31 - New and Developed Methodologies for Testing Porcine and Human Tissue Biomechanical Characteristics

Poster Board Number: 31
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Odd poster #s – first hour
Even poster #s – second hour

Co-authors:

Sorin Darie, RMT - Undergraduate Student, Faculty of Health Sciences, McMaster University; Athena Li, BHsc (Hon.) - Undergraduate Student, Faculty of Health Sciences, McMaster University; Austine Wang, BHsc - Medical Student, DeGroote School of Medicine, McMaster University; Betty Zhang, BHsc - Medical Student, Queen's University's School of Medicine, McMaster University; Andrew Palombella, MSc - Anatomical Technician and Demonstrator, Education Program in Anatomy, McMaster University; Brooke DeCarlo, MSc - Anatomical Technician and Demonstrator, Education Program in Anatomy, McMaster University; Jasmine Rockarts, MSc - Anatomical Technician and Demonstrator, Education Program in Anatomy, McMaster University; Danielle Brewer-deluce, PhD - Assistant Professor, Education Program in Anatomy, McMaster University; Bruce Wainman, PhD - Director, Education Program in Anatomy, McMaster University; Greg Wohl, PhD - Department Chair, Dept of Mechanical Engineering, McMaster University

Abstract Body : Introduction and Objective:

The physical characteristics of differentially embalmed tissues determine the suitability of tissues in surgical skills training. Historically, tissue mechanical testing has been mainly limited to tensile testing. The current work details the development and evaluation of a novel set of testing protocols to measure the mechanical response of tissues relevant to surgical skills training.



Methods:

Skin, muscle and bone tissue samples were excised from seven porcine and four human donors, each embalmed with one of seven different preservation solutions. In addition to tensile testing, protocols for testing tissue properties during surgery-adjacent tasks on each tissue type were developed. For skin: force during needle puncture and scalpel cutting, tissue fluid content, and electroconductivity. For muscle: force during chest tube insertion. And for bone: force while cutting with a bonesaw. An Instron load-testing device was used for tensile testing, chest tube insertion, and bone sawing. Puncture and scalpel tests were performed using an Instron Electropuls, with tissue placed under 7 N tension. Max load, max energy, and stiffness were measured. Fluid retention was measured through mass change analysis after drying in an oven. Electroconductivity was measured by resistance with an ohmeter.



Results:

Within-sample measurement consistency varied between tests. Specifically, tensile strength, needle puncture, scalpel cutting, and tissue drying tests produced highly reproducible, within-sample measures (coefficient of variability < 0.35) which varied appropriately between tissues of differing preservation and required little user judgement throughout the protocol. Conversely, bone sawing, chest tube insertion, and electrocautery lacked reproducibility (coefficient of variability > 0.35) and were subject to user judgement at multiple points during the protocol.



Conclusion:

The testing protocols from this present study for needle puncture, scalpel cutting, and tissue drying are recommended as novel methods to test mechanical response of embalmed tissues to surgical procedures. Bone sawing, electroconductivity, and chest tube insertion protocols showed higher variability and require refinement (such as modifying the boundary conditions) to determine whether it can be effectively used to validate surgical skills training.



Significance and Implication:

Differences in tissue mechanical behaviours have implications for surgical skills training. Having appropriate protocols for testing such behaviours allows anatomical laboratories to objectively validate using high fidelity surrogates in place of human tissues, as well as test the effect of different tissue preservation protocols across a range of tissues.