Colonic Electrical Stimulation for Chronic Constipation: A Perspective Review.

Chronic constipation affects around 20% of the population and there is no efficient solution. This perspective review explores the potential of colonic electric stimulation (CES) using neural implants and methods of bioelectronic medicine as a therapeutic way to treat chronic constipation. The review covers the neurophysiology of colonic peristaltic function, the pathophysiology of chronic constipation, the technical aspects of CES, including stimulation parameters, electrode placement, and neuromodulation target selection, as well as a comprehensive analysis of various animal models highlighting their advantages and limitations in elucidating the mechanistic insights and translational relevance for CES. Finally, the main challenges and trends in CES are discussed.

[Validity studies in laparoscopic simulation. Methodology and design considerations.] / Validación en simulación laparoscópica. Consideraciones metodológicas y de diseño.

OBJECTIVES: To describe a roadmap of the most representative milestones and considerations in the validation of surgical simulators, especially those of laparoscopic surgery. And additionally, help determine when in this process a simulator can be considered as validated. METHODS: A non-systematic review was carried out searching terms like simulation, validation, training, assessment, skills and learning curve, as well as providing the experience accumulated by our center. RESULTS: An ideal classical validation process should consist of the following steps: fidelity, verification/calibration/ reliability, subjective and objective strategies. Baseline tests of fidelity and verification/calibration/ technological reliability are not always detailed in the simulation literature. A simulator can be considered validated if, at least, satisfactorily completed any of the two main objective strategies, that is, constructive and/or criterion validity. CONCLUSIONS: The methodologies to validate simulators as useful and reliable for the improvement of psychomotor/ technical skills are widely analyzed, although there is a variety of approaches depending on the scientific reference consulted, not being implemented equally in all works. This apparent arbitrariness should be considered in advance because it can lead the researcher to misunderstandings, especially when the simulator will be regarded as valid.

OBJETIVOS: Describir una hoja de ruta de los hitos y consideraciones más representativos en la validación de simuladores quirúrgicos, especialmente los de cirugía laparoscópica. Y adicionalmente contribuir a determinar en qué momento de este proceso puede considerarse un simulador como validado.MÉTODOS: Se realizó una revisión no sistemática con los términos simulación, validación, formación, entrenamiento, evaluación, habilidades y curva de aprendizaje, además de aportar la experiencia acumulada por nuestro centro. RESULTADOS: Un proceso ideal clásico de validación debería constar de los siguientes pasos: Fidelidad, Verificación/ Calibración/Fiabilidad, estrategias subjetivas y objetivas. Las pruebas de inicio tanto de Fidelidad como de Verificación/Calibración/Fiabilidad tecnológica no siempre están descritas de manera explícita en los trabajos de validación de simuladores. Un simulador puede considerarse validado si al menos ha completado satisfactoriamente una validación de cualquiera de los dos grandes bloques de tipo objetivo, es decir, constructiva y/o de criterio. CONCLUSIONES: Los métodos que permiten validar simuladores como útiles y fiables para la mejora de habilidades de tipo psicomotor/técnico están ampliamente documentados aunque existe cierta variedad de enfoques en función de la referencia científica que se consulte, no aplicándose por igual en todos los trabajos. Esta aparente arbitrariedad debería ser conocida de antemano porque puede llevar al investigador a ciertos equívocos, especialmente a la hora de afirmar cuándo el simulador se considera plenamente validado.

Comparison of the use of fresh-frozen canine cadavers and a realistic composite ex vivo simulator for training in small animal flexible gastrointestinal endoscopy.

OBJECTIVE To compare the usefulness of fresh-frozen canine cadavers (FFCCs) and a validated canine simulator model for training veterinary students in basic gastrointestinal endoscopic procedures. DESIGN Randomized trial. SAMPLE 48 veterinary students in their final year of training. PROCEDURES Students were randomly assigned to receive basic gastrointestinal endoscopic training on a canine simulator or FFCC. All students were trained as assigned in esophagogastroduodenoscopy, endoscopic gastric biopsy, and gastric foreign body removal for 2 h/d for 5 days. They then performed each procedure on a live dog, and procedure completion time and performance ability were compared between groups. Two experienced endoscopists used a validated Likert-type procedural rating scale to rate the students' performance. Students completed a survey to rate their training model. RESULTS No significant differences were identified between groups in quality of performance of the 3 endoscopic procedures on a live dog. Students required significantly less time to complete the procedures on a live dog when trained on an FFCC versus canine simulator. Although both training models were considered equally useful by students, training on the simulator was significantly more stimulating. CONCLUSIONS AND CLINICAL RELEVANCE Students showed the same skill level in performing basic endoscopic procedures on live dogs regardless of the training model used, although students who trained on the FFCC completed these procedures faster than students trained on the canine simulator. Use of the simulator appeared to be a viable alternative to use of FFCCs for veterinary endoscopic training, providing students with a good level of proficiency before performing endoscopic procedures on live dogs.

