Dr.S.Harsha Vardhan

Sutures, commonly called stitches, are sterile, surgical threads that are used to repair cuts (lacerations). They also are used to close incisions from surgery.

There are many kinds of sutures, with different properties suitable for various uses.

Causes minimal tissue injury or tissue reaction ( nonelectrolytic, noncapillary, nonallergenic, noncarcinogenic)

Easy to handle Holds securely when knotted (no fraying or

cutting) High tensile strength Favorable absorption profile Resistant to infection Can be used in any tissue Good knot security

Sutures must be strong (so they do not break), non-toxic and hypoallergenic (to avoid adverse reactions in the body), and flexible (so they can be tied and knotted easily).

In addition, sutures must lack the so called "wick effect", which means that sutures must not allow fluids to penetrate the body through them from outside, which could easily cause infections.

Sutures can be classified into two groups: absorbable sutures and non-absorbable sutures.

An absorbable suture breaks down in tissue after a given period of time. It degrades as a wound or incision heals.

A non-absorbable suture resists the body's attempt to dissolve it. Non-absorbable sutures may be removed by a surgeon after a surface incision has healed.

Absorbable sutures include :- Polyglycolic Acid sutures, Polyglactin 910 , Catgut, Poliglecaprone 25 and Polydioxanone sutures.

Non-Absorbable sutures include :- Polypropylene sutures, Nylon (poylamide), Polyester, PVDF, silk and stainless steel sutures.

Sutures can also be divided into two types on the basis of material structure i.e. monofilament sutures and multifilament or braided sutures.

Braided sutures provide better knot security whereas monofilament sutures provide better passage through tissues.

In general, Monofilament sutures elicit lower tissue reaction compared to braided sutures.

Multifilament sutures are braided and often coated with various materials like silicon, wax, PTFE, polycaprolactone, calcium stearate etc.

Monofilament sutures include :- Polypropylene sutures, Catgut, Nylon, PVDF, Stainless steel, Poliglecaprone and Polydioxanone sutures.

Multifilament or braided sutures include :- PGA sutures, Polyglactin 910, silk and polyester sutures.

Surgical sutures can also be divided into two types on the basis of raw material origin i.e. natural and synthetic sutures.

Natural sutures include silk and catgut sutures whereas all other sutures are synthetic in nature.

Some types of sutures are available with specialized coatings on the surface to enhance properties like knotting, easy passage through tissue and reduce tissue reaction.

Normally, coating is applied to braided sutures rather than monofilament sutures.

It is easier to coat braided sutures compared to monofilaments.

Coating materials like chromium salt, silicon, wax, PTFE, polycaprolactone, calcium stearate.

Polymeric coating materials are known to be more bio-compatible than conventional coating materials like chromium salts, beeswax, pafaffin, gelatin etc.

There are new functional coatings like antibacterial or antimicrobial coating given to both monofilament and multifilament sutures, stem cell coating for improving healing properties.

Coated sutures include :- PGA sutures, Catgut Chromic, Polyglactin 910, silk and polyester sutures, braided or twisted nylon, Poliglecaprone and Polydioxanone sutures.

Un-coated sutures include :- Monofilament Polypropylene sutures, monofilament Nylon, PVDF, Stainless steel.

Catgut or gut suture is an absorbable suture usually manufactured from the intestine of sheep or goat.

Catgut suture are composed of highly purified connective tissue derived from either beef or sheep intestines.

The membrane is chemically treated and slender strands are woven together to form a suture.

The grinding process creates a strand of uniform diameter.

Plain catgut is usually having shorter absorption periods and is absorbed more rapidly in infected areas.

The percentage of collagen in the catgut suture often determines the quality of the suture.

Higher percentages of collagen allow for: superior tensile strength, longer absorption times, and lower reactions in vivo.

Plain catgut is available in ivory colour.

Chromic catgut is treated with chromium salt solution to resist body enzymes and slower the absorption process thus supporting the wound for longer periods.

Chromic gut is chromicised before it is spun into strands. This allows control over the amount of chromic content for an even absorption rate.

The chromic content not only increases the tensile strength, but also reduces tissue irritation.

