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" (M_beg. = 2.33, M_exp. = 3.94, p < 0.001), "tissue handling" (M_beg. = 2.11, M_exp. = 3.72, p < 0.001), "near misses and errors" (M_beg. = 2.67, M_exp. = 3.67, p < 0.001), and "end-product quality" (M_beg. = 2.78, M_exp. = 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.

Hepatic angiomyolipoma: A case report and literature review

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HAML is a rare mesenchymal liver tumour which belongs to the family of perivascular epithelioid cell tumours.

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HAML is typically composed of blood vessels, smooth muscle, and adipose cells.

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HAML is characteristically positive for HMB-45.

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In patients with symptoms, uncertain diagnosis, or tumour growth, surgical resection should be performed.

Introduction

Hepatic angiomyolipoma (HAML) is a rare mesenchymal liver tumour which belongs to the family of perivascular epithelioid cell tumours (PEComas). It is typically composed of blood vessels, smooth muscle, and adipose cells, and shows strong immunoreactivity for HMB-45.

Presentation of the case

A 57-year-old woman was referred to our hospital with an unclear liver lesion. A fine needle biopsy revealed a suspicion of hepatic angiomyolipoma with extramedullary haematopoiesis. Preoperative imaging revealed a tumour 17 cm in diameter in the left liver lobe segments II and III. A lobectomy of the left lobe segments II and III was performed. The pathological diagnosis of hepatic angiomyolipoma was obtained.

Discussion

Variations in the predominance of the tissue components in HAML impedes diagnosis based on imaging alone. The most promising evidence of HAML is the histological identification of lipomatous, myomatous, and angiomatous tissue combined with immunohistochemical positivity for HMB-45. Although the tumour is considered benign, some cases have been described with malignant behaviour. Surgical resection should be considered in case of symptoms, inconclusive biopsy, or growth in follow-up. Other surgical indications may include aggressive patterns such as vascular invasion, p53 immunoreactivity, or rapidly proliferating tumour cells.

Conclusion

HAML is a rare liver tumour. In patients with symptoms, uncertain diagnosis, or tumour growth, surgical resection should be performed according to oncological criteria.

Improved Learning Gain in Medical Students by Using Animated Whiteboard-Videos in Comparison to Textbooks in Surgery

BACKGROUND

Animated videos have become popular in teaching medical students, although there is a certain lack of evidence concerning its efficacy. Surgery seems to be an ideal field for its application, since animations are very helpful to understand anatomic structures and complex procedures. The aim of this study was to investigate the effects of animated videos compared to textbooks on learning gain.

METHODS

A prospective 2-arm cohort study with 5th-year medical students was conducted during their 2-week surgical training module. The initial cohort of students received textbook sections on 3 major topics in visceral surgery as learning medium (text cohort). During the following semester, the second cohort of students received 3 animated whiteboard videos (animated videos) containing equivalent content (video cohort). All participants completed a multiple-choice test consisting of 15 questions on the learning content at baseline (pre-test) and after the learning period (post-test) and answered an additional evaluation questionnaire.

RESULTS

Both cohorts were similar in their descriptive data and demonstrated significant learning gain during the 2-week learning period. The video cohort achieved better results (80% vs 73% correct answers; P = .028) and a higher learning gain (17% vs 11%; P = .034) in the post-test compared to the text cohort. The estimated learning time was longer in the video cohort (62 min vs 37 min; P < .001) and watching the videos resulted in higher learning gain (21% vs 6%; P < .001). Subgroups with higher learning gain by video learning were female gender (20% vs 11%; P = .040), native German speakers (18% vs 11%; P = .009), students without prior surgical experience (19% vs 12%; P = .033) and those undecided concerning a surgical career (22% vs 9%; P = .020). Interestingly, "low digital orientation" students benefited from videos (22% vs 13%; P = .021), whereas "high digital orientation" students did not.

CONCLUSIONS

Animated videos increase medical students' learning gain and interest in surgery.