[Training in basic and advanced laparoscopy: Evaluation of a 30-year experience in a training program in Spain.] / Formación en cirugía laparoscópica urológica básica y avanzada: evaluación de 30 años de experiencia de un programa de formación en España.

The lack of globally established standards for learning urological laparoscopy has not prevented laparoscopic techniques from evolution and continuous development. Laparoscopy coexists with robotic surgery today, and in the last decade there have been many techniques that have undergone a boom with the use of a laparoscopic approach (total and partial nephrectomy, pyeloplasty, colposacropexy, etc.).We intend to evaluate the progressive incorporation of different surgical techniques in the laparoscopic learning program and, on the other hand, to analyze the evolution of training programs in urological laparoscopy to bring this type of techniques within the hospital surgical activity. We describe our 30-years experience in different training programs in urological laparoscopy that have been sponsored by the Spanish Association of Urology (AEU), and have undergone several validity studies to assess their capacity in order to evaluate effectively basic and advanced laparoscopic skills. We will also highlight the current and future trend towards training models based on surgical competences where individualized training, accreditation and specialization of tutors is crucial, and where the increase in the use of training and evaluation methods based on the simulation are increasingly common.

Muscle activity and hand motion in veterinarians performing laparoscopic training tasks with a box trainer.

OBJECTIVE: To evaluate muscle activity and hand motion in veterinarians performing a standard set of laparoscopic training tasks. SAMPLE: 12 veterinarians with experience performing laparoscopic procedures. PROCEDURES: Participants were asked to perform peg transfer, coordination, precision cutting, and suturing tasks in a laparoscopic box trainer. Activity of the right biceps brachii, triceps brachii, forearm flexor, forearm extensor, and trapezius muscles was analyzed by means of surface electromyography. Right hand movements and wrist angle data were registered through the use of a data glove, and risk levels for the wrist joint were determined by use of a modified rapid upper limb assessment (RULA) method. One-way repeated-measures ANOVA with a Bonferroni post hoc test was performed to compare values between tasks. RESULTS: Activity in the biceps muscle did not differ significantly among the 4 tasks. Activity in the triceps, forearm flexor, and forearm extensor muscles was significantly higher during precision cutting than during the coordination task. Activity in the trapezius muscle was highest during the suturing task and did not differ significantly among the other 3 tasks. The RULA score was unacceptable (score, 3) for the coordination, peg transfer, and precision cutting tasks but was acceptable (score, 2) for the suturing task. CONCLUSIONS AND CLINICAL RELEVANCE: Results indicated that the ergonomics of laparoscopic training depended on the tasks performed and the design of the instruments used. Precision cutting and suturing tasks were associated with the highest muscle activity. Acceptable wrist position, as determined with the RULA method, was found with the suturing task, which was performed with an axial-handled instrument.

Common swine models of cardiovascular disease for research and training.

Cardiovascular diseases are a major health concern and therefore an important topic in biomedical research. Large animal models allow researchers to assess the safety and efficacy of new cardiovascular procedures in systems that resemble human anatomy; additionally, they can be used to emulate scenarios for training purposes. Among the many biomedical models that are described in published literature, it is important that researchers understand and select those that are best suited to achieve the aims of their research, that facilitate the humane care and management of their research animals and that best promote the high ethical standards required of animal research. In this resource the authors describe some common swine models that can be easily incorporated into regular practices of research and training at biomedical institutions. These models use both native and altered vascular anatomy of swine to carry out research protocols, such as testing biological reactions to implanted materials, surgically creating aneurysms using autologous tissue and inducing myocardial infarction through closed-chest procedures. Such models can also be used for training, where native and altered vascular anatomy allow medical professionals to learn and practice challenging techniques in anatomy that closely simulates human systems.

