A new method to measure elastic properties of plastic-viscoelastic connective tissue.

An experimental protocol was tested to measure elastic properties of connective tissue displaying viscoelastic as well as plastic properties. The protocol consisted of a slow rate, linear elongation (0.88 mms(-1), 8 mm) in combination with a superimposed sinusoidal vibration of small amplitude (50 Hz, 0.1 mm). Using digital filters and mathematical algorithms, the force responses to linear elongation and to vibration were obtained. The method was tested on excised fibromuscular tissue of the vaginal wall obtained from women who suffered a vaginal prolapse. The force-stiffness and force-elongation relationships based on the vibration response were unaffected by any long-term deformation of the specimens. The directly measured force-elongation curves were strongly affected by these deformations. It was therefore concluded that with the new method, it is possible to determine the elastic properties accurately. Furthermore, this method seems more sensitive to small changes in elastic properties than the classic tensile test.