Julián Varas

Anatomic hepatectomy as a definitive treatment for hepatolithiasis: a cohort study

BACKGROUND Treatment requirements in hepatolithiasis may vary and may involve a multidisciplinary approach. Surgical resection has been proposed as a definitive treatment. OBJECTIVES This study aimed to evaluate the clinical results of anatomic liver resection among Chilean patients with hepatolithiasis. METHODS An historical cohort study was conducted. Patients who underwent hepatectomy as a definitive treatment for hepatolithiasis from January 1990 to December 2010 were included. Patients with a preoperative diagnosis of cholangiocarcinoma were excluded. Preoperative, operative and postoperative variables were evaluated. RESULTS A total of 52 patients underwent hepatectomy for hepatolithiasis. The mean ± standard deviation patient age was 49.8 ± 11.8 years (range: 24-78 years); 65.4% of study subjects were female. A total of 75.0% of subjects had a history of previous cholecystectomy. The main presenting symptom was abdominal pain (82.7%). Hepatic involvement was noted in the left lobe in 57.7%, the right lobe in 34.6% and bilaterally in 7.7% of subjects. The rate of postoperative clearance of the biliary tree was 90.4%. Postoperative morbidity was 30.8% and there were no postoperative deaths. Three patients had recurrence of hepatolithiasis, which was associated with Carolis disease in two of them. Overall 5-year survival was 94.5%. CONCLUSIONS Anatomic liver resection is an effective treatment in selected patients with hepatolithiasis and is associated with low morbidity and no mortality. At longterm follow-up, anatomic hepatectomy in these patients was associated with a lower rate of recurrence.

Effectiveness of learning advanced laparoscopic skills in a brief intensive laparoscopy training program.

BACKGROUND Intensive training programs arose from limitations in access to simulation centers. The aim of this study is to evaluate the effect and associated factors involved in an intensive course for learning advanced laparoscopic skills, which include validated teaching techniques. METHODS General surgeons and final-year residents were analyzed after completing an intensive 5-session advanced laparoscopy course. Initial (IA) and final assessment (FA) consisted in performing a jejunojejunal anastomosis in a live porcine model, measured using objective structured assessment of technical skill (OSATS) (GRS and SRS, that is, global rating scale and specific rating scale, respectively) and operative time (OT). The 3-session training was structured in a bench model with an ex vivo bowel. For the demographic analysis, 3 groups were defined according to the presentation of relevant changes in OSATS and in OT between IA and FA: group A, no changes; group B, change in 1 variable; and group C, change in both variables. RESULTS After the course, all 114 participants presented a significant improvement in OT (37 vs 24.6min, p < 0.001) and in OSATS; global rating scale (10.5 vs 16 points; p < 0.001) and Specific Rating Scale (8.5 vs 12.7 points; p < 0.001). In the IA, 70 (61%) participants completed the jejunojejunal anastomosis and 105(92%) in the FA (p < 0.01). In the FA, 56% of participants presented relevant changes in both variables (group C). This group was significantly younger (34 vs 45 vs 40y old; p < 0.001), had fewer years of surgical experience (2 vs 9 vs 5y; p < 0.001), and had a proportionally higher concentration of residents (p = 0.01). CONCLUSIONS This intensive course is set out as a viable alternative to teach basic skills in advanced laparoscopy in a short period of time, which is ideal for surgeons with difficult access to training centers. It remains necessary to establish the participant profile for which this type of course is most beneficial.

