Complex Lip Laceration 

The lips are a highly visible facial structure used in speech articulation, food consumption, and tactile sensation. Secondary to their prominent location on the face, lacerations of the lips can be cosmetically deforming. See the images below.

Lip lacerations are commonly seen in emergency departments and are one of the most common oral-maxillofacial injuries.^[1] Careful repair is necessary to ensure the best cosmetic results and patient satisfaction.^[2] The approach in repair depends largely on location and type of injury.^{[3, 4]} For more information, see Medscape Reference articles Facial Soft Tissue Injuries and Facial Soft Tissue Trauma.

Anatomy

• The lips are composed of 3 major layers: skin, muscle, and oral mucosa.
• The philtrum is the vertical groove located directly adjacent to and above the upper lip and below the nose.
• The commissures are the lateral borders of the oral cavity where the upper and lower lips join.
• The vermilion is the white roll that forms the border between the lip and surrounding skin (see the image below). This area is the focus of repair because even 1 mm of vermilion misalignment may be noticeable. Illustration of the upper and lower vermilion border.

Nerve supply

• The upper lip and the skin between the upper lip and lower eyelid are innervated by the infraorbital nerve on either side.
• The lower lip, gums, and skin between the lower lip and chin are innervated by the mental nerve.

For a detailed discussion of lip anatomy, see Medscape Reference article Lips and Perioral Region Anatomy.^[5]

Unlike the cosmetically important facial lacerations that are almost always closed primarily, certain small intraoral lacerations may be left open and will heal well without repair.^[6] Small puncture lacerations through the lip may not require complete closure; the external portion may be repaired while the intraoral portion is allowed to heal without sutures.^[6] Indications for external repair are the same as with any other facial laceration. See the images below for examples of intraoral lacerations.

Indications for intraoral closure

• Mucosal laceration that creates a flap that interferes with chewing
• Mucosal laceration that is large enough to trap food particles
• Wounds longer than 2 cm

• Certain wounds are best closed in consultation with a plastic surgeon.

  • Large flaps
  • Large amounts of the vermilion border missing
  • Macerated wounds
  • Involvement of the commissure
  • Loss of more than 25% of the lip^[7]

For more information, see Medscape Reference article Lip Reconstruction Procedures.^[8]

• Lips are well enervated and very sensitive to pain. They can be difficult to anesthetize locally. In addition, local infiltration of anesthesia into external lip wounds often causes swelling and distortion of original landmarks.
• Performing regional nerve blocks when possible often leads to the best possible results both anesthetically and cosmetically.^[9] To anesthetize the lower lip, perform a mental nerve block; for the upper lip, perform an infraorbital nerve block (see the images below). Areas of regional nerve blocks for the lips. Technique for extraoral infraorbital nerve block. Intraoral approach for infraorbital nerve block.
• Pre-anesthetizing the mucosal area with a topical anesthetic 3 minutes prior to infiltrative injection is recommended.
• For intraoral wounds, consider anesthetizing locally; nerve blocks may not be as effective.
• In small children, consider the use of procedural sedation as an adjunct to the procedure by aiding in immobilization of the field.

Personal protective equipment

• Gloves
• Face shield
• Gown

Anesthesia equipment

• Topical anesthetic
• Lidocaine, typically with epinephrine to reduce bleeding
• Syringe, 10 mL
• Needle, 27 gauge (ga)
• Needle, 18 ga

Irrigation equipment

• Saline or tap water^[10]
• Syringe or irrigation device
• Splash shield
• Basin

Suture material

• Absorbable sutures (eg, plain gut, chromic gut), 4-0 or 5-0^[11]
• Nonabsorbable sutures (eg, nylon), 6-0
• Suture tray
• Suture kit

Assembled equipment is shown in the image below.

Supine patient positioning is preferred. Ensure that the height of the bed is appropriate and that optimal lighting is available for visualization.

Inspection and irrigation

• Once the patient is anesthetized, inspect the wound carefully.
• Gentle probing may be required to visualize through-and-through lacerations (see the image below). Further inspection of the anesthetized wound reveals a through-and-through laceration.
• Check for concurrent chipped, missing, or mobile teeth.^[10] Tooth fragments may be lodged inside the wound and may serve as a nidus of infection if not removed.^[11]
• Intraoral wounds are prone to considerable contamination; therefore, thorough irrigation is necessary.^[12]

Closure

Through-and-through lip wounds are closed in subsequent layers.