Assessment of Laparoscopic Skills in Veterinarians Using a Canine Laparoscopic Simulator.

The aim of the present study was to assess the content and construct validity of the Canine Laparoscopic Simulator (CLS). Forty-two veterinarians were assigned to experienced (n=12), control (n=15), and training (n=15) groups, which were assessed while performing four laparoscopic tasks on the CLS. The initial and final assessments of all tasks were performed blindly by two experienced surgeons using the Global Operative Assessment of Laparoscopic Skills (GOALS) and a task-specific checklist. At the end of the study, the subjects completed an anonymous survey. The experienced group performed all of the tasks faster, with higher GOALS and checklist scores than the training and control groups (p≤.001). In the second assessment, the training group reduced the time needed to complete all of the tasks and obtained significantly higher GOALS and checklist scores than the control group. The participants perceived the CLS and its training program to be positive or very positive. The CLS and its training program demonstrated content and construct validity, supporting the suitability of the simulator for training and teaching and its ability to distinguish the degree of experience in laparoscopic surgery among veterinarians. In addition, face validity showed that the veterinarians fully accepted the CLS's usefulness for learning basic laparoscopic skills.

Development and evaluation of a canine laparoscopic simulator for veterinary clinical training.

Human laparoscopic simulators have been used in medical education for minimally invasive surgery (MIS) in the past years. Simulator-based laparoscopic training has attracted much interest because unique skills have to be learned not only by surgeons in training but also by surgeons in practice. MIS forces the surgeon to adapt to monocular vision and decreased tactile sensation and entails training and improving hand-eye and hand-hand coordination. Those skills require a learning curve that could be overcome gradually with use of simulators. The Canine Laparoscopic Simulator (CLS) for laparoscopic training was developed based on the working and optical space obtained from computed tomography (CT) scan images of three Beagle dogs. Thirty veterinarians (expert group, n=7; novice group, n=23) performed basic laparoscopic exercises in one training session on the CLS. During the performance of the exercises, an experienced laparoscopic veterinarian assessed all the tasks. Afterwards, participants were asked to complete an anonymous survey describing their experience. Most participants expressed positive opinions about the design and usability of the CLS. There were no significant differences between the two groups' opinions. The CLS showed good preliminary acceptance in the basic laparoscopy tasks by veterinarians. They perceived it to be a good training tool, and these results suggest that CLS is an engaging tool for education but still has some limitations inherent in training boxes. Further studies would be needed to establish the validity of training programs performed in the CLS.

Validation of a realistic simulator for veterinary gastrointestinal endoscopy training.

This article reports on the face, content, and construct validity of a new realistic composite simulator (Simuldog) used to provide training in canine gastrointestinal flexible endoscopy. The basic endoscopic procedures performed on the simulator were esophagogastroduodenoscopy (EGD), gastric biopsy (GB), and gastric foreign body removal (FBR). Construct validity was assessed by comparing the performance of novices (final-year veterinary students and recent graduates without endoscopic experience, n=30) versus experienced subjects (doctors in veterinary medicine who had performed more than 50 clinical upper gastrointestinal endoscopic procedures as a surgeon, n=15). Tasks were scored based on completion time, and specific rating scales were developed to assess performance. Internal consistency and inter-rater agreement were assessed. Face and content validity were determined using a 5-point Likert-type scale questionnaire. The novices needed considerably more time than the experts to perform EGD, GB, and FBR, and their performance scores were significantly lower (p<.010). Inter-rater agreement and the internal validity of the rating scales were good. Face validity was excellent, and both groups agreed that the endoscopy scenarios were very realistic. The experts highly valued the usefulness of Simuldog for veterinary training and as a tool for assessing endoscopic skills. Simuldog is the first validated model specifically developed to be used as a training tool for endoscopy techniques in small animals.

Growing cava vein anastomosis: comparison of cross-clamping and suture times using VCS metallic clips, interrupted nonabsorbable, or continuous absorbable suturing techniques.