A Cadaveric Porcine Model for Assessment in Laparoscopic Bariatric Surgery—a Validation Study

BackgroundLaparoscopic Roux-en-Y gastric bypass (LRYGBP) is the most effective surgical therapy for morbid obesity. It is an advanced laparoscopic surgical procedure and has a protracted learning curve. Therefore, it is important to develop innovative ways of training and assessing surgeons. The aim of this study is to determine if a cadaveric porcine jejuno-jejunostomy model is an accurate way of assessing a surgeons technical skills by determining if a correlation exists with how he performs in the operating room.MethodsEight surgeons of varying experience performed a side-to-side stapled jejuno-jejunostomy on a cadaveric bench model before proceeding to perform the procedure on a real patient scheduled for LRYGBP. Performance was assessed using a motion tracking device, the Imperial College Surgical Assessment Device. Each procedure was recorded in video and scored by two blinded expert surgeons using procedure-specific rating scales.ResultsThe cadaveric bench model demonstrated concurrent validity with significant correlations between performance on the cadaveric model and patient for dexterity measures. Left-hand path length, r = 0.857 (median, 27, 41.3; P = 0.007), right-hand path length, r = 0.810 (median, 31.5, 60; P = 0.015) and total number of movements, r = 0.743 (median, 422, 637; P = 0.035). This correlation in performance was also demonstrated in the video rating scales, r = 0.727 (median, 13.2, 14.8; P = 0.041). No correlation was found in operative time (median, 541, 742; P = 0.071).ConclusionsThis study demonstrates the concurrent validity of the cadaveric porcine model, showing similar performances in surgeons completing a jejuno-jejunostomy on the cadaveric model and the patient.

Microsurgery Workout: A Novel Simulation Training Curriculum Based on Nonliving Models.

Background: Currently, there are no valid training programs based solely on nonliving models. The authors aimed to develop and validate a microsurgery training program based on nonliving models and assess the transfer of skills to a live rat model. Methods: Postgraduate year–3 general surgery residents were assessed in a 17-session program, performing arterial and venous end-to-end anastomosis on ex vivo chicken models. Procedures were recorded and rated by two blinded experts using validated global and specific scales (objective structured assessment of technical skills) and a validated checklist. Operating times and patency rates were assessed. Hand-motion analysis was used to measure economy of movements. After training, residents performed an arterial and venous end-to-end anastomosis on live rats. Results were compared to six experienced surgeons in the same models. Values of p < 0.05 were considered statistically significant. Results: Learning curves were achieved. Ten residents improved their median global and specific objective structured assessment of technical skills scores for artery [10 (range, 8 to 10) versus 28 (range, 27 to 29), p < 0.05; and 8 (range, 7 to 9) versus 28 (range, 27 to 28), p < 0.05] and vein [8 (range, 8 to 11) versus 28 (range, 27 to 28), p < 0.05; and 8 (range, 7 to 9) versus 28 (range, 27 to 29), p < 0.05]. Checklist scores also improved for both procedures (p < 0.05). Trainees were slower and less efficient than experienced surgeons (p < 0.05). In the living rat, patency rates at 30 minutes were 100 percent and 50 percent for artery and vein, respectively. Conclusions: Significant acquisition of microsurgical skills was achieved by trainees to a level similar to that of experienced surgeons. Acquired skills were transferred to a more complex live model.

The Role of Microsatellite Instability in Positive Margin Gastric Cancer Patients

Purpose. A positive resection margin (RM+) is acknowledged as a poor prognostic factor after gastrectomy. Microsatellite instability (MSI-H) gastric cancer has been identified as a subgroup of gastric cancer that may be associated with an improved prognosis. The aim of the study was an analysis of MSI status on patients with margin involvement after gastrectomy and examination of the association between MSI, margin status, and survival outcomes. Methods. From a large prospectively annotated surgical database we collected clinicopathological and survival data on patients who had undergone a potentially curative resection for gastric cancer. MSI status was assessed using a standard 5-marker quasi-monomorphic mononucleotide repeat panel. Patients who were R+ and either microsatellite stable (MSS) or MSI-H were identified and clinicopathological characteristics and disease specific survival was compared. Results. Three hundred and eighty-six patients were identified; 102 (26.4%) cancers were MSI-H. The proportion of R+ resections was not significantly different in MSS and MSI-H groups. For MSS patients 3-, 5-, and 10-year disease-specific survival rates were 9.1%, 0%, and 0%, respectively; for patients with MSI-H R+ tumors these were 38.5%, 30.8%, and 15.4%, respectively. In Cox analysis MSI-H, female gender, and T ≥3 were significantly associated with survival. Conclusions. Patients with MSI-H gastric cancer may have long-term survival despite R+ margin status. The molecular division of gastric cancer may be an important step in identifying possible tailored surgical treatments corresponding to clinical and pathological factors.

