Article Written by Dr. Daniel A. Degner, Board-certified Veterinary Surgeon (DACVS)

Key Points

The most common condition requiring bulla osteotomy is inflammatory polyps in cats

Clinical signs vary, but usually include discharge from the ear and scratching at the ear

Bulla osteotomy involves opening the middle ear to remove the offending polyp

Prognosis usually is good following surgery

Definition of Bulla

• Bulla = tympanic bulla = middle ear cavity

Anatomy of the ear

• Ear flap (F)
• Ear canal (C)
• Ear drum (D) or tympanic membrane - which separates the ear canal from the bulla
• Middle ear - bulla (B)
• Auditory tube (A) - is a tube that  connects the bulla to the back of the throat
• Inner ear (I) - contains the hearing apparatus (trochlea) and the balance organ (vestibular canals)
• The illustration below left is a cross section through the head showing the components of the ear;
• The illustration below right is of a magnified view of the bulla, with the thatched area representing the portion of bone that is removed during a ventral bulla osteotomy surgery

Signs of a diseased middle ear cavity (bulla) and inner ear

• Scratching or rubbing the ear
• Discharge coming out of the ear
• Vestibular signs
  • Tilting of the head toward the affected ear
  • walking in circles toward the affected ear
  • nystagnus - eyes shift back and forth
  • incoordination or inability to walk
• Horner's syndrome
  • third eyelid covers eye
  • pupil becomes smaller than the opposite normal eye
  • slight drooping of the upper eyelid
• Facial nerve paralysis is uncommon with middle ear problems, but occasionally is seen in dogs
  • sagging of lips and face on side affected
  • drooling from affected side due to lack of control of lips
  • inability to blink eye on affected side
• Malaise
• Loss of appetite
• Pain upon opening the mouth - due to inflammation of the joint of the jaw (TMJ)
• Breathing difficulty or snorting due to
  • discharge draining into the back of the throat via the auditory tube
  • extension of a polyp from the the middle ear into the back of the throat

Potential disease conditions in the bulla

• Inflammatory polyps - most common in cats
• Cancer
• Infection
• Foreign body

Inflammatory polyps in cats

• Cause is unknown, but may be associated with chronic recurrent upper respiratory infections
• Feline leukemia virus or Feline Immunodeficiency virus may suppress the immune system, resulting in chronic infection that leads to polyp formation
• Ear polyps are commonly found in the younger cats, malignant tumors are more common in older cats
• A polyp is rooted in the middle ear cavity and grows until it ruptures the ear drum, then it continues to grow out of the ear canal
• Some inflammatory polyps will grow through the Eustachian tube (auditory tube) and appear as a mass in the back of the throat
• Removal of the polyp by plucking it out of the ear canal is about 50% successful when medications (oral - Baytril and Dexamethasone, and ear drops - Baytril and Synotic) are also administered
• Ventral bulla osteotomy is a more successful procedure, as the entire polyp can be removed more completely
• Below is a view down the ear canal of a cat that has a polyp (pink mass) that is penetrating through the ear drum

Diagnostic tests

• Blood work - Complete Blood Cell Count and Chemistry Profile
• Cats only - Feline Leukemia and Feline Immunodeficiency Virus tests
• Culture of fluid from the ear or bulla
• Biopsy of tumor if present
• Radiographs (x-rays) of the bulla
• CT scan of the bulla is the most diagnostic test to see the internal structure of the bulla and extent of tumor invasion

Surgery

• An incision is made on the under side of the neck, just behind the jaw bone
• The bulla is exposed and is opened
• If only infection is present, the lining of the bulla is removed and the area is flushed with saline solution
• If present, the tumor or polyp is moved
• In the photo below, a white inflammatory polyp is being removed from the middle ear of a cat

• Below is a photo of a large polyp that was removed from the middle ear cavity in a cat

