What does the auricular cartilage form?
Majority of the pinna and all of vertical ear canal
What are the important ear landmarks?
Helix, antihelix, tragus, antitragus, tragic notches
What is the function of the scutiform cartilage?
Attaches the auricular cartilage to the head medially
What is the blood supply to the ear?
Great auricular artery
Label the landmarks of the ear
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What is an aural haematoma?
Collection of blood within the cartilage plate of the ear from damage to branches of the great auricular artery
What is the cause of an aural haematoma?
Unknown but possibly from physical injury to the pinnae
Headshaking and ear scratching predispose
Aural inflammation, parasites, allergy and FB are predisposing factors
What results if an aural haematoma isn’t treated?
Haematoma -> seroma -> fibrosis -> contraction deformity
What are the treatment aims of aural haematoma?
Address underlying source of infection
Evacuate the haematoma
Prevent recurrence
What is the process of conservative management of an aural haematoma?
Needle aspiration, pressure bandage and/or continuous drainage through a canula/penrose/closed suction drain for 2-3 weeks
How is an aural haematoma managed surgically?
Incise concave surface of pinnae
Evacuate the haematoma
Place sutures parallel to major vessels without tension through cartilage and one/both skin surfaces
Don’t suture incision leave open for drainage
Apply a light bandage for several days
What are the potential complications of aural haematomas?
Recurrence
Cauliflour ear
Abscessation leading to pinnae amputation
What is a pinnectomy?
Amputation of the pinna
What are the indications for a pinnectomy?
Solar injury, cold injury, neoplasia, trauma, vasculitis, permanent marking, recurrent (poly)chondritis in cats
How do feline and canine pinnectomies differ?
In dogs need to ligate vessels before going through cartilage
How is a pinnectomy performed?
Excise with 1cm margins if neoplastic
Close by primary apposition of skin edges over the amputated cartilage
What are the clinical signs of middle ear disease?
Facial nerve (VII) paralysis, Horner’s syndrome, head shaking, rubbing/scratching of affected ear, tilting/rotating of head to affected side
What are the clinical signs of inner ear disease?
Hearing loss, head tilt, circling/leaning/falling to affected side, incoordination, spontaneous horizontal nystagmus
What should be looked at on aural examination prior to surgery?
How stenosed/diseased are the vertical and horizontal canals?
What is the state of the tympanic membrane?
Can you see a mass?
What radiography views should be taken prior to surgery?
DV skull, open-mouth bullae, lateral oblique bullae
What should you look for on radiography of ear canals?
Ear canal stenosis, calcifications, middle ear disease
What is the anatomy of the external ear?
External auditory meatus is opening to ear canal
Vertical ear canal made up of auricular cartilage
Horizontal ear canal made up of annular cartilage
Annular ligament joins vertical and horizontal canals
Lined by stratified squamous epithelium
What is the path of the facial nerve around the ear?
Exits the stylomastoid foramen caudal to the ear and runs ventrolateral in close proximity to the base of the external ear canal/middle ear cavity
What clinical signs result from damage to the facial nerve?
Paresis/paralysis of eyelids and ear if only auriculopalpebral branch
Tear and saliva production decreased
What are the different surgical techniques that can be used to treat endstage OE?
Lateral wall resection
Vertical ear canal ablation
TECALBO (total ear canal ablation and lateral bulla osteotomy)
What are the aims of a lateral wall resection?
Increase drainage and ventilation of the external ear canal
Decrease moisture, humidity and temperature in the external ear canal
What are the indications for a lateral wall resection?
Otitis externa that has not responded or has recurred despite appropriate medical management
What are the contra-indications for a lateral wall resection?
Chronic, endstage OE
Irreversible horizontal canal disease/stenosis
Otitis media
What is are the potential complications for lateral wall resection?
Recurrence of disease
Wound breakdown
Wound infection
How do the aims, indications and contraindications of vertical ear canal ablation differ from lateral wall resection?
Also specifically indicated for excision of tumour on medial wall of vertical canal
What are the complications of a vertical ear canal ablation?
Hair around new stoma
Stenosis
What are the aims of a TECALBO?
Complete removal of all external ear tissue except pinna and removal of infected tissue within the middle ear
What are the indications of a TECALBO?
Chronic endstage otitis externa with obstruction of horizontal and vertical canals Persistent otitis following LWR/VCA Otitis externa and non-responsive OM Neoplasia of the horizontal canal Para-aural abscesses Severe ear canal trauma
What are the contraindications for a TECALBO?
Ear disease which can be effectively treated medically with or without a LWR/VCA
Neoplasia that has extended outside the ear canal and middle ear
What are the complications of a TECALBO?
Conductive deafness rarely a major problem
Facial nerve paresis/paralysis
Haemorrhage
Vestibular disease
Infection and wound breakdown
Fistula/sinus formation
Avascular necrosis of the skin of the pinna
What is the anatomy of the middle ear?
Tympanic membrane, tympanic bulla, eustachian tube Auditory Ossicles (malleus, incus, stapes)
What are the structures of the inner ear?
Cochlea
Vestibulum, semicircular canals, utricle, saccule
What are the important differences between cat and dog middle ear anatomy?
Feline tympanic bulla is divided into two compartments
Sympathetic nerves which distribute through the middle ear are more exposed/sensitive to iatrogenic trauma in cat than the dogs
What clinical signs result from damage to sympathetic nerves that run through middle ear?
Constriction of pupil
Drooping of eyelid
Sinking of eyelid
What are the treatment options for OM?
Medical management
TECALBO
Vental bulla osteotomy
What are the aims of a ventral bulla osteotomy?
Access to the middle ear for diagnostic and theraputic procedures
What are the indications for a ventral bulla osteotomy?
Aural polyps
Middle ear neoplasia
Primary otitis media
What are the contraindications of a ventral bulla osteotomy?
Otitis media with severe external ear disease
What are the complications of a ventral bulla osteotomy?
Recurrence of disease Horners syndrome especially in cats Hypoglossal nerve damage Vestibular syndrome Infection and wound breakdown Facial nerve paralysis