Development of a novel 3D-printed multifunctional thorax model simulator for the simulation-based training of tube thoracostomy.

Tube thoracostomy is a high-acuity, low-occurrence (HALO) procedure with significant morbidity when performed incorrectly; this is amendable through simulation. Commercially available trainers exist but often have limited realism or exorbitant cost. Three-dimensional (3D) printing produces realistic and cost-effective models suitable for simulation, but no simulator has been developed for tube thoracostomy. The aim of this paper is to describe the initial development of a multifunctional 3D-printed thorax trainer for the instruction of tube thoracostomy. The thorax model was developed in conjunction with a multi-disciplinary team using 3D-printing capable software. An existing ribcage model was modified and printed in separate elements, including bony portions (ribcage, sternum and clavicles), flexible joints, skin, heart and lungs and then assembled. The total printing cost was $180 CAD. Future research will focus on incorporating the model's ability to simulate other HALO procedures and evaluating it as a training adjunct.

RéSUMé: La thoracostomie par tube est une procédure de haute acuité et de faible occurrence (HALO) avec une morbidité significative lorsqu'elle est mal exécutée; ceci est modifiable par simulation. Il existe des formateurs disponibles dans le commerce, mais ils sont souvent d'un réalisme limité ou d'un coût exorbitant. L'impression tridimensionnelle (3D) produit des modèles réalistes et rentables adaptés à la simulation, mais aucun simulateur n'a été développé pour la thoracostomie tubulaire. L'objectif de ce document est de décrire le développement initial d'un simulateur de thorax multifonctionnel imprimé en 3D pour l'enseignement de la thoracostomie tubulaire. Le modèle du thorax a été développé en collaboration avec une équipe pluridisciplinaire utilisant un logiciel capable d'imprimer en 3D. Un modèle de cage thoracique existant a été modifié et imprimé en éléments séparés, comprenant des parties osseuses (cage thoracique, sternum et clavicules), des articulations souples, la peau, le cœur et les poumons, puis assemblé. Le coût total d'impression était de 180 $ CAN. Les recherches futures se concentreront sur l'incorporation de la capacité du modèle à simuler d'autres procédures HALO et à l'évaluer en tant que complément de formation.

Long-Term Exposure to Ambient Air Pollution in Childhood-Adolescence and Lung Function in Adulthood.

The aim of the study was to evaluate the effect of air pollution in the dwelling place during childhood-adolescence on respiratory function in early adulthood. The study was conducted in 220 female and 160 male university undergraduates in the cities of Cracow and Wroclaw in Poland and consisted of spirometry to assess lung function. The subjects' exposure to pollution during childhood-adolescence was assessed from the data acquired by the Polish Chief Inspectorate for Environmental Protection. We found differences in all spirometry variables depending on benz[a]piren exposure, in FVC% and FEV1/%FVC depending on PM2.5 content, and in FVC% depending on NO2 content. Statistically significant differences in spirometry variables were also found in relation to the degree of urbanization of the place of living during the early life period in question. The higher the urbanization, the higher is FEV1% and FCV%, and the lower FEV1/%FVC. Additionally, undergraduates of Cracow University had worse lung function compared to those of Wroclaw University. In conclusion, air pollution in the dwelling place during childhood-adolescence has an impact on lung function in early adulthood, independently of the current exposure to pollutants.

Influence of Socioeconomic and Anthropometric Factors on Respiratory Function in Female University Students.

The purpose of this study was to evaluate lung function in healthy young female university students and to seek the relation of lung function to socioeconomic and anthropometric indices. The methodology consisted of spirometry tests, anthropometric measures and a questionnaire conducted in November of 2015 among 152 female university students. At first, lung function was analyzed for any relationship with socioeconomic factors and smoking. The results of a multi-factor analysis of variance demonstrate significant differences in the FEV1/FVC ratio depending on the general socioeconomic status. Then, anthropometric and spirometric parameters were tested for correlations. A comparison of underweight, normal weigh, overweight, and obese subjects revealed statistically significant differences for FVC% and FEV1/FVC, with the highest values noted in the subjects of normal weight. Individuals with abdominal obesity had lower FVC% and FEV1% and a higher FEV1/FVC ratio. The findings of our study confirm that both general obesity and abdominal obesity are related to a reduced lung function.

