Tracheal growth assessment in mongrel puppies (dogs) through multidetector CT.

The aim of this study was to describe the tracheal growth pattern and its zoometric relationship in related medium-sized mongrel puppies through adulthood. Fourteen puppies were studied. CT monitoring was performed monthly, starting in the 1st month of life through the 7th month and subsequently at the 9th and 12th months. Additionally, six zoometric measurements were performed. Dorsoventral (DV) and transverse (TV) diameters and the luminal area from C1 to T2 were obtained. The global tracheal growth pattern revealed an increase up to 13 times its initial size, reaching a plateau phase during the last trimester. The relationship between the DV and the TV internal diameters of the tracheal lumen did not change during growth. As previously reported, the cranial tracheal area was wider, while the caudal part gradually decreased towards T1-T2; this consideration is important since the more distal an endotracheal tube is inserted, the greater the risk that injury may occur. The linear correlation between the zoometric measurements and the tracheal ring areas was positive. This study provides evidence for the evaluation of the morphometry of the canine trachea during physiological growth using helicoidal CT as a non-invasive, accurate tool.

Bioabsorbable implant as a tracheal wall substitute in young developing canines.

This study evaluated a polylactic and polyglycolic acid (PLA/PGA) implant as a partial tracheal substitute in young developing canines. This experimental and longitudinal study included local stray pups that received substitution of a short cervical tracheal segment with a PLA 85%/PGA 15% plaque. We measured clinical, endoscopic, and tomographic variables for 1 year, at which time we performed histomorphological evaluations of the implant using light and electron microscopy. There were no adverse events throughout the clinical progression. On endoscopic evaluation, the implant was covered with mucosal tissue beginning in the first month, without granulation or stenosis, and the circular shape of the trachea was altered. Tomographic images of the tracheal area at the implant site were similar to adjacent healthy areas (p = 0.423). At the end of the follow-up period, the plaque had biodegraded, and the space was covered by pseudostratified epithelium and ciliated cells similar to the neighboring tissue. Implantation of a PLA/PGA plaque constituted an effective (functional) replacement of a short semicircular cervical tracheal segment without limiting the growth of the recipient. Additional studies are required to prove the efficacy of these implants for larger tracheal segment replacements and in subjects at different stages of development.

[Experimental bacterial contamination of bile and liver in mongrel dogs: an alternative treatment with cephalone, a hybrid of cephalosporine fluoroquinolone]. / Contaminación bacteriana experimental de bilis e hígado en perros criollos. Tratamiento alternativo con (cefalona), un híbrido de cefalosporina y fluoroquinolona.

OBJECTIVES: A longitudinal, randomized, single blind study was done to evaluate the efficacy of an antibacterial hybrid molecule (beta-lactamic-fluoroquinolone) named cephalone after biliary-enteric-bypass (BEB). MATERIAL AND METHODS: Four groups of mongrel dogs were operated on three consecutive periods. Cultures of bile and liver were obtained and assessed, followed by obliteration of common bile duct and BEB to groups A, B and C. Group D served as a control. Ten days later the group A received conventional treatment based on ampicillin/gentamicin and groups B and C, cephalone in two different concentration schemes during 10 consecutive days. Further samples were processed for bacteria and additional liver biopsies were obtained for histopathological analysis. RESULTS: All three treatments reverted bacterial contamination in the liver and most of the bile samples were negative or showed a significant decrease in the number of colony forming units (p = 0.002). Histopathological analysis proved no lesions. CONCLUSIONS: Comparison of efficacy among antibacterial treatments revealed undistinguishable efficacy in this short-term assessment of bacterial contamination after BEB in dogs. The use of cephalone could be considered as a viable treatment or prophylaxis in bacterial infections occurring after BEB. Further studies are needed to assess long-term impact of the cephalone in this setting.

Fibrocollagen-covered prosthesis for a noncircumferential segmental tracheal replacement.