Catgut sutures are sterilized by a sterilizing fluid containing EO, distilled water and isopropyl alcohol.

Absorption within 75-90 days for chromic suture and 60-70 days for plain gut suture.

Allows for smooth passage through tissue.

Uniform chrome content provides required wound support and absorption.

Stainless steel sutures are the most inert among all suture materials and provide maximum tensile strength.

Stainless steel sutures are indicated for use in abdominal wound closure, intestinal anastomosis, hernia repair, sternal closure and also for certain orthopedic procedures (cerclage or tendon repair).

The steel suture is very malleable even with high tensile strength and is resistant to breakage during knotting.

The suture merges with the contours of the bone.

Steel suture is a non-absorbable suture.

Sturdy yet soft to have a better knotting and turning without breakages.

Rust proof and stays in the body life long.

Black braided silk suture is a multifilament braided non-absorbable, sterile surgical suture which is available only in black colour.

Surgical silk begins as a filament of natural silk; it is composed of approximately 70% protein fibers & 30% extraneous material or gum.

Silk suture is a non-absorbable suture. Braided to improvise the knot security. Coloured black to have a very good visibility

during surgical procedures. Coated with bee wax for easy pull out suture. Easy pull out sutures. As it a natural material it is very slowly

absorbed in the body over a period of 2 years hence removal is not required from the endodermis.

Polypropylene suture is a non-absorbable, sterile surgical suture composed of an isotactic crystalline stereoisomer of polypropylene or synthetic linear polyolefin.

As it is a monofilament suture, it does not support bacterial growth. It is not affected by blood, or weakened by tissue enzymes.

It offers prolonged tensile strength even in infected areas as it is not degraded over time.

This suture is known for low tissue drag, easy handling and good strength.

Polypropylene suture are normallyavailable in blue colour, allowing for easy identification and better visibility against skin when operating.

Polypropylene suture is a non-absorbable Smooth texture, resulting in minimal tissue

trauma. High plasticity and difficulty of use

compared to standard nylon suture. Uniform diameter with high tensile strength

resists breakage Highly visible in the wound Passes through tissue easily

Polyamide suture is a monofilament non-absorbable, sterile surgical suture composed is a macromolecule with repeating units linked by amide bonds.

Polyamide suture fibres are tough,possessing high tensile strength, as well as elasticity and lustre.

They are wrinkle-proof and highly resistant to abrasion and chemicals such as acids and alkalis.

As it is a monofilament suture, it does not support bacterial growth. It is not affected by blood, or weakened by tissue enzymes.

It offers prolonged tensile strength even in infected areas as it is not degraded over time.

This suture is known for low tissue drag,easy handling, lesser memory and good strength.

Polyamide suture is a non-absorbable Smooth texture, resulting in minimal tissue trauma. Lesser plasticity and easier of use compared to

polypropylene suture. Uniform diameter with high tensile strength, resists

breakage. Available in black colour and is highly visible in the

wound. Passes through tissue easily.

Polyester suture is a multifilament braided non-absorbable, sterile surgical suture which is available in green and white.

Polyester is a category of polymers which contain the ester functional group in their main chain.

Polyester suture is a non-absorbable suture.

Braided to improvise the knot security.

Coloured green and white to differentiate between layers of knotting and differentiate b/w a stay and permanent suture.

High tensile strength

Coated with silicone.

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.

Polyglactin 910 or PGLA suture is an absorbable, sterile, synthetic, braided suture. PGLA suture are indicated for soft tissue approximation and ligation.

The suture’s tensile strength remains for approximately three to four weeks in tissue.

Polyglactin 910 suture is an absorbable braided synthetic fibre. It is available as a plain (uncoated) and coated suture.

The coating is with calcium stearate. This mixture forms an absorbable, adherent, non-flaking lubricant ideal for suture.

These components are water repelling which slows tissue fluid penetration and absorption into the suture.

Clinical trials have shown that after two weeks, approximately 70% of Polyglactin 910 suture’s initial strength remained.

Polyglactin suture are found to be non-antigenic and non-pyrogenic, eliciting only mild tissue reactivity during the absorption process.

Polyglactin 910 suture are available violet and colourless.