A model of cardiopulmonary bypass staged training integrating technical and non-technical skills dedicated to cardiac trainees.

OBJECTIVES: To develop a standardized simulation-based curriculum to teach medical knowledge and technical, communication and critical thinking skills necessary to initiate and wean from cardiopulmonary bypass (CPB) to junior cardiac trainees (CTs) in France. Performance on post-curricular tests was compared between CTs who participated in the new curriculum to those who did not. METHODS: The simulation-based curriculum was developed by content and education experts. Simulations sequentially taught the skills necessary for initiating and weaning from CPB as well as managing crises by adding fidelity and complexity to scenarios. Nine CTs were randomly assigned to the new curriculum (n=5) or the traditional curriculum (n=4). Skills were assessed using tests of medical knowledge and technical, communication (GRS) and critical thinking (SCT) skills. A two-sample Wilcoxon rank-sum test compared average scores between the two groups. Alpha of 0.05 was set to indicate statistically significant differences. RESULTS: The resutls revealed that CTs in the new curriculum significantly outperformed CTs in the traditional curriculum on technical (18.2 vs 14.8, p=0.05) and communication (3.5 vs 2.2, p=0.013) skills. There was no significant difference between CTs in the new curriculum in the Script Concordance Test (16.5 vs 14.8, p=0.141) and knowledge tests (26.9 vs 24.6, p=0.14) compared to CTs in the traditional curriculum. CONCLUSION: Our new curriculum teaches communication and technical skills necessary for CPB. The results of this pilot study are encouraging and relevant. They give grounds for future research with a larger panel of trainees. Based on the current distribution of scores, a sample size of 12 CTs per group should yield significant results for all tests.

What skills should simulation training in arthroscopy teach residents? A focus on resident input.

PURPOSE:    Our purpose was to identify what surgical skills trainees consider important to possess before performing in the operating room and the components of an optimal simulator. METHODS:    An online survey composed of 35 questions was completed by 67 orthopedic residents from across Canada. The questions examined the opinions of residents for their perspective on what constitutes an optimal design of an arthroscopic simulator. RESULTS:    The average year of residency of the respondents was 3.2, and the average number of arthroscopies assisted on was 66.1 with a range of 0-300. Identification of structures and navigation of the arthroscope were ranked highly in terms of importance for trainee surgeons to possess before performing in the operating room. Higher fidelity simulation models such as cadaveric specimens or the use of synthetic knees were preferred over lower fidelity simulation models such as virtual reality simulators or bench top models. CONCLUSION:    The information from trainees can be used in the development of a simulator for medical education as well as program and curriculum design. The report also highlights the importance of the pre-RCT phases leading to the development of the most effective simulation programs.

Application of motor learning principles to complex surgical tasks: searching for the optimal practice schedule.

Practice of complex tasks can be scheduled in several ways: as whole-task practice or as practice of the individual skills composing the task in either a blocked or a random order. The authors used those 3 schedules to study 18 participants' learning of an orthopedic surgical task. They assessed learning by obtaining expert evaluation of performance and objective kinematic measures before, immediately after, and 1 week after practice (transfer test). During acquisition, the blocked group showed superior performance for simple skills but not for more complex skills. For the expert-based measures of performance, all groups improved from pretest to posttest and remained constant from posttest to transfer. Measures of the final product showed that the whole-practice group's outcomes were significantly better than those of the random group on transfer. All groups showed better efficiency of motions in the posttest than in the pretest. Those measures were also poorer on the transfer test than on the posttest. The present evidence does not support the contextual interference effect--hypothetically, because of the inherent cognitive effort effect associated with some of the component skills. The authors recommend that surgical tasks composed of several discrete skills be practiced as a whole. The results of this study demonstrate the importance of critically appraising basic theories in applied environments.

Quantification of process measures in laparoscopic suturing.

