Suture materials

Absorbable vs Non-absorbable

The major subdivision of sutures. Sutures that lose the majority of their tensile strength within 60 days are considered absorbable. They are degraded by tissue enzymes or hydrolysis.

• Absorbable sutures are generally used as deep sutures; they do not need to be removed post-operatively.

• Non-absorbable sutures are used for surface sutures; require manual removal post-operatively.

Tensile Strength

Depends on UPS size (thickness). Surgeons prefer to use the smallest size that will provide adequate strength. The strength increases as the first digit decreases.

• 3-0 is a thick strong suture

• 6-0 is a thin comparatively weak suture.

Plasticity and Elasticity

The ability to retain length and strength after stretch, and the ability to regain its original length after stretch, respectively. This is important:

• To accommodate post-operative oedema without cutting into the tissue

• To maintain epidermal approximation once the oedema has resolved.

Ease of handling and Knot security

Determined by a number of related characteristics.

• A suture with a low coefficient of friction slides through tissue well but the knot will unravel more easily.

• A suture with a high memory will spring back to its original position. While these sutures tend to be strong, they may be difficult to handle and have decreased knot security.

• A suture with high pliability can be easily bent, and will therefore handle well with good knot security.

Multifilament vs Monofilament

• Multifilament braided sutures handle more easily and tie well, but can potentially harbour organisms between fibres leading to increased infection risk. They should be avoided in contaminated wounds. They also tend to have higher capillarity so can absorb and transfer fluid more easily increasing potential for bacteria to enter from the skin surface.

• Monofilament sutures have a lower infection risk and a lower coefficient of friction, but with a lower ease of handling and knot security.

Tissue reactivity

Refers to the degree of inflammatory response to the suture.

• Higher for natural products such and silk and gut

• Lower for synthetic fibres such as nylon.

Surgical Gut

• Plain gut loses its strength in 7-10 days and is completely digested by 60 days. It is seldom used now due to poor strength and high tissue reactivity (due to proteolytic enzyme degradation rather than hydrolysis).

• Chromic gut has been manufactured with chromium salts to reduce enzyme digestion and therefore maintains strength for 10-14 days making it useful for mucosal closures.

• Fast-absorbing gut is produced by pre-heating and can be used for attaching skin grafts, or in areas of low tension where the wound is well supported by deep sutures, and suture removal would be difficult. It maintains strength for 3-5 days.

Polyglactin 910 (Vicryl®, Polysorb®)

• A synthetic braided co-polymer which maintains 75% strength at 2 weeks, and 50% at 3 weeks. Absorption is usually complete by 3 months. It handles well, has minimal tissue reactivity, and does not tear tissue. It may occasionally persist as a small nodule or extrude (‘spitting’).

Poliglecaprone 25 (Monocryl®)

• Monofilament maintaining 50-60% strength at 7 days with complete absorption by 3 months. It offers better handling and knot security than most other monofilament sutures, with even less tissue reaction than Vicryl® and is therefore useful where minimal tissue reaction is essential.

Polydioxanone (PDS II®)

• Monofilament polymer with prolonged tensile strength (70% at 2 weeks, 50% at 4 weeks) and may persist for more than 6 months. Good for high-tension areas or contaminated wounds, but being a monofilament it has poor handling and knot security. Its minimal tissue reaction makes it good for repair of cartilage where inflammation would lead to significant discomfort.

Polytrimethylene carbonate (Maxon®)

• A monofilament that combines the prolonged strength of PDS® and the good handling and knotting of Vicryl®. 80% strength at 2 weeks, 60% at 4 weeks, and complete absorption by 6 months. Minimal tissue reaction.

Glycomer 631 (Biosyn®)

• A monofilament similar to Monocryl® in characteristics but with prolonged strength akin to Maxon®.

Nylon (Ethilon®, Dermalon®, Surgilon®, Nurolon®, Nylene®)

• Inexpensive monofilament with good tensile strength, and minimal tissue reactivity. Disadvantages are its handling and knot security, but it remains one of the most popular non-absorbable sutures in dermatological surgery. Surgilon® and Nurolon® handle better but are more expensive.

Polybutester (Novafil®)

• A monofilament with good handling and excellent elasticity. It responds well to tissue oedema, and is also suited to subcuticular running sutures.

Polypropylene (Prolene®, Surgilene®, Surgipro®)

• A monofilament polymer with a very low coefficient of friction making it the suture of choice for running subcuticular stitches. It has good plasticity but limited elasticity, poor knot security, and it is relatively expensive. Favoured by some for facial repairs.

Silk (Dysilk®)

• Braided natural protein with unsurpassed handling, knot security, and pliability (making it ideal for mucosal surfaces and intertriginous areas) but limited by its low tensile strength, and high coefficient of friction, capillarity, and tissue reactivity.

Polyester (Dacron®, Mersilene®, Ethibond®)

• Braided multifilament suture with high strength, good handling, and low tissue reactivity. Ethibond is coated and has a low coefficient of friction. Pliability makes these excellent for mucosal surfaces without the reactivity of silk.