BACKGROUND: The latest generation in titanium clip application systems, the AnastoClip Vessel Closure System (VCS; LeMaitre Vascular, Burlington, MA), allows surgeons to perform vascular anastomosis more easily and faster than conventional sutures. This system may become the option of choice for vascular reconstruction in pediatric surgery where, as in the case transplant surgery, decreasing vascular occlusion times may influence outcome. The aim of this study was to determine whether VCS metallic clips would allow shorter anastomosis times than conventional interrupted polypropylene or running polyglycolic acid suturing in end-to-end anastomosis performed in the abdominal cava of young pigs. METHODS: Thirty-two domestic swine, 45 days old, were used for this study. All animals were subjected to an end-to-end anastomosis in the abdominal cava. RESULTS: VCS clips are easier to use for the surgeon, significantly decreasing cross-clamping time in caval anastomosis (VCS 10.33 ± 1.75 min vs. interrupted polypropylene sutures 46.00 ± 6.16 min vs. continuous polyglycolic acid sutures 18.16 ± 1.47 min). CONCLUSIONS: VCS clips significantly decrease the time needed for performing an end-to-end anastomosis in the abdominal cava, decreasing cross-clamping time when compared to interrupted polypropylene or running polyglycolic acid sutures.

Ergonomic analysis of muscle activity in the forearm and back muscles during laparoscopic surgery: influence of previous experience and performed task.

PURPOSE: The first aim of this study is to analyze the muscle activity in back and forearm muscles in surgeons during laparoscopic dissection and suturing maneuvers. The second aim is to determine the influence of the surgeons' previous experience in laparoscopic surgery. METHODS: A total of 30 laparoscopic surgeons were divided in 3 groups: novice suturing, novice dissecting, and experts suturing. Electromyography data were collected from the trapezius, forearm flexors, and forearm extensors muscles, during the proposed tasks on physical simulator. RESULTS: Muscle activity was significantly lower in the expert group. Moreover, muscle activity in the trapezius was significantly higher during the completion of intracorporeal suturing when compared with that during dissection. CONCLUSIONS: Results obtained in this study show that the surgeons with a higher degree of laparoscopic experience exhibit a lower level of muscle activity when compared with the novice surgeons. Moreover, in accordance to our results, laparoscopic suturing involves a higher degree of muscle effort than during laparoscopic dissection.

[Pyramid training model in laparoscopic surgery]. / Modelo de formación piramidal para la enseñanza de cirugía laparoscópica.

BACKGROUND: Minimally invasive surgery implementation requires a regulated and orderly learning process. METHODS: Jesús Usón Minimally Invasive Surgery Centre promotes a pyramid training model structured into four levels: training of basic and advanced skills in physical simulator (level 1), training of anatomical protocols and advanced skills with animal models (level 2) training advanced procedural skills with tele-surgical applications (level 3), and training in the operating room (level 4). Training provided at levels 1 and 2 is described and evaluated. RESULTS: 4284 participants have been trained in laparoscopy at our institution. 95.5% surgeons: 49% gastroenterologists, 30% urologists, and 14% gynecologist (14%). 77% of celebrated courses consisted of 20 hours training (8 at level 1 and 12 at level 2). 94.37% of participants considered pyramid model as highly suitable, scoring 9.5 on a scale 1-10 for the model and for the simulation quality. 82.7% perceived the improvement in their laparoscopic skills and 99.56% recommend this training program to other surgeons. DISCUSSION: There are no unified criteria between different training programs but most of them measure laparoscopic skills based on time of execution, quality or mistakes of the exercise, and the student satisfaction test. CONCLUSION: The pyramid training model lead to the acquisition of necessary laparoscopic skills to perform safely advanced minimally invasive techniques.

