Liber-Kneć Aneta, Łagan Sylwia
Institute of Applied Mechanics, Cracow University of Technology, Kraków, Poland.
Polim Med. 2016 Jul-Dec;46(2):111-116. doi: 10.17219/pim/68735.
The exact characteristics of sutures are not only the basis for selecting from among different types of suture, but also provide the necessary information for the design of new surgical sutures. Apart from information relating to the breaking load of a suture reported in pharmacopoeias, the viscoelastic properties of sutures can be an additional selection criterium - one that influences stitching quality, especially when there is a risk of wound dehiscence.
The aim of the study was to assess the stress relaxation process for 3 polymeric sutures in an environment simulating the conditions in a living organism and (for comparison) in room conditions.
Stress relaxation testing was carried out on 3 polymeric sutures: polypropylene (PP), polydioxanone (PDS) and polyglycolic acid (PGA). To identify the mechanical properties of the sutures, uniaxial tensile tests were conducted according to the Polish Pharmacopoeia. The relaxation test was carried out in room conditions and in the bath simulating a biological environment. The sutures being tested were tied with a surgeon's knot.
The PP suture exhibited the greatest stress relaxation (18% of the initial stress in room conditions and 21% of the initial stress in the bath). The PGA suture exhibited the least stress relaxation (approximately 60% of the initial stress in room conditions and 59% of the initial stress in the bath). The PDS suture was tested at a lower strain level and showed stress relaxation similar to the PGA suture (approximately 63% of the initial stress in room conditions and 55% in the bath).
Multifilament braided absorbable (PGA) sutures and monofilament absorbable (PDS) sutures had a higher stress relaxation ratio over time than monofilament non-absorbable (PP) sutures. These findings may indicate higher stress maintained over time in PDS and PGA sutures, and thus higher tension at wound edges, sufficient to resist wound dehiscence.
缝线的确切特性不仅是在不同类型缝线中进行选择的依据，还为新型手术缝线的设计提供必要信息。除了药典中报道的与缝线断裂负荷相关的信息外，缝线的粘弹性特性可以作为一个额外的选择标准——这一特性会影响缝合质量，尤其是在存在伤口裂开风险的情况下。
本研究的目的是评估3种聚合物缝线在模拟生物体内条件的环境中（以及作为对照，在室温条件下）的应力松弛过程。
对3种聚合物缝线进行应力松弛测试：聚丙烯（PP）、聚二氧六环酮（PDS）和聚乙醇酸（PGA）。为了确定缝线的力学性能，根据波兰药典进行单轴拉伸试验。松弛试验在室温条件下和模拟生物环境的浴槽中进行。受试缝线用外科结打结。
PP缝线表现出最大的应力松弛（室温条件下为初始应力的18%，浴槽中为初始应力的21%）。PGA缝线表现出最小的应力松弛（室温条件下约为初始应力的60%，浴槽中为初始应力的59%）。PDS缝线在较低应变水平下进行测试，其应力松弛与PGA缝线相似（室温条件下约为初始应力的63%，浴槽中为55%）。
多股编织可吸收（PGA）缝线和单股可吸收（PDS）缝线随时间的应力松弛率高于单股不可吸收（PP）缝线。这些发现可能表明PDS和PGA缝线随时间维持的应力更高，因此伤口边缘的张力也更高，足以抵抗伤口裂开。