Polyglactin 910 suture is coated in order to create a smoother synthetic absorbable suture that will pass through tissue readily.

Easy tissue passage Precise knot placement as compared with PGA suture Predictable absorption by simple hydrolytic mechanism A decreased tendency to irritate tissue Greater tensile strength A longer absorption period

PGA is an ideal and time tested synthetic absorbable suture, widely used by surgeons all over the world.

PGA's superior features over catgut are predictable absorption, outstanding tensile strength, in-vivo inertness and excellent handling properties.

Polyglycolic Acid Suture is a synthetic, absorbable, sterile, surgical suture .

Polyglycolic Acid Suture has been found to be non-antigenic, non-pyrogenic and elicit only mild tissue reactivity during the absorption process.

The absorption time for Polyglycolic Acid (PGA) is 60 to 90 days.

Absorption of bio-absorbable suture occurs by hydrolysis ; beginning with loss of tensile strength followed by loss of mass.

Polydioxanone or poly-p-dioxanone is a colourless, crystalline, biodegradable polymer.

Polydioxanone suture is an absorbable, sterile, surgical suture composed of the polyester, poly (p-dioxanone).

Polydioxanone suture has been found to be non-antigenic, non-pyrogenic, and elicits only minimal tissue reactivity during the absorption process.

Polydioxanone like suture are provided with a good flexibility.

The suture prepared with this material typically lose half of their mechanical strength in about three weeks and complete degradation takes place in a time frame of around six months.

Minimal tissue reaction. Does not support infection. Absorbed slowly over a period of 6 to 7 months,

thus it provides wound support for longer periods. Polydioxanone suture retain approximately 80% of

initial Tensile strength after 14 days of surgery. Smooth, pliable and minimal memory. Dyed Dark Blue coloured for easy identification

during Surgery.

Staples are formed from highquality stainless steel and are available in regular and wide sizes.

Staples are composed of -(1) a crossmember that lays on the surface of the skin perpendicular to the wound,(2) legs that are vertically placed in the skin, (3) tips that secure the staple parallel to the crossmember.

Staples are relatively easy to place and may shorten the closure time by 70-80%.

The primary utility of staples is in the closure of wounds under high tension on the trunk, extremities, and scalp.

They are also used to secure split thickness skin grafts.

They are not used in delicate tissues or wounds in finely contoured areas, over bony prominences, or in highly mobile areas.

Tapes are strips of microporous nonocclusive material (eg, paper, plastic, rayon fabric) backed by a thin film of acrylic polymer adhesive.

They are useful as an adjunct to or a substitute for other wound closure materials.

Although they are used most often to reinforce a wound after the removal of sutures or staples, they can also be used alone for wounds that are small, nonexudative, and under minimal tension.

The advantages of tapes include ease of use, comfort to the patient, and avoidance of tissue strangulation, infection, and crosshatch marks.

Followup visits for removal are not necessary.

Allergic reaction to the adhesive is uncommon.

Disadvantages include limited wound eversion, imprecise wound edge approximation, and inconsistent adhesion.

Tapes have little usefulness in hairy or highly mobile areas.

Moisture, soap, and wound exudate decrease the duration of tape adhesion.

Commonly available products include- SteriStrip Skin Closures (3M),- Cover Strip II (Beiersdorf), and - ProxiStrip Skin Closures (Ethicon).

Cyanoacrylates for use in surgery have been available .

They polymerize in an exothermic reaction on contact with fluid to form a 3-dimensional, strong, flexible bond, with uses comparable to those of 5 0 monofilament nylon.

Octylcyanoacrylate and N butyl2cyanoacrylate are useful for the closure of simple lacerations in children and uncooperative patients.

They are also useful for the closure of incisions under casts or in cases in which followup is difficult.

They are not for use in areas that are highly mobile or subject to friction (eg, over joints,hands, feet).

Both cyanoacrylates are quick and easy to apply, requiring only one-tenth to one-fourth of the time required for suture placement.

They may also be used to reinforce incisions closed with suture or staples, as they provide an antimicrobial and waterproof coating, but repeated washing removes the adhesive in a few days.

The cosmetic outcome is good, and no postoperative visit is required for removal.