Total Ear Canal Ablation and Lateral Bulla Osteotomy Dr Ross Elliot BVSC MMedVet (Surg) Bryanston Veterinary Hospital, 011 706 6023

The surgical procedure for a TECA-BO entails removal
of both the vertical and horizontal ear canal with all the
secretory epithelial lining of the middle ear.

This surgery has the potential for serious complications and should
not be performed unless the surgeon is familiar with the
anatomy of the ear and associated structures. A total
ear canal ablation should never be performed without
a lateral bulla osteotomy. If the bulla osteotomy is not
performed all the secretory lining of the middle ear is left
behind and this will increase the potential for complications
by as much as 82%.
There are very few cases in dogs where a bulla osteotomy
is performed without a total ear canal ablation. These
Total ear canal ablation and a lateral bulla osteotomy (TECA-BO) are
two separate procedures which are usually combined as a surgical
treatment for otitis externa and media.
are otitis media in the presence of an intact tympanic
membrane. Neoplasia of the middle ear or polyps of the
middle ear in cats that have recurred after previous removal,
generally a ventral bulla osteotomy is performed
in these cases as the ear canal cannot be removed and
the ventral bulla osteotomy is easier to perform.
A lateral ear canal resection or Zepps procedure has little
place in the treatment of otitis externa and media. A
study on its effectiveness showed in all dogs it has a 45%
success rate in the management of otitis externa and
media. Better outcomes have been reported in Sharpei’s
and Spaniels have a very poor outcome with a just a lateral
ear canal resection. The only indication for it is neoplasia of the lateral wall of the vertical ear canal.
The indications for a TECA-BO is severe end stage otitis
externa and media. All of these cases usually have severe
narrowing of the ear canal, which makes topical medical
treatment unsuccessful
These are cases that have failed to respond to appropriate
long term medical management:
• Have severe calcification of the cartilage of the ear canal.
• Have visible sclerosis or fluid accumulation in the tympanic
bulla.
• Have severe soft tissue hyperplasia from chronic inflammation
extending past the vertical canal.
• Have neoplasia of the medial vertical and horizontal ear
canal.
Severe trauma to the ear canal, or congenital malformations
can often require a TECA BO when the integrity of
the ear canal is severely damaged.
A high percentage of dogs with severe otitis have associated
allergic skin disease. This skin disease should be
managed medically prior to resorting to surgery. The otitis
will often benefit greatly from management of the allergic
skin disease. However if there is marked mineralisation of
the ear canal, or secondary changes in the bulla then the
ear disease will eventually require surgery.
The advantages of surgery include:
• No need for continued medical treatment with successful
surgery (can often negatively affect the petowner
relationship)
• Relief of pain and improved quality of life for the patient
• Prevents further secondary change and damage to associated
structures
The disadvantages of surgery include:
• Surgical complications such as facial nerve paralysis,
vestibular syndrome and Horner’s syndrome
• Financial cost of surgery
• Surgical complications
Complete ear work up for surgery
A complete physical examination is part of any work up to
try ascertain if there are any concurrent disease processes
that may complicate the healing of the patient or the ability
to tolerate the anaesthesia and surgery. A full neurological
exam should always be performed to detect any
pre-existing facial nerve or peripheral vestibular involvement.
The owners should be informed of these results as
they may be present in a significant number of dogs. An
abnormal neurological examination may indicate severe
progression of the otitis or other differential diagnoses

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Figure 2. Rostro-caudal skull radiograph. Arrow indicates thickening of right tympanic bulla wall suggestive of otitis media. Arrowhead indicates normal left tympanic bulla