BACKGROUND: Process measures describing the generation of movement are useful for evaluation and performance feedback purposes. This study aimed to identify process measures that differ between novice and advanced laparoscopists while completing a suturing skill. METHODS: A group of junior and a group of senior residents and fellows in surgery (n = 6) placed 10 laparoscopic sutures in a synthetic model. Process measures were quantified using an opto-electric motion/force sensor assembly that recorded: instrument rotation, applied forces, time, and time delays between force application and instrument rotation. RESULTS: Advanced trainees showed increased instrument rotation, higher peak applied force, and faster performance compared to novices (alll p < .01). However, over trials, only novices showed adaptations for instrument rotation and total time (interactions at p < .01) with no adaptation for the force application. The difference between the moments of force application and instrument rotation was not sensitive to participant training. CONCLUSIONS: Movement process measures can enhance our understanding of early adaptation processes and how such factors might be used as feedback to facilitate skill acquisition.

Structural flexibility of laparoscopic instruments: implication for the design of virtual reality simulators.

Laparoscopic training, under simulated settings, benefits from high fidelity models of the actual environment. This study was aimed at reducing uncertainty in the displacement and loads experienced by a laparoscopic instrument during surgical training. Infrared tracking of laparoscopic instruments is ineffective when real tissues attenuate the infrared signals. Incorporating the use of strain gauges for tip deflection measurements allows for online motion and load tracking during a procedure. Strain gauge voltages and infrared markers indicating displacement were both linear with respect to loads up to 700 grams. The resultant strain gauge voltage was equated to deflection values with a calibration constant. The results serve two purposes. First, it may enable the tracking and analysis of the skill level of novice surgeons using bench models. Second, the mechanical model of each instrument can be quantified and incorporated into virtual simulations, thus increasing model fidelity, effectively leading to better learning.

Surface exploration using laparoscopic surgical instruments: the perception of surface roughness.

During laparoscopic surgery video images are used to guide the movements of the hand and instruments, and objects in the operating field often obscure these images. Thus, surgeons often rely heavily on tactile information (sense of touch) to help guide their movements. It is important to understand how tactile perception is affected when using laparoscopic instruments, since many surgical judgements are based on how a tissue 'feels' to the surgeon, particularly in situations where visual inputs are degraded. Twelve naïve participants used either their index finger or a laparoscopic instrument to explore sandpaper surfaces of various grits (60, 100, 150 and 220). These movements were generated with either vision or no vision. Participants were asked to estimate the roughness of the surfaces they explored. The normal and tangential forces of either the finger or instrument on the sandpaper surfaces were measured. Results showed that participants were able to judge the roughness of the sandpaper surfaces when using both the finger and the instrument. However, post hoc comparisons showed that perceptual judgements of surface texture were altered in the no vision condition compared to the vision condition. This was also the case when using the instrument, compared to the judgements provided when exploring with the finger. This highlights the importance of the completeness of the video images during laparoscopic surgery. More normal and tangential force was used when exploring the surfaces with the finger as opposed to the instrument. This was probably an attempt to increase the contact area of the fingertip to maximize tactile input. With the instrument, texture was probably sensed through vibrations of the instrument in the hand. Applications of the findings lie in the field of laparoscopic surgery simulation techniques and tactile perception.

The coordination of hand transport and grasp formation during single- and double-perturbed human prehension movements.

We investigated the mechanisms underlying human prehension movements, by perturbing the size and position of virtual targets. Subjects grasped virtual target discs with thumb and index finger. In 25% of trials, target size or position (single perturbation), or both (double perturbation) were changed 300 ms after target appearance. The experiments were designed such that the kinematic profiles of grasp formation and hand transport had a similar shape, and were analysed by the same algorithm. We found that grasp kinematics were influenced by changes of target position, and transport kinematics by changes of target size; we also found that the kinematics of double-perturbation trials could not be explained as a linear combination of single-perturbation effects. These findings confirm and expand previous evidence against the view that grasp and transport are controlled by fully independent channels. Most importantly, we found that the time of correction onset was not the same for grasp and transport, neither in single- nor in double-perturbation trials. This outcome argues against a holistic (single-channel) model of prehension; instead, our data are consistent with the notion of two mutually coupled channels.

