Ear surgery Flashcards
Describe the anatomical layers of the pinnae
The pinna consists of two layers of skin with a layer of cartilage sandwiched between them
How should you treat lacerations of the pinnae that go through one skin layer?
Clean, debride and suture or leave to heal by second intention if small.
How should you treat lacerations of the pinnae that go through the cartilage?
Suture to avoid deformity of the pinna due to misalignment during healing
Dogs - vertical mattress sutures
In full-thickness lacerations the second skin layer can be repaired with simple interrupted sutures
Bandage the ear postoperatively until healed and sutures are removed
In cats, suture the skin only: close the concave surface of the pinna first, then the convex.
How do aural haematomas form?
Trauma, headshaking or scratching causes separation of the layers of the pinna and a haematoma forms in the resulting dead space
What can happen if aural haematomas are untreated?
Can fibrose and contract, causing distortion of the pinna
Describe medical treatment of aural haematomas
Needle drainage is almost always unsuccessful.
If combined with injection of methylprednisolone into the cavity it can resolve the problem in 90-98% of cases: 2-3 treatments may be required.
Use careful sterile technique to avoid abscess formation after the injection.
When should acute aural haematomas be treated in 1. dogs 2. cats
Immediately in dogs
After 5-6 days in cats to ensure bleeding into the cavity has stopped before surgery
Describe surgical treatment of acute haematomas
Make stab incisions into the proximal and distal ends of the cavity and drain/lavage, then place either a Penrose drain exiting through both stab incisions or a closed suction drain
Describe surgical treatment of chronic haematomas
- Make a s-shaped incision on the concave surface of the pinna, penetrating both the skin and cartilage
- Drain and lavage cavity
- Interrupted mattress sutures
- monofilament nonabsorbable
- Tighten just enough to appose the skin and cartilage
Name some tumours that can form on the pinnae
Actinic keratoses (technically a premalignant change)
Squamous cell carcinoma
Haemangioma / haemangiosarcoma
Basal cell tumours
Mast cell tumours
Histiocytomas
Sebaceous adenomas.
How are neoplasias of the pinnae treated?
Partial or total pinnectomy
Describe when surgical treatment of otitis externa is indicated
- When medical treatment has failed
- Skin of the ear canal has an irreversible change
- Cutaneous fistulae develop
- para-aural abscess forms
- otitis media or interna is present
Name that 3 surgical treatments for otitis externa
- Lateral wall resection
- Vertical canal ablation
- Total ear canal ablation and lateral bulla osteotomy
Describe when lateral wall resection procedure for otitis externa is used.
Improving ventilation of the ear canal to reduce humidity
and temperature and allow easier administration of topical
medication in cases where ear canal changes are thought to be reversible with medical treatment.
Removal of small tumours of the lateral wall of the vertical
canal
Describe when the vertical canal ablation procedure for otitis externa is used.
Treatment of severe disease of the vertical canal where the
horizontal canal is unaffected e.g. severe hyperplastic otitis,
trauma, neoplasia.
Describe when the total canal ablation and lateral bullae osteotomy procedure for otitis externa is used.
Ceruminous gland adenocarcinoma of the ear canal.
Extensive irreversible hyperplastic otitis.
Presence of otitis media / interna.
Failed lateral wall resection.
Describe the lateral wall resection procedure for otitis externa
Remove a strip of skin, subcutaneous tissue, vertical canal cartilage and vertical canal lining from the lateral wall of the vertical canal to the level of the horizontal canal junction.
Suture the lining of the vertical canal to the skin, with a small flap of the ventral end of the lateral wall preserved to form a “drainage board” at the ventral end of the wound, reducing the risk of stricture and simplifying maintenance of the stoma long-term
Describe the vertical canal ablation procedure for otitis externa
Remove almost the entire vertical canal, creating short dorsal and ventral flaps from the medial and lateral walls of the base of the canal to act as drainage boards
Describe the total ear canal ablation and lateral bulla osteotomy procedure for otitis externa
Remove the entire external ear canal by dissecting it free from surrounding tissue to the level of the tympanic bulla then amputating it from the skull. Enlarge the opening into the tympanic bulla ventrolaterally and clean out the bulla by curetting and lavage
Describe the total ear canal ablation and lateral bulla osteotomy procedure potential complications
- Horner’s syndrome
- Facial nerve paresis/paralysis
- Potentially life-threatening haemorrhage from the retroglenoid vein rostral to the ear canal at the level of the bulla
- Infection and dehiscence
- Para-aural abscess formation
- Reduced hearing
What is the cause of septic otitis media?
Due to extension of a bacterial infection across the tympanic membrane from the external ear
What are the clinical signs of septic otitis media?
Ear pain
Altered head carriage
Jaw pain
Purulent discharge in the external ear canal
Neurological signs in some cases
- May extend to cause otitis interna with hearing loss and peripheral vestibular disease.
How is septic otitis media diagnosed?
- Clinical signs.
- Otoscopy
- Detection of loss of air density, thickening of the bulla wall and (less commonly) lysis of the bulla wall on radiographs or cross-sectional imaging (CT or MRI).
- Myringotomy and aspiration of bulla contents for cytology and bacterial culture in patients with an intact tympanic membrane.
How would the otoscopic exam of a patient with septic otitis media present?
Bulging, loss of translucency, changed colour or perforation of the tympanic membrane
Which cases of septic otitis media can be medically managed?
This is only suitable for cases where the underlying disease of the external ear can be satisfactorily controlled
Cases with end-stage, irreversible changes in the external ear canal or extensive changes in the middle / inner ear (e.g. osteomyelitis of the tympanic bulla wall, presence of neurological signs) require surgical treatment.
Describe inflammatory polyp formation in the ears
Non-neoplastic masses arising from the epithelium of the middle ear, almost exclusively seen in cats.
Thought to be due to upper respiratory viral infection disrupting drainage of middle ear secretions through the Eustachian tube, causing inflammation and proliferation of the bulla epithelium.
Describe the clinical signs of inflammatory polyps in the ears
- Swallowing problems
- Stertor and nasal discharge if they protrude into the nasopharynx via the Eustachian tube
- Horner’s syndrome or peripheral vestibular signs due to pressure in the bulla
- Otitis externa if they extend into the ear canal
Describe conservative management of polyps
Polyps visible in the external ear canal or nasopharynx can be removed by traction with follow-up medical treatment with oral prednisolone
When is surgery indicated for inflammatory polyps?
Cases with neurological signs or where medical treatment has failed
