Disorders of the External Ear

Applied Clinical Anatomy and Development


The external ear includes the auricle and auditory canal ( ▶ Fig. 6.1 a). The anterior and posterior surfaces of the auricle are characterized by a typical relief ( ▶ Fig. 6.1 a, b) with a long axis of 62 to 64 mm (in the adult) and an inclination of 15 to 25 degrees. The distance between the anterior helical rim and the mastoid is less than 20 mm ( ▶ Fig. 6.23c). The auricle consists of elastic cartilage (1.0–3.0 mm), enveloped within thick skin and firmly attached to the perichondrium, apart from the lobule which is free of cartilage. The posterior surface has an additional layer of fat between the skin and perichondrium. The auricle develops from the mesenchymal hillocks 1, 2, and 3, arising from the first “branchial arch” and the mesenchymal hillocks 4, 5, and 6 of the second “branchial arch.” The auditory canal develops from the first branchial cleft ( ▶ Fig. 6.2). 1



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Fig. 6.1 External ear and adjacent structures. (a) Anterior auricular surface. (b) Posterior auricular surface. (Modified after Weerda H. Surgery of the Auricle: Tumors, Trauma, Defects, Abnormalities. Stuttgart/New York, NY: Thieme Publishing Group; 2007, with permission.)



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Fig. 6.2 Changes in the developing auricle as it migrates in the course of embryonic development, as described by Leiber, 1 and typical malformations associated with embryonic development. 1, 2, and 3: Hillocks from the first branchial arch. 4, 5, and 6: Hillocks from the second branchial arch. 7: first branchial cleft. (Modified after Weerda H. Surgery of the Auricle: Tumors, Trauma, Defects, Abnormalities. Stuttgart/New York, NY: Thieme Publishing Group; 2007, with permission.)


The auricle migrates from an anterocaudal position to a posterocranial position.


The auricle reaches 85% of its final length by the age of 6 years.


6.3 Acquired Disorders of the External Ear




Inflammatory Diseases of the External Meatal Skin and the Auricle





  • Otitis externa circumscripta (furuncle).



  • Otitis externa diffusa (swimmer’s ear).



  • Eczematous otitis.



  • Otitis bullosa hemorrhagica (bullous otitis).



  • Erysipelas (auricular cellulitis).



  • Chronic otitis externa.



  • Perichondritis.


6.3.1 Furuncle (Otitis Externa Circumscripta)


This is typically caused by a Staphylococcal infection of the hair follicle in the skin of the cartilaginous ear canal.


Diagnosis is made by finding a discrete red swelling of the ear canal with ear pain and tenderness, made worse by gently pulling or pressing the pinna or tragus.


Treatment is with antibiotic and steroid dressings changed daily. Incision and drainage under general anesthesia may be necessary, and in recurrent cases, it is wise to check the child for diabetes mellitus or immune dysfunction.


6.3.2 Swimmer’s Ear (Otitis Externa Diffusa)


This may be caused by traumatization of macerated skin of the ear canal. Other factors include infection of cerumen after cleaning, use of hearing aids, and contamination of the ear canal with materials from water. Bacterial and/or fungal infection may supervene with Pseudomonas aeruginosa (54%), Staphylococcus epidermidis (9.1%), S. aureus (1.0%), Proteus, Candida species, or Aspergillus. The skin is red, edematous, and desquamated. The child may complain of itching, pain, and discharge. He/she may be mildly hearing impaired due to accumulated debris in the ear canal and, in severe cases, may be febrile and unwell. (See ▶ Fig. 6.3.)



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Fig. 6.3 Otitis externa.


Treatment is by meticulous cleaning of the ear (not always easy or possible in a child), adequate analgesia, and topical antimicrobial therapy, ideally with a local steroid, for up to a maximum of 2 weeks to avoid sensitization or mycosis. We recommend ciprofloxacin 0.3% and dexamethasone 0.1% as sterile otic suspension. A soft cotton or small pressed sponge, self-expanding 2 and soaked with antibiotic–steroid solution (based on culture results: Methicillin-resistant S. aureus 60%, clindamycin 33% resistance rate, increased resistance after long-time therapy), may be useful, with antimycotic therapy if necessary. 3


6.3.3 Eczematous Otitis


This occurs with atopic eczema, seborrheic dermatitis, psoriasis, neurodermatitis, and purulent or chronic otitis externa (dermatological diagnoses) ( ▶ Fig. 6.4). Treatment is directed at the dermatological condition, with attention to aural toilet as needed. In susceptible children, it is important to avoid sprays and irritant shampoos.