Figure 3TECA

Figure 3. The patient in position prior to surgery

such as granulomatous menigioencephalitis or central
vestibular disease. Detecting facial nerve damage prior
to surgery prevents its being considered a surgical complication.
Owners will often be concerned about the ability of the
animal to hear after the procedure especially when it has
to be performed bilaterally. This can be assessed with a
BAER test pre-operatively. However in reported owner
perceptions it has been found that there is not a noticeable
loss of hearing after the procedure. The reality is
that the middle ear is already so damaged in the appropriate
surgical candidate for the surgery, that the ability
to hear has already been damaged and the patients have
already adapted.
Otoscopy and culture are essential in the work up. This is
best done under sedation as the ears are often severely
inflamed and painful. The patients should be admitted
and once sedated, otoscopy can be performed and a
culture taken from the middle ear, via a myringotomy
if the tympanic membrane is still intact. The tympanic
is often found to be perforated and otitis media is assumed.
A culture can be taken from the ear canal.
The next step is to perform radiographs or CT/MRI. Plain
film radiographs are most commonly used to evaluate
the outer and middle ear, but they are not considered
highly sensitive. They are however highly specific. CT
shows a higher sensitivity especially when combined
with plain film radiographs. MRI is once again highly sensitive
and specific. In practice the first step is to perform
a standard ventro-dorsal radiograph (Fig 1) to assess the
ear canal and check for calcification of the ear canal. A
frontal open mouth view (Fig 1) is then used to assess the
tympanic bulla for fluid opacity and periosteal reaction,
which would indicate chronic otitis media in most cases.
In cases where there is calcification of the ear canal, periosteal
reaction or fluid in the bulla then a TECA BO is indicated.
These cases are unlikely to respond to medical
management as this can be considered an “end stage” ear.
Surgical procedure
Otitis externa and media is usually bilateral and cases often
require surgery on both ears. It is possible to perform
both surgeries at the same time but this has little advantage
to the patient. It prolongs the anaesthetic time and
doubles the pain experienced by the patient. Generally
the disease process has been going on for many months
to years and to wait 3 weeks between surgery is of little
consequence to the patient.
The surgical site should be widely clipped and aseptically
prepared. The ear canal should be thoroughly lavaged
with 0.5% hibitane and water prior to surgery.
The patient is placed in lateral recumbency with a towel
placed under the head to elevate the head (Fig 3). The
entire ear canal is then sharply dissected out from the
surrounding tissue, staying as close as possible to the
cartilage of the ear canal without penetrating the cartilage
(Fig 4). A recent report of a subtotal ear canal surgical method
has been reported, which will maintain the ear carriage
but this can leave a small amount of diseased tissue just
distal to the pinna which may lead to recurrent dermatological
disease.
The facial nerve courses caudo-ventrally to the horizontal
canal and should be identified and gently retracted
(Fig 5). Where the bulla connects with the horizontal
ear canal is easily digitally palpated. Being careful not to
transect the facial nerve the horizontal canal is sharply
dissected off the bulla (Fig 6 and 7).
The external acoustic meatus can now be seen with a
small rim of remaining cartilage of the horizontal ear canal.
This cartilage is gently removed with a small periosteal
elevator. The meatus is then enlarged in a ventrolateral
direction with a sharp bone Rongeur being careful
to avoid the branches of the internal carotid ventral to
the bulla and the venous sinus caudal to the bulla. The
secretory lining of the middle ear should now be visible.

