The Pinna Flashcards
What is the function of the pinna?
Direct sound to the middle ear
The pinna skin is fixed to the ? on the concave side
perichondrium
What separates the scapha from the external ear canal?
anthelix
What is the tragus made of and what does it mark?
A thick cartilaginous plate that marks the lateral margin of the external ear canal
What marks the caudal border of the external ear canal?
antitragus
What anatomically sits between the tragus and the anti-tragus?
Intertragic incisure
What sits rostral to the tragus as the cranial border of the ear canal
Helix
What separates the intertragic incisure from the helix?
Pretragic
What artery forms the lateral, intermediate and medial vascular rami at the base of the convex surface of the pinna?
The caudal auricular artery
What is The caudal auricular artery a branch of?
External carotid
2 main conditions of the pinna in cats and dogs?
Trauma
Neoplasia
Cat fights are a common cause of pinna trauma. What bacteria is a common contaminant?
Pasteurella multocida
Acute trauma injuries of the pinna - how to manage?
Suture repair
What is the physiological cause of an aural haematoma? (2)
Repeated trauma:
- damage to the auricular cartilage
- shearing of the blood vessels within
If an aural haematoma is not treated, what formed?
Granulation tissue
Following granulation tissue with aural haematomas, what leads to chronic changes and ongoing irritation? (2)
Fibrosis
Ossification of cartilage
In cats how to aural haematomas lead to worsened otitis externa
They may deviate medially blocking the external acoustic meatus
Actinic Keratosis:
A) What causes this?
B) What lesions are seen? (2)
C) What could it develop into?
D) Treatment? (2)
A) Ppre-malignant change that may develop following exposure of non-pigmented skin to UV radiation
B) Erythematous and hyperkeratotic
C) SCC (plaque lesion)
D) Pinnectomy, laser therapy, sunblock/UV avoid
Squamous Cell Carcinoma:
A) How does it normally present?
B) Invasive?
C) Met rate?
A) Raise or erosive and painful lesion. Often bleeding/non healing
B) Locally; into auricular cartilage
C) Low
How to stage SCC?
Although low met. Advsed to thorax and LN
SCC:
A) Recommended treatment?
B) Other options? (4)
A) Partial/total pinnectomy
B) Cryosurgery, laser ablation, radiation therapy, chemo
Haemangioma/Haemangiosarcoma:
A) What induces it?
B) Which cats is it seen in?
A) UVB
B) Light coloured
What lesions are seen with a haemangioma? (6)
(colour)
small, benign, raised, alopecic, subcutaneous or dermal lesions, often blue-tinged in colour
Haemangiosarcoma:
A) Growth rate?
B) Circumscribed?
C) Incasive?
D) Where to met?
A) Fast
B) Poorly
C) Locally
D) Lungs or parenchymal organs
Surgical excision of haemangiosarcomas give a median disease free interval of how long?
9.5 mo
What is the most common feline cutaeneous tumour of the pinna?
Basal Cell Carcinoma
Basal Cell Carcinoma:
A) What do lesions look like? (5)
B) Treatment?
A) small, slow-growing, well-demarcated, raised, white to hyperpigmented nodules
B) Surgical excise; a few millimetres
60% of all head of this type of tumour include the pinna in cats?
MCT
MCT of pinna
malignancy?
Mainly benign
MCT of pinna in cats - treatment?
Treatment is surgical excision with narrow skin margins
T or F
Incomplete excision of mast cell tumours in cats is not necessarily associated with a higher rate of recurrence.
True
MCT of dog pinna; what FNA is advised? (2)
Mass
Local LN
MCT treatment in dogs pinna? What margins? When are etensive margins needed?
Excision with wide (2 cm) margins is recommended with one fascial plane deep unless the MCT is > 5 cm diameter, rapidly growing or ulcerated at which stage excision requires extensive margins
What happens if MCT excision of dog pinna is incomplete? (2)
Re-excision
Follow up RT
When is chemo advised in MCT dogs? (2)
High grade or metastatic
Histiocytoma:
A) What do they look like?
B) What cells are on FNA?
A) Small, raised, hairless, often erythematous cutaneous masses
B) Round
Sebaceous Adenomas:
A) Malignancy?
B) What do they look like? (4) (colour)
C) Treatment? (2)
A) Benign
B) hairless, white-yellow masses, often pedunculated and < 5 mm diameter.
C) Surgery or laser excise
T or F
Haemangiomas are benign lesions, often blue-tinged in colour.
True
T or F
tiocytomas are most commonly seen in old dogs.
False
T or F
The recommended treatment for basal cell carcinoma is surgical excision with a few millimetres of margin.
True
What are the 4 options for an acute aural haematoma?
Needle drain
Teat cannula
Passive penrose drain
Active drain
Which of the 4 aural haematoma tx would have highest recurrence?
Needle drain
How to place a passive drain for an acute aural haematoma?
Stab incisions are made into the proximal and distal region of the haematoma, the haematoma is cleared and lavaged with sterile saline prior to drain placement. The drain should be sutured in position and the ear should be bandaged
How to place an active drain for an aural haematoma
An adapted butterfly catheter attached to a sterile vacutainer may be sutured into position for active suction drainage.
What is the tx advised for a chronic aural haematoma
Srugical debridement
what incision is made during surgical debridement for a chronic haematoma
S zhaped
Chronic haematoma
Following the incision; what happens? How is it sutured?
- The haematoma clot and fibrin is removed.
- Interrupted mattress sutures are placed parallel to the vascular supply in dogs, tightened to appose the skin and cartilage.
What can be placed during surgical debridement of an aural haematoma to avoid over tightening of sutures? (3)
Gauze, buttons or drip tubing
Other than surgical debridement, what are other options of tx of chronic haematoma? (2)
Drainage
CO2 laser ablation
Following aural haemtaoma drainage; what should be applied and why?
bandage- maintain compression of the pinna skin against cartilage and prevents any further trauma due to head shaking or scratching.
Where should an ear be with an ear bandage afetr aural haematoma? How long to keep for?
On top of head or side of neck
until drainage finishes
Medical manage of aural haematoma?
aspiration of haematoma fluid with an intravenous injection of dexamethasone
If a pinna laceration is through the skin surface only; what is advised?
Cleaning, debridement and primary repair or second-intention healing are both appropriate. The ear is bandaged until the wound is fully healed
Pinna trumal if a skin flap develops what is advised?
the flap should be sutured back in position along both sides and with a suture through the centre of the flap and the cartilage underlying it.
Pinna trauma; If the defect is in the tip of the ear, what treatment?
partial pinnectomy
If the pinna is torn and a full-thickness flap is present, primary repair is advised; why?
avoids the development of any deformity that might occur with second-intention healing
How to suture a cat pinna trauma?
Only skin
Inner concave first and then outer convex
Most common reason for Pinnectomy?
SCC
with a Pinnectomy, if the affected region is ulcerated; what margin? What instrument is used?
1-2 cm
Sharp scissors
How to suture following pinnectomy (after vessels cauterised etc).
The skin on the convex outer surface is brought over the cut edge of the cartilage and sutured to the skin on the inner surface with monofilament non-absorbable suture material
What is NOT sutured in a pinnectomy?
Cartilage
