Surgical Suture Information

Sutures are designed to help the body heal by closely opposing two sides of a wound to minimize scar formation or to prevent leaking blood, like in vessels. Sutures have to comply with several regulations and guidelines such as United States Pharmacopeia and the FDA to ensure they meet the necessary requirements.

Essential suture characteristics:

All sutures by DemeTech are manufactured to meet the necessary qualities:

  • Sterility
  • Uniform diameter and size
  • Pliability for ease of handling and knot security
  • Uniform tensile strength by suture type and size
  • Freedom from irritants or impurities that would elicit tissue reaction
United States Pharmacopeia

The United States Pharmacopeia classification system was established in 1937 for standardization and comparison of suture materials, corresponding to metric measures. The 3 classes of sutures are collagen, synthetic absorbable, and nonabsorbable. Size refers to the diameter of the suture strand and is denoted as zeroes. The more zeroes characterizing a suture size, the smaller the resultant strand diameter (eg, 4-0 is larger than 5-0). The smaller the suture, the less tensile strength of the strand.

United States Pharmacopeia classification

 

  • Class I - Silk or synthetic fibers of monofilament, twisted, or braided construction.
  • Class II - Cotton or linen fibers or coated natural or synthetic fibers in which the coating contributes to suture thickness without adding strength.
  • Class III - Metal wire of monofilament or multifilament construction
U.S.P.
Suture Size
Average Minimum
(kgf)
Individual Minimum
(kgf)
11-0
0.007
0.005
10-0
0.014
0.010
9-0
0.021
0.015
8-0
0.050
0.025
7-0
0.080
0.040
6-0
0.170
0.080
5-0
0.230
0.110
4-0
0.450
0.230
3-0
0.680
0.340
2-0
1.100
0.450
0
1.500
0.450
1
1.800
0.600
2+
1.800
0.700
Natural Suture Materials

Natural sutures are made from natural materials such as collagen derived from the gastrointestinal track of animals, woven cotton, raw silk, linen, or steel. Because of the material, tissue reaction is often greater with natural sutures, especially those that are absorbable (e.g. Catgut). Coating agents are often used to help reduce tissue reactivity and to help reduce friction.

Natural Absorbable Sutures
Suture Material Plain Catgut Chromic Catgut
Description Plain Catgut suture is an absorbable, sterile, surgical suture composed of highly purified connective tissue (mostly collagen) derived from either beef or sheep intestines. Chromic Catgut is treated with chromium salt solution to resist body enzymes, thereby prolonging the absorption time to over 90 days.
Tissue reaction Moderate Moderate
Tensile strength Maintains strength for 7-10 days Maintains strength for 10-14 days
Degradation Enzymatic Enzymatic


Natural Non-Absorbable Sutures
Suture Material Silk Surgical Steel
Description Silk suture is a non-absorbable, sterile, surgical suture composed of an organic protein called fibroin. DemeTech's silk sutures are processed to remove the natural waxes and gums from its origin. Surgical Steel sutures are non-absorbable, sterile, surgical sutures composed of high quality stainless steel.
Tissue reaction Moderate Moderate
Tensile strength Srength decreases as moisture is absorbed and is completely lost within 1 year. Minimal loss over time
Degradation None None
Synthetic Sutures Materials

Synthetic sutures are made from synthetic collagen derived from polymers. Synthetic sutures are broken down by hydrolysis as opposite to enzymatic degradation (natural sutures), causing less tissue reaction.

Synthetic Absorbable Sutures
Suture Material Polyglycolic Acid Polyglactin 910 Polydioxanone
Description Polyglycolic Acid suture is a synthetic, absorbable, sterile, surgical suture composed of 100% glycolide. Polyglactin 910 suture is a synthetic, absorbable, sterile, surgical suture composed of copolymers made from 90% glycolide and 10% L-lactide. Polydioxanone suture is an absorbable, sterile, surgical suture composed of the polyester poly (p-dioxanone). DemeTech's Polydioxanone has been found to be nonantigenic, nonpyrogenic, and elicits only minimal tissue reactivity during the absorption process.
Tissue reaction Mild Mild Minimal
Tensile strength 84% at 2 weeks, 23% at 4 weeks. 74% at 2 weeks, 18% at 4 weeks. 80% at 2 weeks, 44% at 8 weeks. Complete absorption within 200 days.
Degradation Hydrolysis Hydrolysis Hydrolysis


Synthetic Non-Absorbable Sutures
Suture Material Polyester Nylon Polypropylene
Description Polyester suture is a non-absorbable, sterile, surgical suture composed of Poly (ethylene terephthalate). DemeTech uniformly coats its Polyester sutures, providing for an improvement in the physical properties of the suture. High quality materials, combined with precise braiding mechanisms, nearly eliminate the occurrence of post-operative suture fragments in the tissue. Nylon suture is a non-absorbable, sterile surgical suture composed of the long chain aliphatic polymers Nylon 6 and Nylon 6.6. DemeTech's Nylon sutures are available in either black or blue, dyed with FDA listed dye(s). DemeTech's Nylon sutures elicit minimal inflammatory reaction in tissue. Polypropylene suture is a non-absorbable, sterile surgical suture composed of a synthetic linear polyolefin. DemeTech's Polypropylene suture elicits a minimal acute inflammatory reaction in the tissue, followed by gradual encapsulation of the suture by fibrous tissue. Due to its monofilament composure, Polypropylene suture resists involvement in infection. Moreover, Polypropylene has been successfully implemented in contaminated and previously infected wounds.
Tissue reaction Minimal Minimal Minimal
Tensile strength Not known to lose tensile strength in vivo. Progressive hydrolysis may cause loss in tensile strength up to 20% per year. Maintains tensile strength up to two years.
Degradation None None None