In the summer of 1996, I was invited to Oticon Headquarters in Copenhagen to conduct demonstrations on how to take CIC impressions. Although it’s routine these days, it was very new then and the audiologists were interested in how to take these impressions. They were actually called “deep canal” impressions, requiring some skills that were not usually acquired by audiologists at the time.
Oticon had an interest in manufacturing CIC products at the time and had six volunteers for deep canal impressions that day. During the examination of the ear, four of the six subjects had significant exostosis and were unable to participate in the impression demonstration. When we tried to find additional suitable participants, many of them also had exostosis. Despite having many years of clinical experience at the time, I had not often seen exostosis in my patients. It turned out that most of the people in Copenhagen with exostosis had grown up in Denmark or other Nordic countries and had often gone swimming, water skiing, and participating in other water sports in the Baltic Sea and other cold bodies of water.
In this part of the world exostosis is rather common, far more than in land-locked Colorado where I practiced. In patients with exostosis, especially in more severe cases, it is not usually possible to fit CIC or mini-CICs without surgically removing bone from the ear canal. So the topic this week at Hearing International is Exostosis–What is it, what does it look like, how is it treated, and why is it “bad to the bone”.
Exostosis–abnormal bone growth–can occur in many parts of the body, but our concern is with abnormal bone growth in the ear canal. Irritation from cold wind and water exposure causes the bone surrounding the ear canal to develop lumps of new bony growth that constrict the canal. In severe cases the ear canal can actually be blocked by, water and wax can become trapped and give rise to infection. This condition is often called Surfer’s Ear due to its prevalence among cold water surfers. In fact, one study found exostoses in the ear canal of 60% of 373 competitive surfers. Even warm water surfers are at risk for exostosis due to the evaporative cooling caused by wind and the presence of water in the ear canal. Most avid surfers have at least some mild bone growths (exostoses), though frequently causing little or no problem.
The condition is progressive, which makes taking early preventive measures important for anyone participating in water sports in cold conditions. This applies not only to surfers, but also to people who kayak, sail, jet ski, kite surf, or dive. Patients usually become aware of the issue in their mid-30s to late 40s. However, ear canal exostosis can occur in people at any age and is directly proportional to the amount of time spent in cold, wet, windy weather without adequate protection.
Normal ear canals are approximately 7-9 mm in diameter with a volume of approximately 0.8 ml. As the exostosis condition progresses, the diameter of the canal narrows and can even close completely if untreated. (See the drawing to the left) Patients generally seek treatment when the canal has constricted to 0.5-2 mm, as this usually creates a noticeable hearing impairment from the ear canal constriction. While not necessarily harmful in and of itself, constriction of the ear canal from these growths can trap debris, leading to painful and difficult-to-treat infections. Upon examination of the
Ear canal exostosis can be very obvious to an examiner, but in its early stages it may be hard to see without a microscope. The pictures to the right are shot through a microscope and are of a normal ear canal, a mild exostosis case and a severe case to demonstrate the differences.
The only treatment for this disorder is surgery. There are two different surgical approaches to remove the bone. Surgical treatment to remove the obstructing ear canal bone is usually performed under general anesthesia in an operating room and aided by the use of a binocular microscope. Most ear surgeons use a drill to remove the bone and may approach the area directly via the ear canal or by making an incision behind the ear and dissecting the ear forward. In using a drilling technique, it is important to keep the thin inner ear canal skin away from the drill to preserve the skin and allow optimal skin coverage post-surgery. After the surgery the patient must avoid cold wind and water for about 2-6 weeks and try not to be exposed again as continuing unprotected exposure of ear canals to cold water and wind after the treatment can lead to a re-growth of the bone. (Click on Dr. Patel’s video (Left) for a surgical demonstration of Exostosis removal.) (Click on the Tahiti picture, right for a super surfing video). Oh, by the way there is a pro surfer competition in Teahupoo, Tahiti, August 15-26, 2013…..anyone up for a bit of exostosis research?