Task-specific Errors Research Articles

Resident Performance on the Fundamentals of Arthroscopic Surgery Training Workstation Does Not Predictably Improve With Postgraduate Year

PurposeThe purpose of this study was to identify differences in performance on the Fundamentals of Arthroscopic Surgery Training (FAST) workstation between residents across different post-graduate years and training sites. MethodsDuring the 2018-2019 academic year, 102 orthopaedic surgery residents from four training sites completed six FAST modules. Failure was defined as either completion time exceeding benchmark time, or commission of task-specific errors. With the exception of knot tying, participants completed each module twice—once with each hand serving as the camera hand. Time to completion (except for knot tying) and errors were recorded for each of the modules. Completion time and failure rates were compared between post-graduate years, seniority groups, and training sites. ResultsIn all modules for which time was recorded, except for the suture passage module, there was no significant difference in time to completion based on seniority (p < 0.01 for suture passage; p > 0.05 for all others). Significant differences in completion time were observed between sites for all modules except for the suture passage module (p = 0.957 for suture passage; p < 0.05 for all others). Site predicted failure by at least one measure (time or technical error) for all modules (p < 0.05) except for number probing and suture passage. Failure rate across training years varied for each module. ConclusionsTime to completion and rate of failure did not predictably decrease with level of training. Training site proved to be a significant predictor of performance. Factors such as hand dominance and familiarity with the equipment proved to be important considerations for some modules.

A direct comparison of two measures of ordinal knowledge among 8-year-olds

Children’s knowledge of the ordinal relations among number symbols is related to their mathematical learning. Ordinal knowledge has been measured using judgment (i.e., decide whether a sequence of three digits is in order) and ordering tasks (i.e., order three digits from smallest to largest). However, the question remains whether performance on these two ordinal tasks tap into similar cognitive processes. Canadian children (N = 87; Age M = 8.7 years, Grade 3) completed symbolic number tasks (i.e., number comparison, ordering, and order judgment) and measures of arithmetic fluency (i.e., addition and subtraction) and working memory (i.e., digit span backward). For both ordinal tasks, there was a reverse distance effect for ordered sequences such that children responded faster to adjacent than to non-adjacent sequences (e.g., 2 3 4 vs. 4 7 9) and a canonical distance effect for unordered sequences such that children responded faster to non-adjacent than to adjacent sequences (e.g., 4 2 3 vs. 4 9 7). Working memory and number comparison each predicted unique variance in the ordinal measures (ordering, order judgment, and a latent ordinal factor based on the two measures). Furthermore, ordinal skills superseded the role of number comparison as the key predictor of arithmetic, controlling for children’s gender and working memory skills. In summary, although both ordering and order judgment tasks index ordinal knowledge, a latent factor that excludes task-specific error may be a better index than either task separately.

Identification and evaluation of maintenance error in catalyst replacement using the HEART technique under a fuzzy environment

Objectives. A necessity for this study was felt in the catalyst replacement process as a maintenance operation, because some fatal incidents have occurred due to human error in process industries during catalyst replacement operation. Identification and evaluation of human error is essential in predicting and reducing accidents in maintenance operation. Methods. The human error assessment and reduction technique (HEART) as a human reliability analysis was applied in this study. Because the HEART method uses expert judgment, it is possible to make a bias in the assessment. Fuzzification and aggregation opinions of a heterogeneous expert group in a trapezoidal fuzzy set were used to mitigate this deficiency. Results. Evaluation results showed that the subtask ‘Entering the reactor’ with human error probability (HEP) of 9.2E–1 and the subtask ‘Reduce temperature while reducing feed’ with HEP 1.3E–3 had the highest and lowest chance of human error, respectively. Conclusions. In order to reduce the likelihood of human error, it is necessary to take appropriate actions based on the task-specific error producing condition (EPC).

Comparison of laparoscopic surgical skills acquired on a virtual reality simulator and a box trainer: an analysis for obstetrics-gynecology residents

