LAUSR

In the process of surgical suturing, friction phenomena at the interface between sutures and tissues can seriously affect the suturing efficiency. However, few studies have assessed the detailed effects of types of sutures or tissues and stitching parameters on the friction behavior. In this paper, the different factors affecting the friction behaviors between sutures and tissues were studied. The unidirectional sliding wear mode in a line-on-flat configuration was selected to simulate the real surgical suturing by using a UMT-II Micro-Tribometer. Artificial skin, porcine muscle and porcine liver were used as experimental samples. Three different surface morphology and structure sutures: multifilament suture (silk), monofilament suture (prolene) and multifilament suture with coating (vicryl), were investigated in this study. The normal load was from 0.1 to 0.5 N, and the unidirectional sliding (suturing) speed was from 5 to 25 mm/s to simulate the suturing operation. Results showed that the friction coefficient at the suture–tissue interface decreased with the increase in normal load and increased with the increase in suturing speed due to the nonlinear viscoelasticity and deformation hysteresis of the soft tissues. The sutures with monofilament structure or coating could effectively reduce the friction coefficient of the suture–tissue interface. Compared to the artificial skin, the porcine tissues had the lower friction coefficients because of 30% blood and 17% interstitial fluid filled in liver and muscle, respectively, which acted as lubricants and reduced the adhesion friction coefficient of the suture–tissue interface. The results can provide guidance for the surgical suture manufacture and the surgical manipulation skills.