Surgery of Exotic Animals. Группа авторов

good knot security, resist infection, and cause no inflammatory, immunogenic, or carcinogenic reactions. The reaction of tissue to sutures depends on several variables such as the type, quantity, and duration of suture implantation as well as the tissues into which suture is implanted.

      Surgeons must be familiar with different suture materials in order to make the most appropriate choice for specific clinical situations (Ratner et al. 1994). It is important to have a thorough understanding of the tissues, healing time required, the time the suture retains sufficient tensile strength to support the tissues as they heal, and time to complete absorption. The suture that is chosen may affect wound healing, functional outcome, and cosmetics. The number of suture types available has increased dramatically, and each suture type has specific physical, handling, and tissue reaction characteristics. Sutures are classified in many ways based on their ability to be absorbed and whether they are single, stranded, or braided. Different suture properties can also affect the knot security which must also be considered when choosing suture materials (Marturello et al. 2014).

Absorbable Suture Materials

Absorbable suture materials are defined as materials that lose their tensile strength within 60 days of implantation (Tan et al. 2003). These sutures are either composed of different synthetic polymers or are of biologic origin. Absorbable sutures that are biologic in origin are broken down by phagocytosis, while synthetic polymers are absorbed by hydrolysis. Hydrolysis involves breaking down polymers into monomers by direct water cleavage, and the monomers are then absorbed and metabolized by the body (Tan et al. 2003). Common absorbable sutures include chromic gut, polydioxanone (PDS™, Ethicon Inc., Cincinnati, OH), poliglecaprone 25 (Monocryl™, Ethicon Inc., Cincinnati, OH), polyglactin 910 (Vicryl™, Ethicon Inc., Cincinnati, OH), polyglyconate (Maxon™, Covidien, Medtronics, Minneapolis, MN), synthetic polyester called Glycomer™ 631 (Covidien, Medtronics, Minneapolis, MN) comprised of glycolide (60%), dioxanone (14%), and trimethyelene carbonate (14%) (Biosyn™, Covidien, Medtronics, Minneapolis, MN), polyglycolic acid (Dexon™, Covidien, Medtronics, Minneapolis, MN), polyglytone 6211 (Caprosyn™, Covidien, Medtronics, Minneapolis, MN), and synthetic polyester called Lactomer™ comprised of a copolymer of glycolide and lactide (Polysorb™, Covidien, Medtronics, Minneapolis, MN).

Figure 2.1 Inflammatory reactions after implantation of different suture materials to demonstrate variation in inflammatory reactions. Samples were chosen as representative examples of zero (a), mild (b), moderate (c), and severe (d) inflammatory responses. Suture material was lost in (a) and (b) during processing, but surrounding inflammatory reaction is intact.

      Images are 20× magnification.

      Various companies manufacture generic versions of most of these suture materials. In one study comparing the same material made by two different companies (Ethicon, Inc., and Hyaiyin Medical Instruments Co. Ltd.), the materials had significantly different tensile strength and stiffness (De La Puerta et al. 2011). In some comparisons, the generic outperformed the brand name materials. Most studies of suture materials are conducted using brand name materials. Based on this study, direct comparisons between brand names and generic materials cannot be made.

Biologic Absorbable Suture Material

      Chromic Gut

      Chromic gut is a monofilament absorbable suture composed of purified connective tissue (mostly collagen) derived from either bovine or ovine intestine and is absorbed by phagocytosis and enzymatic digestion by macrophages (Bellenger 1982; Roush 2003). Chromic salts are used to coat the suture to help delay absorption, increase tensile strength, and decrease tissue reactivity. Chromic gut is rapidly absorbed in mammals, is completely absorbed in approximately 60–90 days, and only maintains tensile strength for 7–10 days (Ratner et al. 1994). Chromic gut has a tendency to cause increased inflammatory response compared to other absorbable sutures which makes it less desirable.

Synthetic Absorbable Suture Materials

      Synthetic absorbable sutures are all composed of different monomers or polymers. Each monomer affects the resultant strength, flexibility, and speed at which the suture is absorbed. Monomers used in most currently available sutures include glycolide, lactide, p‐dioxanone, ε‐caprolactone, and trimethylene carbonate. Glycolide and lactide contribute to the resulting strength of the suture, while ε‐caprolactone and trimethylene carbonate contribute to increased flexibility. p‐Dioxanone contributes moderate strength and moderate flexibility. Combinations of these monomers in different proportions are used to obtain desired properties for different applications.

      Polydioxanone

      Polydioxanone is a monofilament absorbable suture that elicits minimal reaction, is slowly absorbed, and maintains tensile strength for extended periods. It maintains 70% of its tensile strength at 2 weeks, 50% at 4 weeks, and 25% at 6 weeks with complete absorption in approximately 180 days (Bellenger 1982; Ratner et al. 1994; Roush 2003). Initial tensile strength for polydioxanone is greater than surgical gut, polyglycolic acid, or polyglactin 910, but it has the poorest knot security of the synthetic absorbable sutures (Boothe 1998). It is useful when prolonged support of healing tissue is desired (Tan et al. 2003).

      Poliglecaprone 25

      Poliglecaprone 25 is a monofilament absorbable suture composed of segmented block copolymers of ε‐caprolactone and glycolide (Bezwada et al. 1995). Soft segments of ε‐caprolactone and glycolide contribute to favorable handling characteristics and hard segments of polyglycolide contribute to tensile strength. Poliglecaprone 25 is one of the strongest absorbable sutures, although it rapidly weakens after implantation (Tan et al. 2003). Tensile strength of 20–30% is maintained at 2 weeks and complete absorption occurs between 90 and 100 days (Bezwada et al. 1995; Roush 2003).

      Polyglactin 910

      Polyglactin 910 is a multifilament suture composed of a copolymer of lactic and glycolic acids that are coated with calcium stearate and a second copolymer of glycolide and lactide. The braided nature of this suture not only results in good handling properties but also increases tissue drag (Ratner et al. 1994). Tensile strength is approximately 60% at 2 weeks and only 30% at 3 weeks with complete absorption in approximately 60 days (Bellenger 1982; Ratner et al. 1994; Fossum 2002; Roush 2003). Vicryl Rapide™ (polyglactin 910) has 66% of the initial tensile strength and loses tensile strength faster compared to regular polyglactin 910 (Tan et al. 2003). It is designed for rapidly healing tissues where long‐term support is not required.

      Polyglyconate

      Polyglyconate is a monofilament suture composed of copolymers of glycolide and trimethylene carbonate. Tensile strength is approximately 80% at 1 week, 75% at 2 weeks, 50% at 4 weeks, and 25% at 6 weeks with complete absorption at 180 days (Tan et al. 2003).

      Glycomer™ 631

      Glycomer 631 is a monofilament suture composed of synthetic polyesters and alternating segments of glycolide and dioxanone with segments of trimethylene carbonate and dioxanone. It retains 75% of its tensile strength at 2 weeks and 40% at 3 weeks. Complete absorption occurs between 90 and 110 days.

      Polyglycolic Acid

      Polyglycolic acid is