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Fig. 6.4 Eczematous otitis.


6.3.4 Bullous Myringitis (Otitis Externa Bullosa Hemorrhagica)


This is caused by a viral infection (e.g., influenza). Pain is often severe.


Hemorrhagic bullae involve the tympanic membrane, skin, and medial canal, so the effects of otitis media and otitis externa are combined. The child may have a conductive deafness. Treatment is expectant with attention to pain control and draining the blebs.


6.3.5 Erysipelas (Auricular Cellulitis)


This is an acute infection with streptococcus in the ear region ( ▶ Fig. 6.5). It is characterized by a raised intensely red edematous eruption of the skin. The child complains of pain, high temperature, and increasingly bad general condition as the infection spreads into the skin of the face. It is distinguished from dermatitis as the child with erysipelas is usually systemically unwell, and from perichondritis, where the lobule is free of infection. Treatment is with antibiotics (penicillin), modified as needed by culture and sensitivity result, and analgesics.



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Fig. 6.5 Erysipelas of the pinna.


6.3.6 Chronic External Otitis


This is characterized by debris and pus but seldom occurs in children. 4 There may be granulations on the tympanic membrane or the skin of the ear canal. Treatment is as for otitis externa diffusa, with management of acute exacerbations as they occur.


Chronic fungal infection may need antimycotic agents.


6.3.7 Perichondritis


This is covered later in the chapter (see section on Complications of Surgery to the Pinna; see also ▶ Table 6.3) See ▶ Fig. 6.6.



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Fig. 6.6 Perichondritis.


6.4 Trauma


The exposed position of the auricle predisposes it to a large number of different injuries. The cartilage is dependent upon nutrition from its surrounding tissues (a “bradytrophic” structure), so shearing forces can cause devascularization and necrosis.




Varieties of External Ear Trauma





  • Acute penetrating trauma (including piercing).



  • Blunt trauma (hematoma and seroma auris).



  • Chemical burns.



  • Thermal burns.



  • Avulsion injuries.


6.4.1 Penetrating Trauma


Some piercings even in the region of the helix cause inflammation associated with granulation tissue ( ▶ Fig. 6.7). This can lead to loss of the auricle by perichondritis.



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Fig. 6.7 Chronic inflammatory alterations after piercing, displaying in part scar hypertrophy and in part granulation tissue. (Reproduced from Weerda H. Surgery of the Auricle: Tumors, Trauma, Defects, Abnormalities. Stuttgart/New York, NY: Thieme Publishing Group; 2007, with permission)


6.4.2 Chemical Burns


Acid burns result in superficial coagulation necrosis, whereas alkali produces deeper more penetrating injuries.


The ear should be immediately cleaned with clear water with application of sterile, cool compresses, and steroid ointments. Later treatment may involve surgical removal of necrotic tissue and reconstruction at a later stage. 5,​ 6


6.4.3 Thermal Injuries (Burns)


These are frequently caused by hot liquids (scalding) but are sometimes due to exposure to flames, for example, gas explosions or firework injuries.




  • First-degree burns are caused by short exposure giving rise to painful erythema, tissue swelling, and superficial defects. Management is by cooling, local ointments, and analgesia. Complete recovery is usually observed within a few days.



  • Second-degree (partial-thickness) burns involve the superficial layer of skin and the dermis. Therapy is as for first-degree burns, with spontaneous healing expected within 14 days.



  • Third-degree (full-thickness) burns are caused by open fire or electrical burns, lead to tissue destruction and necrosis (even cartilage), and may be complicated by extensive tissue infection and deformity, requiring later reconstructive surgery. 6 Therefore, we need cartilage protection by a cooling sterile dressing. These children benefit from interdisciplinary cooperation (e.g., management on a burns unit) and tetanus prophylaxis.


