Surgical materials testing laboratory

At the Surgical Material Testing Laboratories (SMTL), (Cardiff, UK) Thomas et al. also carried out a number of researches to develop suitable test methods for the wound dressings (Thomas, 1997, 2009 Thomas, Hughes, Fram, Halllet, 2005 Thomas McCunnin, 2003). 

Suture retention strength is given by the force required to pull a suture out of the prosthesis. The maximum force required (N) to pull the suture from the graft is measured using a mechanical tensile tester. The tests are generally conducted at 0° (parallel), 45° and 90° (perpendicular) to the longitudinal axis of the prosthesis to represent the different types of surgical end-to-end and end-to-side anastomoses that may be used to attach the device in vivo. The size and type of suture material may influence the results, so these variables should be recorded and reported with the results. In our laboratory we have found the use of size 0 to 3-0 stainless steel sutures provides reliable data. 

Flammability The flammability of a plastic is most commonly characterised by the Underwriters Laboratory (UL 94) horizontal burning test. The test sample, a rectangular bar 127 mm long, is held horizontally, or at 45°, and clamped at one end. The burning speed of the bar is measured when exposed to a pilot flame. The bar is held 305 mm above the surface of a layer of surgical cotton. The thickness of the bar can be varied, but is quoted as part of the result, e.g. VO, 1.57. The commonly quoted ratings given to a material are ... 

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