A Novel Perforator Flap Training Model Using a Chicken Leg

INTRODUCTION Living animal models are frequently used for perforator flap dissection training, but no ex vivo models have been described. The aim of this study is to present a novel nonliving model for perforator flap training based on a constant perforator in the chicken leg. METHODS A total of 15 chicken legs were used in this study. Anatomical dissection of the perforator was performed after its identification using ink injection, and in four of these specimens a perforator-based flap was raised. RESULTS The anatomical dissection revealed a constant intramuscular perforator with a median length of 5.7 cm. Median proximal and distal vessel diameters were 0.93 and 0.4 mm, respectively. The median dissection time was 77.5 minutes. CONCLUSION This study introduces a novel, affordable, and reproducible model for the intramuscular dissection of a perforator-based flap using an ex vivo animal model. Its consistent perforator and appropriate-sized vessels make it useful for training.

Allowing New Opportunities in Advanced Laparoscopy Training Using a Full High-Definition Training Box

Introduction. Simulated laparoscopy training is limited by its low-quality image. A high-definition (HD) laparoscopic training box was developed under the present necessity of simulating advanced surgery. Objective. To describe and test a new HD laparoscopic training box for advanced simulation training. Methods. We describe the features and image quality of the new training box. The simulator was tested and then evaluated by a group of 76 expert surgeons using a 4-item questionnaire. To assess the effectiveness of training using this simulation box, 15 general surgery residents were trained to perform a laparoscopic jejuno-jejunostomy in a validated simulation program. They were assessed with objective rating scales before and after the training program, and their results were compared with that of experts. Results. The training box was assembled using high-density fiberglass shaped as an insufflated abdomen. It has an adapted full-HD camera with a LED-based illumination system. A manually self-regulated monopod attached to the camera enables training without assistance. Of the expert surgeons who answered the questionnaire, 91% said that the simulation box had a high-quality image and that it was very similar to real laparoscopy. All residents trained improved their rating scores significantly when comparing their initial versus final assessment (P < .001). Their performance after completing the training in the box was similar to that of experts (P > .2). Conclusions. This novel laparoscopic training box presents a high-resolution image and allows training different types of advanced laparoscopic procedures. The simulator box was positively assessed by experts and demonstrated to be effective for laparoscopy training in resident surgeons.

Validation of a Visual-Spatial Secondary Task to Assess Automaticity in Laparoscopic Skills

