9. Surgical diseases of the pinna and external ear canal. Methods of the treatment. Lateral resection of the external ear canal. Partial and total ablation of the EEC. Osteotomy of the bulla tympanica.

What are examples of diseases of the pinna?

1. Aural haematoma (othaematoma auris)

2. Pinna trauma and lacerations

3. Neoplasia

What causes aural haematoma (othematoma auris)?

1. Trauma

2. Violent head shaking or scratching due to otitis externa

3. Coagulopathies

4. Cushing’s disease

5. Vessel fragility

What types of dogs and cats are more predisposed to aural haematomas?

Long-eared breeds

Where does haemorrhage occur in an aural haematoma?

Subcutaneous, subperichondrial, or intrachondral locations

What can untreated aural haematomas lead to?

Clot formation, granulation tissue, fibrosis, cartilage ossification, disfigurement, and irritation. In cats, distorted pinnae can obstruct the ear, leading to otitis externa.

What are the treatment goals for aural haematomas?

Remove the clot, prevent recurrence, and maintain ear appearance. Immediate treatment is key to avoiding deformity.

What are the treatment options for aural haematomas?

1. Needle Aspiration: Local corticosteroids.

2. Passive Drain: Penrose drain placed through incisions, cavity lavaged, sutures secure the drain. Left for 2 weeks.

3. Active Drain: Butterfly catheter inserted, creating suction with a vacuum tube, secured with sutures.

4. Incisional Drainage: S-shaped incision removes the clot. Mattress sutures with gauze stents prevent over tightening. Bandage ear, remove sutures after 2 weeks

How long is a Penrose drain typically left in place for aural haematoma treatment?

2 weeks

What are causes of pinna trauma and lacerations?

Fighting, head trauma, frostbite, and other chronic injuries

How can pinna wounds be classified?

1. Superficial (skin only)

2. Deep (skin and cartilage)

3. Penetration (through the entire ear)

How are superficial pinna wounds treated?

1. Wound cleansing (chlorhexidine)

2. Debridement

3. Either suturing or healing by second intention (granulation, contraction, epithelialization)

How are deep pinna wounds treated?

Cleanse with chlorhexidine and suture if needed

How are perforating pinna wounds treated?

1. Align cartilage and skin with simple interrupted sutures on both sides or a combination of simple interrupted and vertical mattress sutures.

2. Drainage at the outer edge of the wound

3. Cryotherapy to reduce oedema (first 48 hours of injury)

Which surgical method can be used to treat pinna wounds, and how should it be carried out?

Skin flaps. Multi-sided flaps should be sutured along the margins and center of the flap

What should be done if a pinna wound is infected?

Treat the infection before surgical repair.

What are some types of pinnal neoplasia?

1. Actinic keratosis

2. Squamous cell carcinoma

3. Haemangioma/haemangiosarcoma

4. Basal cell tumours

5. Mast cell tumours

6. Histiocytomas

7. Sebaceous adenomas

8. Soft tissue sarcoma

9. Fibrosarcoma

10. Rhabdomyoma

11. Melanoma

What are the treatment options for pinnal neoplasia?

1. Subtotal or total pinnectomy

2. Cryotherapy

3. Ligation

4. Cauterisation

How is a pinnectomy performed?

The pinna is being amputated with scissors at least 1 to 2 cm from the margin of neoplasm. Bleeding is cauterised. The skin on the convex surface is pulled over the cut surface of the auricular cartilage and sutured to the skin on the concave surface with a simple continuous pattern of fine gauze, nonabsorbable monofilament. Do not suture cartilage.

What are examples of diseases of the external ear canal?

1. Otitis externa

2. Otitis hyperplastica

3. Otitis ossificans

4. Neoplasia

What is otitis externa?

Inflammation of the external ear canal, including the pinna, vertical/horizontal canals, and tympanic membrane

What are some causes of otitis externa?

1. Parasites (Otodectes cynotis, Sarcoptes scabiei)

2. Allergies (food, atopy, contact)

3. Bacteria (Staphylococcus pseudointermedius, Proteus, Pseudomonas)

4. Yeast (Malassezia)

5. Foreign bodies (grass seeds)

6. Endocrinopathies (hypothyroidism)

7. Neoplasia

8. Autoimmune disorders (pemphigus)

What are the most common causes of otitis externa in dogs and cats?

• Allergic dermatitis in dogs

• Polyps and ectoparasites in cats

What chronic changes can occur in otitis externa?

Gland hyperplasia, stenosis, scarring, calcification, and tympanic membrane rupture

What are the clinical signs of otitis externa?

Deafness, purulent exudates, inflammation, pain, pruritus, erythema, aural haematoma, head tilt, and stenosis

How is otitis externa diagnosed?

Medical history, otoscopy, cytology, biopsy, culture, and imaging (X-ray)

What are the treatment options for otitis externa?

