University of Pennsylvania Department of Bioengineering Aims/Objective & Hypotheses: Instron Uniaxial Tensile Testing of Suture Performance Group: TA2 Uniaxial tensile testing: interrupted and running suture stitches Determine suitability for cyclic / high stress loading Hypotheses: Running: more suitable for cyclic applications Interrupted: more suitable for high-stress applications

University of Pennsylvania Department of Bioengineering Methods, Protocol & Equipment: Desktop Instron machine Pneumatic 1.5” clamps 1/4-inch polyethylene foam 7-0 Vicryl suture Suture holder, scissors X-acto knife Calipers, ruler, marker pens Digital camcorder and video software Sixteen 1.5  3.5-inch samples 75% depth score to 14 samples Controls Upper and lower bounds 6 surrogates with each stitch type 8 stitches 3 mm from seam Two-stage test Run 1 sample to failure Cyclic loading at 70%  max Videotape each run Run all samples Post-test video analysis T-test analysis of stitch types EquipmentProcedure 3 mm

University of Pennsylvania Department of Bioengineering  max failure strain stress Proposed Results/Findings/Deliverables: Non-cyclic stress/strain curve resembling polymer: Differentiation of stitch type Higher maximum tensile strength or More cycles withstood Stitch type tailored to epidermal region Repetitive motion: cyclic loading ability High epidermal stress: tensile strength Hypothesized results Running stitch: cyclic loading? Interrupted stitch: tensile strength?

University of Pennsylvania Department of Bioengineering Potential Pitfalls: Inconsistency in suture systems Multiple “doctors” Imprecise measurement Suture tension Surgical knots Time limitation Equipment shortcomings Instron clamps Identifying failure Low population size Interrupted suture diagram. (Source: San Francisco General Hospital web resources.

University of Pennsylvania Department of Bioengineering Materials and Budget & Justification: TOTAL