Sutures are classified as absorbable or nonabsorbable, natural or synthetic, and braided or monofilament. Numerous companies manufacture sutures; however, Ethicon, Syneture (United States Surgical/Davis and Geck suture division of Tyco Healthcare), and Look (Surgical Specialties Corporation) manufacture most of the sutures used in wound closure. Most sutures are available in standard 18- and 27-inch lengths. Several manufacturers (eg, Delasco, Look) provide sutures in 8-, 9-, and 10-inch lengths. These shorter sutures are less expensive and are used primarily for biopsy wounds or small wound closures.
Absorbable suture materials
Absorbable sutures are defined by the loss of most of their tensile strength within 60 days after placement. They are used primarily as buried sutures to close the dermis and subcutaneous tissue and reduce wound tension. The only natural absorbable suture available is surgical gut or catgut. Synthetic braided materials include polyglycolic acid (Dexon; Syneture) and Polyglactin 910 (Vicryl; Ethicon). Monofilamentous forms include polydioxanone (PDS; Ethicon), polytrimethylene carbonate (Maxon; Syneture), poliglecaprone (Monocryl; Ethicon), Glycomer 631 (Biosyn; Syneture), and Polyglytone 6211 (Caprosyn; Syneture).
Table 1. Characteristics of Absorbable Sutures (Open Table in a new window)
Property | Gut | Polyglycolic Acid | Polyglactin | Polydioxanone | Polytrimethylene Carbonate | Poliglecaprone |
Handling | Fair | Fair-good | Good | Poor | Good | Excellent |
Knot security | Poor | Fair-good | Fair | Poor | Good | Good |
Tensile strength | Low Proteolysis by 60-90 d, unpredictable | High Hydrolysis by 90-120 d | High Hydrolysis by 60-90 d | Moderate Hydrolysis by 180-210 d | High Hydrolysis by 180-210 d | High Hydrolysis by 90-120 d |
Coefficient of friction | High | High | Medium | Low | Low | Low |
Memory | Low | Low | Low | High | Low | Low |
Tissue reactivity | High | Low-moderate | Low-moderate | Low | Low | Low |
Uses | Mucosal tissues, vessel ligation | Buried | Buried; Vicryl Rapide (Ethicon) in wounds requiring short-term dermal support | Buried; in wounds requiring long-term dermal support | Buried; in wounds requiring long-term dermal support | Buried |
Other | Low elasticity Beige, violet, or green | Low elasticity Clear or violet | Clear or violet | Clear or green | High elasticity Clear |
Surgical gut
Surgical gut or catgut was the first absorbable suture material available. Despite its name, catgut has never been made from cat intestines. It is actually made by twisted fiber formed from the collagen of the intestines of sheep, cattle, or goats. The name refers to a 16th century word for a stringed instrument kit or cat. Gut was another 16th century word for a string. Taken together, catgut means instrument string.
Surgical gut is packaged in alcohol to prevent it from drying and breaking. The three forms available are plain, chromic, and fast-absorbing (Ethicon). Plain gut elicits a marked inflammatory reaction in tissue and maintains its tensile strength for only 7-10 days after implantation. Generally, it is completely absorbed by 70 days; however, loss of strength and absorption vary greatly.
Chromic gut is plain gut treated with chromium salts to slow absorption and decrease tissue reactivity by cross-linking the collagen. Its tensile strength is maintained for as long as 10-21 days, and complete absorption does not occur until at least day 90. Plain and chromic gut have decreased use in modern surgery owing to the development of synthetic sutures that are hydrolyzed and therefore less inflammatory. This material is used in the closure of mucosal surfaces or as ligatures for blood vessels, among other uses.
Fast-absorbing gut is plain gut treated with heat to facilitate more rapid absorption. It was designed for percutaneous suturing and maintains its tensile strength for only 5-7 days. It is completely absorbed within 2-4 weeks. Fast-absorbing gut is useful for the percutaneous closure of facial wounds under low tension and for securing both split- and full-thickness skin grafts.
Polyglycolic acid
Polyglycolic acid (Dexon S; Syneture) was introduced in 1970 as the first synthetic absorbable suture. It has high tensile strength, with a retention of 60% at day 7, 35% at day 14, and only 5% at day 28. Polyglycolic acid is completely hydrolyzed by 90-120 days. This braided suture is uncoated and multifilamentous; therefore, it has good handling and knot security properties. However, its high coefficient of friction results in significant tissue drag. To minimize this drag, a polycaprolate-coated form is available (Dexon II; Syneture). This form slides readily through tissue and is easy to tie; however, 4 throws are recommended to ensure secure knots. The tissue reactivity associated with this material is relatively low, but the multifilament nature may potentiate infection. Polyglycolic acid is available as a clear or green suture.
