Dogs that have long-standing ear infections may develop irreversible disease of the ear canal. Due to chronic inflammation, the ear canal becomes very thickened and can turn into bone. As a result, the infection will not resolve with medications. In about 50% of these patients, the eardrum is ruptured, and a middle ear infection is present. Frequently dogs with chronic ear infections have skin allergies; therefore, a dermatologist should evaluate your companion after surgery.
Cancerous tumors can also affect the ear canal. Eighty-five percent of ear canal tumors are adenocarcinoma, a malignant tumor. Surgery is usually curative for such tumors if the cancer has not invaded the cartilage layer of the ear canal or the middle ear cavity.
The ear canal is a long tube that originates at the base of the earflap and extends to the eardrum to form the external ear. The facial nerve, which controls muscles of facial expression and the eyelids, wraps around the ear canal. The middle ear is a hollow cavity within the skull that is separated by the eardrum and contains three fine bones that transmit sound to the inner ear. The balance organ and a hearing organ that changes sound into electrical signals are located in the inner hear.
Signs and diagnosis
Signs of ear infection or ear canal tumors include shaking of the head, scratching the ear, rubbing the ear, crying out in pain, sensitivity when the ear is touched, thickened ear canals, foul odor from the ear, and bloody or yellow/green discharge in the ear canal. If the infection extends into the inner ear, your companion may keep the head in a tilted position, may have continual shifting of the eyes, or walk in circles. Dogs that have end-stage ear disease do not respond to medical treatment.
Your veterinarian will examine the ear to see if a tumor is in the canal or if there is chronic irreversible infection. A complete blood count, chemistry profile, and urine testing are performed prior to surgery to allow us to select the best anesthetic protocol for your companion. If a tumor is detected in the ear canal, radiographs (X-rays) of the chest are made to determine if the cancer has spread to the lungs. CT scan of the head can be used to evaluate the extent of a chronic ear infection or tumor.
For patients that have a tumor or end-stage age ear infections, surgical removal of the diseased ear canal is recommended. In addition, a bulla osteotomy is performed, which involves removal of the outer wall of the middle ear chamber in order to extract infected or cancerous tissue from this region. After the incision has been closed there will be no visible opening into the ear canal. Surprisingly, dogs that have the procedure performed on both ears still seem to hear sounds.
In general, after surgical healing, most pet owners usually report that their dog “is acting like a puppy again.”
For more information on this subject, speak to the veterinarian who is treating your pet.