A suture is a medical device that doctors use to hold skin, internal organs, blood vessels and all other tissues of the human body together, after they have been severed by injury or surgery. They must be strong enough to hold the tissue and flexible enough to be easily tied into knots.
Suture tensile strength determines where the suture can be used inside or outside of the body and for how long it is intended to remain. Sutures are absorbable or non-absorbable and in some cases, have needles attached.
Below we describe a typical suture tensile test and what type of equipment is needed to perform this test.
Types of suture tests:
- Standard tensile pull test.
- Knot pull tensile test (the knot is centered in between the grips).
- Creep test (pull to a desired load and hold).
Procedure for straight pull:
- Insert non-absorbable suture sample into pneumatic cord and yarn grips. The gauge length is usually 10 in. from grip to grip with a 2.5-in. grip separation. It’s very important that the sample is lined up properly or it will impact the results of the test.
- Set profile to pull suture at desire speed to a desired load or until the sample breaks. We used 12 in./min.
- After the sample breaks, the test stops.
From the data, we can tell the tensile strength and peak load of a non-absorbable suture.
In other tests, we can tell the strength of a suture, with and without a knot pull, and the strength of absorbable or non-absorbable sutures. In addition, you can perform creep tests and cyclic tests.
Suture sizes are defined by the United States Pharmacopeia (U.S.P.). Atraumatic needles are manufactured in all shapes for most sizes. The actual diameter of thread for a given U.S.P. size differs depending on the suture material class.
Many textile ASTM methods are used for thread testing: ASTM D5034-95, ASTM D3787-89 and ASTM D2256.
For more information, call 1-800-667-3220, visit ADMET or email [email protected].
