- Wounds or lacerations must be explored and thoroughly cleaned prior to closure.
- Suture materials vary in their composition and thickness, and the choice of the appropriate material depends upon the nature and location of the wound.
- Staples, Steri-Strips, Band-Aids, and skin glue can be alternatives to suture material for skin closure.
- Dissolvable suture material may be used for the repair of deep tissues.
- Most sutures are left in place for seven to 10 days.
Why is wound closure important?
The ability to close a skin wound is an important skill learned by medical care providers. Whether the skin injury was made by a scalpel in the operating room or by a fall in the street, the decision as to how and when to repair the damage needs to be individualized for each patient and situation.
The skin has many layers from the epidermis on the outside, to the deeper subcutaneous tissues and the dermis in between. Each of these layers has other sub-layers that help the skin perform its functions. The skin provides a barrier to the outside world and the dangers of infection, environmental hazards and chemicals, and temperature. It contains melanocytes that can darken or tan the skin while protecting the body from ultraviolet radiation. It also plays an important role in temperature and fluid regulation.
A picture of stitches or sutures
Different options exist for repairing lacerated skin and providing a nice cosmetic outcome. However, there are two important steps that need to occur before the skin is closed.
- Exploration: Most wounds need to be examined and explored to their full depth, looking for dirt and debris that may have entered and making certain that the anatomic structures beneath the damaged skin are intact and not injured. For example, in a hand or finger laceration, the care provider will want to make certain that the blood vessels, nerves, and tendons beneath the skin have not been cut. This is done both by physical examination of the hand and finger, evaluating their power and motion, blood supply and nerve sensation, and also by looking inside the wound, identifying the tendon and perhaps the artery and nerve bundles to make certain that they are intact.
- Cleaning: When the skin is broken, the outside world invades the body and may cause infection. Before the skin is closed, the wound must be washed out or irrigated thoroughly to prevent the occurrence of an infection. Sometimes, a small amount of dirty tissue needs to be cut out, and this is called debridement.
The purpose of wound care is not simply to yield a good-looking scar. All wounds will eventually heal over time, although closing the skin edges will make that healing time shorter. The primary purpose of seeking medical care from a health-care professional is to get the wound properly cleaned and make certain everything is in good working order beneath the damaged skin.
When a laceration occurs, there are some reasonable first aid and home-care steps to consider. Washing with tap water to clean the wound is always helpful. Studies have shown that plain tap water is as good as any special fluids that are used in hospitals for cleaning wounds. The wound should be lightly bandaged and elevated if possible.
The amount of blood supplied to different parts of the body varies. A wound on the face, scalp, or hand may bleed profusely while one on the shin or back may not. Bleeding will often stop with direct pressure at the bleeding site and elevation of the injured part of the body.
Quick GuideCuts and Scrapes: Caring for Wounds in Pictures
Caring for Stitches
Whenever the skin has been damaged, there is potential for infection. The wound and the stitches that hold it together may be cleansed gently with mild soap and water after 24 hours. Twice daily washing may decrease the risk of infection. Sometimes, your doctor may recommend the use of an antibiotic ointment like bacitracin or Neosporin to help minimize infection.
It is important to avoid getting the wound dirty or very wet. Briefly showering may be advisable, but swimming should be avoided until the stitches are removed. Kids should avoid playing in the mud, sand, or water. A bandage or other covering might be necessary if the wound rubs up against clothing or if it is draining fluid.
How does the health-care professional assess a wound?
Lacerations are common injuries that are seen in physicians' offices, walk-in clinics and emergency departments. The approach to the injury is often the same. The history taken by the health-care provider is very important to decide whether the benefit of repairing the wound outweighs the potential risk of complications. Infection is the most common worrisome complication. The provider will want to know the circumstances of the injury.
- Where did the accident occur? Was it washing dishes in the sink, or did it occur in a farm field, cleaning dirty equipment covered in mud?
- When did it happen? The older the wound, the higher the potential for infection since there is more time for bacteria to invade the wound and begin the infection/inflammation process.
- Was it due to a fall or other trauma so that other parts of the body might be damaged?
- Were there unusual circumstances, like an animal bite, or did it occur underwater in a river or lake (both situations posing a high risk for infection)? One can imagine a variety of scenarios that may greatly increase the infection risk.
Physical examination is key to making certain that underlying structures are not damaged. This is especially important in the extremities where arteries, nerves, and tendons run beneath the skin. When skin is damaged over a broken bone, it is called an open fracture, and often patients with such a fracture are taken to the operating room so that the wound can be extensively cleaned to prevent osteomyelitis (an infection of the bone). This same situation may also occur if the laceration goes deep into a joint.
X-rays may be taken, looking for foreign material that may be imbedded in the laceration. While metal objects are easier to see, nonmetallic foreign objects may also be identified.
Once the decision is made to repair the wound, the health-care provider has many options: sutures, staples, glue, Steri-Strips, and Band-Aids. But first the wound needs to be prepared for sewing (or suturing or stitching; the words all describe the same procedure).
- Ideally, the injured area is exposed and cleaned with water, saline (salt water), and/or soap.
- A local anesthetic is administered to allow full exploration of the wound, looking for foreign objects or damage to underlying structures. Minimizing the pain in the area allows for better exploration and visualization of the underlying anatomy.
- The wound may again be washed or irrigated to try to minimize the risk of infection.
How is the type of closure material chosen?