Antecedentes: la práctica de la cirugía de mínima invasión necesita que el aprendizaje sea estructurado y progresivo. Material y métodos: estudio prospectivo efectuado en el Centro de Cirugía de Mínima Invasión Jesús Usón que propone un modelo de formación piramidal con cuatro niveles: adquisición de habilidades básicas en simulador (nivel 1), desarrollo de técnicas quirúrgicas específicas en modelos animales (nivel 2), telemedicina y telementorización (nivel 3), y aplicación al paciente con supervisión experimentada (nivel 4). Objetivo: describir los niveles 1 y 2 que se practican en el Centro y evaluar la formación impartida. Resultados: 4,284 alumnos han recibido formación en cirugía laparoscópica: 95.5% médicos: cirujanos del aparato digestivo (49%), urólogos (30%) y ginecólogos (14%). En 77% de los cursos celebrados disponen de 20 horas de adiestramiento, 8 en el nivel 1, y 12 en el nivel 2. El 94.37% considera altamente apropiado el modelo de formación piramidal, calificándolo con 9.58 sobre 10 y con 9.5 a la calidad de la simulación. El 82.75% percibe que ha avanzado notablemente en sus destrezas y 99.56% recomendaría a otros cirujanos la realización de actividades en el Centro. Conclusión: el modelo de formación propuesto permite alcanzar las habilidades necesarias para efectuar correctamente procedimientos avanzados en cirugía de mínima invasión.

[Ergonomics in laparoscopic surgery and its importance in surgical training]. / Ergonomía en cirugía laparoscópica y su importancia en la formación quirúrgica.

Despite the many advantages that laparoscopic surgery has for patients, it involves a series of risks for the surgeon. These are related to the reduced freedom of movement and forced postures which lead to greater muscle fatigue than with conventional surgery. In laparoscopic surgery there are few references on the introduction of training programs in ergonomics, despite the numerous advantages demonstrated in other disciplines. The application of ergonomic criteria in the surgical field could have great benefits, both for surgeons and patients. In this work we attempt to review the existing literature and our experience to provide the surgeon with some ergonomic guidelines for body stance and positioning of equipment. We also present a training model based on ergonomics which we have introduced into the training activities carried out in our Centre.

[Preliminary validation of the Simulap(®) physical simulator and its assessment system for laparoscopic surgery]. / Validación preliminar del simulador físico Simulap(®) y de su sistema de evaluación para cirugía laparoscópica.

INTRODUCTION: Our aim is to assess the face and content validities of the physical simulator Simulap(®), as well as the construct validity of its assessment method. MATERIAL AND METHODS: Five novice surgeons (G1) and five experts (G2) performed seven basic tasks and one suturing exercise on Simulap(®), which were assessed through an exam based on mistakes and performance time. Face and content validations were carried out by novice surgeons and expert surgeons, respectively. Both validations consisted of a questionnaire graded on a five-point scale about the Simulap(®) and its tasks. Construct validity of the assessment system was determined by comparing the scores of both groups. RESULTS: Surgeons rated the Simulap(®) simulator and its training program positively, obtaining an average score of 4±1.1 for G1 and of 4.9±0.6 for G2. G2 considered training on Simulap(®) very useful for the training of residents and surgeons, obtaining a maximum score of 5. G2 outperformed G1 in all task scores, with statistically significant differences in the eye-hand coordination (G1: 52.2±6.7 vs. G2: 39.6±6.5; P=.027), dissection (G1: 301.8±100.2 vs. G2: 150.8±66.7; P=.028) and suturing exercises (G1: 258.5±87.0 vs. G2: 108.4±20.2; P=.009). CONCLUSIONS: The assessment method for Simulap(®) is able to distinguish different levels of experience in laparoscopic surgery. Furthermore, this simulator showed a great acceptance by surgeons for the learning of basic skills.

Construct and face validity of SINERGIA laparoscopic virtual reality simulator.

PURPOSE: Laparoscopic techniques have nowadays become a gold standard in many surgical procedures, but they imply a more difficult learning skills process. Simulators have a fundamental role in the formative stage of new surgeons. This paper presents the construct and face validity of SINERGIA laparoscopic virtual reality simulator in order to decide whether it can be considered as an assessment tool. METHODS: Twenty people participated in this study, 14 were novices and 6 were experts. Five tasks of SINERGIA were included in the study: coordination, navigation, navigation and touch, precise grasping and coordinate traction. For each one of these tasks, a certain number of metrics are automatically recorded. All subjects accomplished each task only once and filled in two questionnaires. A statistical analysis was made and results from both groups were compared with the Mann-Whitney U-test, considering significant differences when P < or = 0.05. Internal consistency of the system has been analyzed with the Cronbach's alpha test. RESULTS: Novices and experts positively rated SINERGIA characteristics. At least one of the evaluated metrics of each exercise presented significant differences between both groups. Nevertheless, all metrics under study gave a better punctuation to the executions accomplished by experts (lower time, higher efficiency, fewer errors. . .) than to those made by novices. CONCLUSION: SINERGIA laparoscopic virtual reality simulator is able to discriminate subjects according to their level of experience in laparoscopic surgery; therefore, it can be used within a training program as an assessment tool.