OBJECTIVE: Fibrocollagen-covered polyester meshes can be used as possible substitutions for tracheal segments if they become integrated into the tissue without complications. The aim of this study was to assess a fibrocollagen-covered polyester prosthesis to be used as a substitution for a tracheal segment. METHODS: We performed a blind, randomized experimental assay. Adult Wistar rats were assigned to one of 2 groups. Prostheses were made by implanting polyester tubing in a group of animals to cover them with homologous collagen. They were implanted as substitutions of tracheal segments in the experimental group after creating a defect in the anterior wall of the trachea. Clinical, histomorphologic, and immunohistochemical assessments were made at 4 different time points. RESULTS: The experimental group presented some respiratory distress signs during the first 7 to 10 days, such as stertors, hissing, and low motor activity. After this initial period, the symptoms subsided progressively and disappeared at the end of the first month. These respiratory symptoms caused no mortality. Initially undifferentiated monolayer cells predominated on the implant's surface, but during the last 2 months, the proportion of epithelial and ciliated cells was similar to that seen in control animals. Types I, III, and V collagen fibers were identified around the mesh. The intraluminal area of the tracheas with prostheses and prosthesis thickness were larger during the 4 months of the experiment. The increase in thickness was due to angiogenesis without evidence of fibrosis or chronic inflammation. CONCLUSIONS: Polyester-collagen prostheses used as substitutions of tracheal segments in rats enabled the proliferation of normal respiratory epithelium and maintained tracheal function without collapse, inflammatory reaction, or secondary stenosis.

[Surgical/medical competences, self-perception among a group of students recently graduated]. / Competencias médico-quirúrgicas. Autopercepción en médicos recién egresados de la licenciatura.

BACKGROUND: Medical professional proficiency comprises a set of skills, knowledge, and attitudes necessary to efficiently accomplish the practice of medicine. We undertook this study to identify the surgical/medical competencies (SMC) acquired by a group of students after graduating from the Faculty of Medicine, National Autonomous University of Mexico. METHODS: This was a cross-sectional, comparative, observational, and prospective study. Students from the class (1999-2003) who accepted to participate were included in the study. Thirty SMC were evaluated as well as demographic and academic background data from the graduates. Data were analyzed using Mann-Whitney, Kruskal-Wallis andX2tests. RESULTS: Of 341 interviewees, 310 subjects participated in the study; 61% of all participants were females. Mean age at graduation was 25 years; 66% of all participants concluded their medical training in 6 years; 30% of the interviewees had a < or = 8.0-point grade average score; 62% concluded their 6th school year in a Mexican Institute of Social Security (IMSS) and/or in a Ministry of Health (SSa) facility. Subjects reported having little or no command over 21/30 listed SMCs. Female participants rated themselves as less proficient than their male counterparts (p < or = 0.05). The presence of three other concomitant factors among several participants negatively influenced their self-perception of whether or not they possessed certain skills. CONCLUSIONS: A group of recently graduated physicians subjectively perceived themselves as possessing partial or no command over the SMCs included in the Surgery Department syllabus. These results must be completed through an objective assessment.

Difusión de cotrimoxazol a través de un expansor tisular: Estudio in vitro / Cotrimoxazole diffusion through a tissue expanders: In vitro study

Introducción: La principal complicación del uso de los expansores titulares (ET) son las infecciones. Una alternativa para evitarla, es agregar antibióticos que se difundan a través de la pared de un ET y eviten la colonización bacteriana. El objetivo de este trabajo fue evaluar la eficacia de una presentación nacional de cotrimoxazol, para difundirse a través de un ET en diferentes volúmenes de expansión. Material y método: Se realizó un experimento longitudinal con 12 ET, llenados a 50,100, 150 o 200% de su capacidad nominal, con solución fisiológica y cotrimoxazol a una concentración de 800/4000 ug/mL de trimetoprin/sulfametoxazol (TMX/SMX), sumergidos posteriormente en un sistema cerrado. Se midió la presión en el interior del ET, al inicio y al final del experimento. En los cuatro grupos se cuantificó la concentración de cotrimoxazol en la solución del contenedor, durante nueve días consecutivos. Los resultados se compararon mediante ANOVA de dos vías. Resultados: El SMX se precipitó dentro del ET. Las concentraciones de TMX en la solución del contenedor fueron diferentes en función del tiempo y el porcentaje de expansión. No hubo correlación entre el porcentaje de expansión y la presión dentro del ET. Conclusiones: La sinergia de cotrimoxazol de uso endovenoso disponible en nuestro país, no es una buena opción a emplearse en un ET a las dosis utilizadas, ya que el coeficiente de solubilidad de SMX se saturó y se formaron cristales. El incremento de difusión de TMX estuvo asociado con un mayor porcentaje de expansión, lo que es una ventaja, considerando que las infecciones son más frecuentes al final del proceso de expansión.

