Lecture 16: Surgery of the Ear (Exam 3) Flashcards
What should the owner be aware of before surgery & why
- Be aware of the dog’s hearing deficits
- Reduces owner dissatisfaction associated w/ any perceived hearing loss after sx
When should pain management be used
It should be fully integrated into every phase of dx, tx, & recovery
T/F: Sicker patients may need additional monitoring
True
What are the three parts of the ear
- Inner ear (membranous & bony labyrinth for hearing & balance)
- Middle ear (tympanic cavity that connects to the pharynx)
- External ear (the auditory meatus & a short canal
Describe the feline tympanic cavity
- Divided into two compartments by a thin bony septum that arises along the cranial aspect of the bulla & curves to attach to the midpoint of the lateral wall
What can occur to the postganglionic sympathetic nerves in a feline ear
B/c of their vulnerable location they are often traumatized during surgical curettage of the feline middle ear causing horner’s syndrome
What are the most common clinical signs of horners syndrome
- Drooping of the eyelid on the affected side (ptosis)
- The pupil of the affected eye will be constricted (miosis)
- The affected eye often appears sunken (enophthalmos)
- Prominent third eye lid
What clinical signs are associated w/ facial nerve paralysis
- Diminished palpebral reflex
- Widened palpebral fissure
- Drooping of the ear & lip
- Excessive drooling
- Blepharospasm
- Elevation & wrinkling of the lip
- Caudal displacement of the labial commissure
- Elevation of the ear on the affected side
What can cause facial nerve paralysis & horner syndrome
- Otitis interna
- Otitis media
- Surgery
What are the indications of a lateral ear canal resection in patients
- Minimal hyperplasia of the ear canal epithelium
- Small neoplastic lesions of the lateral aspect of the vertical canal
When is owner satisfaction lower
When lateral ear canal resection is performed for chronic otitis externa in dogs
What is the zep procedure
Modification of the original tech of a lateral ear canal resection, & restricts hair growth @ the horizontal canal opening
What should the owner understand about a lateral ear canal resection
That lateral ear canal resection is not a cure & that medical management of the ear probably will be necessary for the remainder of the animal’s life
When is a vertical ear canal ablation performed
When the entire vertical canal is diseased but the horizontal canal is norm
When is a vertical ear canal ablation the tech of choice
- When neoplasia is confined to the vertical canal
- In some animals w/ chronic otitis externa
T/F: Lateral ear canal resection may provide a better cosmetic appearance of the ear than a vertical ear canal ablation
False: a vertical ear canal ablation may provide a better cosmetic appearance of the ear
Why should a bulla osteotomy (LBO) be performed in conjunction w/ a TECA otitis externa & media
- Most animals w/ severe chronic otitis externa have concurrent otitis media
- Removing the avenue for drainage of exudative material by performing a TECA w/out treating the otitis media is disastrous
Why should a TECA-LBO not be performed on animals w/ mild disease or by surgeons unfamiliar w/ the anatomy of the ear
B/c of the potential for serious complications
What is the tech of choice when middle ear neoplasia is suspected in cats that have nasopharyngeal polyps
Ventral bulla osteotomy
What does a ventral bulla osteotomy allow
Allows both bullae to be opened w/out the need to reposition the animal
What may impair respiration particularly after bilateral TECA & lateral bulla osteotomy
Bandages or excessive swelling
What should cat owners be warned about after a ventral bulla osteotomy
Horner’s syndrome & facial nerve paralysis are common but both are transitory
What are complication of TECA-LBO
- Intraoperative arterial hemorrhage (life threatening)
- Superficial wound infection
- Facial nerve paralysis
- Vestibular dysfunction
- Deafness
- Avascular necrosis of the skin of the pinna
- Chronic fistulation or abscessation
What is the prognosis of facial nerve paralysis
- Usually resolves w/in a few weeks of sx
- Reported to occur in 56% of cats after TECA
- Permanent in approx 1/4th of them