Potential complications after surgery

• Cats
  • Recurrence of inflammatory polyp - 80% cure rate with surgery
  • Vestibular signs - uncommon and usually resolves with time
  • Facial nerve paralysis - uncommon
  • Persistent infection
  • About 80% of cats develop Horner's syndrome after the surgery
    • this can occur following removal of a nasal pharyngeal polyp, removal of a polyp from the ear canal, or removal of a polyp via ventral bulla osteotomy
  • In the photo below, this cat has signs of Horner's syndrome immediately following surgery; take note of the prolapsed third eyelid (white membrane covering the cat's right eye); this problem usually resolves in about 30 days

   

• The photo below was taken 24 hours after surgery demonstrating that the Horner's syndrome has almost completely resolved (minor prolapse of the third eyelid and slightly smaller pupil in the right eye)

• Dogs
  • Same potential complications as cats, but Horner's syndrome is uncommon
  • Dogs that already have vestibular signs, such as a head tilt may have permanent damage to the balance organ, and surgery may not correct this problem; the goal of this surgery is to relieve the infection so that the equilibrium (sense of balance) does not get so bad that the dog is unable to walk

Frequently Asked Questions After Surgery - General Information

When should my cat have the first bowel movement after surgery?

• Many cats will not have a bowel movement for the first 4 to 5 days after surgery
• Reasons that a cat will not have regular bowel movements after surgery include:
  • The cat has been fasted prior to surgery
  • Cats do not eat well during the hospital stay
  • They frequently do not eat well when the go home
  • They are fed highly digestible food that produces little stool
  • Pain medication that contain narcotics (such as fentanyl patches, tramadol, morphine) can be constipating
• If a pet does not have a bowel movement on the 5th day of being home a stool softener such as metamucil can be fed
  • Dose of metamucil 1/4 tsp per mixed in with each meal (canned cat food)

My cat had surgery and will not eat.  What can be done?

• Offer smelly foods that contain fish such as tuna or smelly cat foods
• Try Gerber strained meats for babies such as the chicken, beef, turkey or veal
• Hand feeding;  place a small amount of food in the mouth so that they get the flavor
• Warm the food slightly in a microwave as the food will be more aromatic; remember to stir the food before feeding and test the temperature with your finger; it should  be only luke-warm.
• Some cats will only eat dry food, try kibble if your cat normally has been fed that food
• Petting and stroking your cat frequently will help to stimulate appetite
• Remember that most pets will not eat the first day or two after they get home from surgery
• Appetite stimulants such as cyproheptadine may be helpful
• If your cat refuses to eat anything for 7 days a stomach tube should be placed to provide nutrition so that a serious liver problem (hepatic lipidosis) does not develop

My cat is vomiting now that he/she is at home.  What can be done?

