Evaluation of biomechanical properties of the pancreatic duct

Presenter: Sophia Bidinger | University of Washington Background: Biomechanical characterization of human tissue is of increasing importance as new technologies gain importance in modern medicine. Without haptical sensation, measurement of forces associated with surgical techniques will be the primary source of feedback in these new technology assisted procedures (eg. robotic surgery). An important biomechanical parameter is the suture pullout force (SPOF), indicating the maximum safe force that could be applied to a suture before tearing the tissue. The aim of this study is to analyze suture pullout forces of the pancreatic duct. This data could be used for a wide range of applications including a robot assisted Whipple procedure and for the development of a high-fidelity pancreatic simulation. This data is also useful in understanding how biomechanical properties of the biliary tract change with age, sex, and BMI. Methods: Donated organs used in this study were tested within 72 hours of death. Cross sections of the pancreas were prepared and 4-0 Covidien Sofsilk® sutures were looped through one side of the pancreatic duct wall. The suture strings were clamped to a laboratory developed uniaxial suture instrument. The pancreas was held in place while the suture was pulled in tension at 1.58 mm/sec. The tensile force was measured continuously and the peak force before specimen failure was taken as the SPOF. IBM SPSS Statistics Version 26 was used for statistical analysis of the effect of age (older or younger than 35), sex, and BMI (19-26 or 26+) on SPOF. Results: 103 suture pullout tests were performed on pancreatic ducts from 14 donors. This included 9 males with BMI ranging from 19 to 34 and age ranging from 20 to 69 years old and 6 females with BMI ranging from 20 to 37 and age ranging from 19 to 58 years old. The overall SPOF is 2.87 N ± 1.36 N. The mean SPOF for females is 2.12 N and 3.03 N for males (p=0.019). The SPOF of pancreatic ducts from donors with BMI less than 26 averaged 3.22 N while SPOF for donors with BMI greater than 26 averaged 2.51 N (p=0.045). Donors older than 35 averaged 2.69 N while donors younger than 35 averaged 2.87 N (p=0.123). Conclusion: Preliminary results show a trend suggesting male pancreatic ducts have a higher SPOF than female pancreatic ducts. Additionally, as BMI increases, the pancreatic duct SPOF decreases. The effect of age is inconclusive at this time.