6.4.4 Otohematoma and Otoseroma


Hematomas or seromas ( ▶ Fig. 6.8) develop between the cartilage and the nutrient skin–perichondrium layer. They are caused by tangential shearing movement due to blunt trauma, typically during sports without protective headgear. Approximately 80% of them are found on the superior aspect of the auricle.


Treatment involves drainage to remove the fluid, with secure apposition of the skin–perichondrium flap, otherwise the fluid will refill. This can be brought about by an anterior incision in the antihelical or conchal fold ( ▶ Fig. 6.8), with removal of clotted blood and granulation tissue, and mild compression with mattress sutures for 1 week.




Hematoma of the Pinna





  • Simple aspiration is not usually adequate.



  • If initial treatment is delayed or inadequate, the cartilage may undergo organization and fibrosis with thickened skin and cartilage (cauliflower ear). This may require surgical remolding but the damage may not be easily reversed.



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Fig. 6.8 Approaches of otohematoma otoseroma. (a) Concha hematoma (incision at the rim of antihelix). (b) Upper otohematoma; incision in the scapha (1) or beneath the antihelix for low conchal hematoma (2). (c) Result of (a), 2 months after incision. (Reproduced from Weerda H. Surgery of the Auricle: Tumors, Trauma, Defects, Abnormalities. Stuttgart/New York, NY: Thieme Publishing Group; 2007, with permission.)


6.4.5 Partial and Total Avulsion


Road traffic accidents are the cause in more than 40% of cases, and domestic accidents are the cause in over 30%. Although there will inevitably be overlaps when attempting to classify the defects, we still regard classification as worthwhile for didactic reasons ( ▶ Fig. 6.9, ▶ Table 6.1).


Partial defects and partial and total loss will be reconstructed with different methods in a one- or multistage technique, with cartilage of the contra-lateral auricle or rib cartilage. With modern surgical techniques, we are able to get satisfying results ( ▶ Fig. 6.10, ▶ Fig. 6.11). 5


Reimplantation of the auricle as a composite graft only takes when small parts are amputated. Larger parts will become necrotic and must be reconstructed with cartilage and skin of the surrounding area ( ▶ Fig. 6.10). 5



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Fig. 6.9 Classification of defects: partial and total loss of the auricle ( ▶ Table 6.1). (Reproduced from Weerda H. Surgery of the Auricle: Tumors, Trauma, Defects, Abnormalities. Stuttgart/New York, NY: Thieme Publishing Group; 2007, with permission.)



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Fig. 6.10 Defect of the middle third of the auricle. (a) Necrosis after reimplantation. (b) Reconstruction of the middle part of the auricle with rib cartilage and skin of the mastoid region. (Reproduced from Weerda H. Reconstructive Facial Plastic Surgery. 2nd ed. New York, Stuttgart: Thieme; 2015, with permission.)



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Fig. 6.11 Reconstruction of the auricle after total loss with rib cartilage and skin of the surrounding area in three stages. (a) Defect. (b) Reconstructed auricle. (Reproduced from Weerda H. Surgery of the Auricle: Tumors, Trauma, Defects, Abnormalities. Stuttgart/New York, NY: Thieme Publishing Group; 2007, with permission.)



























Table 6.1 Classification of auricular defects and their treatment ( ▶ Fig. 6.9) 5

Central defects


Concha


Antihelix scapha


Combined central defects


Peripheral defects (helix and helical crus)


Reconstruction with auricular reduction


Reconstruction without auricular reduction


Partial reconstructions


Upper third of the auricle:




  • Reconstruction with auricular reduction



  • Reconstruction without auricular reduction


Middle third of the auricle:




  • Reconstruction with auricular reduction



  • Reconstruction without auricular reduction ( ▶ Fig. 6.10)



  • Lower third of the auricle


Earlobe


Traumatic earlobe cleft


Reduction of the earlobe (hyperplasia)


Defects of the earlobe


Loss of the earlobe (hypoplasia and aplasia)


Hypertrophic scar formation


Keloids


Posterior defects


Postauricular defects (posterior surface of the ear)


Retroauricular defects (mastoid region)


Combined post- and retroauricular defects


Reconstruction after total auricular loss
( ▶ Fig. 6.11)



Source note: Reproduced from Weerda H. Surgery of the Auricle: Tumors, Trauma, Defects, Abnormalities. Stuttgart/New York, NY: Thieme Publishing Group; 2007, with permission.