• The first thing for you to discern is whether your pet is vomiting or regurgitating.  Both will result in fluid or food being brought up.  Vomiting always will have heaving or retching of the abdomen prior to expulsion of the vomitus.  Regurgitation is not associated with heaving and the cat usually just opens the mouth and fluid or food will be expelled.  Usually the regurgitant will be clear or brown colored fluid. 
• Next is to identify the cause of the vomiting or regurgitation.
• Causes and treatment of vomiting after surgery
  • When some pets return home after a stay in the hospital they may drink excessive amounts of water at one time and then vomit; if this appears to be happening the water should be limited to frequent smaller amounts.
  • Medications such as antibiotics are a common cause of vomiting after surgery.  In order to see which medication is causing the problem the administration of each drug should be separated 2 hours apart.  Usually the pet will vomit or appear nauseated (drooling and sick look) within 1 hour of administration of the medication that they are sensitive to.  The antibiotic in some cases may be changed to a different one, or may be discontinued. 
  • Stomach upset from anesthesia is a potential cause of vomiting and will pass within a couple of days. 
  • Unusual cause of vomiting after surgery is internal organ failure.  Blood testing will confirm this problem. For this reason vomiting should not be ignored if it persists for more than 24 hours.
  • If your pet had surgery of the bowels or stomach, vomiting is always a concern, as it may indicate that infection of the abdominal cavity, called peritonitis, is present.  Do not ignore this sign.
  • Symptomatic treatment of vomiting involves with holding food for 12 to 24 hours, then introducing small amounts of bland food such as rice and lean cooked hamburger, if your pet does not vomit after that then.  In order to decrease the acidity of the stomach Pepcid AC 0.5 mg/kg given by mouth twice daily for 5 days can sooth an upset stomach.  Metoclopramide is a good anti-vomiting medication for cats.  You should always consult a veterinary healthcare professional before administering medication.
• Causes and treatment of regurgitation after surgery
• The most common cause of regurgitation is reflux of acid from the stomach into the esophagus while your pet is under anesthesia.  Acidic fluid from the stomach can cause a chemical burn of the esophagus and result in a bad case of heart burn, which is called esophagitis.  This results in poor motility of the esophagus so water and food will accumulate in this structure.  In most cases esphagitis is self-eliminating and will resolve within two or three days. 
• Regurgitation also can be caused by a neuromuscular degeneration of the esophagus and this problem will persist.  It is not associated with surgery, rather other underlying diseases.
• If the esophagitis is severe the esophagus may develop one or more strictures.  A stricture is a narrowing or stenosis of the esophagus, does not allow passage of food down the esophagus, thus the pet has persistent regurgitation.  This problem should be brought to the attention of your doctor within the first two weeks so that it can be treated by ballooning the stricture (minimally invasive procedure as it is done with the aide of an endoscope).  If an esophageal stricture is chronic surgery is needed.
• Symptomatic treatment of regurgitation caused by esophagitis includes feeding bland food, and administering a coating agent such as sucralfate.  You should consult a veterinary health care professional if the regurgitation continues for more than a couple of days.

How do I know that my cat is in pain following surgery?

• Pain is more difficult to assess in cats versus dogs as signs can be more subtle and they usually do not vocalize
• Signs of pain in a cat include the following:
  • biting if you get near the surgical site
  • growling or deep cry
  • not wanting to eat
  • hiding and not wanting to be near owner (remember that this could also be caused by the cat just being upset about leaving home and coming back)

What can be done for pain at home for my cat?

• Pain medication such as buprenorphine or a Duragesic (fentanyl) patch
• Tylenol will kill a cat as they lack abundant glutathione enzyme in the liver
• Anti-inflammatories can be used, but the dose is much less than dogs and they should be given only for a few days

Is it okay for my cat to lick or scratch the incision?

• If a cat licks the incision it will actually delay the healing process because they usually lick too much and traumatize the area.
• Cats have a barbed tongue, therefore a lot of damage can be done in a short period of time
• Licking can remove stitches and cause the incision to open
• Licking can become a severe habit that is difficult to break
• Licking can cause infection as the mouth has many bacteria
• Cats will frequently lick the incision when the owner is not watching such as at night time; if the skin looks red or excoriated the most common cause is from licking.
• To stop your pet from licking/scrtaching the following can be tried:
  • Elizabethan collar can be placed on the neck; this will not help stop your pet from scratching at the region
  • Cervical collar (bite not collar) is a less awkward device and can be effective at stopping a pet from licking the surgical site
  • If the incision is over the chest an infant tee shirt can be put on your pet and the waist of the shirt fastened in place with an ace bandage or duct tape.
  • If the incision is over the paw or lower limb a bandage or sock could be put on and kept up with tape.
  • Bitter apple can be applied around the incision; many dogs will continue to lick  after application of this topical
  • Bitter Apple and Liquid Heet^TM (obtain this from a drugstore...it is used for sore muscles) mixed in a 2:1 ratio can be applied around the skin incision
  • Antipsychotic medication in some cases is needed

Board-certification by the American College of Veterinary Surgeons

What does it mean?

• Four years of advanced training in surgery beyond the Doctor of Veterinary Medicine Degree

• Experience in the development of new surgical treatments

• Rigorous examination by the American College of Veterinary Surgeons to ensure competency in advanced surgical techniques

• Assurance that a veterinarian is a surgical specialist