A fast-absorbing polyglycolic acid suture (Polysyn FA; Surgical Specialties) is available that maintains tensile strength for 7-10 days and is completely hydrolyzed by 42 days. This suture is useful in wounds requiring short-term dermal support.
Polyglactin
Introduced in 1974, polyglactin was the second synthetic absorbable suture material available. Like polyglycolic acid, polyglactin is braided and has similar handling and knot security properties. Polyglactin 910 (Vicryl; Ethicon) is coated with Polyglactin 370, which facilitates knot tying and reduces tissue drag; however, this coating also reduces knot security and may require the use of extra throws.
The initial tensile strength of polyglactin is slightly greater than that of polyglycolic acid and is absorbed more quickly. Polyglactin retains 60% of its tensile strength at day 14 after implantation and only 8% of its original strength at day 28. It is completely hydrolyzed by 60-90 days. Tissue reactivity with polyglactin is low, less than that of polyglycolic acid. Both of these suture materials may be transepidermally eliminated if buried too superficially in the dermis. Although used primarily as a buried suture, polyglactin has been used for percutaneous closures without adverse outcomes and with resultant cost savings. Polyglactin is available as a clear or violet suture.
Two additional Polyglactin 910 sutures have been developed by Ethicon. Vicryl Rapide is Polyglactin 910 that has been ionized with gamma rays to speed its absorption. This product is useful as a buried suture in a wound requiring limited dermal support; it is completely absorbed in 35 days. The newest material is an antibacterial suture (Coated Vicryl Plus Antibacterial; Ethicon). The antibacterial agent used to coat the suture is triclosan. [9] Biocompatibility and implantation studies have shown this to be noncytotoxic and nonirritating. Handling and wound healing characteristics and absorption profile are comparable to the original Polyglactin 910 material.
Ford et al [7] showed that fewer pediatric patients treated with the antibacterial suture had pain on postoperative day 1 when compared with those treated with the original Polyglactin 910 suture (68% vs 89%). Both in vitro and in vivo studies have demonstrated that antibacterial Polyglactin 910 suture inhibits bacterial colonization with both methicillin-sensitive and methicillin-resistant Staphylococcus aureus and Staphylococcus epidermidis. This suture may be useful in wounds at increased risk of infection.
Polydioxanone
A synthetic monofilament absorbable suture, polydioxanone (PDS; Ethicon) was first available in 1982. Although its initial tensile strength is lower than that of the 2 synthetic braided sutures mentioned above, it retains its strength longer. At day 14 after implantation, it has 74% residual initial strength; at day 28, 58%; and at week 6, 41%. Complete hydrolysis occurs by 180-210 days. Polydioxanone is stiff and has poor handling and knot-tying properties. Knot security is likewise low and requires an additional throw. [10, 11] A newer product that has replaced the original product is PDS-II (Ethicon), which has improved handling capabilities.
As a monofilament suture, polydioxanone causes minimal tissue reaction. It is useful in contaminated wounds or wounds in locations at greater risk for infection. Polydioxanone is also useful as a buried suture in wounds that require prolonged dermal support. Dermal support of a wound may reduce the spreading of scars. Elliot and Mahaffey [12] demonstrated that a 16% reduction in the spreading of scars can be accomplished by using dermal support for 3 weeks. They further showed a 38% reduction in spread with the use of dermal support for 6 months. Polydioxanone is available as a clear or violet suture. Polydioxanone is more expensive than polyglycolic acid or polyglactin.
Polytrimethylene carbonate
Polytrimethylene carbonate or polyglyconate (Maxon; Syneture) was introduced in 1985 as another synthetic monofilament absorbable suture. It has a high initial tensile strength (greater than that of polydioxanone), and it retains 81% of its strength at day 14, 59% at day 28, and 30% at week 6. It is completely hydrolyzed by 180-210 days. Polytrimethylene carbonate is easier to handle and has greater knot security than polydioxanone, polyglactin, or polyglycolic acid. Its tissue reactivity is comparable to that of polydioxanone, its uses are the same, and its cost is lower. Polytrimethylene carbonate is available as a clear or green suture.
