The Role of Sutures in Wound Healing

The Role of Sutures in Wound Healing

By Carolyn Ramsey, RN, MSN, CNOR and Fran Koch, RN, MSN, CNOR

1. To understand the impact of medical errors on patient safety.

2. To understand the Joint Commission's new patient safety standards.

3. To understand the integration process and how it affects infection control and patient safety.

The use and selection of suture material frequently poses a problem for the perioperative nurse or surgical technologist. Suture companies have developed more products to meet the needs of the surgeon in closing surgical wounds. Through this article the authors present types of suture materials and their uses, and describe wound closure and surgical techniques to prevent post-op wound infections.

Wound Healing

All wounds heal in one of three ways.

• First intention wound healing is the most desirable. Most surgical wounds heal by first intention if the wound is not contaminated, dead spaces are closed, tissue is handled gently, hemostasis is achieved, and the tissues are approximated accurately.

• Wounds heal by secondary intention if there are post-operative complications such as infection, wound dehiscence, excessive scar, or excessive drainage. If sutures were used prior to the development of the complication, they are removed and the wound is allowed to heal by forming granulation tissue from the bottom of the wound outward. If an infection is present when the surgical procedure takes place, the surgeon may not attempt any suturing of the wound, and allow the wound to head by secondary intention. This type of healing takes much longer than healing by first intention.

• The last type of wound healing is by third intention. When granulation tissue has developed along the edges of a wound the surgeon may use large retention type sutures to assist in healing. Third intention healing is used when there is gross infection, or after tissue has been lost due to traumatic injury or surgical debridement.¹

Patient Factors Affecting Wound Healing

The choice of suture material by the surgeon depends greatly on the overall condition of the patient. Elderly patients' skin and muscle tissue lose tone and elasticity and their circulation may be impaired, which also lengthens healing time. Obese patients are at risk for post-operative wound infections because excess adipose tissue at the wound site may prevent good approximation of tissues. Adipose tissue does not have a good blood supply, therefore making it vulnerable to trauma or infection.

The nutritional status of the patient can effect wound healing. A lack of carbohydrates, proteins, zinc, and vitamins can cause a delay in healing. Without adequate nutrition, collagen synthesis-which is the basis for wound healing-- cannot properly occur.

Dehydration, causing electrolyte imbalance, not only can affect cardiac, kidney, and hormonal function, it also can decrease oxygenation to the tissues, thereby affecting wound healing. Lack of blood supply at the wound site can also slow healing. Areas of the body such as the face and neck receive the most blood supply and heal the fastest, whereas areas such as extremities take longer to heal. Poor circulation in extremities, such as in the diabetic patient, causes even longer healing times. Chronic diseases also can cause post-operative complications.

Immunodeficiencies also are of great concern, since patients who have a poor immune response are more susceptible to infection. Patients who have taken steroids, have undergone chemotherapy, or who are infected with HIV also have a poor immune response. Some patients are allergic to certain suture materials and may exhibit a heightened immune response or allergic reaction. A thorough history should be carried out to detect prior allergic reactions.²

All these factors are taken into consideration when suture material and methods are chosen. The surgeon and perioperative nurse should collaborate in the selection process.

Suture Material Selection: Absorbable

Derived from animal protein, plain and Chromic gut are degraded through the digestive action of proteolytic enzymes produced by inflammatory cells.³ Tensile strength is lost in a relatively short time; for plain gut it can be as little as 7-10 days, and for chromic, 10-14 days. Absorption rates are longer, 70 and 90 days respectively.

In the last two decades synthetic materials have been used to manufacture suturing products. They were developed in an effort to provide more tensile strength in suture material of the same size as natural products. Tensile strength is defined as the point of breakage of suture material and is not related to the size of the suture.

It was also thought that synthetic absorbable materials would cause less tissue reaction. Natural absorbable sutures are made from sheep or cow intestines, not cats as the name "catgut" implies. Questions have been raised over transmission of infectious diseases from animal sources.

