Design of a Dynamic Force Measurement System for Training and Evaluation of Suture Surgical Skills.

The aim of this study is to present the SurgeForce system, a tissue handling training device for analysis of dynamic force applied to the tissue and objective assessment of basic surgical skills during the suture process. The SurgeForce system consists of a mechanical base formed by two platforms joint with three stainless steel springs and a three axial digital accelerometer attached to the upper platform, which detects the dynamic force caused by a surgeon when performing a suture task over a synthetic tissue pad. Accelerometer data is sent to a control unit where preprocessing to transform the raw data into a force signal is done, and then, the force signal is sent to a computer application, which register the force exerted over the synthetic tissue pad. For validation, 17 participants (6 surgeons and 11 medical students) performed three simple interrupted sutures with knot tying using the SurgeForce system. Ten force-based metrics were proposed to evaluate their performance during the suturing task. Results of the validation showed statistical differences in 8 of 10 force-based parameters for assessment of basic surgical skills during the suture task. The SurgeForce system demonstrated its capacity to differentiate force-based performance of surgeons and medical students. The SurgeForce system has been successfully validated. This system was able to distinguish force performance between experts and novices, showing its potential to distinguish surgeons with basic suture skills from those who are not yet prepared.

Construct validity of the SurgForce system for objective assessment of laparoscopic suturing skills.

BACKGROUND: Laparoscopic surgery requires a new set of skill to be learned by the surgeons, of which the most relevant is tissue manipulation. Excessive forces applied to the tissue can cause rupture during manipulation or ischemia when confronting both sides of the tissue. The aim of this study is to establish the construct validity of the SurgForce system for objective assessment of advanced laparoscopic skills, based on the force signal generated during suture tasks, and the development of force parameters for evaluating tissue handling interaction. METHODS: The SurgForce system, a tissue handling training device that measures dynamic force, was used to capture the force generated by surgeons with different levels of laparoscopic experience. For construct validity, 37 participants were enrolled in this study: 19 medical students, 12 residents of surgical specialties and 6 expert surgeons. All participants performed an intracorporeal knotting suture task over a synthetic tissue pad with a laparoscopic box-trainer. The force performance of the participants was analyzed using 11 force-based parameters with the application of the SurgForce system. Statistical analysis was performed between novice, intermediate, and expert groups using a Kruskal-Wallis test, and between the pairs of groups using a Mann-Whitney U-test. RESULTS: Overall, 9 of the 11 force-related parameters showed significant differences between the three study groups. Results between the pairs of groups presented significant differences in 5 force parameters proposed. Construct validity results demonstrated that the SurgForce system was able to differentiate force performance between surgeons with different levels of laparoscopic experience. CONCLUSION: The SurgForce system was successfully validated. This force system showed its potential to measure the force exerted on tissue for objective assessment of tissue handling skills in suturing tasks. Furthermore, its compact design allows the use of this device in conventional laparoscopic box-trainers.

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.

Algunas notas sobre la historia del Laboratorio de Cirugía Experimental: reflexiones sobre su importancia en la educación e investigación quirúrgica / Some notes on the history of the experimental surgery laboratory: reflections on its relevance in education and surgical research

The progress of medicine has largely been due to research, and for surgery, in particular, the experimental surgical laboratory has been considered fundamental to the surgeon's education. In this study, a general view of experimental surgery is given in animal models based on bioethical norms as well as to design, create and apply different surgical procedures before performing in humans. Experimental surgery also facilitates surgical teaching and promotes the surgeon's scientific reasoning. Methods. This is a retrospective and descriptive study. Data were collected from direct and indirect sources of available publications on the historical, bioethical and educational aspects of medicine, focusing on surgery. The important facts corresponding to the field of experimental surgery and applicable in Mexico were selected. Concepts of experimental surgical models and of the experimental surgery laboratory were described. Bioethical considerations are emphasized for care of experimental animals. Finally, this work focuses on the importance of surgical experimentation in current and future development of the surgical researcher. Conclusions. Experimentation with animal models in a surgical laboratory is essential for surgical teaching and promotes development of the scientific thought in the surgeon. It is necessary for surgical research and is fundamental for making progress in surgery, treatment and medicine as science.