Poliglecaprone
Poliglecaprone (Monocryl; Ethicon) is a synthetic absorbable material introduced in 1993. Poliglecaprone is very pliable despite its monofilament nature, and, as a result, its handling and knot strength are excellent. Among all absorbable monofilament sutures, poliglecaprone has the highest tensile strength; however, only 20-30% of its strength is retained at day 14 after implantation. Complete hydrolysis occurs by 90-120 days. Poliglecaprone is most useful as a buried suture in wounds in which prolonged dermal support is not essential. Similar to other monofilament sutures, poliglecaprone has minimal tissue drag and reactivity. It is available as a clear material. The cost of poliglecaprone is comparable to that of polydioxanone.
An antibacterial form of poliglecaprone is now available (Monocryl Plus Antibacterial; Ethicon). The antibacterial agent is triclosan, which has been shown to inhibit colonization of the suture by methicillin-sensitive and methicillin-resistant S aureus and S epidermidis, Escherichia coli, and Klebsiella pneumoniae, even after direct in vivo challenge with bacteria. The tensile strength and absorption profile are similar to that of untreated poliglecaprone.
Other
A monofilament synthetic polyester, Glycomer 631 (Biosyn; Syneture), is another absorbable suture. Rodeheaver et al [13] compared it to Polyglactin 910 and found it to have greater tensile strength 4 weeks after implantation. The handling characteristics and knot security were also superior. Tissue drag and risk of bacterial infection were lower, likely a result of the monofilament construction. Glycomer 631 retains 75% of its tensile strength at day 14 and 40% at day 21. Absorption is complete between 90 and 110 days. This suture is available undyed or in violet.
Polyglytone 6211 (Caprosyn; Syneture) is a synthetic, monofilament suture material with greater tensile strength, lower tissue reactivity, and improved handling characteristics compared with chromic gut suture. Its greatest advantage, however, is its rapid rate of absorption. It provides secure wound approximation for 10 days, and all tensile strength is lost by day 21. It is completely hydrolyzed in 56 days. Polyglytone 6211 is available undyed or in violet.
Poly-4-hydroxybutyrate (P4HB) (TephaFlex) is a unique absorbable monofilament suture material made from a polyhydroxyalkanoate. While absorbable, it degrades very slowly, and its tensile strength exceeds that of polydioxanone and polypropylene. P4HB retains approximately 70% of its strength after 12 weeks in vivo and is essentially fully resorbed by 12-18 months. When stretched, its mechanical strength increases but remains flexible compared with polyglycolides and polylactides. [14]
Nonabsorbable suture material
Nonabsorbable sutures are defined by their resistance to degradation by living tissues. They are most useful in percutaneous closures. Surgical steel, silk, cotton, and linen are natural materials. Synthetic nonabsorbable monofilament sutures are most commonly used in cutaneous procedures and include nylon, polypropylene, and polybutester. Synthetic nonabsorbable braided sutures composed of nylon and polyester are used infrequently in dermatologic surgery.
Table 2. Nonabsorbable Suture Characteristics (Open Table in a new window)
Properties | Silk | Nylon, Monofilament | Nylon, Multifilament | Polyester | Polypropylene | Polybutester |
Handling | Excellent | Poor | Fair-good | Good | Poor | Good |
Knot security | Excellent | Poor | Fair-good | Good | Poor | Fair-good |
Tensile strength | Low | High | High | High | Moderate | High |
Coefficient of friction | High | Low | High | High | Very low | Very low |
Memory | Low | High | Medium | Medium | High | Low |
Tissue reactivity | High | Low | Moderate | Low-moderate | Low | Low |
Uses | Mucosal tissues, conjunctiva or intertriginous zones; to elevate or retract tissues | Percutaneous; buried if prolonged dermal support is needed | Minimal use in dermatologic surgery | Minimal use in dermatologic surgery | Percutaneous; buried if prolonged dermal support is needed; running subcuticular closures | Percutaneous; running subcuticular closures |
Other | Black | Black, green, or clear | Green or clear | High plasticity Blue or clear | High elasticity Blue or clear |
Silk
Silk was first widely used as a suture material in the 1890s. It is a braided material formed from the protein fibers produced by silkworm larvae. Although silk is considered a nonabsorbable material, it is gradually degraded in tissue over 2 years. Silk has excellent handling and knot-tying properties and is the standard to which all other suture materials are compared. Its knot security is high, tensile strength low, and tissue reactivity high. Suture removal can be difficult and painful because the braided material becomes infiltrated with cells and encrusted with debris while implanted in the skin.
