Sutures

The Challenge

Sutures are manufactured from a variety of absorbable and non-absorbable materials, and may be a single filament or braided with or without coating. Tensile strength and strain are critical measures of performance during and after surgical procedures. The strength of different knotting techniques must also be evaluated. The test method must determine breaking strength and corresponding percent elongation, accurately measure strain without damaging material and adhere to Food and Drug Administration (FDA) guidelines.

Our Solution

Typical tests include a 'straight-pull' test, which evaluates the tensile strength and elongation of the suture material itself, and a 'knot-pull' test, which evaluates the tensile strength of specific knotting techniques used during surgery. Tests can be conducted in a saline bath to evaluate the strength of suture material under physiological conditions. The fluid environment and body temperature can change material properties, and such changes must be understood before the materials are used in surgery.

Instron's pneumatically activated cord and yarn grips, as well as manual capstan grips, are ideal for gripping suture material. Wrapping the material around the mandrel ahead of the clamp eliminates high stress points that lead to premature failure. Typical test set-ups use an Instron universal testing system.