The external ear, also known as the auricle or pinna, has unique anatomical features that influence wound management in this area. For today’s POTD, I’m going to review the anatomy of the outer ear and the management of auricular lacerations.
Anatomy
The term “outer ear” specifically refers to the auricle (or pinna) and the external auditory canal. The auricle can be divided into six sub-units: the helix, antihelix, conch, tragus, anti-tragus, and the lobule.
All of these structures, except the lobule, are composed of thick avascular cartilage that supports the ear’s shape and structure. This cartilage is surrounded by a poorly vascularized perichondrium, which is then covered by a tightly adherent connective tissue and skin layer.
Auricular Lacerations
When the ear sustains a laceration, it should be repaired using primary closure, similar to any other laceration. Simple lacerations (involving only the skin) or complex lacerations (exposing or extending through the cartilage layer) can be repaired by us ER doctors. However, for more advanced lacerations such as split earlobes, avulsions, or lacerations extending into the external auditory canal, an evaluation by an ENT or plastic surgeon is recommended.
Auricular Nerve Block
The ear is innervated by several nerves, including the auriculotemporal nerve, greater auricular nerve, lesser occipital nerve, and the vagus nerve. An auricular nerve block can be performed to anesthetize all areas of the ear except the conch (which is innervated by the vagus nerve).
Draw up 10-20 ml of lidocaine without epi and attach a small 25g or 27g needle. (Remember the max dose of lido without epi is 7 mg/kg or 0.7 ml/kg)
Enter skin at the point just below the ear, advance the needle posteriorly along the skin over the mastoid bone behind the ear, and inject 3-5 ml while withdrawing the needle
Once the needle is close to the original puncture site, don’t remove it but redirect it anterior to the ear and inject another 3-5 ml while withdrawing the needle fully out of the skin
Repeat the same process entering from above the ear.
Enter skin at the point just above the ear, advance the needle posteriorly, inject 3-5 ml while withdrawing the needle, redirect the needle anteriorly and inject another 3-5 mL in front of the ear while withdrawing the needle.
Laceration Repair
Once the ear is anesthetized, irrigate the wound and assess for any exposed cartilage.
If there’s no exposed cartilage, repair the skin with 6-0 non-absorbable sutures using a standard simple interrupted technique.
If there’s exposed cartilage, you can still repair the wound with 5-0 or 6-0 non-absorbable sutures. However, you must ensure the skin is well-approximated and fully covers the cartilage. This might require the use of deep 5-0 absorbable sutures if the wound is full-thickness (through and through) or irregular.
Dressing
After the ear has been repaired, it is recommended to apply a bulky pressure dressing to avoid the dreaded cauliflower ear. Cauliflower ear is a deformity of the ear that arises when normal healthy ear cartilage is replaced by fibrocartilage. This occurs when the cartilage is left exposed or it suffers pressure necrosis from a hematoma forming between the skin and cartilage (as shown in the image below).
Head Wrap Technique: Apply petroleum gauze around the wound and pack it into the helix. Apply a generous amount of dry gauze anterior and posterior to the ear. Compress this dressing tightly to the head with kerlix gauze.
Bolster Technique: Sandwich the wounded area between cotton rolls or small rolls of gauze, securing these in place by suturing them to the ear.
Ear Splint technique: Wet a small amount of plaster and coat it with a thin layer of cotton webril dressing to create a splint. Firmly press the splint in place against the ear with a wad of gauze. Cover the ear with several layers of gauze. Secure the splint to the head with a kerlix wrap around the head.
Review the steps here: https://www.aliem.com/trick-of-trade-splinting-ear/
Quick Caveat: Some argue that auricular hematomas are rare, and a pressure dressing can hinder wound healing through vascular compromise.
Antibiotics
As with any wound, ensure the patient’s tetanus status and administer an updated tetanus vaccine if necessary.
Historically, prophylactic antibiotics were commonly prescribed for ear lacerations. Evidence now suggests that they may not be universally required. The consensus among medical professionals, including UpToDate and multiple emergency medicine blogs, is that antibiotics (such as Augmentin or clindamycin) should be prescribed if the wound is visibly contaminated, if cartilage is exposed or requires repair, or if the patient is immunocompromised to increase their risk for infection.
Follow-Up
Technically speaking the best practice is to recommend the patient return in 24 hours to assess the wound for the development of an auricular hematoma. After this initial assessment, they should return in 4-5 days for suture removal.
Sources:
https://accessmedicine.mhmedical.com/content.aspx?bookid=2969§ionid=250461381
https://www.uptodate.com/contents/assessment-and-management-of-auricle-ear-lacerations