Wound Closure

Lacerations are one of the more common presenting complaints to emergency rooms. Left untreated, most wounds will heal without any problem, however some may become infected or leave an ugly scar. So our goals with wound management are simple:

1. avoid infection, and
2. avoid unsightly scarring.

Laceration Assessment

As with all of your patients, your assessment should always begin with addressing the primary survey. Lacerations may be the result of trauma and more serious injuries may also be present.

History

Your history should include any comorbid factors which put the patient at an incresed risk of infection, such as diabetes, obesity, malnutrition, renal failure, steroid use, immunosuppresant drugs or HIV. Ask about allergies, namely local anesthetics and latex.

“When was your last tetanus shot?”

Also note the last time the patient had a tetanus immunization. According to the Center for Disease Control’s website, tetanus prophlyaxis should be given based on the previous immunization and the contamintation of the wound.

Mechanism of Injury

Most lacerations occur on the head or neck (50%) or arms (35%), and most occur in men. The mechanism of injury is usually blunt such as bumping into something or getting hit by an object. The blunt force causes the skin to crush against the underlying bone and split open. Crush injuries area also more likely to cause devitalized tissue, which is more prone to infection.

Remember to ask about wound contamination or foreign bodies in the wound. These can result in infections and poor healing.

Physical Exam

The physical exam should start with an assessment of neurovascular status distally. Check for capillary refill, motor function and sensation.

Then inspect the wound under good lighting. It needs to be clean and dry to properly judge how deep it is, what the wound edges look like (devitalized or healthy), and if there is any foreign matter in there.

Wound Preparation

Wound preparation consists for first anesthetizing the wound. Oftentimes, this needs to be done before even a good exam of the wound can be carried out. The laceration most likely will need to be “numbed up” before it can be cleaned and debrided.

“This is going to sting a little bit.”

Anesthetizing the wound is important to provide pain control during cleansing and closure. Local anesthetics come in two varieties:

• amides – have an “i” in their prefix, such as lidocaine, mepivicaine, and
• esters – don’t have an “i” in their prefix, such as marcaine.

Allergic reactions to one class doesn’t necessarily confer an allergy against the other class. For patient who claim an allergy to both classes, another possible local anesthetic is diluted diphenhydramine.

Local infiltration of local anesthetic tends to be painful. This can be mitigated by buffering the lidocaine with sodium bicarbonate at a 1:10 ratio. This decreases the amount of charged molecules, resulting in less pain with injection. Similarly, warming the solution to body temperature has been shown to decrease the pain with infiltration. Other techniques include slower the rate of injection, injecting through the wound edges instead of through intact skin, using smaller guage needles and the use of topical anesthetics before injection. However, topical anesthetics, such as EMLA (eutactic mixture of local anesthetics) takes nearly an hour to start working, so has little place in the emergency room unless it’s applied in the waiting room.

Another alternative to local anesthetic infiltration is a regional nerve block. Lidocaine injected along a nerve can numb up a large area corresponding to the innervation of that nerve. This is especially useful for large lacerations, large areas which need to be scrubbed (such as in road rash), and areas where the wheal caused by infiltration would distort necessary landmarks (such as when re-approximating the vermillion border of the lip).

Wound preparation

Hair can obscure the laceration, making assessment and closure difficult. Removal of the surrounding hair may make treatment easier. The age old technique of shaving the surrounding hair may actually increase the rate of wound infection. Bacteria normally live in the hair follicles. A better strategy is to clip the hair around the wound.

Nonviable tissue around the wound edges also lead to increased infection rates. Therefore non-viable tissue should first be debrided before the wound is closed. This is a fundamental aspect of wound preparation.

Cleaning the wound

Scrubbing a wound may also lead to increased wound infections. The scrubbing motion may cause tissue damage leading to decreased ability to resist infection. However, scrubbing may be necessary in highly contaminated wounds. If so, use a highly porous sponge and a tissue surfactant such as polxamer 188 (Shur-Clens). These two items come conveniently packaged together.

Irrigation of most wounds can be done with simple tap water, though normal saline is most commonly used in the emergency room. The optimal pressure of irrigation for most wounds is about 5 to 8 psi, which can be done by squirting the irrigant through a 30 to 60 mL syringe through an 18 ga angiocath. Many third party products approximate this as well. However, delicate areas such as eyelids should not be irrigated under pressure.

Wound Closure

Ideally, the best wound closure would be quick, painless, cheap and produce little scarring or infection. The available options include:

• Sutures
• Staples
• Tapes
• Glue

Your other decision is when to close the wound.

“When should I close this wound?”

Most wounds are typically closed within 24 hours of injury. The closer to the time of injury the lesser the infection rate. However, you should also consider how comtaminated the wound is and cosmetic appearance. Contaminated wounds should be have delayed closure. Clean the wound and close it 3 to 5 days later, when the risk of infection is less. However lacerations on the face, where cosmetic considerations are important, should be closed primarily whenever they present.

Puncture wounds are typically considered contaminated as the puncturing instrument will usually innoculate the wound with bacteria. These are often left to close secondarily.

Sutures

Sutures are the mainstay of ED wound closure.

Simple lacerations should be closed with a non-absorbable suture. The different types of sutures have different properties which you can use to your preference.

• Nylon has good tensile strength, low tissue reactivity and the knot holds pretty well.
• Polypropylene (prolene) has the best strength but the the knots tend to slide.
• Silk has the best knot security but the most tissue reactivity.

All these sutures need to be removed once the wound is healed.

Absorbable sutures dissolve with time. They usually retain their strength for about a week to months. They should be used for deeper laceration in order to close dead space and relieve skin tension. To achieve a better outcome in bigger, gaping lacerations, use deeper absorbable sutures to bring the skin edges together and then close the skin with non-absorbables. The closer you are to the skin, the more rapidly those sutures should dissolve, otherwise they may come through the skin. The synthetic absorbables (polyglactin, polygloycolic acid) tend to last longer and shouldn’t be used near the skin.

In general, sutures should stay in about 7 days. They should stay in longer (10-14 days) for areas under tension or repetitive motion (like extremeties or joints) and lesser times (5 days) for the face.

Staples

Staples are applied more quickly than sutures, have less infection and tissue reactivity. They are more cumbersome to use and getting meticulous closure is difficult. They should generally be avoided on the face, but can be useful for the trunk, scalp and extremities. They are also more painful to remove.

Adhesive tapes

Steri-strips are less reactive than staples, but the tincture of benzoin needed to make them stick may increase the risk of wound infections. They do not withstand pressure very well either. They shouldn’t be used for primary closure of wounds, but can be helpful in keep a wound together after sutures have been removed.

Tissue adhesives

Dermabond (2-octylcyanoacrylate) has great utility in small lacerations that are not under tension. It is quick to apply, produces, minimal scarring, painless and has bacteriostatic properties. It should not be applied to wounds which are under tension, near joints, near the eyes or in hair.

Some physicians advocate using dermabond only in “wounds that don’t require closure anyway.” However, they can be useful in carefully selected wounds.

Summary

Laceration management is an important mainstay of emergency medicine. You will be called to close many different types of wounds: dirty or clean, old or new, deep or superficial.