What is an aural hematoma
A collection of blood w/in the cartilage plate of the ear
What is the most common cause of aural hematomas
Usually secondary to otodectes cynotis
What should be done before correcting aural hematomas
The underlying disease must be IDed & treated to reduce the likelihood of recurrence
What does the common treatment of aural hematomas involve
- Incising the tissue overlying the hematoma
- Evacuating blood clots & fibrin
- Holding the cartilage in apposition until scar tissue can form
What is an alternative method for treating aural hematomas
Placement of a drain or cannula to provide drainage for several weeks during healing
What is important to remember about aural hematoma sx
- S shaped incision made on the concave surface
- Incision extends from end to end of the hematoma
- Sutures are parallel to the major vessels (vertical)
- Leave no pockets to collect fluid
- Do not ligate visible branches of the great auricular artery
- Do not suture the incision closed
Describe Neoplasia of the pinna & external ear canal
- Relatively uncommon in dogs & cats
- Can be benign or malignant
- Most common are form the ceruminous glands
- More aggressive in cats than dogs
- Often associated w/ otitis externa, media, interna
What is the most important aspect of sx for ear neoplasms
Achieving wide margins to prevent local recurrence
When should adjunctive therapy be considered
When aggressive surgical therapy cannot provide clean margins
What type of margins should be used when excising malignant ear tumors? What should the owner be advised of?
- Should be excised w/ wide margins of norm tissue
- Owners should be advised of the resulting cosmetic defect before sx is planned
Describe the surgical technique for small tumors on the central portion of the convex surface of the pinna
- Resect the neoplasm & mobilize the skin around the defect by undermining btw/ the cartilage & the skin
- Suture the skin margins or if necessary leave the defect open to heal by secondary intention under a light bandage
Describe the prognosis of various ear neoplasms
- Malignant ceruminous gland tumors - ablation is seldom curative
- Squamous cell carcinoma - common to not obtain wide margins; prognosis is poor when found in the middle or inner ear
- Mast cell tumor - aggressive in the pinnae & may req chemotherapy post op
- Aural cholesteatoma in the bullae - May be curative but recurrence is seen w/ advanced dx
Describe SCC of the Pinna in cats
- Most common tumor of the pinna in cats
- Usually in older cats
- Particularly white cats or cats w/ a lack of protective pigmentation of the ear pinna
- Solar radiation is a causative factor
- Highly invasive
- Metastasis is uncommon
- May be noted on the nares & eyelids
Describe inflammatory polyps
- Second most common cause of nasopharyngeal disease in cats
- May occur in dogs but much more common in cats
- Cause is unknown
- Tends to occur in young cats ( < 2 YO)
What may be seen in the Hx & PE of a cat w/ inflammatory polyps
- Most cats present for eval of dysphagia or upper respiratory signs
- They may present for signs of otitis externa
- May be presented for acute onset of head tilt, nystagmus, &/or vestibular imbalance
- Clinical sx may be present for months before eval
- Most are unilateral
- Usually have upper respiratory obstructive signs
What imaging is the most useful for dxing nasopharyngeal polyps
Lateral radiographic images of the pharyngeal region
What is the gold standard for determining the extent of involvement & whether the nasopharyngeal polyps are unilateral or bilateral
CT
When are the best results seen when performing surgical tx for polyps
- When a ventral bulla osteotomy is performed
- Recurrence rate is less than 2%
When should ventral bulla osteotomy be performed
Allway be performed if middle ear disease is evident on radiography or CT
What is the prognosis of polyp
- Excellent w/ complete removal of the poly p
- Nasopharyngeal polyps may be less likely to recur than aural ones
- Horner’s typically resolves w/in a few weeks
- Rarely temporary or permanent vestibular signs may occur
- Transient facial nerve paralysis is uncommon
- Unlikely to affect hearing
- Polyp recurrence & long term adverse effects are rare
