Validation and educational impact study of the NANEP high-fidelity simulation model for open preperitoneal mesh repair of umbilical hernia.

OBJECTIVE: The aim of the study was to develop, validate and analyze the educational impact of a high-fidelity simulation model for open preperitoneal mesh repair of an umbilical hernia. The number of surgical simulators available for training residents is limited. Primary for ethical reasons and secondary for the emerging pay-per-quality policies, practicing-on simulators rather than patients is considered gold standard. Validated full-procedural surgical models will become more and more important in training residents. Such models may assure that evidence-based standards regarding technical aspects of the procedures become integral part of the curriculum. Furthermore, they can be employed as a quality control of residents' skills (Fonseca et al. in J Surg Educ 70:129-137, 2013). METHODS: In a repeated measures design, medical students, residents in their last year of training and attending surgeons performed an open preperitoneal mesh repair on the NANEP model [NANEP stands for the German acronym Nabelhernien-Netzimplatation-Präperitonal (English: Umbilical hernia mesh implantation preperitoneal)]. Subjects were categorized as "Beginners" (internship students) or "Experts" (residents and surgeons). Content validity was analyzed by criteria of subject-matter-experts. Blinded raters assessed surgical skills by means of the Competency Assessment Tool (CAT) using the online platform "CATLIVE". Differential validity was measured by group differences. Proficiency gain was analyzed by monitoring the learning curve (Gallagher et al. in Ann Surg 241:364-372, 2005). Post-operative examination of the simulators shed light on criterion validity. RESULTS: The NANEP model-proofed content and construct-valid significant Bonferroni-corrected differences were found between beginners and experts (p < 0.05). Beginners showed a significant learning increase from the first to the second surgery (p < 0.05). Post-operative examination data confirmed criterion validity. CONCLUSION: The NANEP model is an inexpensive, simple and efficient simulation model. It has highly realistic features, it has been shown to be of high-fidelity, full-procedural and benchtop-model. The NANEP model meets the main needs of surgical educational courses at the beginning of residency.

Incisional hernia repair in a high-fidelity silicone model for open retro-muscular mesh implantation with preparation of the fatty triangle: validation and educational impact study.

BACKGROUND: Incisional hernia repair requires detailed anatomic knowledge. Regarding median subxiphoidal hernias, the proper preparation of the fatty triangle is challenging. To foster proficiency-based training, a cost-efficient model for open median retromuscular mesh repair resembling the human body was developed, including the main anatomical structures related to the procedure. The aim is to create and validate a high-fidelity model on open retromuscular mesh repair suitable for "training before doing". MATERIALS AND METHODS: Different types of fabrics for imitation of connective tissue and 2-component silicones were used to construct the incisional hernia model. Sample size for validation of the model was determined by a triangular testing approach. Operations from six beginners and six experts were assessed by three blinded-raters. Reliability and construct-validity were evaluated on a behaviorally anchored rating scale (highest score: 4) for the criteria: "instrument use", "tissue handling", "near misses and errors", and "end-product quality". RESULTS: The model authentically mimicked an open median retromuscular mesh repair. Participants considered the procedure realistic. Reliability was excellent, ranging from 0.811 to 0.974 for "end-product quality", and "tissue handling" respectively. Construct-validity was confirmed with experts significantly outperforming beginners in the "use of instruments" (Mbeg. = 2.33, Mexp. = 3.94, p < 0.001), "tissue handling" (Mbeg. = 2.11, Mexp. = 3.72, p < 0.001), "near misses and errors" (Mbeg. = 2.67, Mexp. = 3.67, p < 0.001), and "end-product quality" (Mbeg. = 2.78, Mexp. = 3.72, p < 0.001). Criterion-validity revealed a paradox effect: beginners performed significantly better than experts (p < 0.05) when preparing the fatty triangle. CONCLUSIONS: The model covers all relevant aspects involved in median-open retromuscular incisional hernia mesh repair. Performance differences between beginners and experts confirm construct-validity and thereby realism of the model. It enables to efficiently improve and practice technical skills of the demanding surgery.

EuraHS: the development of an international online platform for registration and outcome measurement of ventral abdominal wall hernia repair.

BACKGROUND: Although the repair of ventral abdominal wall hernias is one of the most commonly performed operations, many aspects of their treatment are still under debate or poorly studied. In addition, there is a lack of good definitions and classifications that make the evaluation of studies and meta-analyses in this field of surgery difficult. MATERIALS AND METHODS: Under the auspices of the board of the European Hernia Society and following the previously published classifications on inguinal and on ventral hernias, a working group was formed to create an online platform for registration and outcome measurement of operations for ventral abdominal wall hernias. Development of such a registry involved reaching agreement about clear definitions and classifications on patient variables, surgical procedures and mesh materials used, as well as outcome parameters. The EuraHS working group (European registry for abdominal wall hernias) comprised of a multinational European expert panel with specific interest in abdominal wall hernias. Over five working group meetings, consensus was reached on definitions for the data to be recorded in the registry. RESULTS: A set of well-described definitions was made. The previously reported EHS classifications of hernias will be used. Risk factors for recurrences and co-morbidities of patients were listed. A new severity of comorbidity score was defined. Post-operative complications were classified according to existing classifications as described for other fields of surgery. A new 3-dimensional numerical quality-of-life score, EuraHS-QoL score, was defined. An online platform is created based on the definitions and classifications, which can be used by individual surgeons, surgical teams or for multicentre studies. A EuraHS website is constructed with easy access to all the definitions, classifications and results from the database. CONCLUSION: An online platform for registration and outcome measurement of abdominal wall hernia repairs with clear definitions and classifications is offered to the surgical community. It is hoped that this registry could lead to better evidence-based guidelines for treatment of abdominal wall hernias based on hernia variables, patient variables, available hernia repair materials and techniques.