Williams⁴ compares catgut, a natural absorbable suture material, to synthetic absorbable sutures. Synthetic sutures degrade at a slower rate than natural sutures and with less tissue reaction. Synthetic sutures offer a more consistent performance, as well. There is little or no variation from batch to batch, as there is with catgut suture material. Absorbable sutures are used to close deep connective tissues following trauma or surgery. Wound tissues must be approximated and supported by the sutures until healing takes place. Synthetic or natural materials may be used, but synthetic materials have almost totally replaced the use of catgut in surgery today.⁴

Choudhary⁵ describes the use of a synthetic absorbable suture designed to degrade rapidly to lessen scar formation. Skin and mucosal tissue were closed following a cleft lip repair of infants. Prior to the use of the synthetic material, Choudhary used a nonabsorbable suture that required removal. The absorbable suture provided much better outcome for the patients, as the need for painful suture removal was eliminated. The absorbable material visible on the skin was able to be wiped off seven to 10 days postoperatively.⁵

The introduction of polyglycolic acid sutures in the 1970s started the transition from natural sutures to more synthetic absorbable products. There is now an array of such sutures in most inventories.

Braided, coated, polyglactin suture has 75% strength retention in two weeks and 50% in 3 weeks. It is completely absorbed between 56 and 70 days. Polyglactin suture is most often used for soft tissue approximation, general closure, bowel reanastomosis, ophthalmic procedures, and orthopedic surgery.

Polyglactin suture retains its strength 50% at 5 days and has lost all strength by 14 days. It is essentially completely absorbed by 42 days. Frequent uses include skin and mucosal closure. It is used for episiotomy repair, to suture skin lacerations that remain under casts and where rapid absorption may be beneficial. It should not be used over joints or in high- stress areas.

Poliglecaprone suture is a monofilament suture and comes both dyed and undyed. Undyed has 50-60% strength retention in 1 week and 20-30% in 2 weeks. The dyed suture has 60-70 strength retention at 1 week and 30-40% at 2 weeks. This suture is essentially completely absorbed between 91 and 119 days. It is used for skin repair, bowel anastamoses, to close the peritoneum, and on the uterus and vaginal cuff.

Nonabsorbable

Silk sutures are old standbys. They are a natural, nonabsorbable material actually produced by the silkworm. They are a braided material that is easily used by the surgeon. Silk is typically not used in the presence of infection. Pecha⁶ describes its use in intestinal surgery, a common practice of surgeons globally. In three cases Pecha described, the silk suture migrated toward the intestinal lumen, causing ulcerations and bleeding up to six months postoperatively. As with natural absorbable sutures, silk also tends to cause more tissue reaction than a synthetic product of the same size. Because silk is used as a braided suture, some feel the crevices caused by the braiding process can harbor bacteria or more foreign material which reacts with body tissues, especially in a bacteria-rich environment such as the bowel.⁶

Synthetic nonabsorbable sutures such as polydioxanone were developed to decrease tissue reaction. These are monofilament sutures that are soft and pliable. They are indicated to close fascia in pediatric cardiovascular and ophthalmic procedures. They provide extended wound support of up to 6 weeks. They have slight tissue reaction and a low affinity for microorganisms; therefore, they are useful in orthopedic patients and for patients with compromised wound healing conditions.

Polyester sutures are braided, multifilament, nonabsorbable sutures used for cardiovascular procedures. They are stronger than natural fibers and do not weaken when wetted. They are available with soft and firm pledgets to seal the puncture site of the attached needle.

Polypropylene is a nonabsorbable, monafilament suture that retains its tensile strength in vivo long term. It is as inert as steel and is unaffected by tissue fluids. It also can be used in the presence of infection. It is now available with a welding device that welds the edges of the suture together. This device is recommended for use in orthopedic and shoulder surgeries. Its disadvantage is that it requires the use of an ultrasonic generator, a reusable handpiece, and a disposable welding component.⁷

Nylon, polyamide polymer, is derived by chemical syntheses and is available in single or multifilament strands. Single strands retain "memory," making tying more difficult and requiring more throws to secure the knots. It has high tensile strength and low tissue reactivity. In vivo it does degrade 15-20% per year.

