10.01 Simple laceration

agk’s Library of Common Simple Emergencies

Presentation

There may be a history of being slashed by a knife, glass shard or other sharp object that results in a clean, straight wound. Impact with a hard object at an angle to the skin may tear up a flap of skin. Crush injury from a direct blow may produce an irregular or stellate laceration with a variable degree of devitalized tissue, abrasion and visible contamination. Wounds may involve vascular areas of the face and scalp where the risk of infection is low, or extremities where infection becomes a greater risk, along with the possibility of tendon and nerve damage. The elderly and patients on chronic steroid therapy may present with “wet tissue paper” skin tears following relatively minor trauma.

What to do:

• Establish the approximate time of injury. After four hours, wounds should be scrubbed to remove the protein coagulum. There is no significant time-related difference in infection rates for wounds closed within 18 hours.
• Determine the exact mechanism of injury, which should alert you to the possibility of an underlying fracture, retained foreign body, wound contamination or tenden or nerve injury.
• Investigate for any underlying factors that may increase the risk of wound infection, like diabetes, malnutrition, morbid obesity, or patients taking chronic immunosupressive doses of corticosteroids, as well as chemotherapy, AIDS, alcoholism and renal failure.
• Ask about tetanus immunization status and provide prophylaxis where indicated.
• Test distal sensory and motor function. Test tendon function against resistance. If function is intact but there is pain, suspect a partial tendon laceration. Tendon and nerve lacerations deserve specialty consultation.
• Consider imaging studies if there might be a radio-opaque retained foreign body.
• Consider anxiolytic conscious sedation for children, like oral, nasal or rectal midazolam (Versed). Follow your hospital protocol.
• Children may also benefit from a topical anesthetic agent, especially for scalp and facial lacerations. Lidocaine 4% plus epinephrine 1:1000 plus tetracaine 0.55 (LET) is safe, effective and inexpensive. Put 3mL on a 2x2" gauze square and press firmly into the wound for 15 minutes either with tape or the parent’s gloved hand. After removing the gauze, test the effectiveness of the anesthesia by touching with a sterile needle. If any sensitivity remains, infiltrated the area with buffered lidocaine as described below.
• Buffer plain lidocaine solution by adding 1mL of sodium bicarbonate solution to 9-10mL and allow it to approximate body temperature in your pocket. Bupivacaine (Marcaine) is slightly slower in onset but has a much longer duraction of action and may be useful for crush injuries and fractures where pain is expected to be prolonged beyond closure of the laceration. Epinephrine added to lidocaine is generally not recommended for its short-lived help with hemostasis and duration of anesthesia, and its use should generally be discouraged because of its increased pain on injection and its slower healing and increased infection rate. Bicarbonate inactivates epinephrine.
• Inject slowly, subdermally, beginning inside the cut margin of the wound, avoiding piercing intact skin, working from the area already anesthetized, using a 27 or 30 gauge needle on a 5 or 10mL syringe.
• Use regional blocks to avoid distorting tissue or where there is no loose areolar tissue to infiltrate, such as the finger tip.
• Clean the wound after anesthesia is complete. Superficial lacerations with little or no visible contamination may be cleaned by gentle scrubbing with a gauze sponge soaked in normal saline or a 1% solution of povidone-iodine (dilute the stock 10% betadine tenfold with 0.9% NaCl). Deeper contaminated lacerations may require pressure irrigation with a syringe and splash shield like Zero-Wet using the same 1% povidone-iodine solution or plain saline if the patient is allergic to iodine. All visible debris and devitalized tissue must be removed, either by scraping with the edge of a scalpel blade or excision with scalpel or scissors. Cosmetic considerations will influence the degree to which you debride facial lacerations, but excision of contaminated, macerated wound edges will often produce a neater scar.
• Hair generally does not need to be removed. When necessary, shorten hair with scissors rather than shaving with a razor.
• Simple lacerations seldom require special techniques for hemostasis. Direct pressure for ten minutes, correct wound closure, and a compression dressing should almost always stop the bleeding.
• Examine the wound free of blood with good lighting. Examine any deep structures like tendons by direct visualization through their full range of motion, looking for partial lacerations. If the wound has been heavily contaminated with debris, crushed, macerated, neglected for a day, exposed to pus, feces, saliva or vaginal discharge, consider excising the entire wound and closing the fresh surgical incision, if practical. Otherwise, provide for open management by packing with sterile fine-mesh gauze covered with multiple layers of coarse absorptive gauze. Unless the patient develops a fever, leave the dressing undisturbed for 4 days. If there are no signs of infection, the granulating wound edges may then be approximated as a delayed primary closure.
• Close the wound primarily only if it is clean and uninfected. Minimize the amount of suture material inside. The less used, the less chance of infection. Wound closure tapes offers the least risk of infection, and are most successfully used on simple superficial lacerations with minimal tension. They are the closure of choice for “Wet tissue paper” skin tears. Prior to application, degrease the skin with alcohol, being careful not to get any into the wound. An adhesive agent such as tincture of benzoin may then be thinly applied to the skin surrounding the laceration (again, avoiding the open wound). Push the wound edges together and apply the stripe to maintain approximation.
• Most scalp lacerations and many trunk and proximal extremity lacerations that are straight without edges that curl under (invert) can be most easily repaired using skin staples. Push edges together and staple so edges evert slightly. Hair does not interfere with this technique and does not cause a problem if caught under a staple.
• For deep or irregular lacerations or on face, hands or feet and skin over joints, use a monofilament non-absorbable suture like nylon or polypropylene either 4-0, 5-0, or 6-0, the smallest diameter with sufficient strength. A good strategy to realign skin and minize sutures is to begin by approximating the midpoint of the wound and then bisect the remaining gaps. Simple interrupted stitches should be about 1cm apart and 1cm deep and 1cm back from from the wound edge, although these dimensions may be reduced for cosmetic closure on the face. Angle the needle going and in and coming out so it grasps more subcutaneous tissue than skin, and the wound edges should evert so the dermis meets and the scar is minimized. Tie each stitch with only enough tension to approximate the edges. A continuous running suture is a more rapid technique of closing a straight laceration. When there is wound edge inversion, the length of the wound edge can be completely excised or vertical mattress sutures can be placed between simple interrupted stitches. Unless deep fascial planes are disrupted, avoid buried sutures because they increase the risk of infection.
• After closing the wound, apply antibiotic ointment and a sterile dressing which will protect the wound and provide absorption, compression and immobilization. Scalp and facial wounds may be covered only with ointment is hemostasis is not required. Splint lacerations over joints. Facial wounds should be cleaned twice a day with half strength hydrogen peroxide on a cotton tipped applicator to prevent crusting between wound edges followed by reapplication of antibiotic ointment.
• Schedule a wound check at two days if the patient is likely to develop any problems with infection, dressing changes, or continued wound care. Instruct patients to return at any time for bleeding, loss of function or signs of infection: increasing pain, pus, fever, swelling, redness, heat. After 48 hours, most sutured wounds can be re-dressed with a simple bandage that can be easily removed and replaced by the patient allowing a shower each day.
• Wound closure strips can be left in place until they fall off on their own. Additional tape can be applied if the original closure falls off prematurely.
• Remove facial sutures in four to five days to reduce visible stitch marks. The epidermis should have resealed by this time, but the dermis has not developed much tensile strength, so reinforce the wound edges with wound closure strips for a few more days.
• Most scalp, chin, trunk and limb stitches should be removed in a week. Sutures may be left in 10-14 days where there is tension across wound edges as on the shin and over the extensor surfaces of large joints. Sutures are easily and painlessly cut with the tip of a scalpel. Cut alternate loops of running sutures.