Introduction: Infection associated with tissue expansion is one of the main complications and force to take away the tissue expander. An alternative to avoid this action is to dilute antibiotics inside it. The aim of this experiment was to quantify the concentration of cotrimoxazole diffused through a tissue expander at different expansion and pressure volumes. Material and methods: A test was performed with 12 tissue expanders immersed in a closed system. These were divided in 4 sets according to the introduced expansion rate. Three independent variables were considered: percentage of lumen volume introduced into the expander, pressure inside the expander, and experiment duration. The concentration of the drug diffused through the expander was taken as dependent variable. The solution in which the expander was immersed was continuously sampled and drug concentration was determined by High Performance Liquid Chromatography (HPLC). ANOVA was used to determine differences between concentrations measured of every variable applied. Results: Only trimethoprim (TMX) diffused. No lineal correlation was observed between expansion rate and pressure inside the expander. The difference with respect to time and concentration of the drug outside the expander was statistically significant among the 4 sets of expanders (p = 0.0000). Conclusion: Sulfametoxazole (SMX) did not diffuse and crystallized inside the expander because of the different pk of the two drugs (SMX-TMX) respect to pH of dilution which was similar to pK of trimethoprim. The expansion rate had a proportional effect on TMX concentration outside the expander: an over-expansion of the system greater than 200% increases diffusion highly.

[Publication profile (1991-2002) of a group of Mexican pediatric surgeons]. / Perfil de las publicaciones efectuadas por cirujanos pediatras mexicanos (1991-2002).

INTRODUCTION: This study was undertaken to determine the characteristics of scientific articles published by Mexican pediatric surgeons (MPS) available in the major electronic databases for international and national medical information. MATERIAL AND METHODS: An observational, descriptive and transversal study was performed. Articles written by pediatric surgeons were localized in the most frequently accessed electronic searches: Medline, EMBASE, LILACS, and ARTEMISA, in the period from January 1991 to December 2002. Articles were grouped into three categories. RESULTS: A total of 247 publications were analyzed, 199 devoted to clinical research, 11 to basic research, and 37 reviews. Of the clinical research studies, 189 were observational-descriptive studies, and 151 of these were retrospective. Only 7.6% of the pediatric surgeons certified by the Mexican Council for Pediatric Surgery published an article (61 authors). Most studies (80%) was performed at Mexico City institutions. CONCLUSIONS: Most studies published by pediatric surgeons describe common problems of the Mexican pediatric population. A smaller percentage focus on comparing therapeutic actions or diagnostic strategies; however, result reliability is questionable due to experimental design. The contribution by MPS to the generation of medical publications during the last decade has been sparse, and more so from places other than Mexico City.

Esophageal anastomotic failure: an experimental study.

BACKGROUND: Postsurgical complications in patients with esophageal atresia have remained unchanged during the last three decades. This study was aimed at investigating certain risk factors for small-sized esophageal anastomosis and to assess the probable relationship between esophageal length and body weight in rabbit. METHODS: Six groups of 10 adult rabbits were subjected to section or 1-cm segmental resection of thoracic esophagus followed by end-to-end anastomosis. Approximation strength of esophageal ends was measured. Three different suture materials were used, and three different surgeons carried out procedures. Observed morbidity was recorded, as well as leakage or stenosis frequency in suture line. Esophageal length and body weight of nonresected rabbits were measured. RESULTS: Fifteen leakages were observed in suture line; there were no differences in relative risk between groups with and without resection, or in ratio of this complication among surgeons; nonetheless, a greater number of leakages (p < 0.05) was observed at higher tension. There were no differences in magnitude of stenosis among surgeons, tension degree, or suture material used. Quadratic association was found between length of thoracic esophagus and body weight in nonresected rabbits. CONCLUSIONS: Rabbit esophagus is a suitable model to assess early surgical complications but not for late complications. Among three assessed factors, increased tension in patients with segmental deficit was the most significant factor in development of anastomotic leakage. Existence of nonlineal correlation between esophageal length and body weight in rabbit showed that resection of 1 cm of esophagus represented a different weight-dependent segmental deficit, which increased as weight decreased.

Short bowel syndrome in patients studied at the National Institute of Pediatrics in mexico. Care, cost and perspectives

