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ePoster 1107

Measuring Knot Security Objectively with a Post-ligation Pressure Test in

Simulation- Based Learning on Surgical Knot-Tying Techniques


Meng-Yu Wu

Cardiac Surgeon and Physician Educator

1Associate Professor in Surgery, Medical school of Chang Gung University, Taiwan.
2Associate Professor in Cardiovascular Surgery, Linko Chang Gung Memorial hospital , Taiwan.

3Chang Gung Medical Education Research Centre

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Tying surgical knot securely is essential

Ligating a pressurized blood vessel without blood leakage is a clinical hallmark of expert competency in surgical knot-tying but is not assessed by current knot-tying simulators. This study aims to develop a novel simulator to recreate this scenario ex vitro and validate it as an appropriate instrument to teach medical students the skill.

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Summary of Work

Testing knot security with a post-ligation pressure test as in true blood vessels

We conducted a mixed-methods study from August 2021 to September 2022. Initially, we designed and 3D- printed a novel vessel ligation simulator. Users can tie knots on the compressible silicon vessel and objectively measure knot security by applying pressure through an upstream air compressor. The pressure value above the ligation site is detected by a pressure gauge, and it should not drop to zero if the ligation knot is secure enough to occlude the vessel. Subsequently, six attending surgeons and thirty Year 5 medical students were recruited for simulator evaluation. Their performance on the simulator and their perceptions of its validity and benefits in teaching and learning surgical knot-tying were collected.

Educational Theory:
Stages of motor skill acquisition
Research Design

Summary of Results

A flipped curriculum of surgical knot-tying ;

3D-printed simulatior and E-learning platform

The simulator received high validity scores from the surgeons (average 4.5 for face validity and 4.77 for content validity). Eighty percent of the medical students achieved expert-level competency in knot-tying by the class's conclusion. The simulator was unanimously found beneficial by the students, who particularly valued its realistic environment and objective feedback, leading to significant improvements in their confidence and skill mastery.

1. E-learning Platform (Chinese)
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2. The novel simulator (English)
3. Trainees' Feedback
The simulator is beneficial to my learning of surgical knot-tying, because it provides me
"Realistic Practice Experience", "Feedback-Driven Skill Mastery",and "Feedback-Informed Technique Mastery".
4. Measurable Competence 

Discussion and Conclusion

Innoations in surgical education

This novel simulator successfully addresses a gap in simulation-based education for surgical knot-tying skills, offering an intuitive method to teach and assess this essential surgical technique, previously untestable with existing simulators. Diverging from typical skill training studies, we adopted a mixed-method design to incorporate both quantitative and qualitative data from participants. This approach allows us, as surgical educators, to gather multi-perspective views on our product from our participants. This enables us to assess whether it meets both the cognitive and psychological needs of trainers and trainees during this educational experience.

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