- Assessing a Wound
- Types of Stitches
- Wound Closure
- Deep Tissue Repair
- Getting Stitches
- Special Considerations
- Wounds or lacerations must be explored and thoroughly cleaned prior to closure.
- Stitching or suturing is considered a form of minor surgery.
- 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 (tissue adhesive) are alternatives to suture material and stitches for skin closure.
- Doctors may use dissolvable (absorbable) suture material for the repair of deep tissues.
- Most sutures stay in place for 7 to 10 days before removal.
Why is wound closure important?
The ability to close a skin wound is an important surgical skill learned by medical care providers. Whether a fall in the street or a scalpel made the skin injury in an operating room, 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.
Different options exist for repairing lacerated skin and providing a nice cosmetic outcome. There are two important steps that need to occur before the skin is closed.
- Exploration: A doctor will need to examine and explore most wounds need 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 closing the skin, a doctor must wash out or thoroughly irrigate a wound to prevent the occurrence of an infection. Sometimes, it's necessary to cut out a small amount of dirty tissue (a process 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 show that plain tap water is as good as any special fluids used in hospitals for cleaning wounds. Lightly bandage the wound and elevate it 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.
How does the health care professional assess a wound?
Lacerations are common injuries treated 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? Is there damage to other parts of the body?
- 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 undamaged. This is especially important in the extremities where arteries, nerves, and tendons run beneath the skin. When there is damage to skin over a broken bone, it is called an open fracture, and often patients with such a fracture require surgery and 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.
It may be necessary to take X-rays to look for foreign material that may be imbedded in the laceration. While metal objects are easier to see, it may also be possible to identify nonmetallic foreign objects.
A doctor has many options when it comes to repairing a wound: sutures, staples, glue, Steri-Strips, and Band-Aids. 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 health care provider administers a local anesthetic 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.
- A health care provider may wash or irrigate a wound a second time to try to minimize the risk of infection.
How do health care providers choose the type of closure material?
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, a doctor uses layers of suture to bring those layers together. A deep wound increases the risk of infection, and if only the skin is closed, empty spaces may exist beneath the outer skin layer. Fluid can accumulate within these empty spaces, and stagnant fluid can increase the risk for infection.
For skin sutures, the hope is to cause minimal inflammation so that the scar will form nicely. When a doctor places deep sutures, that suture material 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.
Doctors use different types of needles depending upon the situation. The two major kinds are cutting and non-cutting. The cutting needles have a diamond-shaped tip designed to "cut" through skin. The non-cutting needle tips are circular and designed for use 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 do doctors close a wound?
Most frequently, the closure of choice for the skin layer repair is a single filament suture, meaning that it is not braided. This non-absorbable suture does not cause irritation and inflammation, minimizing scar formation. The two main choices are nylon and polypropylene (Prolene). Doctors may use staples when potential scarring isn't as important. They often use staples to close scalp wounds. Often surgeons who have made a long incision on the abdomen, back, or extremity use staples to close the skin.
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 not have blood or hair present at the wound site. If a doctor uses Steri-Strips or Dermabond, the principles of wound cleaning and exploration still are important considerations.
In some circumstances, doctors use very thin absorbable sutures to close the skin. A medical professional may use material made of polyglycolic acid (Dexon), polyglactic acid (Vicryl), poliglecaprone (Monocryl), or polydioxanone (PDS II) just beneath the epidermis (subcuticular area) 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 do doctors repair wounds to deep tissues?
If the laceration requires layered closures in which it will not be possible to remove the sutures, dissolvable suture material may be used. Polyglycolic, polyglactic acid, poliglecaprone, and polyglyconate (Maxon) may be considered. Other materials may include silk or catgut (chromic). Depending upon the type of material and the circumstances, absorbable suture may take from 3 weeks to 3 months to dissolve.
What actually happens when a medical professional places stitches?
