Optimization of anastomotic technique and gastric conduit perfusion with hyperspectral imaging and machine learning in an experimental model for minimally invasive esophagectomy

INTRODUCTION

Esophagectomy is the mainstay of esophageal cancer treatment, but anastomotic insufficiency related morbidity and mortality remain challenging for patient outcome. Therefore, the objective of this work was to optimize anastomotic technique and gastric conduit perfusion with hyperspectral imaging (HSI) for total minimally invasive esophagectomy (MIE) with linear stapled anastomosis.

MATERIAL AND METHODS

A live porcine model (n = 58) for MIE was used with gastric conduit formation and simulation of linear stapled side-to-side esophagogastrostomy. Four main experimental groups differed in stapling length (3 vs. 6 cm) and simulation of anastomotic position on the conduit (cranial vs. caudal). Tissue oxygenation around the anastomotic simulation site was evaluated using HSI and was validated with histopathology.

RESULTS

The tissue oxygenation (ΔStO₂) after the anastomotic simulation remained constant only for the short stapler in caudal position (-0.4 ± 4.4%, n.s.) while it was impaired markedly in the other groups (short-cranial: -15.6 ± 11.5%, p = 0.0002; long-cranial: -20.4 ± 7.6%, p = 0.0126; long-caudal: -16.1 ± 9.4%, p < 0.0001). Tissue samples from avascular stomach as measured by HSI showed correspondent eosinophilic pre-necrotic changes in 35.7 ± 9.7% of the surface area.

CONCLUSION

Tissue oxygenation at the site of anastomotic simulation of the gastric conduit during MIE is influenced by stapling technique. Optimal oxygenation was achieved with a short stapler (3 cm) and sufficient distance of the simulated anastomosis to the cranial end of the gastric conduit. HSI tissue deoxygenation corresponded to histopathologic necrotic tissue changes. The experimental model with HSI and ML allow for systematic optimization of gastric conduit perfusion and anastomotic technique while clinical translation will have to be proven.

Teaching clinical practical and communication skills of the clinical skills lab of the University of Veterinary Medicine Hannover, Foundation, Germany during the COVID-19 pandemic

Objective: The aim of the project is to teach clinical practical and communication skills in the Clinical Skills Lab (CSL) of the University of Veterinary Medicine Hannover, Foundation (TiHo) during the COVID-19 pandemic. Methodology: As a measure to limit potential SARS-CoV2 infections, the CSL learning stations were digitised and made available on the Moodle learning platform of the TiHo. Online quiz stations were also developed, as well as improvisations that allowed students to practise practical skills at home using everyday materials. Courses for Practical Year (PY) students were digitised and again combined with classroom exercises throughout the year. The teaching formats could be evaluated by the students by means of a questionnaire using a Likert scale (1=agree; 4=disagree). Results: A total of 24.92% of students (n=1272) completed the learning stations with improvisations. The quiz stations were completed with a percentage of 75.08%. Students indicated that the improvisations were easily implementable from home (M=1.33) and assisted in learning the practical skills in question (M=1.89). The quiz stations were considered helpful (M=1.40) and complementary to previous CSL offers (M=1.13). The PY students found the amount of teaching materials adequate (M=1.76) and described communication with the lecturers as problem-free (compulsory electives=1.24). Conclusions: Digital teaching is suitable as a supplement to existing face-to-face courses at the CSL, but cannot replace on-site training under the guidance of trained personnel. The CSL will continue to strive for a combination of online and face-to-face courses for some learning stations in the future.

TiHoVideos: veterinary students' utilization of instructional videos on clinical skills

BACKGROUND

The YouTube channel "TiHoVideos" was created by the University of Veterinary Medicine Hannover, Foundation (TiHo) to enable easy, public access to the university's instructional videos as an additional support for learning clinical skills. Video production is expensive and time-consuming. To be able to optimize video production and aligning content to student needs we wanted to know if and how our students use these videos.

RESULTS

Results show that the participating students primarily prepared for learning stations in the Clinical Skills Lab (CSL) by watching TiHoVideos at home on tablets or laptops and then concentrated at the CSL on learning the practical skills hands on. The videos available on TiHoVideos are rated as being a "very helpful" educational tool when preparing for CSL learning stations.

CONCLUSIONS

Instructional videos represent an unquestionably suitable medium to aid veterinary students learn practical skills and a contribution to animal welfare by reducing the use of live animals in undergraduate veterinary education. The university's production of educational video material proves to be worth the effort because the videos are being used, appreciated and well-rated by TiHo students for their learning experience.