• Deep soft-tissue layer

  • Use 4-0 or 5-0 absorbable sutures to anchor the fibrous tissue just underneath the anterior and posterior skin surfaces. In deep but not through-and-through lacerations, deep sutures can be placed using a simple interrupted technique that leaves the knot buried deep within the laceration. See the images below. Extraoral approach to close the deep layer. Wound approximation after 2 deep sutures are placed. Intraoral approach to close the deep layer. Wound approximation after placement of deep muscular sutures.

• Vermilion border

• If the vermilion border is involved, approximate it with the first suture placed on facial skin. Use 6-0 nonabsorbable suture material.* The approximation of the vermilion-cutaneous junction is the most crucial step in the closure of lip lacerations that involve the vermilion border. Misalignment of even 1 mm may cause a noticeable step-off when the wound is healed. See the images below. Placement of the first suture through the vermilion border. Placement of the first suture through the vermilion border. First suture aligning the vermilion border.

• Intraoral skin

• Intraoral skin may be closed either before or after the facial skin. Approximate the buccal wet mucosa with simple interrupted absorbable sutures (4-0 or 5-0); absorbable sutures fall out or absorb and do not require removal. Secure each stitch with 4 knots to ensure that the stitches are not untied by the tongue. These sutures can be continued onto the wet and dry vermilion surface of the lip. Silk is best avoided in the mouth, as it can irritate mucosal tissues. Any small intraoral flaps may be excised. See the images below. Closure of an intraoral skin laceration. Placement of intraoral skin suture with buried knot. Closure of an intraoral laceration.

• Facial skin

• Using 6-0 nonabsorbable sutures,* approximate the skin with simple interrupted sutures. This suture material can be continued onto the lip; however, many prefer absorbable sutures on the dry vermilion surface. See the images below. Complete closure of the facial skin. Complete closure of the facial skin.

• Topical adhesives

• There have been some reports that topical adhesives (cyanoacrylate) can achieve adequate closure in small lip wounds.^[13] Topical adhesives have the benefit of less pain from anesthesia techniques and are often advantageous in patients who tend to keloid; however, there is a higher likelihood of dehiscence compared to sutures. While it might be most tempting to use this technique in children, they are more prone to biting or licking off the glue.^[14]

*In young children, consider using all absorbable sutures for repair of these lacerations. Eliminating the need for suture removal may result in decreased emotional and physical trauma, and studies show no discernable difference in cosmetic outcome.^[15]

Aftercare

• Ensure that tetanus status is up to date.^[16]
• Antibiotic ointment or petroleum jelly may be placed daily over the skin surface of the laceration.^[17] This should be avoided with absorbable sutures, however, as it may inappropriately hasten absorption.
• Cold packs, nonsteroidal anti-inflammatory drugs (NSAIDs), or acetaminophen may help with pain control.
• If the laceration involves the oral mucosa, consider recommending a bland diet to avoid irritating the wound.
• For intraoral wounds, especially if left unclosed, consider discharging the patient with a syringe and saline. It may be helpful for them to gently irrigate the wounds after eating to keep them clean of debris.
• Remove nonabsorbable sutures in 4-5 days to prevent scarring.

Antibiotics

The use of prophylactic antibiotics in lip lacerations is controversial but recommended.^[18] Many textbooks recommend the use of prophylactic antibiotics for through-and-through and intraoral lip lacerations; however, not all studies show significant benefit from this use.^[19] Medications used for prophylaxis vary depending on clinician preference and range from oral cephalexin to chlorhexidine rinse.

• Emphasis on accurately approximating the vermilion border is advised for the best cosmetic outcome.
• The location of intraoral lacerations can make repair difficult without assistance for retraction. One option is to have the patient retract his or her own lip.
• Strongly consider the use of regional nerve blocks.
• If a patient with a lip or oral laceration also has a newly chipped tooth, search diligently for tooth fragments in the oral mucosa;^[11] if not removed, such fragments may cause wound infections. Retained tooth fragments can be visualized on radiographs of the soft tissue.^[20]
• Lip wounds are more prone to infections than other wounds due to the saliva and contamination from dental bacterial plaque.^{[12, 18]}
• Have a high index of suspicion for underlying facial fractures in trauma patients with lip lacerations; order imaging as necessary.^[21]
• Remember to update a patient's tetanus vaccination when necessary.

• The risks of contamination and resulting infection are considerable in intraoral lacerations;^[22] these risks may be reduced by administration of prophylactic antibiotics. Patients should be instructed to return if signs of infection develop (eg, fever, swelling, spreading erythema). Remind patients that intraoral wounds may appear white for a few days. A wound check may be arranged within 48 hours.
• Wounds to the vermilion border may result in deep scars and tissue redundancy that may require later revision by a plastic surgeon.^[23]