Silk is a soft, pliable suture material that is comfortable for patients and unlikely to tear through even delicate tissues. As a result, it is a good choice for use in mucosal tissues or intertriginous areas. Silk also is useful as a temporary suture to elevate or retract tissues for improved visibility during surgery. It is available in black.
Nylon
Introduced in 1940, nylon was the first synthetic suture available, and it is the most commonly used nonabsorbable material in wound closure. It is available in both monofilamentous and braided forms. Nylon has a high tensile strength, and, although it is classified as nonabsorbable, it loses tensile strength when buried in tissue. Braided forms retain no tensile strength after being in tissue for 6 months, whereas monofilamentous forms retain as much as two thirds of their original strength after 11 years. Monofilament nylon is stiff; therefore, handling and tying are difficult and knot security is low. The suture also may cut easily through thin tissue.
Braided forms have better handling properties but greater tissue reactivity and cost. They are used infrequently in wound closure. Monofilament nylon is relatively inexpensive and available as black, green, or clear. Although its greatest use is as a percutaneous suture, because of its low tissue reactivity, nylon (clear) can be used as a buried suture in situations in which prolonged dermal support is necessary.
Polyester
Polyester is a braided synthetic suture with uses similar to those of braided nylon. It has high tensile strength, with good handling, good knot security, and relatively low tissue reactivity. Polyester is available in a coated form that decreases tissue drag. It is a pliable, soft suture similar to silk and can be used in mucosal tissues or intertriginous areas. Additional suture tensile strength can be achieved when polyester is braided or blended with other synthetic fibers such as polyethylene in products like Ethibond (Ethicon) and Mersilene (Ethicon). These sutures, however, are costly and infrequently used for skin closure but instead on deep tissues such as tendon or fascia. Fiberwire (Arthrex) is a braided and coated ultra-high molecular weight polyethylene/polyester with high tensile strength used primarily in orthopedic bone, joint, and tendon surgery.
Polypropylene
Polypropylene (Prolene, Ethicon) is a monofilament synthetic suture that was introduced in 1962. Its tensile strength is lower than that of the other synthetic nonabsorbable sutures. Its handling, tying, and knot security are poor as a result of its stiff nature and high memory. An additional throw is needed for adequate knot security. A method to improve security is the use of thermocautery to fuse the knots or transform the ends into small beads. Tissue reactivity is extremely low for polypropylene, and, unlike nylon, gradual absorption does not occur if it is buried in tissue. As a result, polypropylene is an excellent choice for a buried suture for long-term dermal support.
Polypropylene has a low coefficient of friction and easily slides through tissue; this characteristic makes it the suture of choice for a running subcuticular closure. It is a plastic suture that accommodates tissue swelling; therefore, the likelihood of it cutting through the tissue and causing crosshatching is less than that of other materials. However, as swelling of a wound resolves, suture remains loose, and this looseness may affect wound approximation. The plasticity of polypropylene may actually improve knot security in some cases; the knot is tightened as the suture is stretched during wound swelling. Polypropylene is more expensive than nylon and is available as a clear or blue suture.
Polybutester
The newest monofilament nonabsorbable synthetic suture is polybutester (Novafil; Syneture). This suture combines many of the desirable characteristics of polypropylene and polyester. Polybutester has a high tensile strength with good handling qualities. Its memory is lower than that of polypropylene, and therefore, its knots are more secure. Polybutester is not a plastic suture, but it has unique elastic properties that allow it to optimally respond to wound edema. Like polypropylene, polybutester has a low coefficient of friction and is an excellent choice for a running subcuticular closure. Polybutester is available as a clear or blue suture. Its cost is comparable to that of polypropylene.
Other
Polyvinylidene fluoride (PVDF) (Pronova) is nonabsorbable monofilament synthetic suture by Peters Laboratoire Pharmaceutique (Bobigny, France). It is comparable to polypropylene but has added antithrombogenic properties that enhance its use in vascular surgery. [15]
Polytetrafluoroethylene (PTFE) (GoreTex) is a synthetic, nonabsorbable microporous monofilament suture with extremely low coefficient of friction, allowing easy, atraumatic tissue passing. While primarily used in cardiovascular surgery, it has utility in breast reconstruction as a subcuticular suture to evenly distribute forces and prevent scar widening when insetting the circular areola. Exposure of this suture material when placed superficially has been mitigated with newer techniques. [16]
Surgical steel is one of the oldest suture materials still in use. It is nonabsorbable and typically used in sternal wound closures as well as orthopedic surgery on bones and tendons. It has a high cost relative to other nonabsorbable suture material.
Also see the Medscape article Suturing Techniques.