Background/Aims: It is well known that laparoscopic surgery requires the demonstration of a different set of technical skills when compared to open surgery. Laparoscopic training using simulators has been shown to accelerate learning in an efficient and standardized manner. Significant research has been conducted for skills acquisition in abdominal surgery, but in the field of gynecologic laparoscopy the relevant studies are limited. The aim of this study was to compare the training efficacy of virtual reality (VR) simulators and box-trainers (BTs) for skills acquisition in gynecologic surgery, and also to study the transferability of these skills in the performance of more advanced gynecologic operations. Methods: Twenty residents in obstetrics-gynecology with minimal laparoscopic experience were randomized into two equal groups to be trained on either a VR simulator (Group-A) or a BT (Group-B). Group-A was trained on basic tasks (clipping, peg transfer, and cutting), whereas Group-B was trained on ovarian cystectomy and salpingotomy using custom training models. After training, the two groups were assessed on the performance of two laparoscopic gynecologic procedures on a VR simulator (salpingotomy and salpingectomy). Performance metrics included time, instrument pathlength, and various task-specific errors. Results: Both groups demonstrated significant performance improvement in all training tasks, for all but one of the metrics (p &lt; 0.05). After training, both groups had improved performance in the laparoscopic operations using the VR simulator, but this trend was not statistically significant in any metric considered (p &gt; 0.05). Similarly, the post-training performance between the two groups was not statistically different (p &gt; 0.05). Conclusions: Basic skills training on either a VR simulator or BT results in equivalent but not statistically significant performance improvement with more advanced gynecologic laparoscopic tasks on a VR simulator.

Reviving the inter-laboratory comparison measurement results

Key comparison measurements serve as an ultimate tool of quality assurance of results. Whenever the inter-comparison results indicate inconsistency, the participating laboratory needs to take the corrective actions. Practically, the systematic errors involved in the measuring system confines the achievable accuracy. Therefore, the corrective action involves either empirically determine the influences afresh or intuitively reassigns these error values. Alternatively, an analytical method based on inter laboratory comparison results is proposed. The novelty of the proposal is considering task-specific errors in the model that is used for the analysis of interlaboratory comparison results. Without accounting the uncertainties of task-specific errors, the analysis grows complicated and even sometimes it is not feasible. To supplement the proposed method, task-specific errors due to the imperfect geometry of ring gauge, practical inability in implementing the measurement, and unattended environmental influences are explored. The proposed method is demonstrated using some internal diameter key comparison data. The systematic errors responsible for the outlier in the measurement comparison are clearly distinguished.

Potential Errors in Forensic Medicine Practice: Case reports and literature review

In Egypt, the Forensic Medicine profession is a multidisciplinary medical specialty that mainly deals with the examination of deceased persons suspected to have been injured or killed by external influence such as trauma or intoxication. In addition, clinical forensic medicine deals with living persons with violent injuries either intentional or accidental like those resulting from medical errors, sexual assaults or age determination. The forensic medical examiner may be confronted with challenging cases of burned, decomposed, or dismembered bodies. Although the legislation regarding forensic pathology differs between countries, a universal principle is that in the investigation of a possible or suspected criminal death, a forensic examiner is engaged through a formal request from the police or the prosecutor as a medical expert for justice. However, unlike many other medical specialties, malpractice in forensic medicine profession is an issue seldom presented in literature worldwide. The current study aim was to shed lights on some cases as different examples of potential forensic malpractice in Egypt. The five cases discussed indicated that there are several unique features of errors in the performance of medico-legal autopsies beside systematic legal errors that can all distort investigation outcome or interpretation with subsequent unjust sentences or decisions. Those task-specific errors need to be tackled by adopting efficient and different training and qualification policies alongside supporting legislation and financial aids for funding additional complementary facilities.

Flatness measurement of large flat with two-station laser trackers

We present a novel method to accurately measure the flatness of a large flat. The method can be seen as a task-specific error correction of the laser tracker. Laser trackers are positioned at two specific measuring stations and measure the coordinates of the same sample points. The angular errors of the primary laser tracker are compensated with constraint information provided by an additional laser tracker. Using this method, we measure the flatness of a 4.5 m flat. The flatness measurement uncertainty is 1.4 µm in rms (root mean square).

Virtual reality-based assessment of basic laparoscopic skills using the Leap Motion controller

The majority of the current surgical simulators employ specialized sensory equipment for instrument tracking. The Leap Motion controller is a new device able to track linear objects with sub-millimeter accuracy. The aim of this study was to investigate the potential of a virtual reality (VR) simulator for assessment of basic laparoscopic skills, based on the low-cost Leap Motion controller. A simple interface was constructed to simulate the insertion point of the instruments into the abdominal cavity. The controller provided information about the position and orientation of the instruments. Custom tools were constructed to simulate the laparoscopic setup. Three basic VR tasks were developed: camera navigation (CN), instrument navigation (IN), and bimanual operation (BO). The experiments were carried out in two simulation centers: MPLSC (Athens, Greece) and CRESENT (Riyadh, Kingdom of Saudi Arabia). Two groups of surgeons (28 experts and 21 novices) participated in the study by performing the VR tasks. Skills assessment metrics included time, pathlength, and two task-specific errors. The face validity of the training scenarios was also investigated via a questionnaire completed by the participants. Expert surgeons significantly outperformed novices in all assessment metrics for IN and BO (p < 0.05). For CN, a significant difference was found in one error metric (p < 0.05). The greatest difference between the performances of the two groups occurred for BO. Qualitative analysis of the instrument trajectory revealed that experts performed more delicate movements compared to novices. Subjects' ratings on the feedback questionnaire highlighted the training value of the system. This study provides evidence regarding the potential use of the Leap Motion controller for assessment of basic laparoscopic skills. The proposed system allowed the evaluation of dexterity of the hand movements. Future work will involve comparison studies with validated simulators and development of advanced training scenarios on current Leap Motion controller.