INTRODUCTION Our objective was to assess reliability and validity of a visual-spatial secondary task (VSST) as a method to measure automaticity on a basic simulated laparoscopic skill model. In motor skill acquisition, expertise is defined by automaticity. The highest level of performance with less cognitive and attentional resources characterizes this stage, allowing experts to perform multiple tasks. Conventional validated parameters as operative time, objective assessment skills scales (OSATS), and movement economy, are insufficient to distinguish if an individual has reached the more advanced learning phases, such as automaticity. There is literature about using a VSST as an attention indicator that correlates with the automaticity level. METHODS Novices with completed and approved Fundamentals of Laparoscopic Surgery course, and laparoscopy experts were enrolled for an experimental study and measured under dual tasks conditions. Each participant performed the test giving priority to the primary task while at the same time they responded to a VSST. The primary task consisted of 4 interrupted laparoscopic stitches (ILS) on a bench-model. The VSST was a screen that showed different patterns that the surgeon had to recognize and press a pedal while doing the stitches (PsychoPsy software, Python, MacOS). Novices were overtrained on ILS until they reach at least 100 repetitions and then were retested. Participants were video recorded and then assessed by 2 blinded evaluators who measured operative time and OSATS. These scores were considered indicators of quality for the primary task. The VSST performance was measured by the detectability index (DI), which is a ratio between correct and wrong detections. A reliable evaluation was defined as two measures of DI with less than 10% of difference, maintaining the cutoff scores for performance on the primary task (operative time <110 seg and OSATS >17 points). RESULTS Novices (n = 11) achieved reliable measure of the test after 2 (2-5) repetitions on the preassessment and 3.75 (2-5) on the postassessment (p = 0.04); whereas laparoscopy experts (n = 4) did it after 3.5 (3-4) repetitions. Proficiency cutoff scores for the primary task were achieved on every measure for novices (prepost overtraining) and experts. Expert performance on VSST was DI 0.78 (0.69-0.87). Novice performance was significantly better on postassessment (DI-pre 0.48 [0.06-0.71] vs DI-post 0.78 [0.48-0.95], p = 0.003). Overtraining consisted in 140 (100-210) repetitions of ILS for all novices, made in 8 hours (3-15). By categorizing DI based on expert performance, novices with DI-post >0.65 achieved better OSATS score and less operative time than novices with DI-post<0.65 (p = 0.007 y, p = 0.089, respectively). CONCLUSION Measuring automaticity is feasible using a VSST. This instrument is reliable and has a face, content and construct validity. A DI over 0.65 may be a cutoff point correlated with high standard performance on the primary task. This instrument measures performance on laparoscopic skills, and along with conventional indicators, would better define advance levels of expertise. More studies are required applying this VSST to achieve external validity by reproducing our results.

Uniportal video-assisted thoracic surgery lobectomy using a novel perfused ex vivo simulation model

Simulation may provide a solution to acquire advanced skills in thoracic surgery, however to date there are no reports in the English literature about a perfused ex vivo model. We developed a low cost and hi fidelity model using an ex vivo in bloc heart and lung specimen from a swine. The swine was previously used in a non-thoracic experiment, so we extracted the lung and heart for this ex vivo based model to reduce animal use. The cost of the whole model is 70 USD and it can be reused many times changing the ex vivo tissue, so this model may help reduce the costs and animal use associated to this high complexity surgery.

Programa pionero para el entrenamiento de técnicas quirúrgicas en pregrado; propuesta de cambio en la forma de enseñanza

Introduccion La simulacion ha sido demostrada en el entrenamiento de tecnicas minimamente invasivas, faltando herramientas y programas validados para cirugia tradicional abierta. El objetivo de este estudio es analizar un programa de entrenamiento simulado en tecnica de sutura abierta basica para estudiantes de pregrado. Materiales y metodos Estudio experimental entre mayo y junio de 2014. Se seleccionaron estudiantes de pregrado de medicina, con poca experiencia en sutura (menor a 2 h) para participar en un programa de 6 sesiones (100 min c/u). Cada sesion conto con 5 tareas de dificultad progresiva: nudo manual y punto simple (PS), Donati (PD), intradermico interrumpido con nudo invertido (PI) e intradermicocontinuo (PIC). Estas son supervisadas por expertos-cirujanos quienes entregaron retroalimentacion (feedback) efectiva. Las evaluaciones pre-post fueron realizadas en funcion de videos analizados en ciego, utilizando pautas globales validadas (OSATS) y registro de tiempo para cada tarea. Los resultados de los alumnos fueron comparados a los de expertos. Analisis estadistico con test Wilcoxon y Mann-Whitney para variables no parametricas (p significativo Resultados Se seleccionaron 23 participantes, 65% hombres. En todos los procedimientos hubo mejoria significativa respecto a OSATS y disminucion de tiempo. En Nudo, OSATS [5 (5-6) vs. 23 (22-24), p Conclusion Los alumnos adquieren habilidad con entrenamiento simulado en el programa propuesto. Se demuestra validez de constructo al observar diferencias significativas de preentrenamiento vs. expertos en ambas mediciones. El programa descrito, es factible de ser implementado en la formacion de pregrado de medicina, permitiendo la adquisicion de competencias en habilidades tecnicas de sutura en modelo simulado, acercandose al nivel de un experto.