Background. Short bowel syndrome (SBS) continues to be one of the most challenging problems in pediatric surgery. Intestinal transplantation (IT) seems to be best form of treatment for this pathology. However, it is thought that the development of an IT programs may be more expensive than the present manner of treatment. Methods. To assess this item, and to identify potential candidates for IT, we reviewed the charts of all the patients with SBS treated at our Institute from 1989 to 1994. Results. Nine patients were identified as carriers of SBS; six with intestinal atresia, two with midgut volvulus and one with post-traumatic mesenteric thrombosis. The small bowel remnants varied from 1 to 80 cm, seven patients had remnants shorter than 30 cm, and the ileocecal valve was resected in three. Results. The overall morbidity and mortality was extremely high; four patients died within the first 3 months postresection and those still alive have had several complications: sepsis; hydroelectrolyte imbalances secondary to loose stools; thrombosis or infection of the catheter; TPN-related cholestasis, and malabsorption syndromes, etc. No patient survived with an intestinal remnant shorter than 15 cm. Of the five survivors, four have a weight/age deficit greater than 40 percent, two have rickets, one still depends on TPN and all, except one, require special enteral diets. Multiple central venous accesses had to be performed in every patient (mean 4.8). They all required multiple readmissions and have spent a considerable part of their lives as inpatients. The mean of the calculated cost per patient was $50,000 USD, while the minimal wage in mexico is $1,616 USD/year (1). conclusions. The shorter the segment of the retained bowel and the longer the survival, the higher the cost. These results may be further improved with the development of IT and, probably, with the same economic burden

Atresia esofágica: una propuesta de toma de decisiones / Esophageal atresia: marking decisions

La atresia de esófago es una malformación grave que requiere de una estrategia bien definida de manejo médico-quirúrgico; el diagnóstico temprano e integral representa el mejor medio para ubicar la ruta más apropiada de tratamiento y determinar el pronóstico del paciente. En México existe poca información escrita al respecto y la sobrevida difiere significativamente de lo descrito en países desarrollados. En esta revisión se señalan algunos de los aspectos mas sobresalientes de esta enfermedad y se presenta un esquema de toma de decisiones que permite agilizar el diagnóstico y tratamiento subsecuente

Comparación de dos tipos de trasplante experimental en el tratamiento del instestino corto letal / Comparison of two types of experimental transplant in the treatment of lethal shortgut syndrome

Objetivo. Evaluar la respuesta funcional, morbilidad y posibles cambios histoestructurales en animales enterectomizados y sin ciego, sujetos a dos tipos de trasplante anteral singénico. Material y método. Ensayo terapéutico-quirúrgico, aleatorio, controlado. Cuatro grupos de ratas Lewis macho de 8-10 semanas de vida se sometieron a los siguientes tratamientos: 1. Resección enteral letal (n=10). 2. Resección enteral letal + trasplante yeyuno-ileal total (n=28). 3. Resección enteral letal + trasplante segmentario distal de 40 por ciento y ciego (n=32). 4. Grupo testigo (n=10). Resultados. El 11 por ciento de los animales trasplantados falleció por fallas quirúrgicas. Hubo una proporción similar de complicaciones tardías en ambos grupos trasplantados: la más común fue obstrucción enteral; 20 por ciento de los trasplantes yeyuno-ileales presentó diarrea persistente. En los dos grupos trasplantados no se detectaron diferencias significativas, de sobrevida, incremento de peso, niveles séricos de proteínas, triglicéridos y prueba de absorción de la maltosa. En ambos tipos de injertos se observó hipertrofia de vellosidades y criptas. El injerto enteral se acompaño de cambios estructurales semejantes a los que se presentan en los remanentes inestinales en condiciones de déficit enteral postresección. Conclusión. El trasplante segmentario distal de intestino, con válvula íleaca y ciega, puede ser una buena opción terapéutica en la insuficiencia enteral irreversible, dado que la respuesta funcional y la morbilidad asociada no difieren de las del trasplante total

Transplante segmentario enteral experimental. Respuesta funcional y complicaciones quirúrgicas / Enteral segmentary experimental transplant. Functional response and surgical complications

Antecedentes: El trasplante intestinal segmentario es una opción prometedora en el tratamiento del intestino corto letal; el injerto enteral proximal reditúa experimentalmente mejor control inmunológico pero su efectividad funcional respecto a otros segmentos podría ser deficiente. Objetivo: Con el propósito de evaluar la mortalidad quirúrgica y el comportamiento funcional de tres variantes de trasplantes segmentarios enterales, se llevó a cabo el siguiente experimento. Método: Se formaron aleatoriamente cinco grupos de ratas Lewis, singénicas, en fase de crecimiento; en cuatro de ellas se efectuaron enterectomías del 90 por ciento, simultáneamente se trasplantaron segmentos del 30 por ciento de intestino proximal, medial o distal en los tres primeros grupos y del 90 por ciento en el cuarto; el quinto grupo se usó como testigo. Resultados. Se efectuaron 54 trasplantes, un tercio presentó complicaciones tardías, sólo en la mitad de ellos se pudo encontrar causas susceptibles de ser controladas; las complicaciones se presentaron en proporciones similares en todos los grupos. A cuatro meses de realizados los injertos, ninguna rata de las sobrevivientes interrumpió el crecimiento, sin embargo el grupo de trasplante proximal presentó déficit ponderal respecto a los otros grupos P < 0.05; los grupos de trasplante medial, distal y total alcanzaron patrones de crecimientos similar a grupo testigo; los niveles plasmásticos de triglicéridos, colesterol y glucosa después de la prueba de la maltosa fueron similares en todos los grupos, únicamente se observaron niveles inferiores de albúmina en el grupo de trasplante proximal P < 0.05. Conclusiones: los trasplantes segmentarios medial y distal mostraron una mejor respuesta en término de incremento ponderal, comparables a la obtenida en sujetos con restitución total o integridad enteral