What not to do:

• Do not prescribe prophylactic antibiotics for simple lacerations. They do not reduce infection rates, and only select for resistant organisms.
• Do not close a laceration if there is visible contamination, debris, non-viable tissue or signs of infection.
• Do not substitute antibiotics for wound cleansing and debridement. Reserve antimicrobials for infections and deep innoculated puncture wounds which cannot be cleaned.
• Do not substitute x rays for meticulous direct wound examination when a foreign body is suspected by history.
• Do not use undiluted skin cleansing solution like 10% povidone-iodine or any skin-scrub containing detergents or soap within an open wound. It kills tissue and increases the infection rate.
• Do not shave an eyebrow. The hair is a useful marker for re-approximating the skin edges, and can take months to years to grow back.
• Do not remove too much skin or underlying tissue when debriding the face and scalp.
• Do not use buried absorbable sutures in a wound with a high risk of infection.
• Do not insert drains in simple lacerations. They are more likely to introduce infection than prevent it.
• Do not use Neosporin ointment. Many patients are allergic to the neomycin and develop allergic contact dermatitis.

Discussion:

The most important goal of early wound care is preventing infection. Ointments probably facilitate healing and reduce infection by their occlusive rather than antibiotic properties. Extensive primary excision limits options for later scar revision, and sometimes it reasonable to close a contaminated facial laceration for cosmetic reasons, but this is the exception that proves the rule.

Although not yet available in the US outside of veterinary practice, butyl cyanoacrylate (Histoacryl blue) the less toxic version of SuperGlue, works well for minor pediatric lacerations. The technique is to hold edges together (the same as for tape or staples), drip one drop onto the gap every centimeter, and hold for ten seconds.

References:

• Cummings P, Del Beccaro MA: Antibiotics to prevent infection of simple wounds: a meta-analysis of randomized studies. Am J Emerg Med 1995;13:396-400.
• Schilling CG, Bank DE, Borchert BA et al: Tetracaine, epinephrine (adrenaline) and cocaine (TAC) versus lidocaine, epinephrine and tetracaine (LET) for anesthesia of lacerations in children. Ann Emerg Med 1995;25:203-208.
• Mehta PH, Dun KA, Bradfield JF et al: Contaminated wounds: infection rates with subcutaneous sutures. Ann Emerg Med 1996;27:43-48.

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