The purpose of repairing a wound is to provide good cosmetic results. All wounds will eventually heal by themselves; however, bringing the edges together and without tension will allow for a better result. All lacerations will leave a scar, and a good wound closure will minimize the visibility of that scar.
Since there are many layers of skin, there may need to be layers of sutures placed to bring the edges together if the wound is deep and affects more than the superficial dermis and epidermis layers. As well, if the wound is deep and only the skin is closed, empty spaces may be formed beneath the outer skin layer. Fluid may accumulate within these empty spaces, increasing the risk for infection.
For skin sutures, the hope is to cause minimal inflammation so that the scar will form nicely. If deep sutures are placed, the suture material used gradually disintegrates or dissolves as part of the inflammatory response of the body.
The strength of the suture depends upon the thickness of the suture material. Some suture materials used to repair nerves may be so thin that the surgeon needs a microscope to see the suture and be able to sew. Some suture material is as thick as string. The thinner the suture, the less tension it can tolerate and the more stitches need to be placed closer together, to keep the wound from breaking open as it heals.
Different types of needles are used as well, depending upon the situation. The two major kinds are cutting and non-cutting. The cutting needles have a diamond-shaped tip and are designed to "cut" through skin. The non-cutting needle tips are circular and are meant to be used on deep tissues that do not have the resistance of skin. There are different shapes of the needle curve as well to help guide the needle and the attached suture on its path.
Almost all suture material is preloaded on a needle and does not need to be hand-threaded. The care provider will specify the type of suture, the thickness, and the type of needle when planning to repair a laceration.
How is skin closure achieved?
Most frequently, the closure of choice for the skin layer repair, is a single filament suture, meaning that it is not braided and is made of material that does not cause irritation. The two main choices are nylon and polypropylene. Staples may be used when potential scarring isn't as important and may be used in the scalp. Often surgeons who have made a long incision use staples on the abdomen, back, or extremity.
If the laceration follows the crease lines of the body (lines of Langerhans) and is not under stress or stretch, Steri-Strips or butterfly Band-Aids may be considered. Dermabond or skin glue is another potential option for repairing the skin. For this option, the wound must be superficial and run along the crease lines, not be under stress or stretch, and blood or hair may not be present at the wound site. If Steri-Strips or Dermabond are used, the principles of wound cleaning and exploration still are important considerations.
In some circumstances, very thin absorbable sutures are used to close the skin. A material made of polyglycolic acid (Dexon) or polyglactic acid (Vicryl) can be used just beneath the epidermis to allow for good skin closure. The decision to use absorbable suture in the skin depends upon the situation and the skill and experience of the provider performing the repair.
How is repair of deep tissues achieved?
If the laceration requires layered closures in which the sutures will not be able to be removed, dissolvable suture material may be used. Polyglycolic and polyglactic acid or polyglyconate (Maxon) may be considered. Other materials may include silk or catgut (chromic). Often the suture is braided, allowing some cells of the body to "invade" it and thereby allow greater inflammation to cause the suture material to dissolve over a period of time.
Depending upon the type of material and the circumstances, absorbable suture may take from three weeks to three months to dissolve.
When and how are sutures removed?
The optimal time for suture removal depends upon both the location of the laceration and how much stress is placed on the laceration. For example, a knee laceration will require the suture to remain in place longer than on the thigh, since the skin will be stressed each time the knee flexes and extends with walking, sitting, and standing.
Sutures form a loop that surrounds the laceration and when pulled tight cause the wound to close. The body can start to form a scar around the suture itself, and it is important to remember this when deciding the appropriate time to remove the sutures. This scarring tends to occur within seven to eight days and can have an appearance resembling crosshatching or railroad tracks.
Sutures on the face are usually removed within five days since there is such good blood supply in this region and healing occurs more quickly. The goal is to minimize scarring; therefore, the risk of the sutures causing a scar in their own right is balanced against the strength and potential weakness of the healing laceration. Elsewhere on the body, sutures may be left in for seven to 10 days. In some circumstances, in which scarring is not an issue or if there is concern that wound is under mechanical stress (like a laceration over a joint), the sutures may be left in longer.
What happens to the site after suture removal?
While the sutures may be removed, the scar continues to mature over time. For the first three months, there will be a raised, red healing ridge at the laceration site. Over the next two to three months, the ridge will flatten and then will start to weather and lighten. It may take six to eight months or longer before the final result of the laceration repair can be appreciated.
Are there any special considerations regarding wound repair?
People with diabetes or those with peripheral vascular disease may have delayed healing and increased risk of infection.
Animal bites are especially prone to infection, and the decision to repair a bite with sutures must balance the risk of infection with the benefit of a better-looking scar. Approximately 50% of dog bites, 80% of cat bites, and 100% of human bites will become infected.
When the risk of infection is high, the health-care provider may choose from a different options to help the wound to heal. When the laceration is cleansed and dressed and not repaired, it will gradually heal on its own. This called healing by secondary intention. (Primary closure describes a wound that is sutured or stitched.)
Another alternative is delayed primary closure, in which a potential dirty or contaminated wound is cleaned and dressed and then evaluated in a few days (usually two or three). If it has not become infected, it might be possible to then suture it closed, as if it is a new injury.
Pfenninger, J.L., and G.C. Fowler. Procedures for Primary Care, 3rd edition. Philadelphia, PA: Saunders, 2010.
Trott, A.T. Wounds and Lacerations: Emergency Care and Closure, 4th Edition. Philadelphia, PA: Saunders, 2012.