1. Ear cleaning (ceruminolytics)

2. Topical anti-inflammatories (corticosteroids)

3. Topical antibiotics (gentamycin, neomycin), antifungals (imidazoles), antiparasitics (pyrethrin, ivermectin)

4. Drying agents

5. Antiseptics (chlorhexidine)

What is otitis hyperplastica?

Chronic ear canal thickening and hyperplasia due to inflammation, often from allergies

What causes otitis hyperplastica?

Allergic reactions leading to increased cerumen and secondary infections

What are the clinical signs of otitis hyperplastica?

Head tilt, fluid discharge, increased humidity, and canal occlusion

How is otitis hyperplastica treated?

Identifying and managing underlying causes (e.g., allergies with Atopica or Apoquel)

What is otitis ossificans?

Calcification of the ear canal due to chronic inflammation

How is otitis ossificans diagnosed?

X-ray

How is otitis ossificans treated?

Surgery

What types of tumours can occur in the external ear?

Often epithelial and malignant (60%).

• In dogs: ceruminous carcinoma, squamous cell carcinoma, melanoma.

• In cats: ceruminous gland adenocarcinoma, squamous cell carcinoma.

What are the surgical procedures for the ear canal and bulla tympanica?

1. Lateral wall resection (Zepp's method)

2. Partial ear canal ablation (vertical canal ablation)

3. Total ear canal ablation (TECA) with lateral bulla osteotomy

4. Osteotomy of the bulla tympanica

What are the indications for lateral wall resection (Zepp's method)?

Chronic otitis externa, ear canal hyperplasia, congenital canal stenosis, and small tumours

NB. Not in animals with obstruction/stenosis of horizontal ear canal, concurrent otitis media or with severe epithelial hyperplasia

What are the indications for partial ear canal ablation (vertical canal ablation)?

Disease restricted to the vertical canal, such as hyperplastic otitis, trauma, or tumours

What are the indications for total ear canal ablation (TECA) with lateral bulla osteotomy?

Severe chronic otitis externa, otitis media, ear canal calcification/ossification, hyperplastic otitis, and malignant tumours

What are the indications for osteotomy of the bulla tympanica?

Otitis media, middle ear disease, and neoplasia, especially in cats

What is the aim of lateral wall resection (Zepp's method)?

Improve ventilation and drainage, and reduce moisture, humidity, and temperature in the ear canal

What is the consequence of complete removal of the ear canal in TECA?

1. Facial nerve paralysis

2. Infection

3. Haemorrhage

4. Vestibular disease

5. Deafness

What is the procedure for lateral wall resection of the external ear (Zepp’s procedure)?

1. Animal is in lateral recumbency.

2. Skin incisions are made along the vertical ear canal.

3. Vertical canal cartilage is exposed, cut, and partially removed.

4. The remaining cartilage forms a drainage flap, and the skin is sutured to the ear canal epithelium

What is the procedure for a partial ear canal ablation?

1. Animal is in lateral recumbency.

2. A T-shaped skin incision is made over the vertical canal.

3. The vertical canal is separated from soft tissues and removed at the level of the horizontal canal.

4. Flaps are created to aid drainage, and the wound is closed in a T or inverted L shape.

What is the procedure for a total ear canal ablation?

1. The ear canal is fully removed, including the horizontal canal.

2. A lateral bulla osteotomy is performed to remove inflamed tissue in the middle ear.

3. The facial nerve is carefully preserved.

4. Complete removal of the ear canal, tympanic membrane, and sometimes auditory ossicles results in permanent hearing loss.

What is the indication for an osteotomy of the bulla tympanica?

Otitis media and neoplasia, especially in cats

What is the procedure for an osteotomy of the bulla tympanica?

1. Access to the tympanic bulla via a ventral or lateral approach.

2. The bulla is opened, cleaned, and flushed to remove debris or neoplastic tissue.

3. In cats, the procedure preserves hearing by retaining the tympanic membrane

What is the main difference in bulla osteotomy between dogs and cats?

In cats, the procedure aims to preserve hearing by retaining the tympanic membrane.

What is the bulla tympanica attached to?

Horizontal external ear canal (external ear canal) → bulla tympanica (middle ear) → auditory tube (inner ear)

How can problems in the bulla tympanica be assessed?

X-ray

Which positions for x-rays are important for assessing the bulla tympanica?

1. Rostrocaudal/frontal with open mouth

2. Lateral oblique (10-15 degrees)

3. Ventrodorsal/dorsoventral

What are some of the post operative complications that could occur with this osteotomy of the bulla tympanica that you NEED to discuss with the owner?

Deafness, Horner’s syndrome, facial nerve paralysis (sympathetic trunk)

Which nerve can be damaged by osteotomy of the bulla tympanica surgery?

(Ophthalmic?) Branch of trigeminal nerve

What type of Horner’s syndrome can be caused during ostectomy of the bulla tympanica?

Post ganglionic