Otoplasty

ANATOMY

What is the embryologic origin of the ear?

Traditionally, it is thought that the first branchial (mandibular) arch contributes to the tragus and helical crus and the second branchial (hyoid) contributes to the helix, antihelix, scapha, concha, antitragus, and lobule (85% of the ear).

Describe the vascular supply of the ear.

The posterior auricular and superficial temporal arteries provide the blood supply to the ear. The posterior auricular artery is the dominant vessel and is typically used in cases of ear replantation.

Describe the nerves providing sensation to the ear.

The ear is supplied by multiple sensory nerves:

1. The auriculotemporal nerve (V3 branch of the trigeminal nerve) supplies the tragus and helical crus.

2. The great auricular nerve supplies the helix, scapha, antihelix, concha, lobule, antitragus and posterior auricular sulcus, and partially the external auditory meatus.

3. The lesser occipital nerve supplies a small portion of the helix.

4. The vagus nerve (cranial nerve (CN X) supplies a portion of the concha and external auditory meatus (Arnold’s nerve).

5. The glossopharyngeal nerve (CN IX) supplies a portion of the external auditory meatus (Jacobson’s nerve).

Describe how to perform an ear block with local anesthesia.

While it is theoretically possible to perform a regional block of the ear by injecting the great auricular nerve, lesser occipital nerve, and auriculotemporal nerve, it is generally more practical to infiltrate the area where the procedure is occurring so as to take advantage of the epinephrine effect. Contrary to frequent popular belief, there is no problem injecting 1% epinephrine into the ear.

When is the ear its full adult size?

The human ear obtains 80% of its adult size by the age 6 and 90% and above by age 10 years. The width of the ear reaches its full adult size by age 7 for boys and 6 for girls. The ear length reaches its adult size at age 13 for boys and age 12 for girls. The average width of the ear is 3 to 4 cm and the height 5.5 to 7 cm.

Where is the ear typically located in relation to other facial landmarks?

The ear lies approximately one ear length posterolaterally from the lateral orbital rim. The highest point of the ear coincides with the brow and the lowest with the columella.

What is the normal incline of the ear?

The inclination of the ear is somewhat variable and is almost always slightly more vertical than the angle of the nasal dorsum. An average ear typically angles approximately 15 degrees posteriorly.

What is the accepted angle between the ear and temporal scalp?

The normal external ear is typically 20 to 25 degrees angled from the temporal scalp; a more obtuse angle can cause the ear to appear prominent. The upper third of the ear protrudes on average 10 to 12 mm from the scalp, the middle third of the ear protrudes on average 16 to 18 mm from the scalp, and the lower third on average 20 to 22 mm from the scalp.

OTOPLASTY

What are the indications for otoplasty?

Among the indications for otoplasty are include the patient with the prominent ear, constricted ear, Stahl’s ear, or cryptotia. The prominent ear is most common, affecting 5% of the Caucasian population.

Is there a role for nonsurgical otoplasty?

Definitely, if it is performed in the neonatal period. Nonsurgical molding cannot create parts of the ear that are not there but can correct many types of congenital deformities including prominent ears and Stahl’s ear. In 1990, Matsuo reported successful nonsurgical treatment of all protruding ears and other deformities in neonates theorizing that the malleable nature of cartilage is due to elevated level of circulating maternal estrogen. The age at which nonsurgical therapy can be offered is debatable; opinions vary from newborn to up to 6 months of age. It is the opinion of the authors that neonatal ear molding is most effective for minor helical rim deformities and should be started by 6 to 8 weeks of age.

Describe the nonsurgical otoplasty technique.

A molding device is made often by surrounding a thin solder or copper wire with wax, Microfoam tape, or plastic tubing. This is bent to fit the ear and then shaped to press ear into a normal shape. The hair around the ear is shaved and prepped with an adhesive and the device is secured with multiple steristrips. As soon as the ear begins to retain the desired contour, the wire (if present) is removed. Finally, the tape mold is omitted and the ear is held with tape alone until the new position is stable. It is imperative that the patients be seen frequently to rule out pressure injury to the ear.

How long does nonsurgical molding take?

A few months.

What are the causes of ear prominence?

The causes are unknown. Some authors have theorized that abnormalities in the location and attachments of the muscles around the ear may be the cause. Not all prominent ears are the same. The anatomic structures of the ear that may be abnormal in a prominent ear include:

1. Effacement or deficiency of the antihelical fold. This may occur along the entire length of the helix or just involve the inferior or superior crus of the antihelix.

2. Conchal hypertrophy, excess (>1.5 cm depth) or abnormality of shape including an obtuse conchal mastoid angle. The excessive depth of the concha may be unequally distributed between the upper (cymbum) and lower (cavum) poles of the concha.

3. A conchoscaphal angle greater than 90 degrees.

What type of anesthesia is preferred for otoplasty?

Local anesthesia is usually preferred in adults and general anesthesia is usually required in children. In patients less than 12 years of age general anesthesia is recommended. This may vary by patient and surgeon.

What are the preferred markings for otoplasty?

Most otoplasty procedures can be performed through a posterior incision, either in the sulcus or on the posterior surface of the concha. If the patient has macrotia or desires more definition of the helical rim, then an incision is also made just inside the helical rim.

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