Abstract:

Objective The holding force of non-absorbable barbed sutures is a very important index, but its influencing factors have not been systematically studied. Therefore, this work was carried out to explore the influence of needle shape and linear structure on the holding force of non-absorbable barbed sutures.
Method Six kinds of barbed sutures with different needle types and linear structures were prepared and tested via bending model on silica gel artificial skin tissue. The micromorphology of different specimens before and after the holding force test was observed by microscope. Besides, chemical composition and tensile performances of different specimens were tested and analyzed.
Results After the holding force test, silica gel residue can be observed at the roots of the two barbed sutures (Fig. 4), indicating that the barb has a certain ability to hold the silica gel artificial skin tissue. Fourier transform infrared spectroscopy (FT-IR) results illustrated that the chemical structures of sutures A1 and B were both non-absorbable polyamide sutures (Fig. 5). Tensile performances of A1 and B sutures were compared, and there is no significant difference in strength between the two, but suture B showed a better breaking elongation (19.42±2.67)% and flexibility (Tab. 3). Finally, the holding force of the six barbed sutures was tested via bending model on silica gel artificial skin tissue and the influence of barb and needle structure on holding force was analyzed (Fig. 7). The external expansion angle of suture A1 and B were (15.13±2.08)° and (16.32±1.01)°, the cut depth of suture A1 and B were (0.091±0.018) mm and (0.114±0.041) mm. The two parameters of suture 6 were greater than that of suture 1, which is beneficial to improve the holding area of barb to surrounding artificial skin tissue. In addition, the cut distance of suture B was (0.865±0.016) mm, less than that of suture A1, which was (0.982±0.018) mm, indicating a higher barb density for suture B. The influence of needle structure on holding force was further divided into needle shape, chord length, radian and curvature. Results show that the holding force of sutures A1 to A5 were (3.86±0.38) N, (3.95±0.50) N, (5.71±0.62) N, (8.00±1.20) N and (4.56±0.34) N, respectively. Under the same conditions, the holding force of round needle barbed suture A2 and A4 was higher than that of triangular needle barbed suture A1 and A3, respectively. The chord length of suture A3 and A4 are longer than that of suture A1 and A2. The larger the chord length of the suture needle, the greater the holding force of the barbed suture. The radian of needle in suture A5 is smaller than that in suture A3, the holding force of barbed suture produced by small needle was lower than that produced by large radian needle. The curvature of needle in suture A5 is smaller than that in suture A1, the smaller the curvature of the needle, the greater the holding force generated by the corresponding barbed suture.
Conclusion Holding force of six kinds of non-absorbable barbed sutures were tested via bending model on silica gel artificial skin tissue. Under the same conditions, appropriately increasing the external expansion angle or cut depth, reducing the cut distance of the suture can improve the holding force of barbed sutures. The specification and structure of needle also have a certain effect on the holding force of barbed sutures. Under the same conditions, the holding force of round needle barbed suture is greater than that of triangular needle barbed suture. With the same radian, the larger the chord length of needle, the greater the holding force of barbed suture. With the same curvature, the larger the radian length, that is, the longer the chord length and needle length, the higher the holding force of barbed suture. With the same needle length, appropriate reduction of the curvature of needle can increase the holding force of barbed suture.

Key words: barbed suture, non-absorbable, grip force, tensile property, microstructure