Shape memory polymer-based smart plug for inguinal hernia repair

• Author / Creator

  Bilal, Muhammad

• The application of hernia meshes is amongst the most popular techniques used to treat and repair hernias worldwide. While there is no gold standard at this point, the conventional technique involves repositioning of the displaced tissue back into the desired location followed by the application of a hernia mesh which is secured in place by either sutures, stitches, or adhesives. This is critical to ensure that the previously displaced tissue remains in its allocated position, giving the body sufficient time to heal and alleviate reliance from the mesh. In contrast to conventional meshes, 3D meshes have proven to provide a more sustainable recovery pathway for patients and has gained significant traction by the medical community. Given the advantages of 3D meshes over conventional meshes, such as increased motility, reduced pain, reduced scarring as well as increased rate of recovery, this study proposed a new design of a 3D hernia scaffold using a smart material, namely shape memory polymer (SMP). Unlike conventional static meshes which require intricate surgical precision and accuracy to ensure the complete placement of the mesh, the proposed design in this study displays self-deployment capabilities, which is based on shape memory effect (SME), upon activation. Once the device is transferred to the site of the hernia, the self-deployment of the proposed model is achieved by thermal activation, at normal human body temperature, expanding to its full size and gripping the site without the need of sutures with the adjacent tissue to support it. The self gripping nature of the proposed design has the potential to reduce the time and complexity of the hernia repair surgery with the added benefits offered by 3D meshes. The present study compared a multitude of designs based on a design selection criterion including ease of printing, repeatability, design constraints and functionality. After several iterations, a single design was proposed, 3D printed, and then tested to determine mechanical and shape memory properties. The mechanical properties, of the proposed design, were investigated by analyzing the effect of static compressive forces and cyclic compressive forces on 3D printed samples and comparing them to equivalent data found in literature for existing commercial alternatives. The results of the static compression test indicated that the proposed design displayed a maximum force of 18.74 N/cm without signs of failure, conforming to its commercial counterparts which display a range of 11.1 N/cm to 100.9 N/cm before failure. The stiffness parameter for the proposed design was determined in this study to be 1.58 N/mm which is also comparable to the available commercial alternatives exhibiting a range of 0.3 N/mm to 4.6 N/mm. The results of the cyclic compression test displayed a higher plastic deformation of 14.67% in comparison to the range of 0.58% to 8.51% demonstrated by the commercial alternatives compared in this study. These differences were considered acceptable and did not invalidate the effectiveness of the proposed design since this was an indirect comparison and minor differences were expected. The shape memory properties were studied by analyzing the smart plug deployment under controlled conditions to determine the speed of recovery as well as the recovery ratio. While no comparison can be made against a commercial hernia mesh for these shape memory properties, the samples showed shape recovery of more than 90% within four minutes of activation which is a quite promising difference than current surgical procedure time. Due to the ongoing COVID-19 restrictions and laboratory closures, this study experienced significant delays with both the speed of the project and deliverables being affected.

• Subjects / Keywords

  • Shape memory polymer
  • hernia repair
  • smart plug

• Graduation date

  Fall 2021

• Type of Item

  Thesis

• Degree

  Master of Science

• DOI

  https://doi.org/10.7939/r3-env0-pb87

• License

  This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.