A small curette is gently used to try peel off the
membrane from the underlying bone. The dorsomedial
section of the middle ear should be avoided
with the curette as this will damage the structures
of the internal ear. The membrane is usually a grey
black colour, once removed there should be a
shiny white appearance to the bone of the middle
ear (Fig 7).
The surgical site should be irrigated with saline and
the subcutaneous tissues and skin closed. The decision
to place a drain is the choice of the surgeon.
However if the ear has had a culture taken as a part
of the work-up, an appropriate course of intra-operative
antibiotics is sufficient. This varies from case
to case and the amount of contamination during
the surgery and the surgical time. I generally don’t
place a drain after the surgery.
The use of postoperative antibiotics is controversial
as if all tissue has been removed and thorough lavage
performed there should be no need for continued
antibiotics. It would be bad practice to rely
on antibiotics to prevent infection from tissue left
behind. If there is any secretory tissue left behind
regardless of antibiotics used it is likely that the infection
will return. A culture can be taken form the
bulla once the secretory lining has been removed
and lavage has been done.
Postoperative care
Pain control is essential in these patients. This
should be titrated on a patient to patient basis. Basic
pain control can be managed with injectable opioids,
the pure agonists being the obvious choice.
Generally I will start the patient on morphine every
4 hours at 0.5mg/kg. The next stage would be a
fentanyl CRI. In patients that are still assessed to be
in pain then a morphine, lignocaine and ketamine
infusion is administered. Pain control is continued
as long as is required.
These patients are often hypothermic from the extended
surgical time and this complication needs
to be monitored and addressed. The best is to
warm them up with warm air blankets to prevent
thermal burns. I will often use ocular lubricants
post-surgery as there can be a delayed blink reflex
from neuropraxia of the facial nerve. This tends to
return to normal in 24 to 48 hours.
In most cases when there has been no obvious
contamination of the surgical site I will use antibiotics
based on a culture for 12 hours post-surgery.
I generally do not continue them longer than this.

Figure 4TECA

Figure 4. The vertical ear canal is seen with the initial dissection performed. The facial nerve is not visible at this point.

Figure 5 TECA

Figure 5. The vertical (VEC) and horizontal ear canal (HEC) have been dissected and the facial nerve can be seen in close proximity (FN)

Figure 6TECA

Figure 6. The ear canal removed completely.

 

 

However if there is obvious evidence of bulla osteomyelitis
the antibiotics should be continued on the
basis of a culture for 4-6 weeks.

Once the patient is mobile, alert and preferably eating in
hospital I will look to change them onto oral pain medication
and send them home. These patients have often
been on corticosteroids and hence one should be careful
with non-steroidals for pain. If there has been no corticosteroid
use in the last 5 days they can be discharged
on NSAIDs and oral tramadol.
A buster collar is placed to stop the patient scratching
at the wound. If a drain is placed then the head should
be bandaged until the drain is removed. This bandage
needs to be changed every 24 to 48 hours till the drain
is removed.
Complications
The complication rates with a TECA BO are high. Intraoperative
haemorrhage is the most common complication,
which could be fatal if not managed. However the
haemorrhage is usually insignificant and hampers the
surgeon’s ability to see during surgery more than anything
else.
The reported incidence of permanent facial nerve damage
is 31% this can be from transection of the facial nerve
as it exits the stylomastoid foramina, or severe neurontometesis
(traction injury) from inappropriate retraction
directly on the nerve. Signs of facial nerve paralysis are
loss of the palpebral reflex and hemiparesis of that side
of the face. The parasympathetic portion of the facial
nerve innervates the lacrimal glands thus damage to
the facial nerve will cause decreased tear production.
Eye lubricants will be needed to lubricate the eye in the
short term until the lacrimal function returns to normal.
However they are not essential in the long term as the
lacrimal function is normal, passive function of the third
eyelid and retraction of the globe are enough to protect
the globe.
Draining tracts from remaining secretory tissue in the
bulla occur in 5-10% of cases. These will not respond to
antibiotics and will require repeat surgery and curettage
of the bulla. This can be performed through a repeat lateral
approach or through a ventral bulla osteotomy. A
lateral approach would have a higher incidence of facial
nerve damage when compared to a ventral approach.
There can be acute wound complications such as wound
breakdown and soft tissue swelling. These can often be
controlled with good nursing and wound management.
Necrosis of the pinna is seen from damage to the blood
vessels that supply the pinna. These vessels run under the
cartilage on the proximal edge of the pinna margin and
can be damaged when removing the vertical ear canal.

Figure 7 TECA

Figure 7. The opening of the tympanic bulla (TB) can be seen. The facial nerve can be seen in close proximity (FN – arrow).

References
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