External auditory canal exostosis (plural: exostoses) is characterized by outgrowths of bone into the external ear canal. It is common in surfers and other individuals who frequently spend time in the ocean or other aqueous environments, and it is particularly associated with cold air and/or water temperatures. Exostosis is diagnosed by otoscopic examination. New bone growth along the upper edges of the tympanic bone is believed to be the source of exostoses.1 As the exostosis protrudes further into the outer ear canal, the patient may develop conductive hearing loss or recurrent ear infections, due to water being trapped between the tympanic membrane and the exostosis, providing an environment conducive to bacterial growth. Currently, the only treatment for exostoses is removal by a canalplasty surgery of the outer ear canal.
Previous clinical studies, including several epidemiological studies on surfers, have focused on the causes of exostoses, the canalplasty surgery, and the treatment outcomes of canalplasty. The cause of exostoses has not been firmly established, but it has been reported that cold-water exposure is the initiating factor for temporal bone growth.
In 1989, Umeda and Nakajima2 examined the ears of 51 professional surfers in Japan and found that 80% of them had exostoses of the external auditory canal.
Karegeannes3 conducted another prevalence study comparing the incidence of exostoses in 87 U.S. Navy divers compared with an age-matched control group and found that exostosis was present in 26% of the divers and 0% of the controls. He also showed a positive correlation between the severity of exostoses and the relative frequency of exposure to the ocean.
Deleyiannis4 determined a correlation between the degree of exostoses in 21 cold-water Oregon surfers as a function of both the number of years having surfed and the number of sessions surfed per year.
Most recently, Wong5 showed a correlation between cold water exposure and the extent, severity, and location of exostoses by analyzing 307 questionnaires and 600 otoscopic examination descriptions of surfers at the 1994 U.S. Open of Surfing international competition in Huntington Beach, California.
In terms of treatment, canalplasty has been shown to be an effective and safe treatment of exostoses. Sanna6 conducted a retrospective analysis of 65 canalplasty surgeries with only two significant complications, both post-operative stenoses that required further corrective surgery.
In another example, Lavy7 conducted a retrospective study on 100 consecutive canalplasty surgeries by one surgeon. The re-stenosis rate was 4%, and in each case this was associated with the use of a middle temporal artery flap. Partial, transient, delayed facial palsy occurred in 2%, probably relating to thermal injury transmitted from the drill burr, but a full spontaneous recovery of facial function occurred in each case.
The above studies demonstrated a high incidence of exostoses of the outer ear canal amongst surfers and a positive correlation with number of years surfing and frequency and duration of surfing per year. Furthermore, the occurrence of exostoses is positively correlated with exposure to cold water. Canalplasty has been demonstrated to be a safe and effective treatment for exostoses, but some controversy exists over the approach: transcanal removal with an osteotome versus the postauricular approach8.
Transcanal removal with an osteotome involves no incisions behind the ear; the surgery is done entirely through the ear canal. This seems desirable to some patients, since it suggests a faster healing time, which means they’ll be able to get back into the water and surf sooner. However, it is notorious for potential difficulties and complications. These include an increased rate of recurrence due to incomplete removal of exostoses, and increased risk of injuring the facial nerve due to inadequate visibility and control of the osteotome's course through bone.
We feel that the postauricular approach is the most effective and safest approach for removing exostoses, for a number of reasons. First, the exposure is superior, since the margins of the normal ear canal are clearly visible when the ear is opened from behind; therefore, complete removal of exostoses is possible, and this lowers the potential for recurrence. Secondly, because of excellent visibility of the bony landmarks, the course of the facial nerve and location of the temporal mandibular joint (TMJ) and tympanic membrane (eardrum) are evident, decreasing the risk of injury to these structures. Lastly, we use microdrills with copious irrigation to perform exostosis removal; therefore, we are able to detect when the bone overlying these important structures is becoming thin, due to changes in appearance of the bone and the pitch of the drill.
For these reasons, we perform all exostosis removal surgeries via the postauricular approach. The healing time is approximately 4 to 5 weeks, until the patient (surfer, usually) may get back into the water. It is done as outpatient surgery, meaning that the patient does not have to spend the night in the hospital.
References
1. Sheehy J. Osteoma of the external auditory canal. Laryngoscope 1958;68:1667-1673.
2. Umeda Y, Nakajima M. Surfer's ear in Japan. Laryngoscope 1989;99:639-641.
3. Karegeannes JC. Incidence of bony outgrowths of the external ear canal in U.S. Navy divers. Undersea Hyperb Med 1995;22:301-306.
4. Deleyiannis FW, Cockcroft BD, Pinczower EF. Exostoses of the external auditory canal in Oregon surfers. Am J Otolaryngol 1996;17:303-307
5. Wong B. Prevalance of external auditory canal exostosis in surfers. Arch Otolaryngol Head Neck Surg 1999;125:969-972
6. Sanna M. Canalplasty for severe external auditory meatus exostoses. J Laryngol Otol August 2004,Vol. 118, pp. 607–611
7. Lavy J, Fagan P. Canalplasty: review of 100 cases. Laryngol Otol 2001;115:270–3.
8. Hetzler, DG. Osteotome technique for removal of symptomatic ear canal exostoses.
Laryngoscope 2007;117(1 Pt 2 Suppl 113):1-14.
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