Background:
            •  Initial suture testing proved inconclusive due to small sample 
            size and inaccurate testing procedures
            •
             Larger sample size and the use of Instron technology will allow 
            for investigation and comparison of the material properties of two 
            suture techniques
             Hypothesis & Objectives:
             Based on raw data collected in past 
             experiments, it is hypothesized that the 
             horizontal mattress suture technique will 
             have a greater failure strength and higher 
             Young’s Modulus than the vertical mattress 
             suture technique.
         Department of Bioengineering                            Julianne Huegel 
    Methods & Protocol:
      •
       Sample size is ten successful sample failures for each suture technique. 
      •
       Measure and cut 20 samples of the CottonDuck canvas material with 
      dimensions of 7.5 cm by 2.4 cm. Cut each of these in half crosswise.
      •
       Create two groups of 10 “wound” samples and sew 4 stitches into each 
      sample, with one population receiving horizontal mattress stitches and 
      one population receiving vertical mattress stitches.  Each stitch should be 
      of uniform length, spacing, and distance from the edges of the sample to 
      be determined as appropriate by the group.
      •
       Insert each sample into the clamps, run Instron.  Collect Stress-Strain 
      curve data.  Use a speed previously determined to be appropriate by 
      using other materials.  A speed of 60 mm/min is recommended. Use tape 
      to minimize slippage if necessary.
      •
       Save data for further analysis.
         Department of Bioengineering                             Leia Harbour
    Proposed Findings:
    The two populations, vertical and horizontal 
        mattress suture samples, will provide 
        ten trials each. Each trial will produce a:   A sample Stress-Strain curve:
    1. Stress vs. Strain Curve
    2. Young’s Modulus
    3. Failure Strength
    4. Descriptive statistics and t-tests will be 
        used to analyze Items 2 and 3 to 
        investigate possible statistically 
        significant differences between the 
        techniques.  In accordance with the 
        hypothesis, it is expected that vertical 
        mattress sutures will have a lower 
        Young’s modulus and a lower failure 
        strength based on our pilot data.
                                      http://nsmwww.eng.ohio-state.edu/Stamping_Glossary/assets/images/autogen/a_y3.gif
         Department of Bioengineering                          Chia-Heng Wu
   Potential Pitfalls:
     •
       Inability of clamps to secure the sutured material in a fixed 
     position resulting in slippage.
     •
       Experimenter’s inability to have a constant suturing technique 
     which could result in unequally spaced stitches.
     •
       Some sutures may be tighter than others within a test sample.
     •
       May experience failure in the material prior to failure of the 
     sutures.
      Department of Bioengineering        William Okech
   Equipment, Materials and Budget
    Materials to be Purchased:                        •
                                                        The Instron will be utilized to 
                               Individual Price       test for the desired material 
                                                      properties.  
   Straight Roundpoint         $15.56                 •
   Needle (4 in. x 12)                                  Needles and polyester thread 
                                                      are necessary for suturing two 
   Polyester Thread (diam.  $5.16                     pieces of canvas together.  
   0.023 in x 206 yds w/ 21                           •
   lb. tensile strength)                                Polyethylene tape will be 
                                                      provided for preventing slippage. 
   CottonDuck Canvas           $2.08/ft *15 ft =       
   Fabric (0.04 in. thick x    $31.2                  •
                                                        Heavyweight canvas is used in 
   36 in. wide)                                       order to limit material 
   Polyethylene Tape (1/32  $20.13                    deformation to the suture only.  
   in. thick x 72 yds)                                •
                                                        To ensure suture failure, 
   TOTAL PRICE (all mat’ls     $72.05                 polyester thread was chosen 
   supplied by McMaster-                              because it’s tensile strength is 
   Carr)                                              less than that of other suture 
                                                      materials.
        Department of Bioengineering                       Group 102B3