6.5 Congenital Disorders of the External Ear




The development of the external ear is a complex process and abnormalities, mostly minor, are common.


Approximately half of the malformations in the head and neck are in the region of the ear. Brent 7 reports one auricular malformation in approximately 6,000 neonates. Abnormalities may be isolated or may be part of an inherited syndrome such as Franceschetti’s or Goldenhar’s syndrome. Exogenous factors are presumed to be the cause of the malformation in approximately 10% cases. These include maternal toxins such as thalidomide, alcohol, maternal rubella, and other viral infections. 8


6.5.1 Auricular Appendages


These are thought to be due to excess of the mandibular arch (first branchial or pharyngeal arch) formations along the edge of the first branchial (pharyngeal) cleft ( ▶ Fig. 6.12). 9,​ 10 They include minor skin tags and accessory auricles. In the presence of normally developed ears, appendages are best excised in the relaxed skin tension lines.



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Fig. 6.12 Auricular appendages. (a) Location of preauricular appendages (as described by Otto in Weerda [1994]) 9,​ 10 along the edge of the first branchial cleft. (b) Preauricular appendages associated with a normally developed ear. (c) Preauricular appendages associated with anotia. (Reproduced from Weerda H. Surgery of the Auricle: Tumors, Trauma, Defects, Abnormalities. Stuttgart/New York, NY: Thieme Publishing Group; 2007, with permission.)


6.5.2 Fistulas and Sinuses


Congenital auricular fistulas, preauricular fistulas, and sinuses are formed by entrapped remnants of epithelium found in similar locations to those described for auricular appendages ( ▶ Fig. 6.12, ▶ Fig. 6.13, ▶ Fig. 6.14). If they have no tendency to recurrent inflammation, they may not require treatment. They may, especially if the orifice is below the tragus, be intimately associated with the facial nerve and surgery can be very challenging (see ▶ 12). 11




For a fistulogram, aqueous contrast agent should be used. Before surgery, we employ staining of the outline of the fistula with methylene blue.



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Fig. 6.13 Fistulas and sinuses of the auricle. (a) Location of fistulas in the region of the ear as depicted by Gohary et al. 11 Modified after Gohary A, Rangecroft L, Cook R. Congenital Auricular and Preauricular Sinuses in Childhood. Z Kinderchir 1983;38:81–82, with permission.) (b) Infected congenital preauricular sinus, with opening. (Reproduced from Weerda H. Surgery of the Auricle: Tumors, Trauma, Defects, Abnormalities. Stuttgart/New York, NY: Thieme Publishing Group; 2007, with permission.



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Fig. 6.14 Location of fistula openings in the region of the ear and neck as described by Otto. 101: anterior auricular surface: group comprising congenital, preauricular fistulae. 2: postauricular surface: group comprising fistulae of the neck and ear region, also referred to as a “duplication of the external auditory canal.” 3: proximal group of lateral cervical fistulae. (Reproduced from Weerda H. Surgery of the Auricle: Tumors, Trauma, Defects, Abnormalities. Stuttgart/New York, NY: Thieme Publishing Group; 2007, with permission.)


6.5.3 Auricular Dysplasias


Classification of auricular dysplasias is shown in ▶ Table 6.2 and ▶ Fig. 6.15.


Arrested development or failures of differentiation of parts of the auricular primordium or the pharyngeal cleft can result in various types of malformation of the external ear ( ▶ Fig. 6.2 and ▶ Fig. 6.15). The most severe manifestation is anotia or complete absence of the external ear (grade III microtia). Lower grade microtia represents a less severe deformity where some of the components of the ear are present, but they are rudimentary and often greatly malformed. The different types of auricular malformations are related to embryological maldevelopment in the region of the mesenchymal hillocks 1 to 6 ( ▶ Fig. 6.2). 12 Malformations represent an aesthetic impairment that can produce “a significant psychosocial burden during the development of the personality.” 13



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Fig. 6.15 Different types of malformations (see also ▶ Table 6.2).

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Jun 29, 2018 | Posted by in OTOLARYNGOLOGY | Comments Off on Disorders of the External Ear
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