Impact of Stitch Density on Suture Performance GROUP NUMBER: WA3 Aims/Objective & Hypothesis: Hypothesis: Using the running stitch technique, increasing stitch density improves suture performance to a certain stitch density limit. Stitch density is defined by number of stitches per cm Suture performance is indicated by smaller strain values Objectives: To quantify the stitch density limit using the derivative and ANOVA methods To determine the relationship between stitch density and average strain, fitting the data to a regression model

Methods, Protocol & Equipment: System Calibration and Experimental Set-up Position the camera to allow for the best possible precision Use the BE310Camera VI program to acquire real-time measurements Use the ruler for calibration before and throughout testing Wound Surrogate Preparation Each uncut Tyvek sample is 5cm long and 2cm wide Mark each piece 1cm from the top and bottom to control the clamp placement Stitch 5 of each 4, 6, 8, 10 and 12 evenly-distributed running-stitched samples Tensile Testing of Wound Surrogates and Sutures Record the length of each sample in pixels before loading and after 30 seconds of loading a 1kg weight Compute the strain for each sample (displacement/pre-loading length) and use this value for further data analysis

Proposed Results/Findings/Deliverables: Average strain for each group will be calculated and used to create a graph of average strain versus stitch density. Stitch density limit will be quantified using two methods: Derivative of the regression model ANOVA and the Bonferroni test Potential Pitfalls: Unequal distribution of load Limitation of camera resolution Presence of lateral deformation Difficulty stitching the higher densities No limit is reached

Materials and Budget & Justification: Supplies Sheets of Tyvek – surrogate material for skin Marker pens – for marking location of clamps on sample Cotton string & needle – for preparing sample Scissors – for standardizing sample dimension Newly Purchased Equipment None All equipment and materials used are currently available in the lab. No new equipment was deemed necessary for performing the experiment.