Otitis externa is common in small animal medicine, representing 10% to 20% of cases seen. The type of ear cleaning described here is considered "major ear cleaning" and is performed under heavy sedation or general anesthesia.
Excess debris must be removed for appropriate evaluation of the ear canal and tympanic membrane. Removing excess wax and debris increases treatment efficacy through better penetration of topical medications. Proper ear cleaning removes bacterial by-products, degenerating cells, and free fatty acids that contribute to inflammation. Also, pus and inflammatory debris inactivate some antimicrobial agents.
Pro Pearl: Samples for culture and sensitivity should be obtained before flushing the ear canal.
Ear Cleaning Instruments and Techniques
Various techniques have been described for ear cleaning, varying from the bulb syringe to sophisticated flushing systems. I prefer to flush with bulb syringes and a feeding tube-syringe technique combined (see What You'll Need). Increasing availability of fiberoptic otoscopes have made otic examination and cleaning much easier due to improved visualization. However, effective cleaning can be done without such equipment.
Pro Pearl: Saline is preferred for flushing because the condition of the tympanic membrane is often unknown.
Ear Canal Anatomy
Knowledge of ear canal anatomy is helpful during otic examination and cleaning. Cleaning techniques generally focus on the external ear canal, which comprises vertical and horizontal canals.
The canal is generally 2 cm in length and varies from 5 to 10 mm in diameter, depending on breed and size. Lining of the external ear canal contains sebaceous and ceruminous (apocrine) glands. Hair follicles occur throughout the canal; follicle density varies among breeds. Sebum found in the ear canal is sebaceous and ceruminous gland secretions and epithelial cells combined.
The tympanic membrane (TM) separates external and middle ear canals. The TM is thin and opaque, comprising the pars tensa (tightly stretched opaque section) and pars flaccida (dorsal component covering part of the malleus). The middle ear comprises the tympanic cavity and bullae. This cavity can often be viewed if the TM is completely ruptured.
Epithelial migration plays a role in "self-cleaning" of the ears. Migration and production of sebum cause normal accumulation of waxy brown debris on the ventral aspect of the ear canal just distal to the TM.
Pro Pearl: Sedation or general anesthesia is required for proper cleaning and visualization.