Surgical stainless steel is available as a monofilament and multifilament suture. Tensile strength is indefinite. It causes minimal tissue reaction, but should not be used in patients with known sensitivities to stainless steel or constituent metals such as chromium or nickel. It is used for abdominal and sternal wound closure and for orthopedic procedures. Stainless steel sutures sometimes need to be surgically removed due to pain caused by pressing on the cut ends of the wire when the patient leans against a firm object.

The technique of retention sutures using large gage wire has been demonstrated for obese patients to help support the deep tissues while the more superficial fascia and skin tissues heal. Retention sutures are placed through and through the abdominal wall before the abdominal layers are closed to reinforce the suture line.

Lamm⁸ and Pezzella⁹ described this procedure for median sternotomy incisions. After placing the wire suture underneath the sternum and up through the fascia, subcutaneous fat, and skin, buttons or polyethylene plates were placed on the skin to take the stress off the skin when the wire suture was tied. The fascia, subcutaneous, and skin layers also were closed.^8,9

No-Stitch Skin Closure

Adhesive coated fabric strips are frequently used to close the skin. These strips may be used with an adhesive material such as tincture of benzoin to assure that they remain in place. The use of these strips avoids the residual markings left by skin sutures or staples.

Topical Skin Adhesive 2--Octyl Cyanoacrytate is a relatively new product designed to hold closed easily approximated skin edges. It is especially useful for facial lacerations to minimize scarring and with children's minor lacerations. It may be used to close skin incisions including trocar puncture sites. It is contraindicated in the presence of infection and for mucosal surfaces or across mucocutaneous junctions such as the mouth or lips. It should not be used if the skin will regularly be exposed to body fluids or if there is dense natural hair. It should not be used if the patient is allergic to cyanoacrylate or formaldehyde.

Closure procedure kits as well as a needless system that delivers, ties and cuts sutures automatically are also available for closing laparoscopic trocar wounds.⁷

Lastly, a zipper is now available for closing skin edges. The zipper is applied by means of adhesive strips and is then gently closed. This device is noninvasive, fast, safe to apply, and reduces postoperative scarring.

Carolyn Ramsey, RN, MSN, CNOR is nurse educator for Scott & White Hospital in Temple, Texas. Fran Koch, RN, MSN, CNOR is director of OR/SPD for Presbyterian Hospital in Dallas, Texas.

1. Phippen, Mark L., and Wells, Maryann P. Perioperative Nursing Practice. Philadelphia: W.B. Saunders Co., 1994.

2. Ethicon Inc. Ethicon Wound Closure Manual. 1998-2000, Chapter 1.

3. Grundemann, B., and Fernsebner, B. Comprehensive Perioperative Nursing. James and Barlett: Boston, 1995.

4. Williams, D. Catgut sutures: An exercise in discretion. Medical Device Technology. 1998; 9(10):6-8.

5. Choudhary, S. and Cadier, M.A., Cleft lip repair: rub off the sutures, not the smile! Plastic Reconstructive Surgery. 2000;105(4):1566.

6. Pecha, R.E., Prindiville, T., Kotfila, R., Ruebner, B., and Cheung, A.T. Gastrointestional hemorrhage consequent to foreign body reaction to silk sutures: Case Series and Review. Gastrointestional Endoscopy. 1998;48(3):299-301.

7. Metzler, Bill, New options in wound closure, Outpatient Surgery Magazine. 2001:II(4):67-71.

8. Lamm, P., Godje, O.L., Lange, T. and Reichart, B. Reduction of wound healing problems after median sternotomy by use of retention sutures. Annals of Thoracic Surgery. 1998;66(6):2125-2126.

9. Pezzella, A.T. Reduction of wound healing problems after median sternotomy by use of retention sutures. Annals of Thoracic Surgery. 1999;68(5):1891-1892.