A novel augmented reality simulator for skills assessment in minimal invasive surgery.

Over the past decade, simulation-based training has come to the foreground as an efficient method for training and assessment of surgical skills in minimal invasive surgery. Box-trainers and virtual reality (VR) simulators have been introduced in the teaching curricula and have substituted to some extent the traditional model of training based on animals or cadavers. Augmented reality (AR) is a new technology that allows blending of VR elements and real objects within a real-world scene. In this paper, we present a novel AR simulator for assessment of basic laparoscopic skills. The components of the proposed system include: a box-trainer, a camera and a set of laparoscopic tools equipped with custom-made sensors that allow interaction with VR training elements. Three AR tasks were developed, focusing on basic skills such as perception of depth of field, hand-eye coordination and bimanual operation. The construct validity of the system was evaluated via a comparison between two experience groups: novices with no experience in laparoscopic surgery and experienced surgeons. The observed metrics included task execution time, tool pathlength and two task-specific errors. The study also included a feedback questionnaire requiring participants to evaluate the face-validity of the system. Between-group comparison demonstrated highly significant differences (<0.01) in all performance metrics and tasks denoting the simulator's construct validity. Qualitative analysis on the instruments' trajectories highlighted differences between novices and experts regarding smoothness and economy of motion. Subjects' ratings on the feedback questionnaire highlighted the face-validity of the training system. The results highlight the potential of the proposed simulator to discriminate groups with different expertise providing a proof of concept for the potential use of AR as a core technology for laparoscopic simulation training.

Construct validity of individual and summary performance metrics associated with a computer-based laparoscopic simulator

Computer-based surgical simulators capture a multitude of metrics based on different aspects of performance, such as speed, accuracy, and movement efficiency. However, without rigorous assessment, it may be unclear whether all, some, or none of these metrics actually reflect technical skill, which can compromise educational efforts on these simulators. We assessed the construct validity of individual performance metrics on the LapVR simulator (Immersion Medical, San Jose, CA, USA) and used these data to create task-specific summary metrics. Medical students with no prior laparoscopic experience (novices, N=12), junior surgical residents with some laparoscopic experience (intermediates, N=12), and experienced surgeons (experts, N=11) all completed three repetitions of four LapVR simulator tasks. The tasks included three basic skills (peg transfer, cutting, clipping) and one procedural skill (adhesiolysis). We selected 36 individual metrics on the four tasks that assessed six different aspects of performance, including speed, motion path length, respect for tissue, accuracy, task-specific errors, and successful task completion. Four of seven individual metrics assessed for peg transfer, six of ten metrics for cutting, four of nine metrics for clipping, and three of ten metrics for adhesiolysis discriminated between experience levels. Time and motion path length were significant on all four tasks. We used the validated individual metrics to create summary equations for each task, which successfully distinguished between the different experience levels. Educators should maintain some skepticism when reviewing the plethora of metrics captured by computer-based simulators, as some but not all are valid. We showed the construct validity of a limited number of individual metrics and developed summary metrics for the LapVR. The summary metrics provide a succinct way of assessing skill with a single metric for each task, but require further validation.

Feedback-dependent generalization

Generalization provides a window into the representational changes that occur during motor learning. Neural network models have been integral in revealing how the neural representation constrains the extent of generalization. Specifically, two key features are thought to define the pattern of generalization. First, generalization is constrained by the properties of the underlying neural units; with directionally tuned units, the extent of generalization is limited by the width of the tuning functions. Second, error signals are used to update a sensorimotor map to align the desired and actual output, with a gradient-descent learning rule ensuring that the error produces changes in those units responsible for the error. In prior studies, task-specific effects in generalization have been attributed to differences in neural tuning functions. Here we ask whether differences in generalization functions may arise from task-specific error signals. We systematically varied visual error information in a visuomotor adaptation task and found that this manipulation led to qualitative differences in generalization. A neural network model suggests that these differences are the result of error feedback processing operating on a homogeneous and invariant set of tuning functions. Consistent with novel predictions derived from the model, increasing the number of training directions led to specific distortions of the generalization function. Taken together, the behavioral and modeling results offer a parsimonious account of generalization that is based on the utilization of feedback information to update a sensorimotor map with stable tuning functions.