Total ear canal ablation
Normal anatomy of a rabbit's ear
Normal anatomy of a rabbit's ear
The term total ear canal ablation or TECA is used to describe a surgical procedure used to manage severe canal or middle ear disease in rabbits where other methods of treatment have failed.
Normal anatomy of the ears
The pinna is the visible part of a rabbit’s ear. Rabbits can move their ears independently of each other to pick up sounds, which is important for a prey animal.
The appearance of the pinnae varies depending on the breed of rabbit. Up-eared breeds have relatively strong normal cartilage and pinna conformation holding the ear upright. The ear canal is open to air flow. The inner structure of the ear canal consists of a hollow chamber leading from the ear pinna to the middle ear. At the end of the ear canal is the ear drum, a very thin sheet of tissue that separates middle and internal ear structures. The internal structures behind the ear drum are what communicates sound to the brain.
In contrast, lop eared rabbits have a weakened area in the cartilage of the pinna which causes the ears to fall forward and down. This in itself can cause ear problems for rabbits, especially ear infections, and ear mites as the pinna close off air circulation to the ear canal, and make it more difficult for the rabbit to shake lose any foreign matter or parasites.
Common ear problems
Inflammation of the ear is called otitis. Inflammation of the outer ear is called otitis exerna, inflammation within the middle ear is called otitis media and inflammation of the inner ear canal is called otitis interna. Any rabbit can suffer from otitis, but lop-eared rabbits are slightly more prone due to the downward flop of the ears which results in a relatively closed environment within the ear canal, creating a warm, moist environment where bacteria, yeasts, and parasites can take hold. In addition, the narrow angled structure of the middle ear canal makes treatment of ear infections in rabbits difficult.
Other ear problems include abscesses at the base of the pinna, or tumours in and around the ear structures.
Otitis in rabbits can consist of mild infections of the outer or middle ear which are usually easily treated with topical ear drops. Severe infection of the outer or middle ear can cause scarring and narrowing of the ear canal making ongoing treatment less effective. Sometimes ear drops are not effective due to narrowing of the ear canal so systemic (oral or injectable) antibiotics may be given instead.
The blood supply to the deeper ear structures is poor so systemic antibiotics may not always be effective. In addition, the range of antibiotics is limited in rabbits as some of them interfere with beneficial gastrointestinal bacteria which can be fatal to the rabbit. As a result, ear infections can be very difficult to treat in rabbits and treatment is sometimes not effective at eliminating the infection.
Surgical intervention may be indicated for tumours, abscesses, or for infections of the ear canal when other treatment options have failed. Surgery may also be indicated if an ear problem is causing severe pain and discomfort to the rabbit, in an attempt to quickly resolve the issue. The most common ear surgery is called a Total Ear Canal Ablation (TECA). This is a surgical procedure where all of the infected tissues in the middle and inner ear are removed leaving the rabbit with a pinna, but no ear canal opening.
A comprehensive workup is essential before TECA surgery is planned. Including:
- Clinical examination.
- X-rays of the skull to look for any bony changes.
- CT and/or MRI scan to help with the decision making for the surgery. CT provides information on the bony structures, whereas MRI gives much better view of any fluid filled areas and the nerves within the ear structure.
- Neurological examination.
- Blood work to assess renal and liver function prior to anaesthesia.
- Culture and sensitivity of any infectious material to assess what bacteria is present and what antibiotics it may be sensitive to.
What does TECA surgery involve?
A TECA surgery is carried out under a general anaesthetic. Your rabbit will have the fur clipped from one side of their head/face and neck and sometimes further down the body. If both ears are affected, only one is operated upon at a time with the other performed some weeks later, depending upon how well your rabbit recovers from the first surgery.
The surgery involves the removal of the entire ear canal. The pinna and the hearing organ are left in position. Following removal of the diseased ear canal, part of the bony wall of the tympanic bulla (middle ear) is also removed to enable the removal of infected material from the middle ear chamber.
The hearing organ itself is not removed during the TECA operation. However, the removal of the ear canal itself will result in reduced hearing sensitivity. The majority of rabbits that require a TECA have severe changes to the ear canal before the surgery and this will have already resulted in reduced hearing sensitivity. Most owners do not perceive a large difference post-operatively with how well their rabbit can hear.
What are the potential risks and complications to TECA?
There are many possible complications from TECA surgery, and these need careful consideration prior to embarking upon surgery. There is the anaesthetic risk, but in the hands of an experienced veterinary team this is minimised as much as possible but cannot be totally eradicated.
The risks from the surgery include:
- Nerve damage: this may be apparent for up to 2 weeks post-surgery. This can include facial nerve deficits (facial paralysis, absent or reduced blink of the eye, excessive drooling from the mouth) and vestibular signs such as head tilt/ataxia, and nystagmus (eye flicking).
- Infection of the wound.
- Necrosis of the pinna of the ear.
A TECA is a major surgical procedure and must never be embarked upon without serious thought and commitment.”
What does the post-operative care involve?
Your rabbit will be hospitalised until your veterinarian is satisfied that their care can be continued at home by yourself. Your rabbit will likely receive pain relief and antibiotics. You may also need to be syringe feeding your rabbit if they are not eating normally and they may require prokinetic medication to help keep the gastrointestinal tract moving. These medications may need to be given for several weeks after surgery. Wound care is important, and you will need to ensure the wound is kept clean and the rabbit is not trying to interfere with it. If the rabbit has a companion it is best they are kept together, as long as the companion rabbit is not interfering with the wound.
How much does TECA surgery cost?
Some of the work up and surgery are likely to be performed by a specialist and your rabbit may need referring by your veterinary surgeon for this. Costs will vary depending upon the severity of the disease process and the area of the country, but you should expect to pay anywhere from £1500-£3500 for the diagnostics and a further £2000-£4500 for the surgery and aftercare. Pet insurance may cover some of the cost assuming otitis was not a pre-existing condition, and there are no exclusions on your policy for ear diseases. You will need to check this with the company.