[Ultrasonographic histological study on the evolution of a canine model of hormone-induced benign prostatic hyperplasia]. / Estudio ultrasonográfico e histológico de la evolución de un modelo canino de hiperplasia benigna de próstata inducida por hormonas.

INTRODUCTION: Despite exhibiting histological differences from the human process, canine hormone-induced benign prostatic hyperplasia (BPH) is still the most widely used animal model for evaluating treatment strategies. OBJECTIVES: The aim of this study is to determine the optimal moment for starting a therapeutic trial in this animal model. MATERIAL AND METHODS: Six male beagle dogs over one year of age were used in this study. All animals received a combination of steroid hormones, namely 17beta-estradiol and 5alpha-androstene 3alpha 17beta-diol, every other day during three (Group 1, n=3) or five months (Group 2, n=3). Transrectal ultrasonographic examinations to measure prostate volume were performed monthly. Animals were euthanized after five months for histological study of their prostates. RESULTS: All animals developed BPH, with prostate volume increasing over time as hormones were administered (r=0,910). All ultrasonographic studies performed up to the third month evidenced a significant increase in prostate volume when compared to the prior ultrasound measurement. A significant decrease in prostate volume was seen in Group 1 once hormone administration was interrupted, whereas Group 2 animals showed a continuing increase in prostate size. Histological examination showed almost no evidence of BPH in Group 1 animals, while Group 2 animals clearly exhibited moderate epithelial hyperplasia. CONCLUSIONS: The administration of a combination of steroid hormones is effective in inducing benign prostatic hyperplasia in canines, but this hyperplasia disappears when hormone treatment is interrupted. In order to be useful for experimental studies, hormones should be administered for at least three months before commencing any treatment, and they should be continued throughout the length of the study..

[Titanium metallic clips: easier and faster than conventional suturing for heterotopic renal autotransplant in growing pigs]. / Clips metálicos de titanio: una técnica de sutura más rápida y fácil de utilizar que las suturas convencionales en autotrasplantes renales heterotópicos en cerdos en crecimiento.

INTRODUCTION: When performing vascular reconstruction in growing elements, specifically in paediatric transplant surgery, where a short vascular occlusion time is mandatory, master and easily handled suturing methods are needed. Thus the present study compares conventional continuous suturing with polypropylene and dexon versus easier and faster to apply titanium clips in heterotopic renal autotransplants. MATERIAL AND METHODS: 24 growing pigs were used for this study. Heterotopic renal autotransplant was performed when the animals were 45-days-old using VCS clips, continous Polypropylene or Dexon suturing when anastomosing the renal artery and vein to the aorta and cava in an end-to-side fashion RESULTS: VCS clips were easy to use for the surgeon, significantly (P < or = 0.001) decreasing the time needed for end-to-side anastomosis of the renal artery to the aorta (clips, 5.31 +/- 0.80 min/Polypropylene, 14.25 +/- 2.25 min/Dexon, 14.37 +/- 2.97 min); and also the time needed for end-to-side anastomosis of the renal veins to the cava (clips, 8.25 +/- 1.98 min/Polypropylene, 16.25 +/- 2.96 min/Dexon, 19.00 +/- 4.50 min). CONCLUSIONS: The use of VCS clips in heterotopic renal autotransplants significantly decreases the time needed for vascular reconstruction, compared to conventional suturing.

Physiological responses to different ischemic periods during laparoscopic infrarenal aortic cross-clamping: evaluation in an experimental animal model.