Checking concordance between findings and diagnoses in sonographic reports by a knowledge-based documentation system.

PURPOSE: Sonographic reports are examiner-dependent and may not always be reliable. We investigated concordance between documented findings and diagnostic conclusions--not the objective correctness of both--with the help of a knowledge-based documentation system. MATERIALS AND METHODS: The knowledge-based documentation system SonoConsult (SC) is routinely used in the ultrasound unit of a gastroenterological clinic for more than four years. Physicians documented findings with goal directed questionnaires, and diagnostic conclusions with free text. The consistency of documented findings and diagnoses was checked with the help of SC in a two-step process: 1. the diagnoses inferred by SC based on the documented findings were compared to the diagnoses of the physicians stated as free text. 2. In case of discrepancies, a more thorough comparison was performed manually by the medical authors of this study. For judging the practical relevance of discrepancies, diagnostic codes were pre-classified as a) being presumably of higher and lower relevance for the clinician and b) requiring simple or complex inference rules from the findings. RESULTS: In a first series of 250 consecutive cases with 934 diagnoses (3.7 diagnoses per case), 71.1% showed agreement between diagnoses of the physicians and of SC and were judged as consistent compared to the documented findings. 24.4% of the diagnoses suggested by the documented findings, however, were not mentioned by the physicians (false negative) and 4.5% were mentioned by the physicians but not suggested by the documented findings (false positive). From the 24.4% missing diagnoses, 40% were pre-classified as being of higher relevance for the clinician. In a second series of 161 consecutive cases with 501 diagnoses (3.1 diagnoses per case), 61.1% were judged as consistent compared to the documented findings, 36.1% false negative and 2.8% false positive. In this study, we differentiated the missing diagnoses due to their inferential complexity: From the 152 complex diagnoses, 44% were missing, while from the 349 simple diagnoses, 32.7% were missing. CONCLUSION: As shown for a sonographic department of a clinic of internal medicine, in sonographic reports, one has to be aware of discrepancies between question-set-based documentations of findings and diagnostic conclusions of the examiners. While a detailed documentation of findings is the basis of quality control, consistency checks between documented findings and diagnostic conclusions, which might be done automatically in an electronic patient record, would considerably improve the quality of the reports.

HepatoConsult: a knowledge-based second opinion and documentation system.

HepatoConsult is a publicly available knowledge-based second opinion and documentation system aiding in the diagnosis of liver diseases. The positive results of a prospective diagnostic evaluation study encouraged its use in clinical routine, although the available hardware infrastructure was not optimal. The comments of the physicians who used the system confirmed the results of the study and showed that the time for data entering is acceptable and the implicit standardization of terminology and documentation is welcome. Suggestions for improvement included the interface to enter data more easily, the scope to be usable for more patients and the additional capability to generate medical reports from the data.

Learning at the computer: evaluation of an intelligent tutoring system.

The aim of the study was to test the efficacy of a new courseware. In a pre and post test frame, students were given the software to be used during one semester. A significant increase in the students' general study motivation was shown at the end of the semester. A change in the use and attitudes towards computers could not be observed. In a follow-up survey at the end of the semester, the students stated that the program was indeed helpful and useful but that they have had difficulties with the program's technical aspects and the general use. Furthermore, the results show that the majority of the participating students accepted the program's content, the general study motivation was high and the students showed a significant increase in learning gains, determined by the differences from pre and post test values. Especially students with low pre test values seemed to profit from the additional use of learning material, resp. the presented courseware. At the end of the semester the students with low and middle pre test results showed an increase in performance as well as an alignment in the performance for diagnosing rheumatological diseases to the students of the upper third pre test results.

Evaluating four diagnostic methods with acute abdominal pain cases.

Contemporary work in medical decision support is characterized by a multitude of methods. To investigate their relative strengths and weaknesses, we built four diagnostic expert systems based on different methods (Bayes, case-based classification, heuristic classification) for analysis of the same set of 1254 cases of acute abdominal pain previously documented in a prospective multicenter study. The results of the comparative evaluation indicate that differences in overall performance are relatively small (statistically not significant). The performance depends more on the quality of the knowledge base and the case data than on the inference methods of the expert systems. Methods relying exclusively on empirical knowledge (Bayes, case-based classification) tend to have slightly higher overall performance scores due to a diagnostic bias toward ordinary and common diseases. By contrast, methods operating with expert knowledge (e.g., heuristic classification) perform slightly worse overall, but are more sensitive toward uncommon (serious) diseases.

Graphical knowledge acquisition for medical diagnostic expert systems.

Like many textbook authors use text systems for writing their books, expert system authors should have easy to use knowledge acquisition systems for entering and testing their knowledge bases by themselves without much help from 'knowledge engineers'. In this paper, we report on a graphical knowledge acquisition tool (CLASSIKA) based on an expert system shell for heuristic classification (MED2) and designed for direct use by domain experts. We demonstrate how the system has been used for building a rather large expert system for diagnosing rheumatology diseases which is now being tested in clinical use.

MED1: an intelligent computer program for thoracic pain diagnosis.

MED1 is a fully implemented, medical expert system providing assistance in the diagnosis of patients complaining of chest pain. Its reasoning strategy combines efficient mechanisms for hypothesis generation and hypothesis evaluation in a model simulalting the basic features of the hypothesize-and-test approach found to be applied by diagnosing physicians. The knowledge acquisition facility of the program is comfortable enough to allow the expert physician to alter the knowledge base without understanding the basic code (LISP) of the program.