Biomechanical evaluation of different methods for securing cellophane bands for portosystemic shunt attenuation and factors that affect construct failure
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Type
ThesisThesis type
Masters by ResearchAuthor/s
Joffe, Michelle RobynAbstract
Objectives: To secure a cellophane band around a vein with either three or four layers with a polymer or titanium hemostatic clip of either medium or medium-large size, at 25% or 50% vessel attenuation, and observe the conditions under which the construct is more likely to fail and ...
See moreObjectives: To secure a cellophane band around a vein with either three or four layers with a polymer or titanium hemostatic clip of either medium or medium-large size, at 25% or 50% vessel attenuation, and observe the conditions under which the construct is more likely to fail and the pressure at failure. Study design: Ex-vivo mechanical evaluation Methods: Cellophane bands composed of three or four layers were applied around a cadaveric external jugular vein (EJV) to create 25% or 50% attenuation. These bands were secured with Polymer Locking Ligation Clip (PLLC) medium/medium-large, or Titanium Ligation Clip (TLC) medium/medium-large. Sterile saline 0.9% was instilled into the lumen of the EJV until a pressure of 100mmHg was reached. Failure mechanism and luminal pressure at failure were compared between groups. Results: Medium clips were significantly more likely to fail than medium-large clips (P= <0.001). Three-layer cellophane bands were significantly more likely to fail than four-layer bands (P=0.003). Failure also occurred at significantly lower pressures with a 3-layered cellophane band compared to a four-layered band (P=0.027). There was no significant difference between the failure rate of the cellophane band construct secured with PLLC or TLC, (P = 0.635) or with 25% vs 50% attenuation (P=0.780). The four-layer cellophane band, was 4.1 times less likely to fail (CI 1.6-10.2) than the three-layer cellophane band. Conclusion and clinical relevance: One, medium sized clip either PLLC or TLC is sufficient to withstand physiological forces when securing a cellophane band around a vein at up to 50% attenuation. A cellophane band with four layers is less likely to result in clip slippage and failure compared to a cellophane band with three layers. The recommendation would be to secure a four-layer cellophane band with a medium sized PLLC if follow-up CT scans may be required.
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See moreObjectives: To secure a cellophane band around a vein with either three or four layers with a polymer or titanium hemostatic clip of either medium or medium-large size, at 25% or 50% vessel attenuation, and observe the conditions under which the construct is more likely to fail and the pressure at failure. Study design: Ex-vivo mechanical evaluation Methods: Cellophane bands composed of three or four layers were applied around a cadaveric external jugular vein (EJV) to create 25% or 50% attenuation. These bands were secured with Polymer Locking Ligation Clip (PLLC) medium/medium-large, or Titanium Ligation Clip (TLC) medium/medium-large. Sterile saline 0.9% was instilled into the lumen of the EJV until a pressure of 100mmHg was reached. Failure mechanism and luminal pressure at failure were compared between groups. Results: Medium clips were significantly more likely to fail than medium-large clips (P= <0.001). Three-layer cellophane bands were significantly more likely to fail than four-layer bands (P=0.003). Failure also occurred at significantly lower pressures with a 3-layered cellophane band compared to a four-layered band (P=0.027). There was no significant difference between the failure rate of the cellophane band construct secured with PLLC or TLC, (P = 0.635) or with 25% vs 50% attenuation (P=0.780). The four-layer cellophane band, was 4.1 times less likely to fail (CI 1.6-10.2) than the three-layer cellophane band. Conclusion and clinical relevance: One, medium sized clip either PLLC or TLC is sufficient to withstand physiological forces when securing a cellophane band around a vein at up to 50% attenuation. A cellophane band with four layers is less likely to result in clip slippage and failure compared to a cellophane band with three layers. The recommendation would be to secure a four-layer cellophane band with a medium sized PLLC if follow-up CT scans may be required.
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Date
2019-06-14Licence
The author retains copyright of this thesis. It may only be used for the purposes of research and study. It must not be used for any other purposes and may not be transmitted or shared with others without prior permission.Faculty/School
Faculty of Science, Sydney School of Veterinary ScienceAwarding institution
The University of SydneyShare