Our aim was to study the physiological repercussions of varying ischemic times during laparoscopic aortic surgery. After quarantine, laparoscopy was performed in 24 healthy pigs, which were randomly allocated to four study groups: group I (n=6), laparoscopic infrarenal abdominal aortic surgery with 30 min of crossclamping; group II (n=6), laparoscopic infrarenal abdominal aortic surgery with 60 min of cross-clamping; group III (n=6), laparoscopic infrarenal abdominal aortic surgery with 120 min of cross-clamping; group IV (n=6), 120 min pneumoperitoneum in the absence of aortic cross-clamping (control group). Hematological, biochemical, hormone, hemodynamic, and ventilatory studies were conducted during and after surgery; and a postoperative neurological evaluation was performed 10 days after surgery. Group III evidenced an increase in arterial blood pressure and heart rate that was significantly higher than those present in the other groups. Significant decreases in pH were observed in groups II and III, whereas no changes in this parameter were seen in groups I and IV. Catecholamine levels during surgery were similar in all groups (a significant [p<0.001] increase in plasmatic adrenaline and noradrenaline was seen immediately after pneumoperitoneum creation in all groups). A positive association was found between the duration of aortic clamping and hormone values at 30 and 60 min after declamping but not after 24hr. A significant increase in the renal resistive index (RRI) and a significant decrease in urine output were evidenced during laparoscopy, with significantly lower RRI values seen in group IV immediately after surgery. Thus, a synergic effect of pneumoperitoneum and aortic cross-clamping was seen in this study. These two factors together cause a hemodynamic compromise, with decreased renal perfusion and acidosis, thus negatively affecting the patient's general state during this type of surgery. Despite being well tolerated in healthy pigs, a laparoscopic aortic cross-clamping time over 60min produces significant hemodynamic, metabolic, and hormonal changes. Careful patient selection is mandatory to avoid any severe complications.

[Training design and improvement of technical skills in the transvaginal cholecystectomy (NOTES)]. / Diseño del entrenamiento y la adquisición de habilidades técnicas en la colecistectomía transvaginal (NOTES).

INTRODUCTION: The current surgical scenario of the surgery through natural orifices or <> requires acquiring new technical skills by the surgeon. We introduce the initial experience of the Minimally Invasive Surgery Centre Jesús Usón (MISCJU) in the design and setting-up of a surgical training programme using the the natural orifices approach for the acquisition of surgical skills and abilities, based on the preliminary trials in simulators and a pig model. MATERIAL AND METHODS: After initial training, using a laparoscopic pelvic-trainer, 7 female pigs, with weights between 35-40 kg, were operated on. The transvaginal approach was completed using a one-channel gastroscope in all the animals. After accessing the abdomen, the abdominal cavity was explored, and the surgery was concluded with the endoscopic cholecystectomy. RESULTS: Endoscopic cholecystectomy was successfully completed in 6 cases. In one of the animals, the procedure was stopped because of technical problems regarding the endoscope leaning to one end. The average surgical time was 107.14 min (range, 80-150 min). The transvaginal approach enabled the abdominal to be explored and the dissection, ligature and section of the cystic duct and the cystic artery. After cholecystectomy, the gallbladder was extracted through the vagina. After the procedure necropsy did not reveal intra-abdominal lesions or intraoperative complications. CONCLUSIONS: The pure transvaginal cholecystectomy is a feasible and reproducible procedure in the animal model. A systematized training model, which includes physiopathology knowledge as well as technical knowledge, in order to translate these procedures to the clinical practice in a safe way, is needed.

Physiologic Responses to Infrarenal Aortic Cross-Clamping during Laparoscopic or Conventional Vascular Surgery in Experimental Animal Model: Comparative Study.

The aim of this study was to compare the hemodynamic and ventilatory effects of prolonged infrarenal aortic cross-clamping in pigs undergoing either laparotomy or laparoscopy. 18 pigs were used for this study. Infrarenal aortic crossclamping was performed for 60 minutes in groups I (laparotomy, n = 6) and II (laparoscopy, n = 6). Group III (laparoscopy, n = 6) underwent a 120-minute long pneumoperitoneum in absence of aortic clamping (sham group). Ventilatory and hemodynamic parameters and renal function were serially determined in all groups. A significant decrease in pH and significant increase in PaCO(2) were observed in group II, whereas no changes in these parameters were seen in group I and III. All variables returned to values similar to baseline in groups I and II 60 minutes after declamping. A significant increase in renal resistive index was evidenced during laparoscopy, with significantly higher values seen in Group II. Thus a synergic effect of pneumoperitoneum and aortic cross-clamping was seen in this study. These two factors together cause decreased renal perfusion and acidosis, thus negatively affecting the patient's general state during this type of surgery.