Date of Award
Master of Science (MS)
Dr. Melinda K. Harman, PhD
Dr. Jeremy Mercuri, PhD
Dr. B. Todd Heniford, MD
Approximately 5 million Americans have an abdominal wall hernia, and over 700,000 undergo surgical procedures every year to treat them. Surgical procedures have evolved with the goal of preventing recurrences, leading to the current gold standard of treatment: hernia repair with mesh. Hernia repair with mesh consists on augmenting the weakened abdominal wall by implanting a synthetic or biological mesh. Although the adoption of hernia repair with mesh has improved outcomes, recurrence from primary repair procedures with large incisions (>10 cm) remains an alarming 32%.
The wide variety of implanted surgical mesh (materials, structure) and surgical variability (attachment method, laparoscopic versus open surgery) have been voiced as concerns by national and international agencies, which have called for reporting of these variables to relate them to patient outcomes. Variables related to the mechanical aspect of the mesh in situ have yet to receive attention, mainly due to the lack of instrumentation practical for adoption in the surgical setting. A variable currently assessed subjectively by surgeons during implantation is the stiffness of the abdominal wall and mesh, sampled by applying a distension load to mesh in situ using a blunt probe or by hand. Through the work in this thesis, the development of a handheld instrument to measure the stiffness of the abdominal wall and mesh under a distentional load was accomplished.
An iterative design process was followed to meet design requirements established by mechanical tissue models and voice of the customer input. The instrument’s sensing accuracy and precision were confirmed by comparison with standardized bench top equipment. Verification was achieved through in vitro testing of composites simulating iii the abdominal wall and mesh. The instrument consistently measured different stiffness values (p<0.04) on samples overlaid with polyethylene sheets or a commercially available surgical mesh under varying tension. In vivo testing on swine specimens provided preliminary validation of the instrument’s ability to discern distentional stiffness changes of the abdominal wall composite due to mesh implantation (p<0.04). Adoption of the instrument presented here will allow for the study of a mechanical variable considered relevant by surgeons, and may expose a link between mechanical implantation variables and patient outcomes through long term clinical studies.
Hernandez Sanchez, Jorge Ivan, "Development and Initial Validation of a Surgical Instrument for In Situ Mechanical Characterization of Surgical Mesh-tissue Composites" (2016). All Theses. 3727.