Once a doctor decides to sew or stitch up a wound, a medical professional brings an instrument tray to the patient's side. The tray usually contains the following items:
- A needle holder (to grasp the needle and suture material)
- Forceps (medical tweezers) to help grasp the wound edges
- Scissors to cut the suture.
- A syringe with local anesthetic
- Cleansing liquids
The care provider will need to decide the type of suture or thread required, including whether it is absorbable or non-absorbable and its thickness. (The thicker the suture, the higher its tensile strength, and the stronger it is.) Another decision is the size and type of needle; this also affects the size of needle holder required. Tinier needles need smaller instruments to guide them through tissue and skin.
The first step is to clean the wound and inject local anesthetic. Wound exploration and cleansing follows.
How a doctor closes an incision depends upon how the wound was made. A wound created due to a sharp scalpel in the operating room will need less planning for closure than one with a jagged wound edge because of a burst laceration from a fall.
The medical professional needs to bring the skin edges close together with minimal tension. The doctor grasps one side of the wound skin edge with the forceps and brings it near to the other edge. If possible, the doctor passes the needle through both skin edges and by pulling on the suture thread, brings the skin edges together. It is important that there is not too much pulling because the stitch can pull right through the skin.
The skin edges need to be everted, meaning that the undersides of the skin, the layer just below the epidermis, on each side of the laceration need to contact each other. When a health care provider ties and knots the stitch, the edges tend to relax, and the epidermis tends to lay flatter. Without eversion, the scar can cave in and potentially appear depressed.
It is important that a doctor ties the knot with the right amount of tension; too loose and the wound edges separate, widening the scar, but too tight and the skin edges can strangulate and cause damage to the skin surface.
There are different types of stitches, depending upon the situation and the expertise of the care provider. Examples include the following:
- Simple interrupted suture
- Simple running or continuous suture
- Purse-string suture
- Horizontal mattress suture
- Vertical mattress suture
- Subcuticular running suture
Knot tying is very important. The stitch needs to be secure so that it does not unravel and fall out prematurely. The surgical knot really consists of multiple layered knots to prevent the suture from falling out. A doctor needs to tie a knot to make removal easy when the time comes. Tying the knot too tightly results in skin damage from the knot itself.
The equipment used in urgent care or the emergency department to stitch a wound is the same as that found in the operating room. Surgical sutures in the operating room are the same as those used as an outpatient. Those used inside the body for specific purposes may be of different sizes and made of different materials, depending on the tissue they are being used to repair, from arteries and nerves to muscles and bowel and everything in between.
While the surgical incision in the skin is all the patient and family can see, it is the surgical sutures located deep in the body that a doctor really needs to place precisely. Those stitches cannot fail to hold tissue together because a doctor cannot replace them without another surgical procedure.
When and how do medical professionals remove sutures?
The optimal time for suture removal depends upon both the location of the laceration and how much stress one places 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 7 to 8 days and can have an appearance resembling crosshatching or railroad tracks.
Follow-up for suture removal on the face usually occurs within 3 to 5 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, health care providers may leave sutures in for 7 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?
After suture removal, the scar continues to mature over time. For the first 3 months, there will be a raised, red healing ridge at the laceration site. Over the next 2 to 3 months, the ridge will flatten and then will start to weather and lighten. It may take 6 to 8 months or longer before a patient can appreciate the result of the laceration repair.
Are there any special considerations regarding wound repair?
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 develop infections.
When the risk of infection is high, the health care provider may choose from different options to allow wound healing. When a health care provider cleanses and dresses a laceration but does not repair it, 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 health care provider cleans and dresses a dirty or contaminated wound and then evaluates it in a few days (usually 2 or 3). If the wound is not infected, it might be possible to then suture it closed, as if it is a new injury.
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Trott, A.T. Wounds and Lacerations: Emergency Care and Closure, 4th Edition. Philadelphia, PA: Saunders, 2012.
Walls, R., R. Hockberger, and M. Gausche-Hill. Rosen's Emergency Medicine: Concepts and Clinical Practice, 9th Edition. Elsevier 2017.