[Some notes on the history of the experimental surgery laboratory. Reflections on its relevance in education and surgical research]. / Algunas notas sobre la historia del Laboratorio de Cirugía Experimental. Reflexiones sobre su importancia en la educación e investigación quirúrgica.

The progress of medicine has largely been due to research, and for surgery, in particular, the experimental surgical laboratory has been considered fundamental to the surgeon's education. In this study, a general view of experimental surgery is given in animal models based on bioethical norms as well as to design, create and apply different surgical procedures before performing in humans. Experimental surgery also facilitates surgical teaching and promotes the surgeon's scientific reasoning. Methods. This is a retrospective and descriptive study. Data were collected from direct and indirect sources of available publications on the historical, bioethical and educational aspects of medicine, focusing on surgery. The important facts corresponding to the field of experimental surgery and applicable in Mexico were selected. Concepts of experimental surgical models and of the experimental surgery laboratory were described. Bioethical considerations are emphasized for care of experimental animals. Finally, this work focuses on the importance of surgical experimentation in current and future development of the surgical researcher. Conclusions. Experimentation with animal models in a surgical laboratory is essential for surgical teaching and promotes development of the scientific thought in the surgeon. It is necessary for surgical research and is fundamental for making progress in surgery, treatment and medicine as science.

Factores de crecimiento en el tratamiento de úlceras en pacientes diabéticos. Mitos y realidades / Growth factors in treatment of foot ulcers in diabetic patients. Myths and realities

Las úlceras neuropáticas de los pies en los pacientes diabéticos se pueden presentar hasta en 10 por ciento de ellos y tienen una recurrencia a cinco años del 70 por ciento. La infección, isquemia y trauma repetido pueden contribuir al desarrollo de úlceras crónicas en este grupo de pacientes que además presentan como característica alteraciones en los procesos básicos de la cicatrización. Una de estas alteraciones es la disminución de factores de crecimiento de las úlceras crónicas. Se han identificado diversos factores de crecimiento en la reparación de tejidos entre los cuales se encuentra el factor de crecimiento epidérmico, factor de crecimiento transformante beta, factor de crecimiento de fibroblastos, factor de crecimiento derivado de plaquetas y el factor de crecimiento tipo insulina. Estos factores se han estudiado en úlceras de pacientes diabéticos de diferentes etiologías, sin embargo, los mejores resultados han sido observados en úlceras neuropáticas.Algunos de estos como el factor de crecimiento derivado de plaquetas ha sido estudiado incluso en ensayos clínicos fase III y aceptados por la FDA para su aplicación clínica en este tipo de padecimientos. Otros como el factor de crecimiento epidermoide ha demostrado ser útil o incluso superior a otros, sin embargo, aún son pocos los estudios clínicos controlados que demuestran lo anterior. El uso de factores de crecimiento en las úlceras neuropáticas y crónicas de diabéticos es una alternativa más en el manejo de esta compleja patología.

Simposio: cirugía experimental en México (parte I). Historia de la cirugía experimental en México / Symposium: experimental surgery in Mexico (Part I). History of experimental surgery in Mexico

Objetivo: Revisar los principales aspectos históricos del desarrollo de la cirugía experimental en México. Metodología: Revisión bibliohemerográfica de 276 referencias sobre el tema para elaborar un listado de las principales aportaciones de la cirugía experimental en México. Conclusión: Las contribuciones de los pioneros de la cirugía experimental (Darío Fernández Fierro, José Castro Villagran, Julián González Méndez, Alejandro Celis, Trifón de la Sierra) han sido la base para el desarrollo ulterior de la cirugía experimental en México

Micropinzas vasculares: desarrollo tecnológico universitario / Microsurgicals clamps. a university technolocigal development

Un problema importante en el entrenamiento y la enseñanza de la microcirugía es la disponibilidad de micropinzas vasculares debido a su alto costo y la dificultad para su importación. Por estas razones, en nuestro laboratorio, desarrollamos unas micropinzas vasculares, equiparables a las que se producen en otros países. Las pinzas fueron sometidas a pruebas de control. Su empleo resultó satisfactorio en el laboratorio de entrenamiento y enseñanza