Control strategies when intercepting slowly moving targets.

In 3 experiments, the authors investigated and described how individuals control manual interceptive movements to slowly moving targets. Participants (N = 8 in each experiment) used a computer mouse and a graphics tablet assembly to manually intercept targets moving across a computer screen toward a marked target zone. They moved the cursor so that it would arrive in the target zone simultaneously with the target. In Experiment 1, there was a range of target velocities, including some very slow targets. In Experiment 2, there were 2 movement distance conditions. Participants moved the cursor either the same distance as the target or twice as far. For both experiments, hand speed was found to be related to target speed, even for the very slowly moving targets and when the target-to-cursor distance ratios were altered, suggesting that participants may have used a strategy similar to tracking. To test that notion, in Experiment 3, the authors added a tracking task in which the participants tracked the target cursor into the target zone. Longer time was spent planning the interception movements; however, there was a longer time in deceleration for the tracking movements, suggesting that more visually guided trajectory updates were made in that condition. Thus, although participants scaled their interception movements to the cursor speed, they were using a different strategy than they used in tracking. It is proposed that during target interception, anticipatory mechanisms are used rather than the visual feedback mechanism used when tracking and when pointing to stationary targets.

Task dependent processing of visual information about target acceleration.

The objective of this study was to investigate the sensitivity of the perceptual and motor systems to target acceleration information using verbal magnitude estimations of target acceleration and manual interception of these targets. The results showed that in the perceptual task the participants were responding mainly to acceleration threshold values, which is acceleration as a function of initial, final, and average velocities, rather then to the absolute accelerations. When manually intercepting the targets the participants responded mainly to the absolute acceleration value and target initial velocity. Thus, these results suggest that target motion can be processed in the ventral (perception) and dorsal (action) visual streams however different motion characteristics are processed in these streams depending on the required output.

Target velocity effects on manual interception kinematics.

Participants generated manual interception movements toward a target cursor that moved across a computer screen. The target reached its peak velocity either during the first third, at the midpoint, or during the last third of the movement. In Experiment 1 the view of the target was available for either the first 316, 633, 950, or 1267 ms, after which it disappeared. Results showed that for all viewing conditions, the timing of the interception velocity was related to the temporal properties of the target's trajectory. In Experiment 2, when the portion of the target trajectory that was viewed was reversed (such that participants did not see the first 316, 633, 950, or 1267 ms of the trajectory, but instead saw only the later portions of the trajectory), there was no clear relationship between the target trajectory and the timing of the aiming trajectory. These results suggest that participants use visual information early in the target's trajectory to form a representation of the target motion that is used to facilitate manual interception.

The effect of illusory size on force production when grasping objects.

Milner and Goodale (1995) have proposed that visuomotor and perceptual processes are mediated by discrete visual systems that reflect the functional independence of action and perception. The visuomotor system is proposed to be insensitive to pictorial illusions of object size, whereas the perceptual system is reliably "tricked" by such figures. Brenner and Smeets (1996) and Jackson and Shaw (2000) demonstrated that grasp preshaping, but not grasping force, is immune to the Ponzo visual illusion, suggesting that not all visuomotor processes operate independently of the perceptual system. The present study investigated the effect of illusory object size on prehension kinematics and grasping dynamics (i.e., grip force and load force) as well as perceptual judgements of object size. Unlike previous investigations, object mass was held constant independent of changes in size. The Ponzo figure reliably affected perceptual estimates of object size, but this effect was restricted to one form of the illusion. Some aspects of the prehension movement were sensitive to veridical but not illusory object size (peak grip aperture, peak grip force, peak vertical wrist acceleration), whereas other movement parameters demonstrated illusory size effects (movement time, peak wrist velocity). Still other movement parameters were not sensitive to veridical or illusory object size (peak load force). Together the data suggest that certain prehension components are immune to pictorial illusions of object size, whereas others are not. Complex interactions between the perceptual and visuomotor systems appear to underlie the anticipatory scaling of grasping forces in prehension.