Síndrome colestático neonatal: perspectiva y manejo médico-quirúrgico / Neonatal cholestasis. A review of the surgical treatment

El síndrome colestático neonatal obedece a múltiples causas, muchas de las cuales son aún desconocidas; el diagnóstico diferencial suele realizarse en mucho tiempo, lo cual repercute negativamente en la evolución y el pronóstico del lactante con ictericia obstructiva susceptible de corrección quirúrgica. La responsabilidad de agilizar su envío a los servicios quirúrgicos y/o continuar su estudio en el menor tiempo posible, reside en el pediatra clínico. En esta revisión se señalan las causas más frecuentes de colestasis neonatal que requieren tratamiento quirúrgico temprano, se sugiere una estrategia de toma de decisiones rápida para mejorar los resultados a corto y mediano plazo, con las técnicas actuales de tratamiento

Resección enteral en el conejo lactante: estudio experimental / Intestinal resection in the lactating rabbit

La respuesta de la resección enteral hecha en humanos recién nacidos y lactantes, depende del sitio y la magnitud del segmento amputado; habitualmente la recuperación de estos pacientes es satisfactoria, aunque a menudo son necesarias medidas de apoyo prolongado que prevengan complicaciones nutricionales y en tubo digestivo. En este estudio se evaluó el comportamiento post-operatorio de 6 grupos de conejos lactantes con resecciones selectivas del 0, 40, 50, 60, 75 y 90 por ciento de intestino delgado. Se observó un mayor número de complicaciones quirúrgicas, cuanto mayor fue el grado de manipulación y resección. Sólo hubo hipertrofia de las vellosidades en los extremos distales de los remanentes enterales de los animales con un 40 por cinto de resección yeyunal del 75 y 90 por ciento de resección yeyuno-ileal. En ninguno de los grupos se interrumpió el crecimiento; sólo en los conejos con resección superiores al 60 por ciento se observó unas disminución significativa de peso. La resección enteral, preferentemente proximal o distal del 40 y 60 por ciento respectivamente, no produjo déficit pondoestatural con respecto al grupo control

Modelo técnico experimental para la práctica de anastomosis esofágica en conejos / An experimental technical model for the practice of esophageal anastomosis in rabbits

Con el objeto de desarrollar y optimizar el entrenamiento técnico-quirúrgico, requerido para la corrección de las atresias esofágicas por cirujanos pediatras en formación, se describen las técnicas de anastomosis esofágicas empleadas en conejos Nueva Zalanda, como una propuesta de modelo experimental, para reproducir estos procedimientos quirúrgicos y disminuir la morbiletalidad de una insuficiente destreza operatoria en este rubro. El abordaje, diámetro y consistencia del esófago del modelo empleado, guarda características muy parecidas a las que se observan en el recién nacido con atresia de esófago

Los grandes defectos de la pared abdominal en el niño / The main defects of the abdominal wall in the children

Se describen algunas características sobresalientes de los 2 defectos congénitos de mayor magnitud de la pared abdominal (gastrosquisis y onfalocele). Adicionalmente, se propone una ruta crítica a manejo médico-quirúrgico dividida en 3 etapas: preoperatoria, transoperatoria y postoperatoria. No es aconsejable como parte del tratamiento, dejar un defecto herniano para cierre ulterior.

Derivación bilioentérica convergente con mecanismo antireflujo: estudio experimental / Biliary-enteric derivation with antirefluz technic: an experimental study

Con el objeto de evitar reflujo en las derivaciones bilio-entéricas y las complicaciones que se derivan de este fenómeno: se puso a prueba una nueva técnica de derivación, denominada convergente con plicatura entero-entérica. Dicho procedimiento se llevó a cabo en un grupo de perros mestizos recién destetados. Los resultados mostraron que la nueva técnica presentó un menor número de complicaciones, comparada con las que se observaron en sujetos con la derivación "habitual en Y de Roux. No obstante, no suprime los efectos iniciales de la contaminación bilio-hepática