusual manifestation of hypothyroidism. However the possibility of hypothyroidism should be considered in patients presenting with von Willebrand disease.

Cirugía paliativa mediante operación de Norwood en distintas formas de corazón univentricular: resultados quirúrgicos inmediatos / Immediate results of palliative surgery for different forms of univentricular heart using the Norwood procedure

Background: Norwood procedure is used as the first stage in the palliative treatment of the hypoplastic heart syndrome and can be used, with some technical modifications, in other forms of univentricular heart with aortic stenosis or hypoplasia. These patients have a high mortality (50 percent), derived from the procedure itself and from their abnormal physiological status. Aim: To report our experience with the Norwood procedure. Patients and methods: Retrospective analysis of all patients subjected to the Norwood procedure between February 2000 and June 2003. Results: Thirteen patients (9 females, age range 5-60 days and median weight of 3.3 kg) were operated. Eight had hypoplastic heart syndrome and five had a single ventricle with aortic arch hypoplasia. The diagnosis was done in utero in eight patients. All technical variations, according to the disposition and anatomy of the great vessels, are described. Cardiac arrest with profound hypothermia was used in all and regional cerebral perfusion was used in nine. Three patients died in the perioperative period and three died in the follow up (two, four and 10 months after the procedure). Gleen and Fontan procedures were completed in five and one patients, respectively. Conclusions: Our results with the Norwood procedure are similar to other series. There is an important mortality in the immediate operative period and prior to the Glenn procedure (Rev MÚd Chile 2004; 132: 556-63).

Operación de Fontan: resultados inmediatos y a mediano plazo con anastomosis cavopulmonar total / Fontan procedure: early and mid-term results wiht total cavopulmonary anastomosis

Background: During the last five years, 65 patients with univentricular heart have been treated surgically in our institution, according to a protocol of staged operations that have been previously reported. Aim: To evaluate the early and mid-term outcome of those patients that have completed their staging protocol by means of a Fontan procedure. Patients and Methods: Between April 1996 and June 2001, 23 patients (age 16 to 223 months) underwent a Fontan procedure, 15 with an intracardiac lateral tunnel technique and 8 with an extracardiac conduit. A retrospective review of their clinical, surgical, echocardiographic, angiographic and hemodynamic data was performed, trying to identify risk factors for both mortality and functional capacity (FC). Follow up was complete in all survivors. Results: Three patients died early after surgery (13.04 percent). Excessive pulmonary blood flow was a risk factor for early death (p= 0.03). One patient died at 14 months. Follow up was 29.9 months (1-63). For those who survived the operation, five years survival was 93.3 percent. The majority of patients are in FC I or II, with no related risk factors. Conclusions: Our current results are comparable with those of larger series. Patients reach good FC and mid-term survival, irrespective of type of single ventricle or the surgical strategy

Nódulo pulmonar solitario / Solitary pulmonary nodule

El nódulo pulmonar solitario se define en la radiografía de tórax como una imagen del bordes bien definidos, cuyo diámetro es inferior a 3 cm. Lo más relevante frente a un nódulo pulmonar solitario es definir si se trata de una imagen de carácter benigno o maligno. Se han descrito factores de riesgo tanto clínicos como radiológicos de tabaquismo y de malignidad previa. Debido a la importancia de precisar la naturaleza de la lesión, consideramos interesante analizar el diagnóstico histológico de los nódulos pulmonares solitarios estudiados en el Hospital San Juan de Dios entre los años 1990 a 2000. Nuestros objetivos fueron conocer el porcentaje de malignidad (32 por ciento) y de benignidad (68 por ciento) Como diagnósticos histológicos benignos más frecuentes encabezaron la lista el tuberculoma y hamartoma. La asociación de factores de riesgo fue clara; el 85 por ciento de la población en estudio presentaba algun factor siendo la edad y el tabaquismo los más prevalentes. El método diagnóstico utilizado en casi todos los pacientes fue la radiografía de tórax. El estudio preoperatorio contó con tomografía axial en un 70 por ciento y en un 25 por ciento con fibrobroncoscopia

Aspectos que afectan el análisis de contenido de ADN por citometría de flujo / Factors that affect DNA content analysis by flow cytometry

DNA ploidy and cell cycle analysis by flow cytometry is used to obtain additional information about the diagnosis and prognosis of different types of cancer. However, there are several disagreements among authors about the tissue source (fresh-frozen or paraffin embedded), cellular dissociation methods (mechanical, enzymatic or other), use of different dyes, lasers, analysis software with different mathematical models and interpretation of results. A discussion about the different aspects that affect the study of DNA ploidy and cell cycle and a consensus in publications is mandatory. A strict control of analysis processes and data interpretation is also necessary

Reparación de fístula traqueoesofágica intratorácica post quimioterapia en pacientes con cáncer de esófago / Reparation of intrathoracic tracheoesophageal fistule post-chemotherapy in patients with esophageal neoplasms

Una de las complicaciones más graves que ocurren en las quimioterapias y radioterapias que se realizan como tratamiento del Ca de esófago es la fístula traqueoesofágica (FTE). Se presenta caso clínico de paciente de 33 años con Ca de esófago que mientras era tratado con una quimioterapia, presenta una FTE ubicada a la altura de la carina, el tumor presentó una remisión completa, no así la fístula que persistió. Se realizó reparación quirúrgica en dos etapas: en la primera, por esofagectomía vía torácica con cierre de la fístula traqueal, esofagostomía cervical, cierre de muñón gástrico y yeyunostomía; en un segundo tiempo, ascenso gástrico al cuello. controlado hasta un año y nueve meses el paciente se mantiene bien sin signos de recidiva. En las cirugías más recomendadas actualmente como tratamiento (paliativo) de la FTE por Ca, no se practica el cierre de la fístula, dejando unida ésta a un segmento cerrado de esófago, lo que es causa que el 50 por ciento de estos pacientes fallezcan posteriormente por infecciones respiratorias, complicación que se evita con la reparación aquí presentada